August 2021 - Kernel - mailweb.openeuler.org

[PATCH OLK-5.10 2/9] x86, kfence: enable KFENCE for x86
by 1415317271＠qq.com 23 Aug '21

23 Aug '21

From: Alexander Potapenko <glider(a)google.com> Add architecture specific implementation details for KFENCE and enable KFENCE for the x86 architecture. In particular, this implements the required interface in <asm/kfence.h> for setting up the pool and providing helper functions for protecting and unprotecting pages. For x86, we need to ensure that the pool uses 4K pages, which is done using the set_memory_4k() helper function. [elver(a)google.com: add missing copyright and description header] Link: https://lkml.kernel.org/r/20210118092159.145934-2-elver@google.com Link: https://lkml.kernel.org/r/20201103175841.3495947-3-elver@google.com Signed-off-by: Marco Elver <elver(a)google.com> Signed-off-by: Alexander Potapenko <glider(a)google.com> Reviewed-by: Dmitry Vyukov <dvyukov(a)google.com> Co-developed-by: Marco Elver <elver(a)google.com> Reviewed-by: Jann Horn <jannh(a)google.com> Cc: Andrey Konovalov <andreyknvl(a)google.com> Cc: Andrey Ryabinin <aryabinin(a)virtuozzo.com> Cc: Andy Lutomirski <luto(a)kernel.org> Cc: Borislav Petkov <bp(a)alien8.de> Cc: Catalin Marinas <catalin.marinas(a)arm.com> Cc: Christopher Lameter <cl(a)linux.com> Cc: Dave Hansen <dave.hansen(a)linux.intel.com> Cc: David Rientjes <rientjes(a)google.com> Cc: Eric Dumazet <edumazet(a)google.com> Cc: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Cc: Hillf Danton <hdanton(a)sina.com> Cc: "H. Peter Anvin" <hpa(a)zytor.com> Cc: Ingo Molnar <mingo(a)redhat.com> Cc: Joern Engel <joern(a)purestorage.com> Cc: Jonathan Corbet <corbet(a)lwn.net> Cc: Joonsoo Kim <iamjoonsoo.kim(a)lge.com> Cc: Kees Cook <keescook(a)chromium.org> Cc: Mark Rutland <mark.rutland(a)arm.com> Cc: Paul E. McKenney <paulmck(a)kernel.org> Cc: Pekka Enberg <penberg(a)kernel.org> Cc: Peter Zijlstra <peterz(a)infradead.org> Cc: SeongJae Park <sjpark(a)amazon.de> Cc: Thomas Gleixner <tglx(a)linutronix.de> Cc: Vlastimil Babka <vbabka(a)suse.cz> Cc: Will Deacon <will(a)kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds(a)linux-foundation.org> Signed-off-by: Yingjie Shang <1415317271(a)qq.com> Reviewed-by: Bixuan Cui <cuibixuan(a)huawei.com> --- arch/x86/Kconfig | 1 + arch/x86/include/asm/kfence.h | 70 +++++++++++++++++++++++++++++++++++ arch/x86/mm/fault.c | 4 ++ 3 files changed, 75 insertions(+) create mode 100644 arch/x86/include/asm/kfence.h diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index af7123b5b493..37a7b2c8fdd6 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -148,6 +148,7 @@ config X86 select HAVE_ARCH_JUMP_LABEL_RELATIVE select HAVE_ARCH_KASAN if X86_64 select HAVE_ARCH_KASAN_VMALLOC if X86_64 + select HAVE_ARCH_KFENCE select HAVE_ARCH_KGDB select HAVE_ARCH_MMAP_RND_BITS if MMU select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT diff --git a/arch/x86/include/asm/kfence.h b/arch/x86/include/asm/kfence.h new file mode 100644 index 000000000000..a0659dbd93ea --- /dev/null +++ b/arch/x86/include/asm/kfence.h @@ -0,0 +1,70 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * x86 KFENCE support. + * + * Copyright (C) 2020, Google LLC. + */ + +#ifndef _ASM_X86_KFENCE_H +#define _ASM_X86_KFENCE_H + +#include <linux/bug.h> +#include <linux/kfence.h> + +#include <asm/pgalloc.h> +#include <asm/pgtable.h> +#include <asm/set_memory.h> +#include <asm/tlbflush.h> + +/* + * The page fault handler entry function, up to which the stack trace is + * truncated in reports. + */ +#define KFENCE_SKIP_ARCH_FAULT_HANDLER "asm_exc_page_fault" + +/* Force 4K pages for __kfence_pool. */ +static inline bool arch_kfence_init_pool(void) +{ + unsigned long addr; + + for (addr = (unsigned long)__kfence_pool; is_kfence_address((void *)addr); + addr += PAGE_SIZE) { + unsigned int level; + + if (!lookup_address(addr, &level)) + return false; + + if (level != PG_LEVEL_4K) + set_memory_4k(addr, 1); + } + + return true; +} + +/* Protect the given page and flush TLB. */ +static inline bool kfence_protect_page(unsigned long addr, bool protect) +{ + unsigned int level; + pte_t *pte = lookup_address(addr, &level); + + if (WARN_ON(!pte || level != PG_LEVEL_4K)) + return false; + + /* + * We need to avoid IPIs, as we may get KFENCE allocations or faults + * with interrupts disabled. Therefore, the below is best-effort, and + * does not flush TLBs on all CPUs. We can tolerate some inaccuracy; + * lazy fault handling takes care of faults after the page is PRESENT. + */ + + if (protect) + set_pte(pte, __pte(pte_val(*pte) & ~_PAGE_PRESENT)); + else + set_pte(pte, __pte(pte_val(*pte) | _PAGE_PRESENT)); + + /* Flush this CPU's TLB. */ + flush_tlb_one_kernel(addr); + return true; +} + +#endif /* _ASM_X86_KFENCE_H */ diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index 9c1545c376e9..35901aa6ad1c 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -9,6 +9,7 @@ #include <linux/kdebug.h> /* oops_begin/end, ... */ #include <linux/extable.h> /* search_exception_tables */ #include <linux/memblock.h> /* max_low_pfn */ +#include <linux/kfence.h> /* kfence_handle_page_fault */ #include <linux/kprobes.h> /* NOKPROBE_SYMBOL, ... */ #include <linux/mmiotrace.h> /* kmmio_handler, ... */ #include <linux/perf_event.h> /* perf_sw_event */ @@ -732,6 +733,9 @@ no_context(struct pt_regs *regs, unsigned long error_code, if (IS_ENABLED(CONFIG_EFI)) efi_recover_from_page_fault(address); + /* Only not-present faults should be handled by KFENCE. */ + if (!(error_code & X86_PF_PROT) && kfence_handle_page_fault(address)) + return; oops: /* * Oops. The kernel tried to access some bad page. We'll have to -- 2.25.1

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[PATCH OLK-5.10 0/9]
by 1415317271＠qq.com 23 Aug '21

23 Aug '21

From: shang <1415317271(a)qq.com> Transplantation of KFENCE KFENCE could detect many types of memory safety errors. The test cases successfully output the log when booting the kernel after enabling the KFENCE and KFENCE integration test suite at the openEuler OLK 5.10 kernel compile. Yingjie Shang: Transplant KFENCE from Linux kernel v5.13 to openEuler kernel OLK 5.10. Bixuan Cui: Reviewd the transplant patches. Alexander Potapenko (5): mm: add Kernel Electric-Fence infrastructure x86, kfence: enable KFENCE for x86 mm, kfence: insert KFENCE hooks for SLAB mm, kfence: insert KFENCE hooks for SLUB kfence, kasan: make KFENCE compatible with KASAN Marco Elver (4): arm64, kfence: enable KFENCE for ARM64 kfence: use pt_regs to generate stack trace on faults kfence, Documentation: add KFENCE documentation kfence: add test suite Documentation/dev-tools/index.rst | 1 + Documentation/dev-tools/kfence.rst | 298 ++++++++++ arch/arm64/Kconfig | 1 + arch/arm64/include/asm/kfence.h | 22 + arch/arm64/mm/fault.c | 4 + arch/arm64/mm/mmu.c | 7 +- arch/x86/Kconfig | 1 + arch/x86/include/asm/kfence.h | 64 +++ arch/x86/mm/fault.c | 5 + include/linux/kfence.h | 222 ++++++++ include/linux/slab_def.h | 3 + include/linux/slub_def.h | 3 + init/main.c | 3 + lib/Kconfig.debug | 1 + lib/Kconfig.kfence | 82 +++ mm/Makefile | 1 + mm/kasan/common.c | 6 + mm/kasan/generic.c | 3 +- mm/kfence/Makefile | 6 + mm/kfence/core.c | 845 ++++++++++++++++++++++++++++ mm/kfence/kfence.h | 113 ++++ mm/kfence/kfence_test.c | 858 +++++++++++++++++++++++++++++ mm/kfence/report.c | 258 +++++++++ mm/slab.c | 38 +- mm/slab_common.c | 5 +- mm/slub.c | 61 +- 26 files changed, 2884 insertions(+), 27 deletions(-) create mode 100644 Documentation/dev-tools/kfence.rst create mode 100644 arch/arm64/include/asm/kfence.h create mode 100644 arch/x86/include/asm/kfence.h create mode 100644 include/linux/kfence.h create mode 100644 lib/Kconfig.kfence create mode 100644 mm/kfence/Makefile create mode 100644 mm/kfence/core.c create mode 100644 mm/kfence/kfence.h create mode 100644 mm/kfence/kfence_test.c create mode 100644 mm/kfence/report.c -- 2.25.1

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[PATCH openEuler-21.09 1/7] net: hns3: add support for triggering reset by ethtool
by Zheng Zengkai 21 Aug '21

21 Aug '21

From: Yufeng Mo <moyufeng(a)huawei.com> mainline inclusion from mainline-master commit ddccc5e368a33daeb6862192d4dca8e59af9234a category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/I46N7D CVE: NA Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?… ---------------------------------------------------------------------- Currently, four reset types are supported for the HNS3 ethernet driver: IMP reset, global reset, function reset, and FLR. Only FLR can now be triggered by the user. To restore the device when an exception occurs, add support for triggering reset by ethtool. Run the "ethtool --reset DEVNAME mgmt | all | dedicated" to trigger the IMP | global | function reset manually. In addition, VF can only trigger function reset. Signed-off-by: Yufeng Mo <moyufeng(a)huawei.com> Signed-off-by: Guangbin Huang <huangguangbin2(a)huawei.com> Link: https://lore.kernel.org/r/1628602128-15640-1-git-send-email-huangguangbin2@… Signed-off-by: Jakub Kicinski <kuba(a)kernel.org> Reviewed-by: Yongxin Li <liyongxin1(a)huawei.com> Signed-off-by: Junxin Chen <chenjunxin1(a)huawei.com> Signed-off-by: Zheng Zengkai <zhengzengkai(a)huawei.com> --- .../net/ethernet/hisilicon/hns3/hns3_enet.h | 5 ++ .../ethernet/hisilicon/hns3/hns3_ethtool.c | 56 +++++++++++++++++++ .../hisilicon/hns3/hns3pf/hclge_main.c | 6 ++ .../hisilicon/hns3/hns3pf/hclge_main.h | 1 + 4 files changed, 68 insertions(+) diff --git a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.h b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.h index 15af3d93857b..f40d44a7994e 100644 --- a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.h +++ b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.h @@ -593,6 +593,11 @@ struct hns3_hw_error_info { const char *msg; }; +struct hns3_reset_type_map { + enum ethtool_reset_flags rst_flags; + enum hnae3_reset_type rst_type; +}; + static inline int ring_space(struct hns3_enet_ring *ring) { /* This smp_load_acquire() pairs with smp_store_release() in diff --git a/drivers/net/ethernet/hisilicon/hns3/hns3_ethtool.c b/drivers/net/ethernet/hisilicon/hns3/hns3_ethtool.c index 82061ab6930f..c8f09b07185e 100644 --- a/drivers/net/ethernet/hisilicon/hns3/hns3_ethtool.c +++ b/drivers/net/ethernet/hisilicon/hns3/hns3_ethtool.c @@ -953,6 +953,60 @@ static int hns3_get_rxnfc(struct net_device *netdev, } } +static const struct hns3_reset_type_map hns3_reset_type[] = { + {ETH_RESET_MGMT, HNAE3_IMP_RESET}, + {ETH_RESET_ALL, HNAE3_GLOBAL_RESET}, + {ETH_RESET_DEDICATED, HNAE3_FUNC_RESET}, +}; + +static const struct hns3_reset_type_map hns3vf_reset_type[] = { + {ETH_RESET_DEDICATED, HNAE3_VF_FUNC_RESET}, +}; + +static int hns3_set_reset(struct net_device *netdev, u32 *flags) +{ + enum hnae3_reset_type rst_type = HNAE3_NONE_RESET; + struct hnae3_handle *h = hns3_get_handle(netdev); + struct hnae3_ae_dev *ae_dev = pci_get_drvdata(h->pdev); + const struct hnae3_ae_ops *ops = h->ae_algo->ops; + const struct hns3_reset_type_map *rst_type_map; + u32 i, size; + + if (ops->ae_dev_resetting && ops->ae_dev_resetting(h)) + return -EBUSY; + + if (!ops->set_default_reset_request || !ops->reset_event) + return -EOPNOTSUPP; + + if (h->flags & HNAE3_SUPPORT_VF) { + rst_type_map = hns3vf_reset_type; + size = ARRAY_SIZE(hns3vf_reset_type); + } else { + rst_type_map = hns3_reset_type; + size = ARRAY_SIZE(hns3_reset_type); + } + + for (i = 0; i < size; i++) { + if (rst_type_map[i].rst_flags == *flags) { + rst_type = rst_type_map[i].rst_type; + break; + } + } + + if (rst_type == HNAE3_NONE_RESET || + (rst_type == HNAE3_IMP_RESET && + ae_dev->dev_version <= HNAE3_DEVICE_VERSION_V2)) + return -EOPNOTSUPP; + + netdev_info(netdev, "Setting reset type %d\n", rst_type); + + ops->set_default_reset_request(ae_dev, rst_type); + + ops->reset_event(h->pdev, h); + + return 0; +} + static void hns3_change_all_ring_bd_num(struct hns3_nic_priv *priv, u32 tx_desc_num, u32 rx_desc_num) { @@ -1699,6 +1753,7 @@ static const struct ethtool_ops hns3vf_ethtool_ops = { .set_priv_flags = hns3_set_priv_flags, .get_tunable = hns3_get_tunable, .set_tunable = hns3_set_tunable, + .reset = hns3_set_reset, }; static const struct ethtool_ops hns3_ethtool_ops = { @@ -1740,6 +1795,7 @@ static const struct ethtool_ops hns3_ethtool_ops = { .get_ts_info = hns3_get_ts_info, .get_tunable = hns3_get_tunable, .set_tunable = hns3_set_tunable, + .reset = hns3_set_reset, }; void hns3_ethtool_set_ops(struct net_device *netdev) diff --git a/drivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_main.c b/drivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_main.c index f15d76ec0068..9fd15287986f 100644 --- a/drivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_main.c +++ b/drivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_main.c @@ -3789,6 +3789,12 @@ static void hclge_do_reset(struct hclge_dev *hdev) } switch (hdev->reset_type) { + case HNAE3_IMP_RESET: + dev_info(&pdev->dev, "IMP reset requested\n"); + val = hclge_read_dev(&hdev->hw, HCLGE_PF_OTHER_INT_REG); + hnae3_set_bit(val, HCLGE_TRIGGER_IMP_RESET_B, 1); + hclge_write_dev(&hdev->hw, HCLGE_PF_OTHER_INT_REG, val); + break; case HNAE3_GLOBAL_RESET: dev_info(&pdev->dev, "global reset requested\n"); val = hclge_read_dev(&hdev->hw, HCLGE_GLOBAL_RESET_REG); diff --git a/drivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_main.h b/drivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_main.h index cc31b12904ad..ada5c68f2851 100644 --- a/drivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_main.h +++ b/drivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_main.h @@ -194,6 +194,7 @@ enum HLCGE_PORT_TYPE { #define HCLGE_VECTOR0_IMP_CMDQ_ERR_B 4U #define HCLGE_VECTOR0_IMP_RD_POISON_B 5U #define HCLGE_VECTOR0_ALL_MSIX_ERR_B 6U +#define HCLGE_TRIGGER_IMP_RESET_B 7U #define HCLGE_MAC_DEFAULT_FRAME \ (ETH_HLEN + ETH_FCS_LEN + 2 * VLAN_HLEN + ETH_DATA_LEN) -- 2.20.1

1 6

[PATCH 00/14] lib/xshm: Add a interval manage mechanism to kernel
by Zhou Guanghui 21 Aug '21

21 Aug '21

From: Wang Wensheng <wangwensheng4(a)huawei.com> Some platform software or library may service a secondary management of the share memory used by the processes running on the platform. The services may first alloc a large size of memory and make it as a POOL, the users then would alloc memory from the POOL. Then the users could and must access the management structure for the POOL. That works well generally when the structrues are all saved in userspace. But they can be broken when some users were killed unexpectedlly. Managing the interval in kernel would sovle the problem. Wang Wensheng (14): lib/xshm: Add xshmem framework in kernel lib/xshm: Add FSC algorithms to the kernel lib/xshm: Add refcnt for BLOCK in kernel lib/xshm: Extend the BLOCKs' refcnt to per-task lib/xshm: Add BLOCK delete interface that ignores reference lib/xshm: Introduce a xshm_pool_same hook in xshm_algo lib/xshm: Add BLK algorithms to the kernel lib/xshm: Use type long for POOL size and offset lib/xshm: Return if the POOL was deleted when unregister it lib/xshm: Show xshmem info in procfs lib/xshm: Add register count for each node lib/xshm: Split big function lib/xshm: Use rbtree to organize all allocated BLOCKs lib/xshm: Add algorithm vma for xshmem_framework include/uapi/linux/xshmem_framework.h | 42 ++ lib/Kconfig | 7 + lib/Makefile | 1 + lib/xshmem/Makefile | 2 + lib/xshmem/xshmem_blk.c | 131 +++++ lib/xshmem/xshmem_framework.c | 907 ++++++++++++++++++++++++++++++++++ lib/xshmem/xshmem_framework.h | 62 +++ lib/xshmem/xshmem_fsc.c | 281 +++++++++++ lib/xshmem/xshmem_vma.c | 343 +++++++++++++ 9 files changed, 1776 insertions(+) create mode 100644 include/uapi/linux/xshmem_framework.h create mode 100644 lib/xshmem/Makefile create mode 100644 lib/xshmem/xshmem_blk.c create mode 100644 lib/xshmem/xshmem_framework.c create mode 100644 lib/xshmem/xshmem_framework.h create mode 100644 lib/xshmem/xshmem_fsc.c create mode 100644 lib/xshmem/xshmem_vma.c -- 2.9.4

2 15

[PATCH kernel-4.19] blk-mq: blk-mq: provide forced completion method
by Yang Yingliang 20 Aug '21

20 Aug '21

From: Keith Busch <kbusch(a)kernel.org> mainline inclusion from mainline-5.8-rc1 commit 7b11eab041dacfeaaa6d27d9183b247a995bc16d category: bugfix bugzilla: 175150 CVE: NA --------------------------- Drivers may need to bypass error injection for error recovery. Rename __blk_mq_complete_request() to blk_mq_force_complete_rq() and export that function so drivers may skip potential fake timeouts after they've reclaimed lost requests. Signed-off-by: Keith Busch <kbusch(a)kernel.org> Reviewed-by: Daniel Wagner <dwagner(a)suse.de> Signed-off-by: Jens Axboe <axboe(a)kernel.dk> Conflicts: block/blk-mq.c include/linux/blk-mq.h [ Non bugfix patch c7bb9ad1744ea14e6("block: get rid of q->softirq_done_fn()") is not applied. ] Signed-off-by: Zhihao Cheng <chengzhihao1(a)huawei.com> Reviewed-by: Hou Tao <houtao1(a)huawei.com> Signed-off-by: Yang Yingliang <yangyingliang(a)huawei.com> --- block/blk-mq.c | 15 +++++++++++++-- include/linux/blk-mq.h | 1 + 2 files changed, 14 insertions(+), 2 deletions(-) diff --git a/block/blk-mq.c b/block/blk-mq.c index dc96754abc2cd..b5b41b9a72294 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -582,7 +582,17 @@ static void __blk_mq_complete_request_remote(void *data) rq->q->softirq_done_fn(rq); } -static void __blk_mq_complete_request(struct request *rq) +/** + * blk_mq_force_complete_rq() - Force complete the request, bypassing any error + * injection that could drop the completion. + * @rq: Request to be force completed + * + * Drivers should use blk_mq_complete_request() to complete requests in their + * normal IO path. For timeout error recovery, drivers may call this forced + * completion routine after they've reclaimed timed out requests to bypass + * potentially subsequent fake timeouts. + */ +void blk_mq_force_complete_rq(struct request *rq) { struct blk_mq_ctx *ctx = rq->mq_ctx; bool shared = false; @@ -612,6 +622,7 @@ static void __blk_mq_complete_request(struct request *rq) } put_cpu(); } +EXPORT_SYMBOL_GPL(blk_mq_force_complete_rq); static void hctx_unlock(struct blk_mq_hw_ctx *hctx, int srcu_idx) __releases(hctx->srcu) @@ -645,7 +656,7 @@ void blk_mq_complete_request(struct request *rq) { if (unlikely(blk_should_fake_timeout(rq->q))) return; - __blk_mq_complete_request(rq); + blk_mq_force_complete_rq(rq); } EXPORT_SYMBOL(blk_mq_complete_request); diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h index 730de600075b5..f81bbcdbce0f8 100644 --- a/include/linux/blk-mq.h +++ b/include/linux/blk-mq.h @@ -299,6 +299,7 @@ void blk_mq_add_to_requeue_list(struct request *rq, bool at_head, void blk_mq_kick_requeue_list(struct request_queue *q); void blk_mq_delay_kick_requeue_list(struct request_queue *q, unsigned long msecs); void blk_mq_complete_request(struct request *rq); +void blk_mq_force_complete_rq(struct request *rq); bool blk_mq_bio_list_merge(struct request_queue *q, struct list_head *list, struct bio *bio); bool blk_mq_queue_stopped(struct request_queue *q); -- 2.25.1

1 0

[PATCH kernel-4.19] nvme: force complete cancelled requests
by Yang Yingliang 20 Aug '21

20 Aug '21

From: Keith Busch <kbusch(a)kernel.org> mainline inclusion from mainline-5.8-rc1 commit 3382a567efd4015697f087f2e91ac08b90577876 category: bugfix bugzilla: 175150 CVE: NA --------------------------- Use blk_mq_foce_complete_rq() to bypass fake timeout error injection so that request reclaim may proceed. Signed-off-by: Keith Busch <kbusch(a)kernel.org> Reviewed-by: Johannes Thumshirn <johannes.thumshirn(a)wdc.com> Reviewed-by: Ming Lei <ming.lei(a)redhat.com> Reviewed-by: Daniel Wagner <dwagner(a)suse.de> Signed-off-by: Jens Axboe <axboe(a)kernel.dk> Conflicts: drivers/nvme/host/core.c [ 7baa85727d04("blk-mq-tag: change busy_iter_fn to return whether to continue or not") is not applied. ] Signed-off-by: Zhihao Cheng <chengzhihao1(a)huawei.com> Reviewed-by: Hou Tao <houtao1(a)huawei.com> Signed-off-by: Yang Yingliang <yangyingliang(a)huawei.com> --- drivers/nvme/host/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c index aab3d9a950a5e..c1e6c513c7956 100644 --- a/drivers/nvme/host/core.c +++ b/drivers/nvme/host/core.c @@ -330,7 +330,7 @@ void nvme_cancel_request(struct request *req, void *data, bool reserved) return; nvme_req(req)->status = NVME_SC_HOST_ABORTED_CMD; - blk_mq_complete_request(req); + blk_mq_force_complete_rq(req); } EXPORT_SYMBOL_GPL(nvme_cancel_request); -- 2.25.1

1 0

[PATCH kernel-4.19] scsi: hisi_sas: Flush workqueue in hisi_sas_v3_remove()
by Yang Yingliang 20 Aug '21

20 Aug '21

From: Luo Jiaxing <luojiaxing(a)huawei.com> mainline inclusion from mainline-v5.12-rc1 commit 6834ec8b23c3eb345936022d46179b9d371e2344 category: bugfix bugzilla: 176139 CVE: NA ------------------------------------------------------------------------ If the controller reset occurs at the same time as driver removal, it may be possible that the interrupts have been released prior to the host softreset, and calling pci_irq_vector() there causes a WARN: WARNING: CPU: 37 PID: 1542 /pci/msi.c:1275 pci_irq_vector+0xc0/0xd0 Call trace: pci_irq_vector+0xc0/0xd0 disable_host_v3_hw+0x58/0x5b0 [hisi_sas_v3_hw] soft_reset_v3_hw+0x40/0xc0 [hisi_sas_v3_hw] hisi_sas_controller_reset+0x150/0x260 [hisi_sas_main] hisi_sas_rst_work_handler+0x3c/0x58 [hisi_sas_main] To fix, flush the driver workqueue prior to releasing the interrupts to ensure any resets have been completed. Link: https://lore.kernel.org/r/1611659068-131975-5-git-send-email-john.garry@hua… Signed-off-by: Luo Jiaxing <luojiaxing(a)huawei.com> Signed-off-by: John Garry <john.garry(a)huawei.com> Signed-off-by: Martin K. Petersen <martin.petersen(a)oracle.com> Reviewed-by: Ouyangdelong <ouyangdelong(a)huawei.com> Signed-off-by: Nifujia <nifujia1(a)hisilicon.com> Signed-off-by: Yang Yingliang <yangyingliang(a)huawei.com> --- drivers/scsi/hisi_sas/hisi_sas_v3_hw.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/scsi/hisi_sas/hisi_sas_v3_hw.c b/drivers/scsi/hisi_sas/hisi_sas_v3_hw.c index 512f96b80ecc0..b38aa8d0a2242 100644 --- a/drivers/scsi/hisi_sas/hisi_sas_v3_hw.c +++ b/drivers/scsi/hisi_sas/hisi_sas_v3_hw.c @@ -3505,6 +3505,7 @@ static void hisi_sas_v3_remove(struct pci_dev *pdev) del_timer(&hisi_hba->timer); sas_unregister_ha(sha); + flush_workqueue(hisi_hba->wq); sas_remove_host(sha->core.shost); hisi_sas_v3_destroy_irqs(pdev, hisi_hba); -- 2.25.1

1 0

[PATCH kernel-4.19] ext4: flush s_error_work before journal destroy in ext4_fill_super
by Yang Yingliang 20 Aug '21

20 Aug '21

From: yangerkun <yangerkun(a)huawei.com> hulk inclusion category: bugfix bugzilla: 172146 CVE: NA --------------------------- 'commit c92dc856848f ("ext4: defer saving error info from atomic context")' and '2d01ddc86606 ("ext4: save error info to sb through journal if available")' add s_error_work to fix checksum error problem. But the error path in ext4_fill_super can lead the follow BUG_ON. Our testcase got follow BUG: [32031.759805] ------------[ cut here ]------------ [32031.759807] kernel BUG at fs/jbd2/transaction.c:373! [32031.760075] invalid opcode: 0000 [#1] SMP PTI [32031.760336] CPU: 5 PID: 1029268 Comm: kworker/5:1 Kdump: loaded Tainted: G OE --------- - - 4.18.0 ... [32031.766665] jbd2__journal_start+0xf1/0x1f0 [jbd2] [32031.766934] jbd2_journal_start+0x19/0x20 [jbd2] [32031.767218] flush_stashed_error_work+0x30/0x90 [ext4] [32031.767487] process_one_work+0x195/0x390 [32031.767747] worker_thread+0x30/0x390 [32031.768007] ? process_one_work+0x390/0x390 [32031.768265] kthread+0x10d/0x130 [32031.768521] ? kthread_flush_work_fn+0x10/0x10 [32031.768778] ret_from_fork+0x35/0x40 static int start_this_handle(...) BUG_ON(journal->j_flags & JBD2_UNMOUNT); <---- Trigger this flush_stashed_error_work will try to access journal. We cannot flush s_error_work after journal destroy. Fixes: c92dc856848f ("ext4: defer saving error info from atomic context") Fixes: 2d01ddc86606 ("ext4: save error info to sb through journal if available") Signed-off-by: yangerkun <yangerkun(a)huawei.com> Reviewed-by: Zhang Yi <yi.zhang(a)huawei.com> Signed-off-by: Yang Yingliang <yangyingliang(a)huawei.com> --- fs/ext4/super.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/fs/ext4/super.c b/fs/ext4/super.c index d793e597c0623..0783f85a1c6cc 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -4831,14 +4831,15 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent) ext4_xattr_destroy_cache(sbi->s_ea_block_cache); sbi->s_ea_block_cache = NULL; } - if (sbi->s_journal) { - jbd2_journal_destroy(sbi->s_journal); - sbi->s_journal = NULL; - } failed_mount3a: ext4_es_unregister_shrinker(sbi); failed_mount3: flush_work(&sbi->s_error_work); + + if (sbi->s_journal) { + jbd2_journal_destroy(sbi->s_journal); + sbi->s_journal = NULL; + } del_timer_sync(&sbi->s_err_report); ext4_stop_mmpd(sbi); failed_mount2: -- 2.25.1

1 0

[PATCH openEuler-1.0-LTS] Revert "net: make get_net_ns return error if NET_NS is disabled"
by Yang Yingliang 19 Aug '21

19 Aug '21

hulk inclusion category: bugfix bugzilla: NA CVE: NA -------------------------------- The commit a7957d8c2e5f8 ("net: make get_net_ns return error...") breaks the kabi, it fixes the bug only with CONFIG_NET_NS disabled, the config is always enabled, so it can be revert. Signed-off-by: Yang Yingliang <yangyingliang(a)huawei.com> Reviewed-by: Yue Haibing <yuehaibing(a)huawei.com> Signed-off-by: Yang Yingliang <yangyingliang(a)huawei.com> --- include/linux/socket.h | 2 ++ include/net/net_namespace.h | 7 ------- net/core/net_namespace.c | 12 ------------ net/socket.c | 13 +++++++++++++ 4 files changed, 15 insertions(+), 19 deletions(-) diff --git a/include/linux/socket.h b/include/linux/socket.h index 15a7eb24f63c9..cc1d3f1b76568 100644 --- a/include/linux/socket.h +++ b/include/linux/socket.h @@ -384,4 +384,6 @@ extern int __sys_getpeername(int fd, struct sockaddr __user *usockaddr, extern int __sys_socketpair(int family, int type, int protocol, int __user *usockvec); extern int __sys_shutdown(int fd, int how); + +extern struct ns_common *get_net_ns(struct ns_common *ns); #endif /* _LINUX_SOCKET_H */ diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h index 2df3e47608bdd..dbfc56676eeef 100644 --- a/include/net/net_namespace.h +++ b/include/net/net_namespace.h @@ -177,8 +177,6 @@ struct net *copy_net_ns(unsigned long flags, struct user_namespace *user_ns, void net_ns_get_ownership(const struct net *net, kuid_t *uid, kgid_t *gid); void net_ns_barrier(void); - -struct ns_common *get_net_ns(struct ns_common *ns); #else /* CONFIG_NET_NS */ #include <linux/sched.h> #include <linux/nsproxy.h> @@ -198,11 +196,6 @@ static inline void net_ns_get_ownership(const struct net *net, } static inline void net_ns_barrier(void) {} - -static inline struct ns_common *get_net_ns(struct ns_common *ns) -{ - return ERR_PTR(-EINVAL); -} #endif /* CONFIG_NET_NS */ diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c index 5d997df949c56..973d00a7fb591 100644 --- a/net/core/net_namespace.c +++ b/net/core/net_namespace.c @@ -612,18 +612,6 @@ void __put_net(struct net *net) } EXPORT_SYMBOL_GPL(__put_net); -/** - * get_net_ns - increment the refcount of the network namespace - * @ns: common namespace (net) - * - * Returns the net's common namespace. - */ -struct ns_common *get_net_ns(struct ns_common *ns) -{ - return &get_net(container_of(ns, struct net, ns))->ns; -} -EXPORT_SYMBOL_GPL(get_net_ns); - struct net *get_net_ns_by_fd(int fd) { struct file *file; diff --git a/net/socket.c b/net/socket.c index f14bca00ff010..1ed7be54815aa 100644 --- a/net/socket.c +++ b/net/socket.c @@ -1048,6 +1048,19 @@ static long sock_do_ioctl(struct net *net, struct socket *sock, * what to do with it - that's up to the protocol still. */ +/** + * get_net_ns - increment the refcount of the network namespace + * @ns: common namespace (net) + * + * Returns the net's common namespace. + */ + +struct ns_common *get_net_ns(struct ns_common *ns) +{ + return &get_net(container_of(ns, struct net, ns))->ns; +} +EXPORT_SYMBOL_GPL(get_net_ns); + static long sock_ioctl(struct file *file, unsigned cmd, unsigned long arg) { struct socket *sock; -- 2.25.1

1 0

[PATCH kernel-4.19] kthread: Fix PF_KTHREAD vs to_kthread() race
by Yang Yingliang 19 Aug '21

19 Aug '21

From: Peter Zijlstra <peterz(a)infradead.org> mainline inclusion from mainline-v5.13-rc1 commit 3a7956e25e1d7b3c148569e78895e1f3178122a9 bugzilla: 52510 CVE: NA -------------------------------- The kthread_is_per_cpu() construct relies on only being called on PF_KTHREAD tasks (per the WARN in to_kthread). This gives rise to the following usage pattern: if ((p->flags & PF_KTHREAD) && kthread_is_per_cpu(p)) However, as reported by syzcaller, this is broken. The scenario is: CPU0 CPU1 (running p) (p->flags & PF_KTHREAD) // true begin_new_exec() me->flags &= ~(PF_KTHREAD|...); kthread_is_per_cpu(p) to_kthread(p) WARN(!(p->flags & PF_KTHREAD) <-- *SPLAT* Introduce __to_kthread() that omits the WARN and is sure to check both values. Use this to remove the problematic pattern for kthread_is_per_cpu() and fix a number of other kthread_*() functions that have similar issues but are currently not used in ways that would expose the problem. Notably kthread_func() is only ever called on 'current', while kthread_probe_data() is only used for PF_WQ_WORKER, which implies the task is from kthread_create*(). Fixes: ac687e6e8c26 ("kthread: Extract KTHREAD_IS_PER_CPU") Signed-off-by: Peter Zijlstra (Intel) <peterz(a)infradead.org> Reviewed-by: Valentin Schneider <Valentin.Schneider(a)arm.com> Link: https://lkml.kernel.org/r/YH6WJc825C4P0FCK@hirez.programming.kicks-ass.net Signed-off-by: Zheng Zucheng <zhengzucheng.huawei.com> Conflicts: kernel/kthread.c kernel/sched/core.c kernel/sched/fair.c Reviewed-by: Cheng Jian <cj.chengjian(a)huawei.com> Reviewed-by: Cheng Jian <cj.chengjian(a)huawei.com> Reviewed-by: Chen Hui <judy.chenhui(a)huawei.com> Signed-off-by: Yang Yingliang <yangyingliang(a)huawei.com> --- kernel/kthread.c | 28 ++++++++++++++++++++++++---- 1 file changed, 24 insertions(+), 4 deletions(-) diff --git a/kernel/kthread.c b/kernel/kthread.c index fee5cc055791b..8873128ef6498 100644 --- a/kernel/kthread.c +++ b/kernel/kthread.c @@ -74,6 +74,25 @@ static inline struct kthread *to_kthread(struct task_struct *k) return (__force void *)k->set_child_tid; } +/* + * Variant of to_kthread() that doesn't assume @p is a kthread. + * + * Per construction; when: + * + * (p->flags & PF_KTHREAD) && p->set_child_tid + * + * the task is both a kthread and struct kthread is persistent. However + * PF_KTHREAD on it's own is not, kernel_thread() can exec() (See umh.c and + * begin_new_exec()). + */ +static inline struct kthread *__to_kthread(struct task_struct *p) +{ + void *kthread = (__force void *)p->set_child_tid; + if (kthread && !(p->flags & PF_KTHREAD)) + kthread = NULL; + return kthread; +} + void free_kthread_struct(struct task_struct *k) { struct kthread *kthread; @@ -177,10 +196,11 @@ void set_kthreadd_affinity(void) */ void *kthread_probe_data(struct task_struct *task) { - struct kthread *kthread = to_kthread(task); + struct kthread *kthread = __to_kthread(task); void *data = NULL; - probe_kernel_read(&data, &kthread->data, sizeof(data)); + if (kthread) + probe_kernel_read(&data, &kthread->data, sizeof(data)); return data; } @@ -492,9 +512,9 @@ void kthread_set_per_cpu(struct task_struct *k, int cpu) set_bit(KTHREAD_IS_PER_CPU, &kthread->flags); } -bool kthread_is_per_cpu(struct task_struct *k) +bool kthread_is_per_cpu(struct task_struct *p) { - struct kthread *kthread = to_kthread(k); + struct kthread *kthread = __to_kthread(p); if (!kthread) return false; -- 2.25.1

1 0

[PATCH kernel-4.19] share_pool: Don't do direct reclaim or compact for vmalloc_huge* funcs
by Yang Yingliang 19 Aug '21

19 Aug '21

From: Tang Yizhou <tangyizhou(a)huawei.com> ascend inclusion category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I46DPJ CVE: NA ------------------------------------------------- We found a hungtask problem when do direct compact in __alloc_pages_nodemask: vmalloc_hugepage_user -> __vmalloc_node_range -> __vmalloc_area_node -> sp_alloc_pages -> alloc_huge_page_node -> alloc_fresh_huge_page -> __alloc_pages_nodemask. Set PF_MEMALLOC then direct reclaim and direct compact won't be called. Signed-off-by: Tang Yizhou <tangyizhou(a)huawei.com> Reviewed-by: Ding Tianhong <dingtianhong(a)huawei.com> Signed-off-by: Yang Yingliang <yangyingliang(a)huawei.com> --- mm/share_pool.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/mm/share_pool.c b/mm/share_pool.c index 3e4e05f20c5ce..e5a71e25964c1 100644 --- a/mm/share_pool.c +++ b/mm/share_pool.c @@ -3219,9 +3219,15 @@ void sp_group_post_exit(struct mm_struct *mm) struct page *sp_alloc_pages(struct vm_struct *area, gfp_t mask, unsigned int page_order, int node) { - if (area->flags & VM_HUGE_PAGES) - return hugetlb_alloc_hugepage(NUMA_NO_NODE, HUGETLB_ALLOC_NONE); - else + struct page *page; + unsigned int noreclaim_flag = 0; + + if (area->flags & VM_HUGE_PAGES) { + noreclaim_flag = memalloc_noreclaim_save(); + page = hugetlb_alloc_hugepage(NUMA_NO_NODE, HUGETLB_ALLOC_NONE); + memalloc_noreclaim_restore(noreclaim_flag); + return page; + } else return alloc_pages_node(node, mask, page_order); } -- 2.25.1

1 0

[PATCH kernel-4.19] share_pool: Eliminate compiler warning for atomic64_t in arm32
by Yang Yingliang 19 Aug '21

19 Aug '21

From: Tang Yizhou <tangyizhou(a)huawei.com> ascend inclusion category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I46CWD?from=project-issue CVE: NA ------------------------------------------------- atomic64_t is type long in arm64, and type long long in arm32. So use %lld to print. Signed-off-by: Tang Yizhou <tangyizhou(a)huawei.com> Reviewed-by: Weilong Chen <chenweilong(a)huawei.com> Signed-off-by: Yang Yingliang <yangyingliang(a)huawei.com> --- mm/oom_kill.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/mm/oom_kill.c b/mm/oom_kill.c index 065636869e9bc..ea1382910ebb5 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -480,9 +480,9 @@ static void dump_tasks(struct mem_cgroup *memcg, const nodemask_t *nodemask) if (!stat) pr_cont("%-9c %-9c ", '-', '-'); else { - pr_cont("%-9ld %-9ld ", /* byte to KB */ - atomic64_read(&stat->alloc_size) >> 10, - atomic64_read(&stat->k2u_size) >> 10); + pr_cont("%-9lld %-9lld ", /* byte to KB */ + (long long)atomic64_read(&stat->alloc_size) >> 10, + (long long)atomic64_read(&stat->k2u_size) >> 10); sp_proc_stat_drop(stat); } pr_cont("%8ld %8lu %5hd %s\n", -- 2.25.1

1 0

[PATCH openEuler-1.0-LTS 1/4] x86/boot/compressed: Don't declare __force_order in kaslr_64.c
by Yang Yingliang 19 Aug '21

19 Aug '21

From: "H.J. Lu" <hjl.tools(a)gmail.com> stable inclusion from linux-4.19.109 commit d71f8bd18cdfd8b5ea94acbd6248951d51e3770b -------------------------------- [ Upstream commit df6d4f9db79c1a5d6f48b59db35ccd1e9ff9adfc ] GCC 10 changed the default to -fno-common, which leads to LD arch/x86/boot/compressed/vmlinux ld: arch/x86/boot/compressed/pgtable_64.o:(.bss+0x0): multiple definition of `__force_order'; \ arch/x86/boot/compressed/kaslr_64.o:(.bss+0x0): first defined here make[2]: *** [arch/x86/boot/compressed/Makefile:119: arch/x86/boot/compressed/vmlinux] Error 1 Since __force_order is already provided in pgtable_64.c, there is no need to declare __force_order in kaslr_64.c. Signed-off-by: H.J. Lu <hjl.tools(a)gmail.com> Signed-off-by: Borislav Petkov <bp(a)suse.de> Link: https://lkml.kernel.org/r/20200124181811.4780-1-hjl.tools@gmail.com Signed-off-by: Sasha Levin <sashal(a)kernel.org> Signed-off-by: Yang Yingliang <yangyingliang(a)huawei.com> Signed-off-by: Hanjun Guo <guohanjun(a)huawei.com> Reviewed-by: Xie XiuQi <xiexiuqi(a)huawei.com> Signed-off-by: Yang Yingliang <yangyingliang(a)huawei.com> --- arch/x86/boot/compressed/kaslr_64.c | 3 --- 1 file changed, 3 deletions(-) diff --git a/arch/x86/boot/compressed/kaslr_64.c b/arch/x86/boot/compressed/kaslr_64.c index 748456c365f46..9557c5a15b91e 100644 --- a/arch/x86/boot/compressed/kaslr_64.c +++ b/arch/x86/boot/compressed/kaslr_64.c @@ -29,9 +29,6 @@ #define __PAGE_OFFSET __PAGE_OFFSET_BASE #include "../../mm/ident_map.c" -/* Used by pgtable.h asm code to force instruction serialization. */ -unsigned long __force_order; - /* Used to track our page table allocation area. */ struct alloc_pgt_data { unsigned char *pgt_buf; -- 2.25.1

1 3

【Meeting Notice】openEuler kernel 技术分享第十期 & 双周例会 Time: 2021-08-20 14:00-17:00
by Meeting Book 19 Aug '21

19 Aug '21

1 0

[PATCH kernel-4.19 1/3] Remove MODULE_ALIAS() calls that take undefined macro
by Yang Yingliang 19 Aug '21

19 Aug '21

From: Masahiro Yamada <yamada.masahiro(a)socionext.com> mainline inclusion from mainline-v5.2-rc1 commit 4c11edfcf70bea4cb0a3f4992ac6a4852e8bdc31 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I46CWD?from=project-issue CVE: NA In file included from /builds/linux/include/linux/module.h:19, from /builds/linux/arch/arm/plat-omap/dma.c:28: /builds/linux/arch/arm/plat-omap/dma.c:1452:26: error: expected ',' or ';' before 'DRIVER_NAME' 1452 | MODULE_ALIAS("platform:" DRIVER_NAME); | ^~~~~~~~~~~ /builds/linux/include/linux/moduleparam.h:26:47: note: in definition of macro '__MODULE_INFO' 26 | = __MODULE_INFO_PREFIX __stringify(tag) "=" info | ^~~~ /builds/linux/include/linux/module.h:166:30: note: in expansion of macro 'MODULE_INFO' 166 | #define MODULE_ALIAS(_alias) MODULE_INFO(alias, _alias) | ^~~~~~~~~~~ /builds/linux/arch/arm/plat-omap/dma.c:1452:1: note: in expansion of macro 'MODULE_ALIAS' 1452 | MODULE_ALIAS("platform:" DRIVER_NAME); | ^~~~~~~~~~~~ make[2]: *** [/builds/linux/scripts/Makefile.build:303: arch/arm/plat-omap/dma.o] Error 1 make[2]: Target '__build' not remade because of errors. make[1]: *** [/builds/linux/Makefile:1070: arch/arm/plat-omap] Error 2 --------------------------------- These files do not define (USBHS_)DRIVER_NAME. Yet, they can be successfully compiled because they are never built as a module by anyone, i.e, the MODULE_ALIAS() calls are always no-op. A problem showed up when a patch "moduleparam: Save information about built-in modules in separate file" was applied. With this new feature, MODULE_*() will be populated even if the callers are built-in. To avoid the build errors, the lines referencing to the undefined macro must be removed. The complete fix is to remove all MODULE_* and #include <linux/module.h> like many "make ... explicitly non-modular" commits did. For now, I am touching only the offending lines. Reported-by: Stephen Rothwell <sfr(a)canb.auug.org.au> Signed-off-by: Masahiro Yamada <yamada.masahiro(a)socionext.com> Acked-by: Daniel Lezcano <daniel.lezcano(a)linaro.org> Acked-by: Tony Lindgren <tony(a)atomide.com> Signed-off-by: Hanjun Guo <guohanjun(a)huawei.com> Reviewed-by: Xie XiuQi <xiexiuqi(a)huawei.com> Signed-off-by: Yang Yingliang <yangyingliang(a)huawei.com> --- arch/arm/plat-omap/dma.c | 1 - drivers/clocksource/timer-ti-dm.c | 1 - drivers/mfd/omap-usb-tll.c | 1 - 3 files changed, 3 deletions(-) diff --git a/arch/arm/plat-omap/dma.c b/arch/arm/plat-omap/dma.c index d4012d6c0dcb2..5ca4c5fd627a5 100644 --- a/arch/arm/plat-omap/dma.c +++ b/arch/arm/plat-omap/dma.c @@ -1449,7 +1449,6 @@ static void __exit omap_system_dma_exit(void) MODULE_DESCRIPTION("OMAP SYSTEM DMA DRIVER"); MODULE_LICENSE("GPL"); -MODULE_ALIAS("platform:" DRIVER_NAME); MODULE_AUTHOR("Texas Instruments Inc"); /* diff --git a/drivers/clocksource/timer-ti-dm.c b/drivers/clocksource/timer-ti-dm.c index 23414dddc3bae..c4bb2c7cd8854 100644 --- a/drivers/clocksource/timer-ti-dm.c +++ b/drivers/clocksource/timer-ti-dm.c @@ -999,5 +999,4 @@ module_platform_driver(omap_dm_timer_driver); MODULE_DESCRIPTION("OMAP Dual-Mode Timer Driver"); MODULE_LICENSE("GPL"); -MODULE_ALIAS("platform:" DRIVER_NAME); MODULE_AUTHOR("Texas Instruments Inc"); diff --git a/drivers/mfd/omap-usb-tll.c b/drivers/mfd/omap-usb-tll.c index 446713dbee27a..93177d85e7a95 100644 --- a/drivers/mfd/omap-usb-tll.c +++ b/drivers/mfd/omap-usb-tll.c @@ -459,7 +459,6 @@ EXPORT_SYMBOL_GPL(omap_tll_disable); MODULE_AUTHOR("Keshava Munegowda <keshava_mgowda(a)ti.com>"); MODULE_AUTHOR("Roger Quadros <rogerq(a)ti.com>"); -MODULE_ALIAS("platform:" USBHS_DRIVER_NAME); MODULE_LICENSE("GPL v2"); MODULE_DESCRIPTION("usb tll driver for TI OMAP EHCI and OHCI controllers"); -- 2.25.1

1 2

[PATCH 1/3] bpf: track spill/fill of constants
by Yang Yingliang 18 Aug '21

18 Aug '21

From: Alexei Starovoitov <ast(a)kernel.org> mainline inclusion from mainline-v5.3-rc1 commit f7cf25b2026dc8441e0fa3a202c2aa8a56211e30 category: bugfix bugzilla: NA CVE: CVE-2021-34556 --------------------------- Compilers often spill induction variables into the stack, hence it is necessary for the verifier to track scalar values of the registers through stack slots. Also few bpf programs were incorrectly rejected in the past, since the verifier was not able to track such constants while they were used to compute offsets into packet headers. Tracking constants through the stack significantly decreases the chances of state pruning, since two different constants are considered to be different by state equivalency. End result that cilium tests suffer serious degradation in the number of states processed and corresponding verification time increase. before after bpf_lb-DLB_L3.o 1838 6441 bpf_lb-DLB_L4.o 3218 5908 bpf_lb-DUNKNOWN.o 1064 1064 bpf_lxc-DDROP_ALL.o 26935 93790 bpf_lxc-DUNKNOWN.o 34439 123886 bpf_netdev.o 9721 31413 bpf_overlay.o 6184 18561 bpf_lxc_jit.o 39389 359445 After further debugging turned out that cillium progs are getting hurt by clang due to the same constant tracking issue. Newer clang generates better code by spilling less to the stack. Instead it keeps more constants in the registers which hurts state pruning since the verifier already tracks constants in the registers: old clang new clang (no spill/fill tracking introduced by this patch) bpf_lb-DLB_L3.o 1838 1923 bpf_lb-DLB_L4.o 3218 3077 bpf_lb-DUNKNOWN.o 1064 1062 bpf_lxc-DDROP_ALL.o 26935 166729 bpf_lxc-DUNKNOWN.o 34439 174607 bpf_netdev.o 9721 8407 bpf_overlay.o 6184 5420 bpf_lcx_jit.o 39389 39389 The final table is depressing: old clang old clang new clang new clang const spill/fill const spill/fill bpf_lb-DLB_L3.o 1838 6441 1923 8128 bpf_lb-DLB_L4.o 3218 5908 3077 6707 bpf_lb-DUNKNOWN.o 1064 1064 1062 1062 bpf_lxc-DDROP_ALL.o 26935 93790 166729 380712 bpf_lxc-DUNKNOWN.o 34439 123886 174607 440652 bpf_netdev.o 9721 31413 8407 31904 bpf_overlay.o 6184 18561 5420 23569 bpf_lxc_jit.o 39389 359445 39389 359445 Tracking constants in the registers hurts state pruning already. Adding tracking of constants through stack hurts pruning even more. The later patch address this general constant tracking issue with coarse/precise logic. Signed-off-by: Alexei Starovoitov <ast(a)kernel.org> Acked-by: Andrii Nakryiko <andriin(a)fb.com> Signed-off-by: Daniel Borkmann <daniel(a)iogearbox.net> Conflicts: kernel/bpf/verifier.c Signed-off-by: He Fengqing<hefengqing(a)huawei.com> Reviewed-by: Yue Haibing <yuehaibing(a)huawei.com> Signed-off-by: Yang Yingliang <yangyingliang(a)huawei.com> --- kernel/bpf/verifier.c | 90 +++++++++++++++++++++++++++++++------------ 1 file changed, 66 insertions(+), 24 deletions(-) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index f6d092809ec3f..5ca4b137a25a7 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -981,6 +981,23 @@ static bool register_is_null(struct bpf_reg_state *reg) return reg->type == SCALAR_VALUE && tnum_equals_const(reg->var_off, 0); } +static bool register_is_const(struct bpf_reg_state *reg) +{ + return reg->type == SCALAR_VALUE && tnum_is_const(reg->var_off); +} + +static void save_register_state(struct bpf_func_state *state, + int spi, struct bpf_reg_state *reg) +{ + int i; + + state->stack[spi].spilled_ptr = *reg; + state->stack[spi].spilled_ptr.live |= REG_LIVE_WRITTEN; + + for (i = 0; i < BPF_REG_SIZE; i++) + state->stack[spi].slot_type[i] = STACK_SPILL; +} + /* check_stack_read/write functions track spill/fill of registers, * stack boundary and alignment are checked in check_mem_access() */ @@ -990,7 +1007,7 @@ static int check_stack_write(struct bpf_verifier_env *env, { struct bpf_func_state *cur; /* state of the current function */ int i, slot = -off - 1, spi = slot / BPF_REG_SIZE, err; - enum bpf_reg_type type; + struct bpf_reg_state *reg = NULL; err = realloc_func_state(state, round_up(slot + 1, BPF_REG_SIZE), true); @@ -1007,27 +1024,36 @@ static int check_stack_write(struct bpf_verifier_env *env, } cur = env->cur_state->frame[env->cur_state->curframe]; - if (value_regno >= 0 && - is_spillable_regtype((type = cur->regs[value_regno].type))) { + if (value_regno >= 0) + reg = &cur->regs[value_regno]; + if (reg && size == BPF_REG_SIZE && register_is_const(reg) && + !register_is_null(reg) && env->allow_ptr_leaks) { + save_register_state(state, spi, reg); + } else if (reg && is_spillable_regtype(reg->type)) { /* register containing pointer is being spilled into stack */ if (size != BPF_REG_SIZE) { verbose(env, "invalid size of register spill\n"); return -EACCES; } - if (state != cur && type == PTR_TO_STACK) { + if (state != cur && reg->type == PTR_TO_STACK) { verbose(env, "cannot spill pointers to stack into stack frame of the caller\n"); return -EINVAL; } - /* save register state */ - state->stack[spi].spilled_ptr = cur->regs[value_regno]; - state->stack[spi].spilled_ptr.live |= REG_LIVE_WRITTEN; - - for (i = 0; i < BPF_REG_SIZE; i++) { - if (state->stack[spi].slot_type[i] == STACK_MISC && - !env->allow_ptr_leaks) { + if (!env->allow_ptr_leaks) { + bool sanitize = false; + + if (state->stack[spi].slot_type[0] == STACK_SPILL && + register_is_const(&state->stack[spi].spilled_ptr)) + sanitize = true; + for (i = 0; i < BPF_REG_SIZE; i++) + if (state->stack[spi].slot_type[i] == STACK_MISC) { + sanitize = true; + break; + } + if (sanitize) { int *poff = &env->insn_aux_data[insn_idx].sanitize_stack_off; int soff = (-spi - 1) * BPF_REG_SIZE; @@ -1050,8 +1076,8 @@ static int check_stack_write(struct bpf_verifier_env *env, } *poff = soff; } - state->stack[spi].slot_type[i] = STACK_SPILL; } + save_register_state(state, spi, reg); } else { u8 type = STACK_MISC; @@ -1070,8 +1096,7 @@ static int check_stack_write(struct bpf_verifier_env *env, state->stack[spi].spilled_ptr.live |= REG_LIVE_WRITTEN; /* when we zero initialize stack slots mark them as such */ - if (value_regno >= 0 && - register_is_null(&cur->regs[value_regno])) + if (reg && register_is_null(reg)) type = STACK_ZERO; for (i = 0; i < size; i++) @@ -1088,6 +1113,7 @@ static int check_stack_read(struct bpf_verifier_env *env, struct bpf_verifier_state *vstate = env->cur_state; struct bpf_func_state *state = vstate->frame[vstate->curframe]; int i, slot = -off - 1, spi = slot / BPF_REG_SIZE; + struct bpf_reg_state *reg; u8 *stype; if (reg_state->allocated_stack <= slot) { @@ -1096,11 +1122,20 @@ static int check_stack_read(struct bpf_verifier_env *env, return -EACCES; } stype = reg_state->stack[spi].slot_type; + reg = &reg_state->stack[spi].spilled_ptr; if (stype[0] == STACK_SPILL) { if (size != BPF_REG_SIZE) { - verbose(env, "invalid size of register spill\n"); - return -EACCES; + if (reg->type != SCALAR_VALUE) { + verbose(env, "invalid size of register fill\n"); + return -EACCES; + } + if (value_regno >= 0) { + mark_reg_unknown(env, state->regs, value_regno); + state->regs[value_regno].live |= REG_LIVE_WRITTEN; + } + mark_reg_read(env, reg, reg->parent); + return 0; } for (i = 1; i < BPF_REG_SIZE; i++) { if (stype[(slot - i) % BPF_REG_SIZE] != STACK_SPILL) { @@ -1111,16 +1146,14 @@ static int check_stack_read(struct bpf_verifier_env *env, if (value_regno >= 0) { /* restore register state from stack */ - state->regs[value_regno] = reg_state->stack[spi].spilled_ptr; + state->regs[value_regno] = *reg; /* mark reg as written since spilled pointer state likely * has its liveness marks cleared by is_state_visited() * which resets stack/reg liveness for state transitions */ state->regs[value_regno].live |= REG_LIVE_WRITTEN; } - mark_reg_read(env, &reg_state->stack[spi].spilled_ptr, - reg_state->stack[spi].spilled_ptr.parent); - return 0; + mark_reg_read(env, reg, reg->parent); } else { int zeros = 0; @@ -1135,8 +1168,7 @@ static int check_stack_read(struct bpf_verifier_env *env, off, i, size); return -EACCES; } - mark_reg_read(env, &reg_state->stack[spi].spilled_ptr, - reg_state->stack[spi].spilled_ptr.parent); + mark_reg_read(env, reg, reg->parent); if (value_regno >= 0) { if (zeros == size) { /* any size read into register is zero extended, @@ -1149,8 +1181,8 @@ static int check_stack_read(struct bpf_verifier_env *env, } state->regs[value_regno].live |= REG_LIVE_WRITTEN; } - return 0; } + return 0; } static int check_stack_access(struct bpf_verifier_env *env, @@ -1810,7 +1842,7 @@ static int check_stack_boundary(struct bpf_verifier_env *env, int regno, { struct bpf_reg_state *reg = cur_regs(env) + regno; struct bpf_func_state *state = func(env, reg); - int off, i, slot, spi; + int off, i, j, slot, spi; if (reg->type != PTR_TO_STACK) { /* Allow zero-byte read from NULL, regardless of pointer type */ @@ -1862,6 +1894,16 @@ static int check_stack_boundary(struct bpf_verifier_env *env, int regno, *stype = STACK_MISC; goto mark; } + + if (state->stack[spi].slot_type[0] == STACK_SPILL && + state->stack[spi].spilled_ptr.type == SCALAR_VALUE) { + __mark_reg_unknown(&state->stack[spi].spilled_ptr); + for (j = 0; j < BPF_REG_SIZE; j++) + state->stack[spi].slot_type[j] = STACK_MISC; + goto mark; + } + + err: verbose(env, "invalid indirect read from stack off %d+%d size %d\n", off, i, access_size); -- 2.25.1

1 2

[PATCH openEuler-21.03 1/2] usb: cdns3: Fix runtime PM imbalance on error
by Zheng Zengkai 18 Aug '21

18 Aug '21

From: Dinghao Liu <dinghao.liu(a)zju.edu.cn> stable inclusion from stable-v5.10.44 commit 2f523cd4a9311cba629facc7d353eabbd492bd5b bugzilla: https://bugzilla.openeuler.org/show_bug.cgi?id=345 CVE: NA -------------------------------- [ Upstream commit 07adc0225484fc199e3dc15ec889f75f498c4fca ] When cdns3_gadget_start() fails, a pairing PM usage counter decrement is needed to keep the counter balanced. Signed-off-by: Dinghao Liu <dinghao.liu(a)zju.edu.cn> Link: https://lore.kernel.org/r/20210412054908.7975-1-dinghao.liu(a)zju.edu.cn Signed-off-by: Peter Chen <peter.chen(a)kernel.org> Signed-off-by: Sasha Levin <sashal(a)kernel.org> Signed-off-by: Xu Zehui <zehuixu(a)whu.edu.cn> Reviewed-by: Hanjun Guo <guohanjun(a)huawei.com> Signed-off-by: Zheng Zengkai <zhengzengkai(a)huawei.com> --- drivers/usb/cdns3/gadget.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/usb/cdns3/gadget.c b/drivers/usb/cdns3/gadget.c index 0aa85cc07ff1..c24c0e3440e3 100644 --- a/drivers/usb/cdns3/gadget.c +++ b/drivers/usb/cdns3/gadget.c @@ -3255,8 +3255,10 @@ static int __cdns3_gadget_init(struct cdns3 *cdns) pm_runtime_get_sync(cdns->dev); ret = cdns3_gadget_start(cdns); - if (ret) + if (ret) { + pm_runtime_put_sync(cdns->dev); return ret; + } /* * Because interrupt line can be shared with other components in -- 2.20.1

1 1

[PATCH 9/9] kfence: add test suite
by 1415317271＠qq.com 18 Aug '21

18 Aug '21

From: Marco Elver <elver(a)google.com> Add KFENCE test suite, testing various error detection scenarios. Makes use of KUnit for test organization. Since KFENCE's interface to obtain error reports is via the console, the test verifies that KFENCE outputs expected reports to the console. [elver(a)google.com: fix typo in test] Link: https://lkml.kernel.org/r/X9lHQExmHGvETxY4@elver.google.com [elver(a)google.com: show access type in report] Link: https://lkml.kernel.org/r/20210111091544.3287013-2-elver@google.com Link: https://lkml.kernel.org/r/20201103175841.3495947-9-elver@google.com Signed-off-by: Alexander Potapenko <glider(a)google.com> Signed-off-by: Marco Elver <elver(a)google.com> Reviewed-by: Dmitry Vyukov <dvyukov(a)google.com> Co-developed-by: Alexander Potapenko <glider(a)google.com> Reviewed-by: Jann Horn <jannh(a)google.com> Cc: Andrey Konovalov <andreyknvl(a)google.com> Cc: Andrey Ryabinin <aryabinin(a)virtuozzo.com> Cc: Andy Lutomirski <luto(a)kernel.org> Cc: Borislav Petkov <bp(a)alien8.de> Cc: Catalin Marinas <catalin.marinas(a)arm.com> Cc: Christopher Lameter <cl(a)linux.com> Cc: Dave Hansen <dave.hansen(a)linux.intel.com> Cc: David Rientjes <rientjes(a)google.com> Cc: Eric Dumazet <edumazet(a)google.com> Cc: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Cc: Hillf Danton <hdanton(a)sina.com> Cc: "H. Peter Anvin" <hpa(a)zytor.com> Cc: Ingo Molnar <mingo(a)redhat.com> Cc: Joern Engel <joern(a)purestorage.com> Cc: Jonathan Corbet <corbet(a)lwn.net> Cc: Joonsoo Kim <iamjoonsoo.kim(a)lge.com> Cc: Kees Cook <keescook(a)chromium.org> Cc: Mark Rutland <mark.rutland(a)arm.com> Cc: Paul E. McKenney <paulmck(a)kernel.org> Cc: Pekka Enberg <penberg(a)kernel.org> Cc: Peter Zijlstra <peterz(a)infradead.org> Cc: SeongJae Park <sjpark(a)amazon.de> Cc: Thomas Gleixner <tglx(a)linutronix.de> Cc: Vlastimil Babka <vbabka(a)suse.cz> Cc: Will Deacon <will(a)kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds(a)linux-foundation.org> Signed-off-by: Yingjie Shang <1415317271(a)qq.com> Reviewed-by: Bixuan Cui <cuibixuan(a)huawei.com> --- Documentation/dev-tools/kfence.rst | 12 +- arch/arm64/mm/fault.c | 2 +- arch/x86/mm/fault.c | 3 +- include/linux/kfence.h | 9 +- lib/Kconfig.kfence | 13 + mm/kfence/Makefile | 3 + mm/kfence/core.c | 11 +- mm/kfence/kfence.h | 2 +- mm/kfence/kfence_test.c | 858 +++++++++++++++++++++++++++++ mm/kfence/report.c | 27 +- 10 files changed, 915 insertions(+), 25 deletions(-) create mode 100644 mm/kfence/kfence_test.c diff --git a/Documentation/dev-tools/kfence.rst b/Documentation/dev-tools/kfence.rst index 0e2fb6ef3016..58a0a5fa1ddc 100644 --- a/Documentation/dev-tools/kfence.rst +++ b/Documentation/dev-tools/kfence.rst @@ -65,9 +65,9 @@ Error reports A typical out-of-bounds access looks like this:: ================================================================== - BUG: KFENCE: out-of-bounds in test_out_of_bounds_read+0xa3/0x22b + BUG: KFENCE: out-of-bounds read in test_out_of_bounds_read+0xa3/0x22b - Out-of-bounds access at 0xffffffffb672efff (1B left of kfence-#17): + Out-of-bounds read at 0xffffffffb672efff (1B left of kfence-#17): test_out_of_bounds_read+0xa3/0x22b kunit_try_run_case+0x51/0x85 kunit_generic_run_threadfn_adapter+0x16/0x30 @@ -94,9 +94,9 @@ its origin. Note that, real kernel addresses are only shown for Use-after-free accesses are reported as:: ================================================================== - BUG: KFENCE: use-after-free in test_use_after_free_read+0xb3/0x143 + BUG: KFENCE: use-after-free read in test_use_after_free_read+0xb3/0x143 - Use-after-free access at 0xffffffffb673dfe0 (in kfence-#24): + Use-after-free read at 0xffffffffb673dfe0 (in kfence-#24): test_use_after_free_read+0xb3/0x143 kunit_try_run_case+0x51/0x85 kunit_generic_run_threadfn_adapter+0x16/0x30 @@ -193,9 +193,9 @@ where it was not possible to determine an associated object, e.g. if adjacent object pages had not yet been allocated:: ================================================================== - BUG: KFENCE: invalid access in test_invalid_access+0x26/0xe0 + BUG: KFENCE: invalid read in test_invalid_access+0x26/0xe0 - Invalid access at 0xffffffffb670b00a: + Invalid read at 0xffffffffb670b00a: test_invalid_access+0x26/0xe0 kunit_try_run_case+0x51/0x85 kunit_generic_run_threadfn_adapter+0x16/0x30 diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c index a5fe9f7b423b..8f4ceab2fa35 100644 --- a/arch/arm64/mm/fault.c +++ b/arch/arm64/mm/fault.c @@ -323,7 +323,7 @@ static void __do_kernel_fault(unsigned long addr, unsigned int esr, } else if (addr < PAGE_SIZE) { msg = "NULL pointer dereference"; } else { - if (kfence_handle_page_fault(addr, regs)) + if (kfence_handle_page_fault(addr, esr & ESR_ELx_WNR, regs)) return; msg = "paging request"; diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index f5f359ccaeae..738985c131ea 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -734,7 +734,8 @@ no_context(struct pt_regs *regs, unsigned long error_code, efi_recover_from_page_fault(address); /* Only not-present faults should be handled by KFENCE. */ - if (!(error_code & X86_PF_PROT) && kfence_handle_page_fault(address, regs)) + if (!(error_code & X86_PF_PROT) && + kfence_handle_page_fault(address, error_code & X86_PF_WRITE, regs)) return; oops: /* diff --git a/include/linux/kfence.h b/include/linux/kfence.h index 5a56bcf5606c..a70d1ea03532 100644 --- a/include/linux/kfence.h +++ b/include/linux/kfence.h @@ -186,6 +186,7 @@ static __always_inline __must_check bool kfence_free(void *addr) /** * kfence_handle_page_fault() - perform page fault handling for KFENCE pages * @addr: faulting address + * @is_write: is access a write * @regs: current struct pt_regs (can be NULL, but shows full stack trace) * * Return: @@ -197,7 +198,7 @@ static __always_inline __must_check bool kfence_free(void *addr) * cases KFENCE prints an error message and marks the offending page as * present, so that the kernel can proceed. */ -bool __must_check kfence_handle_page_fault(unsigned long addr, struct pt_regs *regs); +bool __must_check kfence_handle_page_fault(unsigned long addr, bool is_write, struct pt_regs *regs); #else /* CONFIG_KFENCE */ @@ -210,7 +211,11 @@ static inline size_t kfence_ksize(const void *addr) { return 0; } static inline void *kfence_object_start(const void *addr) { return NULL; } static inline void __kfence_free(void *addr) { } static inline bool __must_check kfence_free(void *addr) { return false; } -static inline bool __must_check kfence_handle_page_fault(unsigned long addr, struct pt_regs *regs) { return false; } +static inline bool __must_check kfence_handle_page_fault(unsigned long addr, bool is_write, + struct pt_regs *regs) +{ + return false; +} #endif diff --git a/lib/Kconfig.kfence b/lib/Kconfig.kfence index 605125ac2ae0..78f50ccb3b45 100644 --- a/lib/Kconfig.kfence +++ b/lib/Kconfig.kfence @@ -66,4 +66,17 @@ config KFENCE_STRESS_TEST_FAULTS Only for KFENCE testing; set to 0 if you are not a KFENCE developer. +config KFENCE_KUNIT_TEST + tristate "KFENCE integration test suite" if !KUNIT_ALL_TESTS + default KUNIT_ALL_TESTS + depends on TRACEPOINTS && KUNIT + help + Test suite for KFENCE, testing various error detection scenarios with + various allocation types, and checking that reports are correctly + output to console. + + Say Y here if you want the test to be built into the kernel and run + during boot; say M if you want the test to build as a module; say N + if you are unsure. + endif # KFENCE diff --git a/mm/kfence/Makefile b/mm/kfence/Makefile index d991e9a349f0..6872cd5e5390 100644 --- a/mm/kfence/Makefile +++ b/mm/kfence/Makefile @@ -1,3 +1,6 @@ # SPDX-License-Identifier: GPL-2.0 obj-$(CONFIG_KFENCE) := core.o report.o + +CFLAGS_kfence_test.o := -g -fno-omit-frame-pointer -fno-optimize-sibling-calls +obj-$(CONFIG_KFENCE_KUNIT_TEST) += kfence_test.o diff --git a/mm/kfence/core.c b/mm/kfence/core.c index 7692af715fdb..cfe3d32ac5b7 100644 --- a/mm/kfence/core.c +++ b/mm/kfence/core.c @@ -216,7 +216,7 @@ static inline bool check_canary_byte(u8 *addr) return true; atomic_long_inc(&counters[KFENCE_COUNTER_BUGS]); - kfence_report_error((unsigned long)addr, NULL, addr_to_metadata((unsigned long)addr), + kfence_report_error((unsigned long)addr, false, NULL, addr_to_metadata((unsigned long)addr), KFENCE_ERROR_CORRUPTION); return false; } @@ -355,7 +355,8 @@ static void kfence_guarded_free(void *addr, struct kfence_metadata *meta, bool z if (meta->state != KFENCE_OBJECT_ALLOCATED || meta->addr != (unsigned long)addr) { /* Invalid or double-free, bail out. */ atomic_long_inc(&counters[KFENCE_COUNTER_BUGS]); - kfence_report_error((unsigned long)addr, NULL, meta, KFENCE_ERROR_INVALID_FREE); + kfence_report_error((unsigned long)addr, false, NULL, meta, + KFENCE_ERROR_INVALID_FREE); raw_spin_unlock_irqrestore(&meta->lock, flags); return; } @@ -770,7 +771,7 @@ void __kfence_free(void *addr) kfence_guarded_free(addr, meta, false); } -bool kfence_handle_page_fault(unsigned long addr, struct pt_regs *regs) +bool kfence_handle_page_fault(unsigned long addr, bool is_write, struct pt_regs *regs) { const int page_index = (addr - (unsigned long)__kfence_pool) / PAGE_SIZE; struct kfence_metadata *to_report = NULL; @@ -833,11 +834,11 @@ bool kfence_handle_page_fault(unsigned long addr, struct pt_regs *regs) out: if (to_report) { - kfence_report_error(addr, regs, to_report, error_type); + kfence_report_error(addr, is_write, regs, to_report, error_type); raw_spin_unlock_irqrestore(&to_report->lock, flags); } else { /* This may be a UAF or OOB access, but we can't be sure. */ - kfence_report_error(addr, regs, NULL, KFENCE_ERROR_INVALID); + kfence_report_error(addr, is_write, regs, NULL, KFENCE_ERROR_INVALID); } return kfence_unprotect(addr); /* Unprotect and let access proceed. */ diff --git a/mm/kfence/kfence.h b/mm/kfence/kfence.h index 0d83e628a97d..1accc840dbbe 100644 --- a/mm/kfence/kfence.h +++ b/mm/kfence/kfence.h @@ -105,7 +105,7 @@ enum kfence_error_type { KFENCE_ERROR_INVALID_FREE, /* Invalid free. */ }; -void kfence_report_error(unsigned long address, struct pt_regs *regs, +void kfence_report_error(unsigned long address, bool is_write, struct pt_regs *regs, const struct kfence_metadata *meta, enum kfence_error_type type); void kfence_print_object(struct seq_file *seq, const struct kfence_metadata *meta); diff --git a/mm/kfence/kfence_test.c b/mm/kfence/kfence_test.c new file mode 100644 index 000000000000..db1bb596acaf --- /dev/null +++ b/mm/kfence/kfence_test.c @@ -0,0 +1,858 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Test cases for KFENCE memory safety error detector. Since the interface with + * which KFENCE's reports are obtained is via the console, this is the output we + * should verify. For each test case checks the presence (or absence) of + * generated reports. Relies on 'console' tracepoint to capture reports as they + * appear in the kernel log. + * + * Copyright (C) 2020, Google LLC. + * Author: Alexander Potapenko <glider(a)google.com> + * Marco Elver <elver(a)google.com> + */ + +#include <kunit/test.h> +#include <linux/jiffies.h> +#include <linux/kernel.h> +#include <linux/kfence.h> +#include <linux/mm.h> +#include <linux/random.h> +#include <linux/slab.h> +#include <linux/spinlock.h> +#include <linux/string.h> +#include <linux/tracepoint.h> +#include <trace/events/printk.h> + +#include "kfence.h" + +/* Report as observed from console. */ +static struct { + spinlock_t lock; + int nlines; + char lines[2][256]; +} observed = { + .lock = __SPIN_LOCK_UNLOCKED(observed.lock), +}; + +/* Probe for console output: obtains observed lines of interest. */ +static void probe_console(void *ignore, const char *buf, size_t len) +{ + unsigned long flags; + int nlines; + + spin_lock_irqsave(&observed.lock, flags); + nlines = observed.nlines; + + if (strnstr(buf, "BUG: KFENCE: ", len) && strnstr(buf, "test_", len)) { + /* + * KFENCE report and related to the test. + * + * The provided @buf is not NUL-terminated; copy no more than + * @len bytes and let strscpy() add the missing NUL-terminator. + */ + strscpy(observed.lines[0], buf, min(len + 1, sizeof(observed.lines[0]))); + nlines = 1; + } else if (nlines == 1 && (strnstr(buf, "at 0x", len) || strnstr(buf, "of 0x", len))) { + strscpy(observed.lines[nlines++], buf, min(len + 1, sizeof(observed.lines[0]))); + } + + WRITE_ONCE(observed.nlines, nlines); /* Publish new nlines. */ + spin_unlock_irqrestore(&observed.lock, flags); +} + +/* Check if a report related to the test exists. */ +static bool report_available(void) +{ + return READ_ONCE(observed.nlines) == ARRAY_SIZE(observed.lines); +} + +/* Information we expect in a report. */ +struct expect_report { + enum kfence_error_type type; /* The type or error. */ + void *fn; /* Function pointer to expected function where access occurred. */ + char *addr; /* Address at which the bad access occurred. */ + bool is_write; /* Is access a write. */ +}; + +static const char *get_access_type(const struct expect_report *r) +{ + return r->is_write ? "write" : "read"; +} + +/* Check observed report matches information in @r. */ +static bool report_matches(const struct expect_report *r) +{ + bool ret = false; + unsigned long flags; + typeof(observed.lines) expect; + const char *end; + char *cur; + + /* Doubled-checked locking. */ + if (!report_available()) + return false; + + /* Generate expected report contents. */ + + /* Title */ + cur = expect[0]; + end = &expect[0][sizeof(expect[0]) - 1]; + switch (r->type) { + case KFENCE_ERROR_OOB: + cur += scnprintf(cur, end - cur, "BUG: KFENCE: out-of-bounds %s", + get_access_type(r)); + break; + case KFENCE_ERROR_UAF: + cur += scnprintf(cur, end - cur, "BUG: KFENCE: use-after-free %s", + get_access_type(r)); + break; + case KFENCE_ERROR_CORRUPTION: + cur += scnprintf(cur, end - cur, "BUG: KFENCE: memory corruption"); + break; + case KFENCE_ERROR_INVALID: + cur += scnprintf(cur, end - cur, "BUG: KFENCE: invalid %s", + get_access_type(r)); + break; + case KFENCE_ERROR_INVALID_FREE: + cur += scnprintf(cur, end - cur, "BUG: KFENCE: invalid free"); + break; + } + + scnprintf(cur, end - cur, " in %pS", r->fn); + /* The exact offset won't match, remove it; also strip module name. */ + cur = strchr(expect[0], '+'); + if (cur) + *cur = '\0'; + + /* Access information */ + cur = expect[1]; + end = &expect[1][sizeof(expect[1]) - 1]; + + switch (r->type) { + case KFENCE_ERROR_OOB: + cur += scnprintf(cur, end - cur, "Out-of-bounds %s at", get_access_type(r)); + break; + case KFENCE_ERROR_UAF: + cur += scnprintf(cur, end - cur, "Use-after-free %s at", get_access_type(r)); + break; + case KFENCE_ERROR_CORRUPTION: + cur += scnprintf(cur, end - cur, "Corrupted memory at"); + break; + case KFENCE_ERROR_INVALID: + cur += scnprintf(cur, end - cur, "Invalid %s at", get_access_type(r)); + break; + case KFENCE_ERROR_INVALID_FREE: + cur += scnprintf(cur, end - cur, "Invalid free of"); + break; + } + + cur += scnprintf(cur, end - cur, " 0x" PTR_FMT, (void *)r->addr); + + spin_lock_irqsave(&observed.lock, flags); + if (!report_available()) + goto out; /* A new report is being captured. */ + + /* Finally match expected output to what we actually observed. */ + ret = strstr(observed.lines[0], expect[0]) && strstr(observed.lines[1], expect[1]); +out: + spin_unlock_irqrestore(&observed.lock, flags); + return ret; +} + +/* ===== Test cases ===== */ + +#define TEST_PRIV_WANT_MEMCACHE ((void *)1) + +/* Cache used by tests; if NULL, allocate from kmalloc instead. */ +static struct kmem_cache *test_cache; + +static size_t setup_test_cache(struct kunit *test, size_t size, slab_flags_t flags, + void (*ctor)(void *)) +{ + if (test->priv != TEST_PRIV_WANT_MEMCACHE) + return size; + + kunit_info(test, "%s: size=%zu, ctor=%ps\n", __func__, size, ctor); + + /* + * Use SLAB_NOLEAKTRACE to prevent merging with existing caches. Any + * other flag in SLAB_NEVER_MERGE also works. Use SLAB_ACCOUNT to + * allocate via memcg, if enabled. + */ + flags |= SLAB_NOLEAKTRACE | SLAB_ACCOUNT; + test_cache = kmem_cache_create("test", size, 1, flags, ctor); + KUNIT_ASSERT_TRUE_MSG(test, test_cache, "could not create cache"); + + return size; +} + +static void test_cache_destroy(void) +{ + if (!test_cache) + return; + + kmem_cache_destroy(test_cache); + test_cache = NULL; +} + +static inline size_t kmalloc_cache_alignment(size_t size) +{ + return kmalloc_caches[kmalloc_type(GFP_KERNEL)][kmalloc_index(size)]->align; +} + +/* Must always inline to match stack trace against caller. */ +static __always_inline void test_free(void *ptr) +{ + if (test_cache) + kmem_cache_free(test_cache, ptr); + else + kfree(ptr); +} + +/* + * If this should be a KFENCE allocation, and on which side the allocation and + * the closest guard page should be. + */ +enum allocation_policy { + ALLOCATE_ANY, /* KFENCE, any side. */ + ALLOCATE_LEFT, /* KFENCE, left side of page. */ + ALLOCATE_RIGHT, /* KFENCE, right side of page. */ + ALLOCATE_NONE, /* No KFENCE allocation. */ +}; + +/* + * Try to get a guarded allocation from KFENCE. Uses either kmalloc() or the + * current test_cache if set up. + */ +static void *test_alloc(struct kunit *test, size_t size, gfp_t gfp, enum allocation_policy policy) +{ + void *alloc; + unsigned long timeout, resched_after; + const char *policy_name; + + switch (policy) { + case ALLOCATE_ANY: + policy_name = "any"; + break; + case ALLOCATE_LEFT: + policy_name = "left"; + break; + case ALLOCATE_RIGHT: + policy_name = "right"; + break; + case ALLOCATE_NONE: + policy_name = "none"; + break; + } + + kunit_info(test, "%s: size=%zu, gfp=%x, policy=%s, cache=%i\n", __func__, size, gfp, + policy_name, !!test_cache); + + /* + * 100x the sample interval should be more than enough to ensure we get + * a KFENCE allocation eventually. + */ + timeout = jiffies + msecs_to_jiffies(100 * CONFIG_KFENCE_SAMPLE_INTERVAL); + /* + * Especially for non-preemption kernels, ensure the allocation-gate + * timer can catch up: after @resched_after, every failed allocation + * attempt yields, to ensure the allocation-gate timer is scheduled. + */ + resched_after = jiffies + msecs_to_jiffies(CONFIG_KFENCE_SAMPLE_INTERVAL); + do { + if (test_cache) + alloc = kmem_cache_alloc(test_cache, gfp); + else + alloc = kmalloc(size, gfp); + + if (is_kfence_address(alloc)) { + struct page *page = virt_to_head_page(alloc); + struct kmem_cache *s = test_cache ?: kmalloc_caches[kmalloc_type(GFP_KERNEL)][kmalloc_index(size)]; + + /* + * Verify that various helpers return the right values + * even for KFENCE objects; these are required so that + * memcg accounting works correctly. + */ + KUNIT_EXPECT_EQ(test, obj_to_index(s, page, alloc), 0U); + KUNIT_EXPECT_EQ(test, objs_per_slab_page(s, page), 1); + + if (policy == ALLOCATE_ANY) + return alloc; + if (policy == ALLOCATE_LEFT && IS_ALIGNED((unsigned long)alloc, PAGE_SIZE)) + return alloc; + if (policy == ALLOCATE_RIGHT && + !IS_ALIGNED((unsigned long)alloc, PAGE_SIZE)) + return alloc; + } else if (policy == ALLOCATE_NONE) + return alloc; + + test_free(alloc); + + if (time_after(jiffies, resched_after)) + cond_resched(); + } while (time_before(jiffies, timeout)); + + KUNIT_ASSERT_TRUE_MSG(test, false, "failed to allocate from KFENCE"); + return NULL; /* Unreachable. */ +} + +static void test_out_of_bounds_read(struct kunit *test) +{ + size_t size = 32; + struct expect_report expect = { + .type = KFENCE_ERROR_OOB, + .fn = test_out_of_bounds_read, + .is_write = false, + }; + char *buf; + + setup_test_cache(test, size, 0, NULL); + + /* + * If we don't have our own cache, adjust based on alignment, so that we + * actually access guard pages on either side. + */ + if (!test_cache) + size = kmalloc_cache_alignment(size); + + /* Test both sides. */ + + buf = test_alloc(test, size, GFP_KERNEL, ALLOCATE_LEFT); + expect.addr = buf - 1; + READ_ONCE(*expect.addr); + KUNIT_EXPECT_TRUE(test, report_matches(&expect)); + test_free(buf); + + buf = test_alloc(test, size, GFP_KERNEL, ALLOCATE_RIGHT); + expect.addr = buf + size; + READ_ONCE(*expect.addr); + KUNIT_EXPECT_TRUE(test, report_matches(&expect)); + test_free(buf); +} + +static void test_out_of_bounds_write(struct kunit *test) +{ + size_t size = 32; + struct expect_report expect = { + .type = KFENCE_ERROR_OOB, + .fn = test_out_of_bounds_write, + .is_write = true, + }; + char *buf; + + setup_test_cache(test, size, 0, NULL); + buf = test_alloc(test, size, GFP_KERNEL, ALLOCATE_LEFT); + expect.addr = buf - 1; + WRITE_ONCE(*expect.addr, 42); + KUNIT_EXPECT_TRUE(test, report_matches(&expect)); + test_free(buf); +} + +static void test_use_after_free_read(struct kunit *test) +{ + const size_t size = 32; + struct expect_report expect = { + .type = KFENCE_ERROR_UAF, + .fn = test_use_after_free_read, + .is_write = false, + }; + + setup_test_cache(test, size, 0, NULL); + expect.addr = test_alloc(test, size, GFP_KERNEL, ALLOCATE_ANY); + test_free(expect.addr); + READ_ONCE(*expect.addr); + KUNIT_EXPECT_TRUE(test, report_matches(&expect)); +} + +static void test_double_free(struct kunit *test) +{ + const size_t size = 32; + struct expect_report expect = { + .type = KFENCE_ERROR_INVALID_FREE, + .fn = test_double_free, + }; + + setup_test_cache(test, size, 0, NULL); + expect.addr = test_alloc(test, size, GFP_KERNEL, ALLOCATE_ANY); + test_free(expect.addr); + test_free(expect.addr); /* Double-free. */ + KUNIT_EXPECT_TRUE(test, report_matches(&expect)); +} + +static void test_invalid_addr_free(struct kunit *test) +{ + const size_t size = 32; + struct expect_report expect = { + .type = KFENCE_ERROR_INVALID_FREE, + .fn = test_invalid_addr_free, + }; + char *buf; + + setup_test_cache(test, size, 0, NULL); + buf = test_alloc(test, size, GFP_KERNEL, ALLOCATE_ANY); + expect.addr = buf + 1; /* Free on invalid address. */ + test_free(expect.addr); /* Invalid address free. */ + test_free(buf); /* No error. */ + KUNIT_EXPECT_TRUE(test, report_matches(&expect)); +} + +static void test_corruption(struct kunit *test) +{ + size_t size = 32; + struct expect_report expect = { + .type = KFENCE_ERROR_CORRUPTION, + .fn = test_corruption, + }; + char *buf; + + setup_test_cache(test, size, 0, NULL); + + /* Test both sides. */ + + buf = test_alloc(test, size, GFP_KERNEL, ALLOCATE_LEFT); + expect.addr = buf + size; + WRITE_ONCE(*expect.addr, 42); + test_free(buf); + KUNIT_EXPECT_TRUE(test, report_matches(&expect)); + + buf = test_alloc(test, size, GFP_KERNEL, ALLOCATE_RIGHT); + expect.addr = buf - 1; + WRITE_ONCE(*expect.addr, 42); + test_free(buf); + KUNIT_EXPECT_TRUE(test, report_matches(&expect)); +} + +/* + * KFENCE is unable to detect an OOB if the allocation's alignment requirements + * leave a gap between the object and the guard page. Specifically, an + * allocation of e.g. 73 bytes is aligned on 8 and 128 bytes for SLUB or SLAB + * respectively. Therefore it is impossible for the allocated object to + * contiguously line up with the right guard page. + * + * However, we test that an access to memory beyond the gap results in KFENCE + * detecting an OOB access. + */ +static void test_kmalloc_aligned_oob_read(struct kunit *test) +{ + const size_t size = 73; + const size_t align = kmalloc_cache_alignment(size); + struct expect_report expect = { + .type = KFENCE_ERROR_OOB, + .fn = test_kmalloc_aligned_oob_read, + .is_write = false, + }; + char *buf; + + buf = test_alloc(test, size, GFP_KERNEL, ALLOCATE_RIGHT); + + /* + * The object is offset to the right, so there won't be an OOB to the + * left of it. + */ + READ_ONCE(*(buf - 1)); + KUNIT_EXPECT_FALSE(test, report_available()); + + /* + * @buf must be aligned on @align, therefore buf + size belongs to the + * same page -> no OOB. + */ + READ_ONCE(*(buf + size)); + KUNIT_EXPECT_FALSE(test, report_available()); + + /* Overflowing by @align bytes will result in an OOB. */ + expect.addr = buf + size + align; + READ_ONCE(*expect.addr); + KUNIT_EXPECT_TRUE(test, report_matches(&expect)); + + test_free(buf); +} + +static void test_kmalloc_aligned_oob_write(struct kunit *test) +{ + const size_t size = 73; + struct expect_report expect = { + .type = KFENCE_ERROR_CORRUPTION, + .fn = test_kmalloc_aligned_oob_write, + }; + char *buf; + + buf = test_alloc(test, size, GFP_KERNEL, ALLOCATE_RIGHT); + /* + * The object is offset to the right, so we won't get a page + * fault immediately after it. + */ + expect.addr = buf + size; + WRITE_ONCE(*expect.addr, READ_ONCE(*expect.addr) + 1); + KUNIT_EXPECT_FALSE(test, report_available()); + test_free(buf); + KUNIT_EXPECT_TRUE(test, report_matches(&expect)); +} + +/* Test cache shrinking and destroying with KFENCE. */ +static void test_shrink_memcache(struct kunit *test) +{ + const size_t size = 32; + void *buf; + + setup_test_cache(test, size, 0, NULL); + KUNIT_EXPECT_TRUE(test, test_cache); + buf = test_alloc(test, size, GFP_KERNEL, ALLOCATE_ANY); + kmem_cache_shrink(test_cache); + test_free(buf); + + KUNIT_EXPECT_FALSE(test, report_available()); +} + +static void ctor_set_x(void *obj) +{ + /* Every object has at least 8 bytes. */ + memset(obj, 'x', 8); +} + +/* Ensure that SL*B does not modify KFENCE objects on bulk free. */ +static void test_free_bulk(struct kunit *test) +{ + int iter; + + for (iter = 0; iter < 5; iter++) { + const size_t size = setup_test_cache(test, 8 + prandom_u32_max(300), 0, + (iter & 1) ? ctor_set_x : NULL); + void *objects[] = { + test_alloc(test, size, GFP_KERNEL, ALLOCATE_RIGHT), + test_alloc(test, size, GFP_KERNEL, ALLOCATE_NONE), + test_alloc(test, size, GFP_KERNEL, ALLOCATE_LEFT), + test_alloc(test, size, GFP_KERNEL, ALLOCATE_NONE), + test_alloc(test, size, GFP_KERNEL, ALLOCATE_NONE), + }; + + kmem_cache_free_bulk(test_cache, ARRAY_SIZE(objects), objects); + KUNIT_ASSERT_FALSE(test, report_available()); + test_cache_destroy(); + } +} + +/* Test init-on-free works. */ +static void test_init_on_free(struct kunit *test) +{ + const size_t size = 32; + struct expect_report expect = { + .type = KFENCE_ERROR_UAF, + .fn = test_init_on_free, + .is_write = false, + }; + int i; + + if (!IS_ENABLED(CONFIG_INIT_ON_FREE_DEFAULT_ON)) + return; + /* Assume it hasn't been disabled on command line. */ + + setup_test_cache(test, size, 0, NULL); + expect.addr = test_alloc(test, size, GFP_KERNEL, ALLOCATE_ANY); + for (i = 0; i < size; i++) + expect.addr[i] = i + 1; + test_free(expect.addr); + + for (i = 0; i < size; i++) { + /* + * This may fail if the page was recycled by KFENCE and then + * written to again -- this however, is near impossible with a + * default config. + */ + KUNIT_EXPECT_EQ(test, expect.addr[i], (char)0); + + if (!i) /* Only check first access to not fail test if page is ever re-protected. */ + KUNIT_EXPECT_TRUE(test, report_matches(&expect)); + } +} + +/* Ensure that constructors work properly. */ +static void test_memcache_ctor(struct kunit *test) +{ + const size_t size = 32; + char *buf; + int i; + + setup_test_cache(test, size, 0, ctor_set_x); + buf = test_alloc(test, size, GFP_KERNEL, ALLOCATE_ANY); + + for (i = 0; i < 8; i++) + KUNIT_EXPECT_EQ(test, buf[i], (char)'x'); + + test_free(buf); + + KUNIT_EXPECT_FALSE(test, report_available()); +} + +/* Test that memory is zeroed if requested. */ +static void test_gfpzero(struct kunit *test) +{ + const size_t size = PAGE_SIZE; /* PAGE_SIZE so we can use ALLOCATE_ANY. */ + char *buf1, *buf2; + int i; + + if (CONFIG_KFENCE_SAMPLE_INTERVAL > 100) { + kunit_warn(test, "skipping ... would take too long\n"); + return; + } + + setup_test_cache(test, size, 0, NULL); + buf1 = test_alloc(test, size, GFP_KERNEL, ALLOCATE_ANY); + for (i = 0; i < size; i++) + buf1[i] = i + 1; + test_free(buf1); + + /* Try to get same address again -- this can take a while. */ + for (i = 0;; i++) { + buf2 = test_alloc(test, size, GFP_KERNEL | __GFP_ZERO, ALLOCATE_ANY); + if (buf1 == buf2) + break; + test_free(buf2); + + if (i == CONFIG_KFENCE_NUM_OBJECTS) { + kunit_warn(test, "giving up ... cannot get same object back\n"); + return; + } + } + + for (i = 0; i < size; i++) + KUNIT_EXPECT_EQ(test, buf2[i], (char)0); + + test_free(buf2); + + KUNIT_EXPECT_FALSE(test, report_available()); +} + +static void test_invalid_access(struct kunit *test) +{ + const struct expect_report expect = { + .type = KFENCE_ERROR_INVALID, + .fn = test_invalid_access, + .addr = &__kfence_pool[10], + .is_write = false, + }; + + READ_ONCE(__kfence_pool[10]); + KUNIT_EXPECT_TRUE(test, report_matches(&expect)); +} + +/* Test SLAB_TYPESAFE_BY_RCU works. */ +static void test_memcache_typesafe_by_rcu(struct kunit *test) +{ + const size_t size = 32; + struct expect_report expect = { + .type = KFENCE_ERROR_UAF, + .fn = test_memcache_typesafe_by_rcu, + .is_write = false, + }; + + setup_test_cache(test, size, SLAB_TYPESAFE_BY_RCU, NULL); + KUNIT_EXPECT_TRUE(test, test_cache); /* Want memcache. */ + + expect.addr = test_alloc(test, size, GFP_KERNEL, ALLOCATE_ANY); + *expect.addr = 42; + + rcu_read_lock(); + test_free(expect.addr); + KUNIT_EXPECT_EQ(test, *expect.addr, (char)42); + /* + * Up to this point, memory should not have been freed yet, and + * therefore there should be no KFENCE report from the above access. + */ + rcu_read_unlock(); + + /* Above access to @expect.addr should not have generated a report! */ + KUNIT_EXPECT_FALSE(test, report_available()); + + /* Only after rcu_barrier() is the memory guaranteed to be freed. */ + rcu_barrier(); + + /* Expect use-after-free. */ + KUNIT_EXPECT_EQ(test, *expect.addr, (char)42); + KUNIT_EXPECT_TRUE(test, report_matches(&expect)); +} + +/* Test krealloc(). */ +static void test_krealloc(struct kunit *test) +{ + const size_t size = 32; + const struct expect_report expect = { + .type = KFENCE_ERROR_UAF, + .fn = test_krealloc, + .addr = test_alloc(test, size, GFP_KERNEL, ALLOCATE_ANY), + .is_write = false, + }; + char *buf = expect.addr; + int i; + + KUNIT_EXPECT_FALSE(test, test_cache); + KUNIT_EXPECT_EQ(test, ksize(buf), size); /* Precise size match after KFENCE alloc. */ + for (i = 0; i < size; i++) + buf[i] = i + 1; + + /* Check that we successfully change the size. */ + buf = krealloc(buf, size * 3, GFP_KERNEL); /* Grow. */ + /* Note: Might no longer be a KFENCE alloc. */ + KUNIT_EXPECT_GE(test, ksize(buf), size * 3); + for (i = 0; i < size; i++) + KUNIT_EXPECT_EQ(test, buf[i], (char)(i + 1)); + for (; i < size * 3; i++) /* Fill to extra bytes. */ + buf[i] = i + 1; + + buf = krealloc(buf, size * 2, GFP_KERNEL); /* Shrink. */ + KUNIT_EXPECT_GE(test, ksize(buf), size * 2); + for (i = 0; i < size * 2; i++) + KUNIT_EXPECT_EQ(test, buf[i], (char)(i + 1)); + + buf = krealloc(buf, 0, GFP_KERNEL); /* Free. */ + KUNIT_EXPECT_EQ(test, (unsigned long)buf, (unsigned long)ZERO_SIZE_PTR); + KUNIT_ASSERT_FALSE(test, report_available()); /* No reports yet! */ + + READ_ONCE(*expect.addr); /* Ensure krealloc() actually freed earlier KFENCE object. */ + KUNIT_ASSERT_TRUE(test, report_matches(&expect)); +} + +/* Test that some objects from a bulk allocation belong to KFENCE pool. */ +static void test_memcache_alloc_bulk(struct kunit *test) +{ + const size_t size = 32; + bool pass = false; + unsigned long timeout; + + setup_test_cache(test, size, 0, NULL); + KUNIT_EXPECT_TRUE(test, test_cache); /* Want memcache. */ + /* + * 100x the sample interval should be more than enough to ensure we get + * a KFENCE allocation eventually. + */ + timeout = jiffies + msecs_to_jiffies(100 * CONFIG_KFENCE_SAMPLE_INTERVAL); + do { + void *objects[100]; + int i, num = kmem_cache_alloc_bulk(test_cache, GFP_ATOMIC, ARRAY_SIZE(objects), + objects); + if (!num) + continue; + for (i = 0; i < ARRAY_SIZE(objects); i++) { + if (is_kfence_address(objects[i])) { + pass = true; + break; + } + } + kmem_cache_free_bulk(test_cache, num, objects); + /* + * kmem_cache_alloc_bulk() disables interrupts, and calling it + * in a tight loop may not give KFENCE a chance to switch the + * static branch. Call cond_resched() to let KFENCE chime in. + */ + cond_resched(); + } while (!pass && time_before(jiffies, timeout)); + + KUNIT_EXPECT_TRUE(test, pass); + KUNIT_EXPECT_FALSE(test, report_available()); +} + +/* + * KUnit does not provide a way to provide arguments to tests, and we encode + * additional info in the name. Set up 2 tests per test case, one using the + * default allocator, and another using a custom memcache (suffix '-memcache'). + */ +#define KFENCE_KUNIT_CASE(test_name) \ + { .run_case = test_name, .name = #test_name }, \ + { .run_case = test_name, .name = #test_name "-memcache" } + +static struct kunit_case kfence_test_cases[] = { + KFENCE_KUNIT_CASE(test_out_of_bounds_read), + KFENCE_KUNIT_CASE(test_out_of_bounds_write), + KFENCE_KUNIT_CASE(test_use_after_free_read), + KFENCE_KUNIT_CASE(test_double_free), + KFENCE_KUNIT_CASE(test_invalid_addr_free), + KFENCE_KUNIT_CASE(test_corruption), + KFENCE_KUNIT_CASE(test_free_bulk), + KFENCE_KUNIT_CASE(test_init_on_free), + KUNIT_CASE(test_kmalloc_aligned_oob_read), + KUNIT_CASE(test_kmalloc_aligned_oob_write), + KUNIT_CASE(test_shrink_memcache), + KUNIT_CASE(test_memcache_ctor), + KUNIT_CASE(test_invalid_access), + KUNIT_CASE(test_gfpzero), + KUNIT_CASE(test_memcache_typesafe_by_rcu), + KUNIT_CASE(test_krealloc), + KUNIT_CASE(test_memcache_alloc_bulk), + {}, +}; + +/* ===== End test cases ===== */ + +static int test_init(struct kunit *test) +{ + unsigned long flags; + int i; + + spin_lock_irqsave(&observed.lock, flags); + for (i = 0; i < ARRAY_SIZE(observed.lines); i++) + observed.lines[i][0] = '\0'; + observed.nlines = 0; + spin_unlock_irqrestore(&observed.lock, flags); + + /* Any test with 'memcache' in its name will want a memcache. */ + if (strstr(test->name, "memcache")) + test->priv = TEST_PRIV_WANT_MEMCACHE; + else + test->priv = NULL; + + return 0; +} + +static void test_exit(struct kunit *test) +{ + test_cache_destroy(); +} + +static struct kunit_suite kfence_test_suite = { + .name = "kfence", + .test_cases = kfence_test_cases, + .init = test_init, + .exit = test_exit, +}; +static struct kunit_suite *kfence_test_suites[] = { &kfence_test_suite, NULL }; + +static void register_tracepoints(struct tracepoint *tp, void *ignore) +{ + check_trace_callback_type_console(probe_console); + if (!strcmp(tp->name, "console")) + WARN_ON(tracepoint_probe_register(tp, probe_console, NULL)); +} + +static void unregister_tracepoints(struct tracepoint *tp, void *ignore) +{ + if (!strcmp(tp->name, "console")) + tracepoint_probe_unregister(tp, probe_console, NULL); +} + +/* + * We only want to do tracepoints setup and teardown once, therefore we have to + * customize the init and exit functions and cannot rely on kunit_test_suite(). + */ +static int __init kfence_test_init(void) +{ + /* + * Because we want to be able to build the test as a module, we need to + * iterate through all known tracepoints, since the static registration + * won't work here. + */ + for_each_kernel_tracepoint(register_tracepoints, NULL); + return __kunit_test_suites_init(kfence_test_suites); +} + +static void kfence_test_exit(void) +{ + __kunit_test_suites_exit(kfence_test_suites); + for_each_kernel_tracepoint(unregister_tracepoints, NULL); + tracepoint_synchronize_unregister(); +} + +late_initcall(kfence_test_init); +module_exit(kfence_test_exit); + +MODULE_LICENSE("GPL v2"); +MODULE_AUTHOR("Alexander Potapenko <glider(a)google.com>, Marco Elver <elver(a)google.com>"); diff --git a/mm/kfence/report.c b/mm/kfence/report.c index 4dbfa9a382e4..901bd7ee83d8 100644 --- a/mm/kfence/report.c +++ b/mm/kfence/report.c @@ -156,7 +156,12 @@ static void print_diff_canary(unsigned long address, size_t bytes_to_show, pr_cont(" ]"); } -void kfence_report_error(unsigned long address, struct pt_regs *regs, +static const char *get_access_type(bool is_write) +{ + return is_write ? "write" : "read"; +} + +void kfence_report_error(unsigned long address, bool is_write, struct pt_regs *regs, const struct kfence_metadata *meta, enum kfence_error_type type) { unsigned long stack_entries[KFENCE_STACK_DEPTH] = { 0 }; @@ -194,17 +199,19 @@ void kfence_report_error(unsigned long address, struct pt_regs *regs, case KFENCE_ERROR_OOB: { const bool left_of_object = address < meta->addr; - pr_err("BUG: KFENCE: out-of-bounds in %pS\n\n", (void *)stack_entries[skipnr]); - pr_err("Out-of-bounds access at 0x" PTR_FMT " (%luB %s of kfence-#%zd):\n", - (void *)address, + pr_err("BUG: KFENCE: out-of-bounds %s in %pS\n\n", get_access_type(is_write), + (void *)stack_entries[skipnr]); + pr_err("Out-of-bounds %s at 0x" PTR_FMT " (%luB %s of kfence-#%zd):\n", + get_access_type(is_write), (void *)address, left_of_object ? meta->addr - address : address - meta->addr, left_of_object ? "left" : "right", object_index); break; } case KFENCE_ERROR_UAF: - pr_err("BUG: KFENCE: use-after-free in %pS\n\n", (void *)stack_entries[skipnr]); - pr_err("Use-after-free access at 0x" PTR_FMT " (in kfence-#%zd):\n", - (void *)address, object_index); + pr_err("BUG: KFENCE: use-after-free %s in %pS\n\n", get_access_type(is_write), + (void *)stack_entries[skipnr]); + pr_err("Use-after-free %s at 0x" PTR_FMT " (in kfence-#%zd):\n", + get_access_type(is_write), (void *)address, object_index); break; case KFENCE_ERROR_CORRUPTION: pr_err("BUG: KFENCE: memory corruption in %pS\n\n", (void *)stack_entries[skipnr]); @@ -213,8 +220,10 @@ void kfence_report_error(unsigned long address, struct pt_regs *regs, pr_cont(" (in kfence-#%zd):\n", object_index); break; case KFENCE_ERROR_INVALID: - pr_err("BUG: KFENCE: invalid access in %pS\n\n", (void *)stack_entries[skipnr]); - pr_err("Invalid access at 0x" PTR_FMT ":\n", (void *)address); + pr_err("BUG: KFENCE: invalid %s in %pS\n\n", get_access_type(is_write), + (void *)stack_entries[skipnr]); + pr_err("Invalid %s at 0x" PTR_FMT ":\n", get_access_type(is_write), + (void *)address); break; case KFENCE_ERROR_INVALID_FREE: pr_err("BUG: KFENCE: invalid free in %pS\n\n", (void *)stack_entries[skipnr]); -- 2.25.1

1 0

[PATCH 8/9] kfence, Documentation: add KFENCE documentation
by 1415317271＠qq.com 18 Aug '21

18 Aug '21

From: Marco Elver <elver(a)google.com> Add KFENCE documentation in dev-tools/kfence.rst, and add to index. [elver(a)google.com: add missing copyright header to documentation] Link: https://lkml.kernel.org/r/20210118092159.145934-4-elver@google.com Link: https://lkml.kernel.org/r/20201103175841.3495947-8-elver@google.com Signed-off-by: Alexander Potapenko <glider(a)google.com> Signed-off-by: Marco Elver <elver(a)google.com> Reviewed-by: Dmitry Vyukov <dvyukov(a)google.com> Co-developed-by: Alexander Potapenko <glider(a)google.com> Reviewed-by: Jann Horn <jannh(a)google.com> Cc: Andrey Konovalov <andreyknvl(a)google.com> Cc: Andrey Ryabinin <aryabinin(a)virtuozzo.com> Cc: Andy Lutomirski <luto(a)kernel.org> Cc: Borislav Petkov <bp(a)alien8.de> Cc: Catalin Marinas <catalin.marinas(a)arm.com> Cc: Christopher Lameter <cl(a)linux.com> Cc: Dave Hansen <dave.hansen(a)linux.intel.com> Cc: David Rientjes <rientjes(a)google.com> Cc: Eric Dumazet <edumazet(a)google.com> Cc: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Cc: Hillf Danton <hdanton(a)sina.com> Cc: "H. Peter Anvin" <hpa(a)zytor.com> Cc: Ingo Molnar <mingo(a)redhat.com> Cc: Joern Engel <joern(a)purestorage.com> Cc: Jonathan Corbet <corbet(a)lwn.net> Cc: Joonsoo Kim <iamjoonsoo.kim(a)lge.com> Cc: Kees Cook <keescook(a)chromium.org> Cc: Mark Rutland <mark.rutland(a)arm.com> Cc: Paul E. McKenney <paulmck(a)kernel.org> Cc: Pekka Enberg <penberg(a)kernel.org> Cc: Peter Zijlstra <peterz(a)infradead.org> Cc: SeongJae Park <sjpark(a)amazon.de> Cc: Thomas Gleixner <tglx(a)linutronix.de> Cc: Vlastimil Babka <vbabka(a)suse.cz> Cc: Will Deacon <will(a)kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds(a)linux-foundation.org> Signed-off-by: Yingjie Shang <1415317271(a)qq.com> Reviewed-by: Bixuan Cui <cuibixuan(a)huawei.com> --- Documentation/dev-tools/index.rst | 1 + Documentation/dev-tools/kfence.rst | 298 +++++++++++++++++++++++++++++ lib/Kconfig.kfence | 2 + 3 files changed, 301 insertions(+) create mode 100644 Documentation/dev-tools/kfence.rst diff --git a/Documentation/dev-tools/index.rst b/Documentation/dev-tools/index.rst index f7809c7b1ba9..1b1cf4f5c9d9 100644 --- a/Documentation/dev-tools/index.rst +++ b/Documentation/dev-tools/index.rst @@ -22,6 +22,7 @@ whole; patches welcome! ubsan kmemleak kcsan + kfence gdb-kernel-debugging kgdb kselftest diff --git a/Documentation/dev-tools/kfence.rst b/Documentation/dev-tools/kfence.rst new file mode 100644 index 000000000000..0e2fb6ef3016 --- /dev/null +++ b/Documentation/dev-tools/kfence.rst @@ -0,0 +1,298 @@ +.. SPDX-License-Identifier: GPL-2.0 +.. Copyright (C) 2020, Google LLC. + +Kernel Electric-Fence (KFENCE) +============================== + +Kernel Electric-Fence (KFENCE) is a low-overhead sampling-based memory safety +error detector. KFENCE detects heap out-of-bounds access, use-after-free, and +invalid-free errors. + +KFENCE is designed to be enabled in production kernels, and has near zero +performance overhead. Compared to KASAN, KFENCE trades performance for +precision. The main motivation behind KFENCE's design, is that with enough +total uptime KFENCE will detect bugs in code paths not typically exercised by +non-production test workloads. One way to quickly achieve a large enough total +uptime is when the tool is deployed across a large fleet of machines. + +Usage +----- + +To enable KFENCE, configure the kernel with:: + + CONFIG_KFENCE=y + +To build a kernel with KFENCE support, but disabled by default (to enable, set +``kfence.sample_interval`` to non-zero value), configure the kernel with:: + + CONFIG_KFENCE=y + CONFIG_KFENCE_SAMPLE_INTERVAL=0 + +KFENCE provides several other configuration options to customize behaviour (see +the respective help text in ``lib/Kconfig.kfence`` for more info). + +Tuning performance +~~~~~~~~~~~~~~~~~~ + +The most important parameter is KFENCE's sample interval, which can be set via +the kernel boot parameter ``kfence.sample_interval`` in milliseconds. The +sample interval determines the frequency with which heap allocations will be +guarded by KFENCE. The default is configurable via the Kconfig option +``CONFIG_KFENCE_SAMPLE_INTERVAL``. Setting ``kfence.sample_interval=0`` +disables KFENCE. + +The KFENCE memory pool is of fixed size, and if the pool is exhausted, no +further KFENCE allocations occur. With ``CONFIG_KFENCE_NUM_OBJECTS`` (default +255), the number of available guarded objects can be controlled. Each object +requires 2 pages, one for the object itself and the other one used as a guard +page; object pages are interleaved with guard pages, and every object page is +therefore surrounded by two guard pages. + +The total memory dedicated to the KFENCE memory pool can be computed as:: + + ( #objects + 1 ) * 2 * PAGE_SIZE + +Using the default config, and assuming a page size of 4 KiB, results in +dedicating 2 MiB to the KFENCE memory pool. + +Note: On architectures that support huge pages, KFENCE will ensure that the +pool is using pages of size ``PAGE_SIZE``. This will result in additional page +tables being allocated. + +Error reports +~~~~~~~~~~~~~ + +A typical out-of-bounds access looks like this:: + + ================================================================== + BUG: KFENCE: out-of-bounds in test_out_of_bounds_read+0xa3/0x22b + + Out-of-bounds access at 0xffffffffb672efff (1B left of kfence-#17): + test_out_of_bounds_read+0xa3/0x22b + kunit_try_run_case+0x51/0x85 + kunit_generic_run_threadfn_adapter+0x16/0x30 + kthread+0x137/0x160 + ret_from_fork+0x22/0x30 + + kfence-#17 [0xffffffffb672f000-0xffffffffb672f01f, size=32, cache=kmalloc-32] allocated by task 507: + test_alloc+0xf3/0x25b + test_out_of_bounds_read+0x98/0x22b + kunit_try_run_case+0x51/0x85 + kunit_generic_run_threadfn_adapter+0x16/0x30 + kthread+0x137/0x160 + ret_from_fork+0x22/0x30 + + CPU: 4 PID: 107 Comm: kunit_try_catch Not tainted 5.8.0-rc6+ #7 + Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1 04/01/2014 + ================================================================== + +The header of the report provides a short summary of the function involved in +the access. It is followed by more detailed information about the access and +its origin. Note that, real kernel addresses are only shown for +``CONFIG_DEBUG_KERNEL=y`` builds. + +Use-after-free accesses are reported as:: + + ================================================================== + BUG: KFENCE: use-after-free in test_use_after_free_read+0xb3/0x143 + + Use-after-free access at 0xffffffffb673dfe0 (in kfence-#24): + test_use_after_free_read+0xb3/0x143 + kunit_try_run_case+0x51/0x85 + kunit_generic_run_threadfn_adapter+0x16/0x30 + kthread+0x137/0x160 + ret_from_fork+0x22/0x30 + + kfence-#24 [0xffffffffb673dfe0-0xffffffffb673dfff, size=32, cache=kmalloc-32] allocated by task 507: + test_alloc+0xf3/0x25b + test_use_after_free_read+0x76/0x143 + kunit_try_run_case+0x51/0x85 + kunit_generic_run_threadfn_adapter+0x16/0x30 + kthread+0x137/0x160 + ret_from_fork+0x22/0x30 + + freed by task 507: + test_use_after_free_read+0xa8/0x143 + kunit_try_run_case+0x51/0x85 + kunit_generic_run_threadfn_adapter+0x16/0x30 + kthread+0x137/0x160 + ret_from_fork+0x22/0x30 + + CPU: 4 PID: 109 Comm: kunit_try_catch Tainted: G W 5.8.0-rc6+ #7 + Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1 04/01/2014 + ================================================================== + +KFENCE also reports on invalid frees, such as double-frees:: + + ================================================================== + BUG: KFENCE: invalid free in test_double_free+0xdc/0x171 + + Invalid free of 0xffffffffb6741000: + test_double_free+0xdc/0x171 + kunit_try_run_case+0x51/0x85 + kunit_generic_run_threadfn_adapter+0x16/0x30 + kthread+0x137/0x160 + ret_from_fork+0x22/0x30 + + kfence-#26 [0xffffffffb6741000-0xffffffffb674101f, size=32, cache=kmalloc-32] allocated by task 507: + test_alloc+0xf3/0x25b + test_double_free+0x76/0x171 + kunit_try_run_case+0x51/0x85 + kunit_generic_run_threadfn_adapter+0x16/0x30 + kthread+0x137/0x160 + ret_from_fork+0x22/0x30 + + freed by task 507: + test_double_free+0xa8/0x171 + kunit_try_run_case+0x51/0x85 + kunit_generic_run_threadfn_adapter+0x16/0x30 + kthread+0x137/0x160 + ret_from_fork+0x22/0x30 + + CPU: 4 PID: 111 Comm: kunit_try_catch Tainted: G W 5.8.0-rc6+ #7 + Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1 04/01/2014 + ================================================================== + +KFENCE also uses pattern-based redzones on the other side of an object's guard +page, to detect out-of-bounds writes on the unprotected side of the object. +These are reported on frees:: + + ================================================================== + BUG: KFENCE: memory corruption in test_kmalloc_aligned_oob_write+0xef/0x184 + + Corrupted memory at 0xffffffffb6797ff9 [ 0xac . . . . . . ] (in kfence-#69): + test_kmalloc_aligned_oob_write+0xef/0x184 + kunit_try_run_case+0x51/0x85 + kunit_generic_run_threadfn_adapter+0x16/0x30 + kthread+0x137/0x160 + ret_from_fork+0x22/0x30 + + kfence-#69 [0xffffffffb6797fb0-0xffffffffb6797ff8, size=73, cache=kmalloc-96] allocated by task 507: + test_alloc+0xf3/0x25b + test_kmalloc_aligned_oob_write+0x57/0x184 + kunit_try_run_case+0x51/0x85 + kunit_generic_run_threadfn_adapter+0x16/0x30 + kthread+0x137/0x160 + ret_from_fork+0x22/0x30 + + CPU: 4 PID: 120 Comm: kunit_try_catch Tainted: G W 5.8.0-rc6+ #7 + Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1 04/01/2014 + ================================================================== + +For such errors, the address where the corruption occurred as well as the +invalidly written bytes (offset from the address) are shown; in this +representation, '.' denote untouched bytes. In the example above ``0xac`` is +the value written to the invalid address at offset 0, and the remaining '.' +denote that no following bytes have been touched. Note that, real values are +only shown for ``CONFIG_DEBUG_KERNEL=y`` builds; to avoid information +disclosure for non-debug builds, '!' is used instead to denote invalidly +written bytes. + +And finally, KFENCE may also report on invalid accesses to any protected page +where it was not possible to determine an associated object, e.g. if adjacent +object pages had not yet been allocated:: + + ================================================================== + BUG: KFENCE: invalid access in test_invalid_access+0x26/0xe0 + + Invalid access at 0xffffffffb670b00a: + test_invalid_access+0x26/0xe0 + kunit_try_run_case+0x51/0x85 + kunit_generic_run_threadfn_adapter+0x16/0x30 + kthread+0x137/0x160 + ret_from_fork+0x22/0x30 + + CPU: 4 PID: 124 Comm: kunit_try_catch Tainted: G W 5.8.0-rc6+ #7 + Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1 04/01/2014 + ================================================================== + +DebugFS interface +~~~~~~~~~~~~~~~~~ + +Some debugging information is exposed via debugfs: + +* The file ``/sys/kernel/debug/kfence/stats`` provides runtime statistics. + +* The file ``/sys/kernel/debug/kfence/objects`` provides a list of objects + allocated via KFENCE, including those already freed but protected. + +Implementation Details +---------------------- + +Guarded allocations are set up based on the sample interval. After expiration +of the sample interval, the next allocation through the main allocator (SLAB or +SLUB) returns a guarded allocation from the KFENCE object pool (allocation +sizes up to PAGE_SIZE are supported). At this point, the timer is reset, and +the next allocation is set up after the expiration of the interval. To "gate" a +KFENCE allocation through the main allocator's fast-path without overhead, +KFENCE relies on static branches via the static keys infrastructure. The static +branch is toggled to redirect the allocation to KFENCE. + +KFENCE objects each reside on a dedicated page, at either the left or right +page boundaries selected at random. The pages to the left and right of the +object page are "guard pages", whose attributes are changed to a protected +state, and cause page faults on any attempted access. Such page faults are then +intercepted by KFENCE, which handles the fault gracefully by reporting an +out-of-bounds access, and marking the page as accessible so that the faulting +code can (wrongly) continue executing (set ``panic_on_warn`` to panic instead). + +To detect out-of-bounds writes to memory within the object's page itself, +KFENCE also uses pattern-based redzones. For each object page, a redzone is set +up for all non-object memory. For typical alignments, the redzone is only +required on the unguarded side of an object. Because KFENCE must honor the +cache's requested alignment, special alignments may result in unprotected gaps +on either side of an object, all of which are redzoned. + +The following figure illustrates the page layout:: + + ---+-----------+-----------+-----------+-----------+-----------+--- + | xxxxxxxxx | O : | xxxxxxxxx | : O | xxxxxxxxx | + | xxxxxxxxx | B : | xxxxxxxxx | : B | xxxxxxxxx | + | x GUARD x | J : RED- | x GUARD x | RED- : J | x GUARD x | + | xxxxxxxxx | E : ZONE | xxxxxxxxx | ZONE : E | xxxxxxxxx | + | xxxxxxxxx | C : | xxxxxxxxx | : C | xxxxxxxxx | + | xxxxxxxxx | T : | xxxxxxxxx | : T | xxxxxxxxx | + ---+-----------+-----------+-----------+-----------+-----------+--- + +Upon deallocation of a KFENCE object, the object's page is again protected and +the object is marked as freed. Any further access to the object causes a fault +and KFENCE reports a use-after-free access. Freed objects are inserted at the +tail of KFENCE's freelist, so that the least recently freed objects are reused +first, and the chances of detecting use-after-frees of recently freed objects +is increased. + +Interface +--------- + +The following describes the functions which are used by allocators as well as +page handling code to set up and deal with KFENCE allocations. + +.. kernel-doc:: include/linux/kfence.h + :functions: is_kfence_address + kfence_shutdown_cache + kfence_alloc kfence_free __kfence_free + kfence_ksize kfence_object_start + kfence_handle_page_fault + +Related Tools +------------- + +In userspace, a similar approach is taken by `GWP-ASan +<http://llvm.org/docs/GwpAsan.html>`_. GWP-ASan also relies on guard pages and +a sampling strategy to detect memory unsafety bugs at scale. KFENCE's design is +directly influenced by GWP-ASan, and can be seen as its kernel sibling. Another +similar but non-sampling approach, that also inspired the name "KFENCE", can be +found in the userspace `Electric Fence Malloc Debugger +<https://linux.die.net/man/3/efence>`_. + +In the kernel, several tools exist to debug memory access errors, and in +particular KASAN can detect all bug classes that KFENCE can detect. While KASAN +is more precise, relying on compiler instrumentation, this comes at a +performance cost. + +It is worth highlighting that KASAN and KFENCE are complementary, with +different target environments. For instance, KASAN is the better debugging-aid, +where test cases or reproducers exists: due to the lower chance to detect the +error, it would require more effort using KFENCE to debug. Deployments at scale +that cannot afford to enable KASAN, however, would benefit from using KFENCE to +discover bugs due to code paths not exercised by test cases or fuzzers. diff --git a/lib/Kconfig.kfence b/lib/Kconfig.kfence index edfecb5d6165..605125ac2ae0 100644 --- a/lib/Kconfig.kfence +++ b/lib/Kconfig.kfence @@ -13,6 +13,8 @@ menuconfig KFENCE to have negligible cost to permit enabling it in production environments. + See <file:Documentation/dev-tools/kfence.rst> for more details. + Note that, KFENCE is not a substitute for explicit testing with tools such as KASAN. KFENCE can detect a subset of bugs that KASAN can detect, albeit at very different performance profiles. If you can -- 2.25.1

1 0

[PATCH 7/9] kfence, kasan: make KFENCE compatible with KASAN
by 1415317271＠qq.com 18 Aug '21

18 Aug '21

From: Alexander Potapenko <glider(a)google.com> Make KFENCE compatible with KASAN. Currently this helps test KFENCE itself, where KASAN can catch potential corruptions to KFENCE state, or other corruptions that may be a result of freepointer corruptions in the main allocators. [akpm(a)linux-foundation.org: merge fixup] [andreyknvl(a)google.com: untag addresses for KFENCE] Link: https://lkml.kernel.org/r/9dc196006921b191d25d10f6e611316db7da2efc.16119461… Link: https://lkml.kernel.org/r/20201103175841.3495947-7-elver@google.com Signed-off-by: Marco Elver <elver(a)google.com> Signed-off-by: Alexander Potapenko <glider(a)google.com> Signed-off-by: Andrey Konovalov <andreyknvl(a)google.com> Reviewed-by: Dmitry Vyukov <dvyukov(a)google.com> Reviewed-by: Jann Horn <jannh(a)google.com> Co-developed-by: Marco Elver <elver(a)google.com> Cc: Andrey Konovalov <andreyknvl(a)google.com> Cc: Andrey Ryabinin <aryabinin(a)virtuozzo.com> Cc: Andy Lutomirski <luto(a)kernel.org> Cc: Borislav Petkov <bp(a)alien8.de> Cc: Catalin Marinas <catalin.marinas(a)arm.com> Cc: Christopher Lameter <cl(a)linux.com> Cc: Dave Hansen <dave.hansen(a)linux.intel.com> Cc: David Rientjes <rientjes(a)google.com> Cc: Eric Dumazet <edumazet(a)google.com> Cc: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Cc: Hillf Danton <hdanton(a)sina.com> Cc: "H. Peter Anvin" <hpa(a)zytor.com> Cc: Ingo Molnar <mingo(a)redhat.com> Cc: Joern Engel <joern(a)purestorage.com> Cc: Jonathan Corbet <corbet(a)lwn.net> Cc: Joonsoo Kim <iamjoonsoo.kim(a)lge.com> Cc: Kees Cook <keescook(a)chromium.org> Cc: Mark Rutland <mark.rutland(a)arm.com> Cc: Paul E. McKenney <paulmck(a)kernel.org> Cc: Pekka Enberg <penberg(a)kernel.org> Cc: Peter Zijlstra <peterz(a)infradead.org> Cc: SeongJae Park <sjpark(a)amazon.de> Cc: Thomas Gleixner <tglx(a)linutronix.de> Cc: Vlastimil Babka <vbabka(a)suse.cz> Cc: Will Deacon <will(a)kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds(a)linux-foundation.org> Signed-off-by: Yingjie Shang <1415317271(a)qq.com> Reviewed-by: Bixuan Cui <cuibixuan(a)huawei.com> --- lib/Kconfig.kfence | 2 +- mm/kasan/common.c | 6 ++++++ mm/kasan/generic.c | 3 ++- 3 files changed, 9 insertions(+), 2 deletions(-) diff --git a/lib/Kconfig.kfence b/lib/Kconfig.kfence index b88ac9d6b2e6..edfecb5d6165 100644 --- a/lib/Kconfig.kfence +++ b/lib/Kconfig.kfence @@ -5,7 +5,7 @@ config HAVE_ARCH_KFENCE menuconfig KFENCE bool "KFENCE: low-overhead sampling-based memory safety error detector" - depends on HAVE_ARCH_KFENCE && !KASAN && (SLAB || SLUB) + depends on HAVE_ARCH_KFENCE && (SLAB || SLUB) select STACKTRACE help KFENCE is a low-overhead sampling-based detector of heap out-of-bounds diff --git a/mm/kasan/common.c b/mm/kasan/common.c index 950fd372a07e..d9a25af29354 100644 --- a/mm/kasan/common.c +++ b/mm/kasan/common.c @@ -396,6 +396,9 @@ static bool __kasan_slab_free(struct kmem_cache *cache, void *object, tagged_object = object; object = reset_tag(object); + if (is_kfence_address(object)) + return false; + if (unlikely(nearest_obj(cache, virt_to_head_page(object), object) != object)) { kasan_report_invalid_free(tagged_object, ip); @@ -444,6 +447,9 @@ static void *__kasan_kmalloc(struct kmem_cache *cache, const void *object, if (unlikely(object == NULL)) return NULL; + if (is_kfence_address(kasan_reset_tag(object))) + return (void *)object; + redzone_start = round_up((unsigned long)(object + size), KASAN_SHADOW_SCALE_SIZE); redzone_end = round_up((unsigned long)object + cache->object_size, diff --git a/mm/kasan/generic.c b/mm/kasan/generic.c index 2efc48444e77..c4c56ec8a472 100644 --- a/mm/kasan/generic.c +++ b/mm/kasan/generic.c @@ -21,6 +21,7 @@ #include <linux/init.h> #include <linux/kasan.h> #include <linux/kernel.h> +#include <linux/kfence.h> #include <linux/kmemleak.h> #include <linux/linkage.h> #include <linux/memblock.h> @@ -332,7 +333,7 @@ void kasan_record_aux_stack(void *addr) struct kasan_alloc_meta *alloc_info; void *object; - if (!(page && PageSlab(page))) + if (is_kfence_address(addr) || !(page && PageSlab(page))) return; cache = page->slab_cache; -- 2.25.1

1 0

[PATCH 6/9] mm, kfence: insert KFENCE hooks for SLUB
by 1415317271＠qq.com 18 Aug '21

18 Aug '21

From: Alexander Potapenko <glider(a)google.com> Inserts KFENCE hooks into the SLUB allocator. To pass the originally requested size to KFENCE, add an argument 'orig_size' to slab_alloc*(). The additional argument is required to preserve the requested original size for kmalloc() allocations, which uses size classes (e.g. an allocation of 272 bytes will return an object of size 512). Therefore, kmem_cache::size does not represent the kmalloc-caller's requested size, and we must introduce the argument 'orig_size' to propagate the originally requested size to KFENCE. Without the originally requested size, we would not be able to detect out-of-bounds accesses for objects placed at the end of a KFENCE object page if that object is not equal to the kmalloc-size class it was bucketed into. When KFENCE is disabled, there is no additional overhead, since slab_alloc*() functions are __always_inline. Link: https://lkml.kernel.org/r/20201103175841.3495947-6-elver@google.com Signed-off-by: Marco Elver <elver(a)google.com> Signed-off-by: Alexander Potapenko <glider(a)google.com> Reviewed-by: Dmitry Vyukov <dvyukov(a)google.com> Reviewed-by: Jann Horn <jannh(a)google.com> Co-developed-by: Marco Elver <elver(a)google.com> Cc: Andrey Konovalov <andreyknvl(a)google.com> Cc: Andrey Ryabinin <aryabinin(a)virtuozzo.com> Cc: Andy Lutomirski <luto(a)kernel.org> Cc: Borislav Petkov <bp(a)alien8.de> Cc: Catalin Marinas <catalin.marinas(a)arm.com> Cc: Christopher Lameter <cl(a)linux.com> Cc: Dave Hansen <dave.hansen(a)linux.intel.com> Cc: David Rientjes <rientjes(a)google.com> Cc: Eric Dumazet <edumazet(a)google.com> Cc: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Cc: Hillf Danton <hdanton(a)sina.com> Cc: "H. Peter Anvin" <hpa(a)zytor.com> Cc: Ingo Molnar <mingo(a)redhat.com> Cc: Joern Engel <joern(a)purestorage.com> Cc: Jonathan Corbet <corbet(a)lwn.net> Cc: Joonsoo Kim <iamjoonsoo.kim(a)lge.com> Cc: Kees Cook <keescook(a)chromium.org> Cc: Mark Rutland <mark.rutland(a)arm.com> Cc: Paul E. McKenney <paulmck(a)kernel.org> Cc: Pekka Enberg <penberg(a)kernel.org> Cc: Peter Zijlstra <peterz(a)infradead.org> Cc: SeongJae Park <sjpark(a)amazon.de> Cc: Thomas Gleixner <tglx(a)linutronix.de> Cc: Vlastimil Babka <vbabka(a)suse.cz> Cc: Will Deacon <will(a)kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds(a)linux-foundation.org> Signed-off-by: Yingjie Shang <1415317271(a)qq.com> Reviewed-by: Bixuan Cui <cuibixuan(a)huawei.com> --- include/linux/slub_def.h | 3 ++ mm/kfence/core.c | 2 ++ mm/slub.c | 61 ++++++++++++++++++++++++++++++---------- 3 files changed, 51 insertions(+), 15 deletions(-) diff --git a/include/linux/slub_def.h b/include/linux/slub_def.h index 1be0ed5befa1..dcde82a4434c 100644 --- a/include/linux/slub_def.h +++ b/include/linux/slub_def.h @@ -7,6 +7,7 @@ * * (C) 2007 SGI, Christoph Lameter */ +#include <linux/kfence.h> #include <linux/kobject.h> #include <linux/reciprocal_div.h> @@ -185,6 +186,8 @@ static inline unsigned int __obj_to_index(const struct kmem_cache *cache, static inline unsigned int obj_to_index(const struct kmem_cache *cache, const struct page *page, void *obj) { + if (is_kfence_address(obj)) + return 0; return __obj_to_index(cache, page_address(page), obj); } diff --git a/mm/kfence/core.c b/mm/kfence/core.c index 05c18aa11851..7692af715fdb 100644 --- a/mm/kfence/core.c +++ b/mm/kfence/core.c @@ -317,6 +317,8 @@ static void *kfence_guarded_alloc(struct kmem_cache *cache, size_t size, gfp_t g /* Set required struct page fields. */ page = virt_to_page(meta->addr); page->slab_cache = cache; + if (IS_ENABLED(CONFIG_SLUB)) + page->objects = 1; if (IS_ENABLED(CONFIG_SLAB)) page->s_mem = addr; diff --git a/mm/slub.c b/mm/slub.c index f06f002bb098..678c29105d7f 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -28,6 +28,7 @@ #include <linux/ctype.h> #include <linux/debugobjects.h> #include <linux/kallsyms.h> +#include <linux/kfence.h> #include <linux/memory.h> #include <linux/math64.h> #include <linux/fault-inject.h> @@ -1560,6 +1561,11 @@ static inline bool slab_free_freelist_hook(struct kmem_cache *s, void *old_tail = *tail ? *tail : *head; int rsize; + if (is_kfence_address(next)) { + slab_free_hook(s, next); + return true; + } + /* Head and tail of the reconstructed freelist */ *head = NULL; *tail = NULL; @@ -2801,7 +2807,7 @@ static __always_inline void maybe_wipe_obj_freeptr(struct kmem_cache *s, * Otherwise we can simply pick the next object from the lockless free list. */ static __always_inline void *slab_alloc_node(struct kmem_cache *s, - gfp_t gfpflags, int node, unsigned long addr) + gfp_t gfpflags, int node, unsigned long addr, size_t orig_size) { void *object; struct kmem_cache_cpu *c; @@ -2812,6 +2818,11 @@ static __always_inline void *slab_alloc_node(struct kmem_cache *s, s = slab_pre_alloc_hook(s, &objcg, 1, gfpflags); if (!s) return NULL; + + object = kfence_alloc(s, orig_size, gfpflags); + if (unlikely(object)) + goto out; + redo: /* * Must read kmem_cache cpu data via this cpu ptr. Preemption is @@ -2883,21 +2894,21 @@ static __always_inline void *slab_alloc_node(struct kmem_cache *s, if (unlikely(slab_want_init_on_alloc(gfpflags, s)) && object) memset(object, 0, s->object_size); - +out: slab_post_alloc_hook(s, objcg, gfpflags, 1, &object); return object; } static __always_inline void *slab_alloc(struct kmem_cache *s, - gfp_t gfpflags, unsigned long addr) + gfp_t gfpflags, unsigned long addr, size_t orig_size) { - return slab_alloc_node(s, gfpflags, NUMA_NO_NODE, addr); + return slab_alloc_node(s, gfpflags, NUMA_NO_NODE, addr, orig_size); } void *kmem_cache_alloc(struct kmem_cache *s, gfp_t gfpflags) { - void *ret = slab_alloc(s, gfpflags, _RET_IP_); + void *ret = slab_alloc(s, gfpflags, _RET_IP_, s->object_size); trace_kmem_cache_alloc(_RET_IP_, ret, s->object_size, s->size, gfpflags); @@ -2909,7 +2920,7 @@ EXPORT_SYMBOL(kmem_cache_alloc); #ifdef CONFIG_TRACING void *kmem_cache_alloc_trace(struct kmem_cache *s, gfp_t gfpflags, size_t size) { - void *ret = slab_alloc(s, gfpflags, _RET_IP_); + void *ret = slab_alloc(s, gfpflags, _RET_IP_, size); trace_kmalloc(_RET_IP_, ret, size, s->size, gfpflags); ret = kasan_kmalloc(s, ret, size, gfpflags); return ret; @@ -2920,7 +2931,7 @@ EXPORT_SYMBOL(kmem_cache_alloc_trace); #ifdef CONFIG_NUMA void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t gfpflags, int node) { - void *ret = slab_alloc_node(s, gfpflags, node, _RET_IP_); + void *ret = slab_alloc_node(s, gfpflags, node, _RET_IP_, s->object_size); trace_kmem_cache_alloc_node(_RET_IP_, ret, s->object_size, s->size, gfpflags, node); @@ -2934,7 +2945,7 @@ void *kmem_cache_alloc_node_trace(struct kmem_cache *s, gfp_t gfpflags, int node, size_t size) { - void *ret = slab_alloc_node(s, gfpflags, node, _RET_IP_); + void *ret = slab_alloc_node(s, gfpflags, node, _RET_IP_, size); trace_kmalloc_node(_RET_IP_, ret, size, s->size, gfpflags, node); @@ -2968,6 +2979,9 @@ static void __slab_free(struct kmem_cache *s, struct page *page, stat(s, FREE_SLOWPATH); + if (kfence_free(head)) + return; + if (kmem_cache_debug(s) && !free_debug_processing(s, page, head, tail, cnt, addr)) return; @@ -3212,6 +3226,13 @@ int build_detached_freelist(struct kmem_cache *s, size_t size, df->s = cache_from_obj(s, object); /* Support for memcg */ } + if (is_kfence_address(object)) { + slab_free_hook(df->s, object); + __kfence_free(object); + p[size] = NULL; /* mark object processed */ + return size; + } + /* Start new detached freelist */ df->page = page; set_freepointer(df->s, object, NULL); @@ -3287,8 +3308,14 @@ int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size, c = this_cpu_ptr(s->cpu_slab); for (i = 0; i < size; i++) { - void *object = c->freelist; + void *object = kfence_alloc(s, s->object_size, flags); + if (unlikely(object)) { + p[i] = object; + continue; + } + + object = c->freelist; if (unlikely(!object)) { /* * We may have removed an object from c->freelist using @@ -3953,7 +3980,7 @@ void *__kmalloc(size_t size, gfp_t flags) if (unlikely(ZERO_OR_NULL_PTR(s))) return s; - ret = slab_alloc(s, flags, _RET_IP_); + ret = slab_alloc(s, flags, _RET_IP_, size); trace_kmalloc(_RET_IP_, ret, size, s->size, flags); @@ -4001,7 +4028,7 @@ void *__kmalloc_node(size_t size, gfp_t flags, int node) if (unlikely(ZERO_OR_NULL_PTR(s))) return s; - ret = slab_alloc_node(s, flags, node, _RET_IP_); + ret = slab_alloc_node(s, flags, node, _RET_IP_, size); trace_kmalloc_node(_RET_IP_, ret, size, s->size, flags, node); @@ -4027,6 +4054,7 @@ void __check_heap_object(const void *ptr, unsigned long n, struct page *page, struct kmem_cache *s; unsigned int offset; size_t object_size; + bool is_kfence = is_kfence_address(ptr); ptr = kasan_reset_tag(ptr); @@ -4039,10 +4067,13 @@ void __check_heap_object(const void *ptr, unsigned long n, struct page *page, to_user, 0, n); /* Find offset within object. */ - offset = (ptr - page_address(page)) % s->size; + if (is_kfence) + offset = ptr - kfence_object_start(ptr); + else + offset = (ptr - page_address(page)) % s->size; /* Adjust for redzone and reject if within the redzone. */ - if (kmem_cache_debug_flags(s, SLAB_RED_ZONE)) { + if (!is_kfence && kmem_cache_debug_flags(s, SLAB_RED_ZONE)) { if (offset < s->red_left_pad) usercopy_abort("SLUB object in left red zone", s->name, to_user, offset, n); @@ -4459,7 +4490,7 @@ void *__kmalloc_track_caller(size_t size, gfp_t gfpflags, unsigned long caller) if (unlikely(ZERO_OR_NULL_PTR(s))) return s; - ret = slab_alloc(s, gfpflags, caller); + ret = slab_alloc(s, gfpflags, caller, size); /* Honor the call site pointer we received. */ trace_kmalloc(caller, ret, size, s->size, gfpflags); @@ -4490,7 +4521,7 @@ void *__kmalloc_node_track_caller(size_t size, gfp_t gfpflags, if (unlikely(ZERO_OR_NULL_PTR(s))) return s; - ret = slab_alloc_node(s, gfpflags, node, caller); + ret = slab_alloc_node(s, gfpflags, node, caller, size); /* Honor the call site pointer we received. */ trace_kmalloc_node(caller, ret, size, s->size, gfpflags, node); -- 2.25.1

1 0

[PATCH 5/9] mm, kfence: insert KFENCE hooks for SLAB
by 1415317271＠qq.com 18 Aug '21

18 Aug '21

From: Alexander Potapenko <glider(a)google.com> Inserts KFENCE hooks into the SLAB allocator. To pass the originally requested size to KFENCE, add an argument 'orig_size' to slab_alloc*(). The additional argument is required to preserve the requested original size for kmalloc() allocations, which uses size classes (e.g. an allocation of 272 bytes will return an object of size 512). Therefore, kmem_cache::size does not represent the kmalloc-caller's requested size, and we must introduce the argument 'orig_size' to propagate the originally requested size to KFENCE. Without the originally requested size, we would not be able to detect out-of-bounds accesses for objects placed at the end of a KFENCE object page if that object is not equal to the kmalloc-size class it was bucketed into. When KFENCE is disabled, there is no additional overhead, since slab_alloc*() functions are __always_inline. Link: https://lkml.kernel.org/r/20201103175841.3495947-5-elver@google.com Signed-off-by: Marco Elver <elver(a)google.com> Signed-off-by: Alexander Potapenko <glider(a)google.com> Reviewed-by: Dmitry Vyukov <dvyukov(a)google.com> Co-developed-by: Marco Elver <elver(a)google.com> Cc: Christoph Lameter <cl(a)linux.com> Cc: Pekka Enberg <penberg(a)kernel.org> Cc: David Rientjes <rientjes(a)google.com> Cc: Joonsoo Kim <iamjoonsoo.kim(a)lge.com> Cc: Andrey Konovalov <andreyknvl(a)google.com> Cc: Andrey Ryabinin <aryabinin(a)virtuozzo.com> Cc: Andy Lutomirski <luto(a)kernel.org> Cc: Borislav Petkov <bp(a)alien8.de> Cc: Catalin Marinas <catalin.marinas(a)arm.com> Cc: Dave Hansen <dave.hansen(a)linux.intel.com> Cc: Eric Dumazet <edumazet(a)google.com> Cc: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Cc: Hillf Danton <hdanton(a)sina.com> Cc: "H. Peter Anvin" <hpa(a)zytor.com> Cc: Ingo Molnar <mingo(a)redhat.com> Cc: Jann Horn <jannh(a)google.com> Cc: Joern Engel <joern(a)purestorage.com> Cc: Jonathan Corbet <corbet(a)lwn.net> Cc: Kees Cook <keescook(a)chromium.org> Cc: Mark Rutland <mark.rutland(a)arm.com> Cc: Paul E. McKenney <paulmck(a)kernel.org> Cc: Peter Zijlstra <peterz(a)infradead.org> Cc: SeongJae Park <sjpark(a)amazon.de> Cc: Thomas Gleixner <tglx(a)linutronix.de> Cc: Vlastimil Babka <vbabka(a)suse.cz> Cc: Will Deacon <will(a)kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds(a)linux-foundation.org> Signed-off-by: Yingjie Shang <1415317271(a)qq.com> Reviewed-by: Bixuan Cui <cuibixuan(a)huawei.com> --- include/linux/slab_def.h | 3 +++ mm/kfence/core.c | 2 ++ mm/slab.c | 38 +++++++++++++++++++++++++++++--------- mm/slab_common.c | 5 ++++- 4 files changed, 38 insertions(+), 10 deletions(-) diff --git a/include/linux/slab_def.h b/include/linux/slab_def.h index 9eb430c163c2..3aa5e1e73ab6 100644 --- a/include/linux/slab_def.h +++ b/include/linux/slab_def.h @@ -2,6 +2,7 @@ #ifndef _LINUX_SLAB_DEF_H #define _LINUX_SLAB_DEF_H +#include <linux/kfence.h> #include <linux/reciprocal_div.h> /* @@ -114,6 +115,8 @@ static inline unsigned int obj_to_index(const struct kmem_cache *cache, static inline int objs_per_slab_page(const struct kmem_cache *cache, const struct page *page) { + if (is_kfence_address(page_address(page))) + return 1; return cache->num; } diff --git a/mm/kfence/core.c b/mm/kfence/core.c index 61c76670a7a9..05c18aa11851 100644 --- a/mm/kfence/core.c +++ b/mm/kfence/core.c @@ -317,6 +317,8 @@ static void *kfence_guarded_alloc(struct kmem_cache *cache, size_t size, gfp_t g /* Set required struct page fields. */ page = virt_to_page(meta->addr); page->slab_cache = cache; + if (IS_ENABLED(CONFIG_SLAB)) + page->s_mem = addr; raw_spin_unlock_irqrestore(&meta->lock, flags); diff --git a/mm/slab.c b/mm/slab.c index b2cc2cf7d8a3..4b526a0434f5 100644 --- a/mm/slab.c +++ b/mm/slab.c @@ -100,6 +100,7 @@ #include <linux/seq_file.h> #include <linux/notifier.h> #include <linux/kallsyms.h> +#include <linux/kfence.h> #include <linux/cpu.h> #include <linux/sysctl.h> #include <linux/module.h> @@ -3207,7 +3208,7 @@ static void *____cache_alloc_node(struct kmem_cache *cachep, gfp_t flags, } static __always_inline void * -slab_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid, +slab_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid, size_t orig_size, unsigned long caller) { unsigned long save_flags; @@ -3220,6 +3221,10 @@ slab_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid, if (unlikely(!cachep)) return NULL; + ptr = kfence_alloc(cachep, orig_size, flags); + if (unlikely(ptr)) + goto out_hooks; + cache_alloc_debugcheck_before(cachep, flags); local_irq_save(save_flags); @@ -3252,6 +3257,7 @@ slab_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid, if (unlikely(slab_want_init_on_alloc(flags, cachep)) && ptr) memset(ptr, 0, cachep->object_size); +out_hooks: slab_post_alloc_hook(cachep, objcg, flags, 1, &ptr); return ptr; } @@ -3289,7 +3295,7 @@ __do_cache_alloc(struct kmem_cache *cachep, gfp_t flags) #endif /* CONFIG_NUMA */ static __always_inline void * -slab_alloc(struct kmem_cache *cachep, gfp_t flags, unsigned long caller) +slab_alloc(struct kmem_cache *cachep, gfp_t flags, size_t orig_size, unsigned long caller) { unsigned long save_flags; void *objp; @@ -3300,6 +3306,10 @@ slab_alloc(struct kmem_cache *cachep, gfp_t flags, unsigned long caller) if (unlikely(!cachep)) return NULL; + objp = kfence_alloc(cachep, orig_size, flags); + if (unlikely(objp)) + goto out; + cache_alloc_debugcheck_before(cachep, flags); local_irq_save(save_flags); objp = __do_cache_alloc(cachep, flags); @@ -3310,6 +3320,7 @@ slab_alloc(struct kmem_cache *cachep, gfp_t flags, unsigned long caller) if (unlikely(slab_want_init_on_alloc(flags, cachep)) && objp) memset(objp, 0, cachep->object_size); +out: slab_post_alloc_hook(cachep, objcg, flags, 1, &objp); return objp; } @@ -3415,6 +3426,12 @@ static void cache_flusharray(struct kmem_cache *cachep, struct array_cache *ac) static __always_inline void __cache_free(struct kmem_cache *cachep, void *objp, unsigned long caller) { + if (is_kfence_address(objp)) { + kmemleak_free_recursive(objp, cachep->flags); + __kfence_free(objp); + return; + } + /* Put the object into the quarantine, don't touch it for now. */ if (kasan_slab_free(cachep, objp, _RET_IP_)) return; @@ -3480,7 +3497,7 @@ void ___cache_free(struct kmem_cache *cachep, void *objp, */ void *kmem_cache_alloc(struct kmem_cache *cachep, gfp_t flags) { - void *ret = slab_alloc(cachep, flags, _RET_IP_); + void *ret = slab_alloc(cachep, flags, cachep->object_size, _RET_IP_); trace_kmem_cache_alloc(_RET_IP_, ret, cachep->object_size, cachep->size, flags); @@ -3513,7 +3530,7 @@ int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size, local_irq_disable(); for (i = 0; i < size; i++) { - void *objp = __do_cache_alloc(s, flags); + void *objp = kfence_alloc(s, s->object_size, flags) ?: __do_cache_alloc(s, flags); if (unlikely(!objp)) goto error; @@ -3546,7 +3563,7 @@ kmem_cache_alloc_trace(struct kmem_cache *cachep, gfp_t flags, size_t size) { void *ret; - ret = slab_alloc(cachep, flags, _RET_IP_); + ret = slab_alloc(cachep, flags, size, _RET_IP_); ret = kasan_kmalloc(cachep, ret, size, flags); trace_kmalloc(_RET_IP_, ret, @@ -3572,7 +3589,7 @@ EXPORT_SYMBOL(kmem_cache_alloc_trace); */ void *kmem_cache_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid) { - void *ret = slab_alloc_node(cachep, flags, nodeid, _RET_IP_); + void *ret = slab_alloc_node(cachep, flags, nodeid, cachep->object_size, _RET_IP_); trace_kmem_cache_alloc_node(_RET_IP_, ret, cachep->object_size, cachep->size, @@ -3590,7 +3607,7 @@ void *kmem_cache_alloc_node_trace(struct kmem_cache *cachep, { void *ret; - ret = slab_alloc_node(cachep, flags, nodeid, _RET_IP_); + ret = slab_alloc_node(cachep, flags, nodeid, size, _RET_IP_); ret = kasan_kmalloc(cachep, ret, size, flags); trace_kmalloc_node(_RET_IP_, ret, @@ -3651,7 +3668,7 @@ static __always_inline void *__do_kmalloc(size_t size, gfp_t flags, cachep = kmalloc_slab(size, flags); if (unlikely(ZERO_OR_NULL_PTR(cachep))) return cachep; - ret = slab_alloc(cachep, flags, caller); + ret = slab_alloc(cachep, flags, size, caller); ret = kasan_kmalloc(cachep, ret, size, flags); trace_kmalloc(caller, ret, @@ -4150,7 +4167,10 @@ void __check_heap_object(const void *ptr, unsigned long n, struct page *page, BUG_ON(objnr >= cachep->num); /* Find offset within object. */ - offset = ptr - index_to_obj(cachep, page, objnr) - obj_offset(cachep); + if (is_kfence_address(ptr)) + offset = ptr - kfence_object_start(ptr); + else + offset = ptr - index_to_obj(cachep, page, objnr) - obj_offset(cachep); /* Allow address range falling entirely within usercopy region. */ if (offset >= cachep->useroffset && diff --git a/mm/slab_common.c b/mm/slab_common.c index 79ae785f2c9f..89022933dfa6 100644 --- a/mm/slab_common.c +++ b/mm/slab_common.c @@ -12,6 +12,7 @@ #include <linux/memory.h> #include <linux/cache.h> #include <linux/compiler.h> +#include <linux/kfence.h> #include <linux/module.h> #include <linux/cpu.h> #include <linux/uaccess.h> @@ -428,6 +429,7 @@ static void slab_caches_to_rcu_destroy_workfn(struct work_struct *work) rcu_barrier(); list_for_each_entry_safe(s, s2, &to_destroy, list) { + kfence_shutdown_cache(s); #ifdef SLAB_SUPPORTS_SYSFS sysfs_slab_release(s); #else @@ -453,6 +455,7 @@ static int shutdown_cache(struct kmem_cache *s) list_add_tail(&s->list, &slab_caches_to_rcu_destroy); schedule_work(&slab_caches_to_rcu_destroy_work); } else { + kfence_shutdown_cache(s); #ifdef SLAB_SUPPORTS_SYSFS sysfs_slab_unlink(s); sysfs_slab_release(s); @@ -1156,7 +1159,7 @@ size_t ksize(const void *objp) if (unlikely(ZERO_OR_NULL_PTR(objp)) || !__kasan_check_read(objp, 1)) return 0; - size = __ksize(objp); + size = kfence_ksize(objp) ?: __ksize(objp); /* * We assume that ksize callers could use whole allocated area, * so we need to unpoison this area. -- 2.25.1

1 0

[PATCH 4/9] kfence: use pt_regs to generate stack trace on faults
by 1415317271＠qq.com 18 Aug '21

18 Aug '21

From: Marco Elver <elver(a)google.com> Instead of removing the fault handling portion of the stack trace based on the fault handler's name, just use struct pt_regs directly. Change kfence_handle_page_fault() to take a struct pt_regs, and plumb it through to kfence_report_error() for out-of-bounds, use-after-free, or invalid access errors, where pt_regs is used to generate the stack trace. If the kernel is a DEBUG_KERNEL, also show registers for more information. Link: https://lkml.kernel.org/r/20201105092133.2075331-1-elver@google.com Signed-off-by: Marco Elver <elver(a)google.com> Suggested-by: Mark Rutland <mark.rutland(a)arm.com> Acked-by: Mark Rutland <mark.rutland(a)arm.com> Cc: Alexander Potapenko <glider(a)google.com> Cc: Dmitry Vyukov <dvyukov(a)google.com> Cc: Jann Horn <jannh(a)google.com> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds(a)linux-foundation.org> Signed-off-by: Yingjie Shang <1415317271(a)qq.com> Reviewed-by: Bixuan Cui <cuibixuan(a)huawei.com> --- arch/arm64/include/asm/kfence.h | 2 -- arch/arm64/mm/fault.c | 2 +- arch/x86/include/asm/kfence.h | 6 ---- arch/x86/mm/fault.c | 2 +- include/linux/kfence.h | 5 +-- mm/kfence/core.c | 10 +++--- mm/kfence/kfence.h | 4 +-- mm/kfence/report.c | 63 +++++++++++++++++++-------------- 8 files changed, 48 insertions(+), 46 deletions(-) diff --git a/arch/arm64/include/asm/kfence.h b/arch/arm64/include/asm/kfence.h index 42a06f83850a..d061176d57ea 100644 --- a/arch/arm64/include/asm/kfence.h +++ b/arch/arm64/include/asm/kfence.h @@ -10,8 +10,6 @@ #include <asm/cacheflush.h> -#define KFENCE_SKIP_ARCH_FAULT_HANDLER "el1_sync" - static inline bool arch_kfence_init_pool(void) { return true; } static inline bool kfence_protect_page(unsigned long addr, bool protect) diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c index d1a8b523d28e..a5fe9f7b423b 100644 --- a/arch/arm64/mm/fault.c +++ b/arch/arm64/mm/fault.c @@ -323,7 +323,7 @@ static void __do_kernel_fault(unsigned long addr, unsigned int esr, } else if (addr < PAGE_SIZE) { msg = "NULL pointer dereference"; } else { - if (kfence_handle_page_fault(addr)) + if (kfence_handle_page_fault(addr, regs)) return; msg = "paging request"; diff --git a/arch/x86/include/asm/kfence.h b/arch/x86/include/asm/kfence.h index a0659dbd93ea..97bbb4a9083a 100644 --- a/arch/x86/include/asm/kfence.h +++ b/arch/x86/include/asm/kfence.h @@ -16,12 +16,6 @@ #include <asm/set_memory.h> #include <asm/tlbflush.h> -/* - * The page fault handler entry function, up to which the stack trace is - * truncated in reports. - */ -#define KFENCE_SKIP_ARCH_FAULT_HANDLER "asm_exc_page_fault" - /* Force 4K pages for __kfence_pool. */ static inline bool arch_kfence_init_pool(void) { diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index 35901aa6ad1c..f5f359ccaeae 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -734,7 +734,7 @@ no_context(struct pt_regs *regs, unsigned long error_code, efi_recover_from_page_fault(address); /* Only not-present faults should be handled by KFENCE. */ - if (!(error_code & X86_PF_PROT) && kfence_handle_page_fault(address)) + if (!(error_code & X86_PF_PROT) && kfence_handle_page_fault(address, regs)) return; oops: /* diff --git a/include/linux/kfence.h b/include/linux/kfence.h index 81f3911cb298..5a56bcf5606c 100644 --- a/include/linux/kfence.h +++ b/include/linux/kfence.h @@ -186,6 +186,7 @@ static __always_inline __must_check bool kfence_free(void *addr) /** * kfence_handle_page_fault() - perform page fault handling for KFENCE pages * @addr: faulting address + * @regs: current struct pt_regs (can be NULL, but shows full stack trace) * * Return: * * false - address outside KFENCE pool, @@ -196,7 +197,7 @@ static __always_inline __must_check bool kfence_free(void *addr) * cases KFENCE prints an error message and marks the offending page as * present, so that the kernel can proceed. */ -bool __must_check kfence_handle_page_fault(unsigned long addr); +bool __must_check kfence_handle_page_fault(unsigned long addr, struct pt_regs *regs); #else /* CONFIG_KFENCE */ @@ -209,7 +210,7 @@ static inline size_t kfence_ksize(const void *addr) { return 0; } static inline void *kfence_object_start(const void *addr) { return NULL; } static inline void __kfence_free(void *addr) { } static inline bool __must_check kfence_free(void *addr) { return false; } -static inline bool __must_check kfence_handle_page_fault(unsigned long addr) { return false; } +static inline bool __must_check kfence_handle_page_fault(unsigned long addr, struct pt_regs *regs) { return false; } #endif diff --git a/mm/kfence/core.c b/mm/kfence/core.c index d6a32c13336b..61c76670a7a9 100644 --- a/mm/kfence/core.c +++ b/mm/kfence/core.c @@ -216,7 +216,7 @@ static inline bool check_canary_byte(u8 *addr) return true; atomic_long_inc(&counters[KFENCE_COUNTER_BUGS]); - kfence_report_error((unsigned long)addr, addr_to_metadata((unsigned long)addr), + kfence_report_error((unsigned long)addr, NULL, addr_to_metadata((unsigned long)addr), KFENCE_ERROR_CORRUPTION); return false; } @@ -351,7 +351,7 @@ static void kfence_guarded_free(void *addr, struct kfence_metadata *meta, bool z if (meta->state != KFENCE_OBJECT_ALLOCATED || meta->addr != (unsigned long)addr) { /* Invalid or double-free, bail out. */ atomic_long_inc(&counters[KFENCE_COUNTER_BUGS]); - kfence_report_error((unsigned long)addr, meta, KFENCE_ERROR_INVALID_FREE); + kfence_report_error((unsigned long)addr, NULL, meta, KFENCE_ERROR_INVALID_FREE); raw_spin_unlock_irqrestore(&meta->lock, flags); return; } @@ -766,7 +766,7 @@ void __kfence_free(void *addr) kfence_guarded_free(addr, meta, false); } -bool kfence_handle_page_fault(unsigned long addr) +bool kfence_handle_page_fault(unsigned long addr, struct pt_regs *regs) { const int page_index = (addr - (unsigned long)__kfence_pool) / PAGE_SIZE; struct kfence_metadata *to_report = NULL; @@ -829,11 +829,11 @@ bool kfence_handle_page_fault(unsigned long addr) out: if (to_report) { - kfence_report_error(addr, to_report, error_type); + kfence_report_error(addr, regs, to_report, error_type); raw_spin_unlock_irqrestore(&to_report->lock, flags); } else { /* This may be a UAF or OOB access, but we can't be sure. */ - kfence_report_error(addr, NULL, KFENCE_ERROR_INVALID); + kfence_report_error(addr, regs, NULL, KFENCE_ERROR_INVALID); } return kfence_unprotect(addr); /* Unprotect and let access proceed. */ diff --git a/mm/kfence/kfence.h b/mm/kfence/kfence.h index 1014060f9707..0d83e628a97d 100644 --- a/mm/kfence/kfence.h +++ b/mm/kfence/kfence.h @@ -105,8 +105,8 @@ enum kfence_error_type { KFENCE_ERROR_INVALID_FREE, /* Invalid free. */ }; -void kfence_report_error(unsigned long address, const struct kfence_metadata *meta, - enum kfence_error_type type); +void kfence_report_error(unsigned long address, struct pt_regs *regs, + const struct kfence_metadata *meta, enum kfence_error_type type); void kfence_print_object(struct seq_file *seq, const struct kfence_metadata *meta); diff --git a/mm/kfence/report.c b/mm/kfence/report.c index 64f27c8d46a3..4dbfa9a382e4 100644 --- a/mm/kfence/report.c +++ b/mm/kfence/report.c @@ -10,6 +10,7 @@ #include <linux/kernel.h> #include <linux/lockdep.h> #include <linux/printk.h> +#include <linux/sched/debug.h> #include <linux/seq_file.h> #include <linux/stacktrace.h> #include <linux/string.h> @@ -41,7 +42,6 @@ static int get_stack_skipnr(const unsigned long stack_entries[], int num_entries { char buf[64]; int skipnr, fallback = 0; - bool is_access_fault = false; if (type) { /* Depending on error type, find different stack entries. */ @@ -49,8 +49,12 @@ static int get_stack_skipnr(const unsigned long stack_entries[], int num_entries case KFENCE_ERROR_UAF: case KFENCE_ERROR_OOB: case KFENCE_ERROR_INVALID: - is_access_fault = true; - break; + /* + * kfence_handle_page_fault() may be called with pt_regs + * set to NULL; in that case we'll simply show the full + * stack trace. + */ + return 0; case KFENCE_ERROR_CORRUPTION: case KFENCE_ERROR_INVALID_FREE: break; @@ -60,26 +64,21 @@ static int get_stack_skipnr(const unsigned long stack_entries[], int num_entries for (skipnr = 0; skipnr < num_entries; skipnr++) { int len = scnprintf(buf, sizeof(buf), "%ps", (void *)stack_entries[skipnr]); - if (is_access_fault) { - if (!strncmp(buf, KFENCE_SKIP_ARCH_FAULT_HANDLER, len)) - goto found; - } else { - if (str_has_prefix(buf, "kfence_") || str_has_prefix(buf, "__kfence_") || - !strncmp(buf, "__slab_free", len)) { - /* - * In case of tail calls from any of the below - * to any of the above. - */ - fallback = skipnr + 1; - } - - /* Also the *_bulk() variants by only checking prefixes. */ - if (str_has_prefix(buf, "kfree") || - str_has_prefix(buf, "kmem_cache_free") || - str_has_prefix(buf, "__kmalloc") || - str_has_prefix(buf, "kmem_cache_alloc")) - goto found; + if (str_has_prefix(buf, "kfence_") || str_has_prefix(buf, "__kfence_") || + !strncmp(buf, "__slab_free", len)) { + /* + * In case of tail calls from any of the below + * to any of the above. + */ + fallback = skipnr + 1; } + + /* Also the *_bulk() variants by only checking prefixes. */ + if (str_has_prefix(buf, "kfree") || + str_has_prefix(buf, "kmem_cache_free") || + str_has_prefix(buf, "__kmalloc") || + str_has_prefix(buf, "kmem_cache_alloc")) + goto found; } if (fallback < num_entries) return fallback; @@ -157,13 +156,20 @@ static void print_diff_canary(unsigned long address, size_t bytes_to_show, pr_cont(" ]"); } -void kfence_report_error(unsigned long address, const struct kfence_metadata *meta, - enum kfence_error_type type) +void kfence_report_error(unsigned long address, struct pt_regs *regs, + const struct kfence_metadata *meta, enum kfence_error_type type) { unsigned long stack_entries[KFENCE_STACK_DEPTH] = { 0 }; - int num_stack_entries = stack_trace_save(stack_entries, KFENCE_STACK_DEPTH, 1); - int skipnr = get_stack_skipnr(stack_entries, num_stack_entries, &type); const ptrdiff_t object_index = meta ? meta - kfence_metadata : -1; + int num_stack_entries; + int skipnr = 0; + + if (regs) { + num_stack_entries = stack_trace_save_regs(regs, stack_entries, KFENCE_STACK_DEPTH, 0); + } else { + num_stack_entries = stack_trace_save(stack_entries, KFENCE_STACK_DEPTH, 1); + skipnr = get_stack_skipnr(stack_entries, num_stack_entries, &type); + } /* Require non-NULL meta, except if KFENCE_ERROR_INVALID. */ if (WARN_ON(type != KFENCE_ERROR_INVALID && !meta)) @@ -227,7 +233,10 @@ void kfence_report_error(unsigned long address, const struct kfence_metadata *me /* Print report footer. */ pr_err("\n"); - dump_stack_print_info(KERN_ERR); + if (IS_ENABLED(CONFIG_DEBUG_KERNEL) && regs) + show_regs(regs); + else + dump_stack_print_info(KERN_ERR); pr_err("==================================================================\n"); lockdep_on(); -- 2.25.1

1 0

[PATCH 3/9] arm64, kfence: enable KFENCE for ARM64
by 1415317271＠qq.com 18 Aug '21

18 Aug '21

From: Marco Elver <elver(a)google.com> Add architecture specific implementation details for KFENCE and enable KFENCE for the arm64 architecture. In particular, this implements the required interface in <asm/kfence.h>. KFENCE requires that attributes for pages from its memory pool can individually be set. Therefore, force the entire linear map to be mapped at page granularity. Doing so may result in extra memory allocated for page tables in case rodata=full is not set; however, currently CONFIG_RODATA_FULL_DEFAULT_ENABLED=y is the default, and the common case is therefore not affected by this change. [elver(a)google.com: add missing copyright and description header] Link: https://lkml.kernel.org/r/20210118092159.145934-3-elver@google.com Link: https://lkml.kernel.org/r/20201103175841.3495947-4-elver@google.com Signed-off-by: Alexander Potapenko <glider(a)google.com> Signed-off-by: Marco Elver <elver(a)google.com> Reviewed-by: Dmitry Vyukov <dvyukov(a)google.com> Co-developed-by: Alexander Potapenko <glider(a)google.com> Reviewed-by: Jann Horn <jannh(a)google.com> Reviewed-by: Mark Rutland <mark.rutland(a)arm.com> Cc: Andrey Konovalov <andreyknvl(a)google.com> Cc: Andrey Ryabinin <aryabinin(a)virtuozzo.com> Cc: Andy Lutomirski <luto(a)kernel.org> Cc: Borislav Petkov <bp(a)alien8.de> Cc: Catalin Marinas <catalin.marinas(a)arm.com> Cc: Christopher Lameter <cl(a)linux.com> Cc: Dave Hansen <dave.hansen(a)linux.intel.com> Cc: David Rientjes <rientjes(a)google.com> Cc: Eric Dumazet <edumazet(a)google.com> Cc: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Cc: Hillf Danton <hdanton(a)sina.com> Cc: "H. Peter Anvin" <hpa(a)zytor.com> Cc: Ingo Molnar <mingo(a)redhat.com> Cc: Joern Engel <joern(a)purestorage.com> Cc: Jonathan Corbet <corbet(a)lwn.net> Cc: Joonsoo Kim <iamjoonsoo.kim(a)lge.com> Cc: Kees Cook <keescook(a)chromium.org> Cc: Paul E. McKenney <paulmck(a)kernel.org> Cc: Pekka Enberg <penberg(a)kernel.org> Cc: Peter Zijlstra <peterz(a)infradead.org> Cc: SeongJae Park <sjpark(a)amazon.de> Cc: Thomas Gleixner <tglx(a)linutronix.de> Cc: Vlastimil Babka <vbabka(a)suse.cz> Cc: Will Deacon <will(a)kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds(a)linux-foundation.org> Signed-off-by: Yingjie Shang <1415317271(a)qq.com> Reviewed-by: Bixuan Cui <cuibixuan(a)huawei.com> --- arch/arm64/Kconfig | 1 + arch/arm64/include/asm/kfence.h | 24 ++++++++++++++++++++++++ arch/arm64/mm/fault.c | 4 ++++ arch/arm64/mm/mmu.c | 7 ++++++- 4 files changed, 35 insertions(+), 1 deletion(-) create mode 100644 arch/arm64/include/asm/kfence.h diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 109d8a18f268..6331f54b493a 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -138,6 +138,7 @@ config ARM64 select HAVE_ARCH_JUMP_LABEL_RELATIVE select HAVE_ARCH_KASAN if !(ARM64_16K_PAGES && ARM64_VA_BITS_48) select HAVE_ARCH_KASAN_SW_TAGS if HAVE_ARCH_KASAN + select HAVE_ARCH_KFENCE select HAVE_ARCH_KGDB select HAVE_ARCH_MMAP_RND_BITS select HAVE_ARCH_MMAP_RND_COMPAT_BITS if COMPAT diff --git a/arch/arm64/include/asm/kfence.h b/arch/arm64/include/asm/kfence.h new file mode 100644 index 000000000000..42a06f83850a --- /dev/null +++ b/arch/arm64/include/asm/kfence.h @@ -0,0 +1,24 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * arm64 KFENCE support. + * + * Copyright (C) 2020, Google LLC. + */ + +#ifndef __ASM_KFENCE_H +#define __ASM_KFENCE_H + +#include <asm/cacheflush.h> + +#define KFENCE_SKIP_ARCH_FAULT_HANDLER "el1_sync" + +static inline bool arch_kfence_init_pool(void) { return true; } + +static inline bool kfence_protect_page(unsigned long addr, bool protect) +{ + set_memory_valid(addr, 1, !protect); + + return true; +} + +#endif /* __ASM_KFENCE_H */ diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c index 795d224f184f..d1a8b523d28e 100644 --- a/arch/arm64/mm/fault.c +++ b/arch/arm64/mm/fault.c @@ -10,6 +10,7 @@ #include <linux/acpi.h> #include <linux/bitfield.h> #include <linux/extable.h> +#include <linux/kfence.h> #include <linux/signal.h> #include <linux/mm.h> #include <linux/hardirq.h> @@ -322,6 +323,9 @@ static void __do_kernel_fault(unsigned long addr, unsigned int esr, } else if (addr < PAGE_SIZE) { msg = "NULL pointer dereference"; } else { + if (kfence_handle_page_fault(addr)) + return; + msg = "paging request"; } diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index 1ec57fd87ef7..2af6d99a8c2e 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -1452,7 +1452,12 @@ int arch_add_memory(int nid, u64 start, u64 size, return -EINVAL; } - if (rodata_full || debug_pagealloc_enabled()) + /* + * KFENCE requires linear map to be mapped at page granularity, so that + * it is possible to protect/unprotect single pages in the KFENCE pool. + */ + if (rodata_full || debug_pagealloc_enabled() || + IS_ENABLED(CONFIG_KFENCE)) flags = NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS; __create_pgd_mapping(swapper_pg_dir, start, __phys_to_virt(start), -- 2.25.1

1 0

[PATCH 2/9] x86, kfence: enable KFENCE for x86
by 1415317271＠qq.com 18 Aug '21

18 Aug '21

From: Alexander Potapenko <glider(a)google.com> Add architecture specific implementation details for KFENCE and enable KFENCE for the x86 architecture. In particular, this implements the required interface in <asm/kfence.h> for setting up the pool and providing helper functions for protecting and unprotecting pages. For x86, we need to ensure that the pool uses 4K pages, which is done using the set_memory_4k() helper function. [elver(a)google.com: add missing copyright and description header] Link: https://lkml.kernel.org/r/20210118092159.145934-2-elver@google.com Link: https://lkml.kernel.org/r/20201103175841.3495947-3-elver@google.com Signed-off-by: Marco Elver <elver(a)google.com> Signed-off-by: Alexander Potapenko <glider(a)google.com> Reviewed-by: Dmitry Vyukov <dvyukov(a)google.com> Co-developed-by: Marco Elver <elver(a)google.com> Reviewed-by: Jann Horn <jannh(a)google.com> Cc: Andrey Konovalov <andreyknvl(a)google.com> Cc: Andrey Ryabinin <aryabinin(a)virtuozzo.com> Cc: Andy Lutomirski <luto(a)kernel.org> Cc: Borislav Petkov <bp(a)alien8.de> Cc: Catalin Marinas <catalin.marinas(a)arm.com> Cc: Christopher Lameter <cl(a)linux.com> Cc: Dave Hansen <dave.hansen(a)linux.intel.com> Cc: David Rientjes <rientjes(a)google.com> Cc: Eric Dumazet <edumazet(a)google.com> Cc: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Cc: Hillf Danton <hdanton(a)sina.com> Cc: "H. Peter Anvin" <hpa(a)zytor.com> Cc: Ingo Molnar <mingo(a)redhat.com> Cc: Joern Engel <joern(a)purestorage.com> Cc: Jonathan Corbet <corbet(a)lwn.net> Cc: Joonsoo Kim <iamjoonsoo.kim(a)lge.com> Cc: Kees Cook <keescook(a)chromium.org> Cc: Mark Rutland <mark.rutland(a)arm.com> Cc: Paul E. McKenney <paulmck(a)kernel.org> Cc: Pekka Enberg <penberg(a)kernel.org> Cc: Peter Zijlstra <peterz(a)infradead.org> Cc: SeongJae Park <sjpark(a)amazon.de> Cc: Thomas Gleixner <tglx(a)linutronix.de> Cc: Vlastimil Babka <vbabka(a)suse.cz> Cc: Will Deacon <will(a)kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds(a)linux-foundation.org> Signed-off-by: Yingjie Shang <1415317271(a)qq.com> Reviewed-by: Bixuan Cui <cuibixuan(a)huawei.com> --- arch/x86/Kconfig | 1 + arch/x86/include/asm/kfence.h | 70 +++++++++++++++++++++++++++++++++++ arch/x86/mm/fault.c | 4 ++ 3 files changed, 75 insertions(+) create mode 100644 arch/x86/include/asm/kfence.h diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index af7123b5b493..37a7b2c8fdd6 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -148,6 +148,7 @@ config X86 select HAVE_ARCH_JUMP_LABEL_RELATIVE select HAVE_ARCH_KASAN if X86_64 select HAVE_ARCH_KASAN_VMALLOC if X86_64 + select HAVE_ARCH_KFENCE select HAVE_ARCH_KGDB select HAVE_ARCH_MMAP_RND_BITS if MMU select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT diff --git a/arch/x86/include/asm/kfence.h b/arch/x86/include/asm/kfence.h new file mode 100644 index 000000000000..a0659dbd93ea --- /dev/null +++ b/arch/x86/include/asm/kfence.h @@ -0,0 +1,70 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * x86 KFENCE support. + * + * Copyright (C) 2020, Google LLC. + */ + +#ifndef _ASM_X86_KFENCE_H +#define _ASM_X86_KFENCE_H + +#include <linux/bug.h> +#include <linux/kfence.h> + +#include <asm/pgalloc.h> +#include <asm/pgtable.h> +#include <asm/set_memory.h> +#include <asm/tlbflush.h> + +/* + * The page fault handler entry function, up to which the stack trace is + * truncated in reports. + */ +#define KFENCE_SKIP_ARCH_FAULT_HANDLER "asm_exc_page_fault" + +/* Force 4K pages for __kfence_pool. */ +static inline bool arch_kfence_init_pool(void) +{ + unsigned long addr; + + for (addr = (unsigned long)__kfence_pool; is_kfence_address((void *)addr); + addr += PAGE_SIZE) { + unsigned int level; + + if (!lookup_address(addr, &level)) + return false; + + if (level != PG_LEVEL_4K) + set_memory_4k(addr, 1); + } + + return true; +} + +/* Protect the given page and flush TLB. */ +static inline bool kfence_protect_page(unsigned long addr, bool protect) +{ + unsigned int level; + pte_t *pte = lookup_address(addr, &level); + + if (WARN_ON(!pte || level != PG_LEVEL_4K)) + return false; + + /* + * We need to avoid IPIs, as we may get KFENCE allocations or faults + * with interrupts disabled. Therefore, the below is best-effort, and + * does not flush TLBs on all CPUs. We can tolerate some inaccuracy; + * lazy fault handling takes care of faults after the page is PRESENT. + */ + + if (protect) + set_pte(pte, __pte(pte_val(*pte) & ~_PAGE_PRESENT)); + else + set_pte(pte, __pte(pte_val(*pte) | _PAGE_PRESENT)); + + /* Flush this CPU's TLB. */ + flush_tlb_one_kernel(addr); + return true; +} + +#endif /* _ASM_X86_KFENCE_H */ diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index 9c1545c376e9..35901aa6ad1c 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -9,6 +9,7 @@ #include <linux/kdebug.h> /* oops_begin/end, ... */ #include <linux/extable.h> /* search_exception_tables */ #include <linux/memblock.h> /* max_low_pfn */ +#include <linux/kfence.h> /* kfence_handle_page_fault */ #include <linux/kprobes.h> /* NOKPROBE_SYMBOL, ... */ #include <linux/mmiotrace.h> /* kmmio_handler, ... */ #include <linux/perf_event.h> /* perf_sw_event */ @@ -732,6 +733,9 @@ no_context(struct pt_regs *regs, unsigned long error_code, if (IS_ENABLED(CONFIG_EFI)) efi_recover_from_page_fault(address); + /* Only not-present faults should be handled by KFENCE. */ + if (!(error_code & X86_PF_PROT) && kfence_handle_page_fault(address)) + return; oops: /* * Oops. The kernel tried to access some bad page. We'll have to -- 2.25.1

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Kernel August 2021