August 2024 - Kernel - mailweb.openeuler.org

[PATCH OLK-6.6 0/1] kvm : add coda feature
by y00878127 05 Aug '24

05 Aug '24

From: Xiangkai Yang <yangxiangkai(a)huawei.com> virtCCA feature Xiangkai Yang (1): clean code drivers/iommu/arm/arm-smmu-v3/arm-s-smmu-v3.c | 3 ++- virt/kvm/vfio.c | 1 - 2 files changed, 2 insertions(+), 2 deletions(-) -- 2.25.1

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[PATCH openEuler-22.03-LTS-SP1 0/2] fix CVE-2024-41062
by Zhengchao Shao 05 Aug '24

05 Aug '24

Fix CVE-2024-41062 Edward Adam Davis (1): bluetooth/l2cap: sync sock recv cb and release Luiz Augusto von Dentz (1): Bluetooth: L2CAP: Fix deadlock net/bluetooth/l2cap_core.c | 3 +++ net/bluetooth/l2cap_sock.c | 10 +++++++++- 2 files changed, 12 insertions(+), 1 deletion(-) -- 2.34.1

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[PATCH OLK-5.10 0/2] fix CVE-2024-41062
by Zhengchao Shao 05 Aug '24

05 Aug '24

Fix CVE-2024-41062 Edward Adam Davis (1): bluetooth/l2cap: sync sock recv cb and release Luiz Augusto von Dentz (1): Bluetooth: L2CAP: Fix deadlock net/bluetooth/l2cap_core.c | 3 +++ net/bluetooth/l2cap_sock.c | 10 +++++++++- 2 files changed, 12 insertions(+), 1 deletion(-) -- 2.34.1

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[PATCH OLK-6.6 0/1] kvm : add coda feature
by l00500167 05 Aug '24

05 Aug '24

From: JunBin Li <lijunbin4(a)huawei.com> virtCCA feature JunBin Li (1): coda feature arch/arm64/Kconfig | 8 + arch/arm64/configs/openeuler_defconfig | 5 +- arch/arm64/include/asm/kvm_emulate.h | 18 + arch/arm64/include/asm/kvm_host.h | 15 +- arch/arm64/include/asm/kvm_tmi.h | 410 +++++++ arch/arm64/include/asm/kvm_tmm.h | 52 +- arch/arm64/include/asm/set_memory.h | 1 + arch/arm64/include/asm/virtcca_cvm_guest.h | 39 + arch/arm64/include/uapi/asm/kvm.h | 4 + arch/arm64/kernel/Makefile | 1 + arch/arm64/kernel/virtcca_cvm_guest.c | 93 ++ arch/arm64/kvm/Kconfig | 6 +- arch/arm64/kvm/Makefile | 3 + arch/arm64/kvm/arch_timer.c | 93 ++ arch/arm64/kvm/arm.c | 134 ++- arch/arm64/kvm/guest.c | 5 + arch/arm64/kvm/mmio.c | 14 +- arch/arm64/kvm/mmu.c | 33 + arch/arm64/kvm/pmu-emul.c | 9 + arch/arm64/kvm/psci.c | 10 +- arch/arm64/kvm/reset.c | 11 + arch/arm64/kvm/tmi.c | 279 +++++ arch/arm64/kvm/vgic/vgic-v3.c | 14 +- arch/arm64/kvm/vgic/vgic.c | 52 +- arch/arm64/kvm/virtcca_cvm.c | 1065 +++++++++++++++++ arch/arm64/kvm/virtcca_cvm_exit.c | 221 ++++ arch/arm64/mm/init.c | 3 + arch/arm64/mm/mmu.c | 5 +- arch/arm64/mm/pageattr.c | 3 + drivers/iommu/arm/arm-smmu-v3/Makefile | 1 + drivers/iommu/arm/arm-smmu-v3/arm-s-smmu-v3.c | 809 +++++++++++++ drivers/iommu/arm/arm-smmu-v3/arm-s-smmu-v3.h | 160 +++ drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 178 ++- drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h | 16 + drivers/iommu/io-pgtable-arm.c | 60 + drivers/iommu/iommu.c | 11 + drivers/irqchip/irq-gic-v3-its.c | 231 +++- drivers/pci/access.c | 33 + drivers/pci/msi/msi.c | 90 +- drivers/perf/arm_pmu.c | 17 + drivers/vfio/pci/vfio_pci_core.c | 5 + drivers/vfio/pci/vfio_pci_rdwr.c | 27 +- drivers/vfio/vfio_iommu_type1.c | 17 + drivers/vfio/vfio_main.c | 18 + include/kvm/arm_arch_timer.h | 4 + include/linux/iommu.h | 9 + include/linux/iopoll.h | 38 + include/linux/kvm_host.h | 22 + include/linux/pci.h | 4 + include/linux/perf/arm_pmu.h | 4 + include/linux/vfio.h | 5 + include/uapi/linux/kvm.h | 13 + include/uapi/linux/vfio.h | 3 + kernel/dma/swiotlb.c | 16 + virt/kvm/kvm_main.c | 4 + virt/kvm/vfio.c | 121 +- virt/kvm/vfio.h | 10 + 57 files changed, 4461 insertions(+), 71 deletions(-) create mode 100644 arch/arm64/include/asm/kvm_tmi.h create mode 100644 arch/arm64/include/asm/virtcca_cvm_guest.h create mode 100644 arch/arm64/kernel/virtcca_cvm_guest.c create mode 100644 arch/arm64/kvm/tmi.c create mode 100644 arch/arm64/kvm/virtcca_cvm.c create mode 100644 arch/arm64/kvm/virtcca_cvm_exit.c create mode 100644 drivers/iommu/arm/arm-smmu-v3/arm-s-smmu-v3.c create mode 100644 drivers/iommu/arm/arm-smmu-v3/arm-s-smmu-v3.h -- 2.25.1

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[PATCH OLK-6.6 0/1] kvm : add coda feature
by l00500167 05 Aug '24

05 Aug '24

From: JunBin Li <lijunbin4(a)huawei.com> virtCCA feature JunBin Li (1): coda feature arch/arm64/Kconfig | 8 + arch/arm64/configs/openeuler_defconfig | 5 +- arch/arm64/include/asm/kvm_emulate.h | 18 + arch/arm64/include/asm/kvm_host.h | 15 +- arch/arm64/include/asm/kvm_tmi.h | 410 +++++++ arch/arm64/include/asm/kvm_tmm.h | 52 +- arch/arm64/include/asm/set_memory.h | 1 + arch/arm64/include/asm/virtcca_cvm_guest.h | 39 + arch/arm64/include/uapi/asm/kvm.h | 4 + arch/arm64/kernel/Makefile | 1 + arch/arm64/kernel/virtcca_cvm_guest.c | 93 ++ arch/arm64/kvm/Kconfig | 6 +- arch/arm64/kvm/Makefile | 3 + arch/arm64/kvm/arch_timer.c | 93 ++ arch/arm64/kvm/arm.c | 134 ++- arch/arm64/kvm/guest.c | 5 + arch/arm64/kvm/mmio.c | 14 +- arch/arm64/kvm/mmu.c | 33 + arch/arm64/kvm/pmu-emul.c | 9 + arch/arm64/kvm/psci.c | 10 +- arch/arm64/kvm/reset.c | 11 + arch/arm64/kvm/tmi.c | 279 +++++ arch/arm64/kvm/vgic/vgic-v3.c | 14 +- arch/arm64/kvm/vgic/vgic.c | 52 +- arch/arm64/kvm/virtcca_cvm.c | 1065 +++++++++++++++++ arch/arm64/kvm/virtcca_cvm_exit.c | 221 ++++ arch/arm64/mm/init.c | 3 + arch/arm64/mm/mmu.c | 5 +- arch/arm64/mm/pageattr.c | 3 + drivers/iommu/arm/arm-smmu-v3/Makefile | 1 + drivers/iommu/arm/arm-smmu-v3/arm-s-smmu-v3.c | 809 +++++++++++++ drivers/iommu/arm/arm-smmu-v3/arm-s-smmu-v3.h | 160 +++ drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 178 ++- drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h | 16 + drivers/iommu/io-pgtable-arm.c | 60 + drivers/iommu/iommu.c | 11 + drivers/irqchip/irq-gic-v3-its.c | 231 +++- drivers/pci/access.c | 33 + drivers/pci/msi/msi.c | 90 +- drivers/perf/arm_pmu.c | 17 + drivers/vfio/pci/vfio_pci_core.c | 5 + drivers/vfio/pci/vfio_pci_rdwr.c | 27 +- drivers/vfio/vfio_iommu_type1.c | 17 + drivers/vfio/vfio_main.c | 18 + include/kvm/arm_arch_timer.h | 4 + include/linux/iommu.h | 9 + include/linux/iopoll.h | 38 + include/linux/kvm_host.h | 22 + include/linux/pci.h | 4 + include/linux/perf/arm_pmu.h | 4 + include/linux/vfio.h | 5 + include/uapi/linux/kvm.h | 13 + include/uapi/linux/vfio.h | 3 + kernel/dma/swiotlb.c | 16 + virt/kvm/kvm_main.c | 4 + virt/kvm/vfio.c | 121 +- virt/kvm/vfio.h | 10 + 57 files changed, 4461 insertions(+), 71 deletions(-) create mode 100644 arch/arm64/include/asm/kvm_tmi.h create mode 100644 arch/arm64/include/asm/virtcca_cvm_guest.h create mode 100644 arch/arm64/kernel/virtcca_cvm_guest.c create mode 100644 arch/arm64/kvm/tmi.c create mode 100644 arch/arm64/kvm/virtcca_cvm.c create mode 100644 arch/arm64/kvm/virtcca_cvm_exit.c create mode 100644 drivers/iommu/arm/arm-smmu-v3/arm-s-smmu-v3.c create mode 100644 drivers/iommu/arm/arm-smmu-v3/arm-s-smmu-v3.h -- 2.25.1

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[PATCH OLK-6.6 0/3] CVE-2024-35860
by Pu Lehui 05 Aug '24

05 Aug '24

Andrii Nakryiko (1): bpf: support deferring bpf_link dealloc to after RCU grace period Cong Wang (1): bpf: Fix a potential use-after-free in bpf_link_free() Tengda Wu (1): Fix kabi breakage in struct bpf_link and bpf_link_ops include/linux/bpf.h | 17 +++++++++++++++-- kernel/bpf/syscall.c | 38 ++++++++++++++++++++++++++++++++++---- kernel/trace/bpf_trace.c | 4 ++-- 3 files changed, 51 insertions(+), 8 deletions(-) -- 2.34.1

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[PATCH OLK-6.6 0/1] kvm : add coda feature
by y00878127 05 Aug '24

05 Aug '24

From: Xiangkai Yang <yangxiangkai(a)huawei.com> virtCCA feature Xiangkai Yang (1): clean code drivers/iommu/arm/arm-smmu-v3/arm-s-smmu-v3.c | 3 ++- virt/kvm/vfio.c | 1 - 2 files changed, 2 insertions(+), 2 deletions(-) -- 2.25.1

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[PATCH OLK-6.6] KVM: PPC: Book3S HV: Prevent UAF in kvm_spapr_tce_attach_iommu_group()
by Zheng Zucheng 04 Aug '24

04 Aug '24

From: Michael Ellerman <mpe(a)ellerman.id.au> stable inclusion from stable-v6.6.41 commit 82c7a4cf14aa866f8f7f09e662b02eddc49ee0bf category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IAGEKF CVE: CVE-2024-41070 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id… -------------------------------- [ Upstream commit a986fa57fd81a1430e00b3c6cf8a325d6f894a63 ] Al reported a possible use-after-free (UAF) in kvm_spapr_tce_attach_iommu_group(). It looks up `stt` from tablefd, but then continues to use it after doing fdput() on the returned fd. After the fdput() the tablefd is free to be closed by another thread. The close calls kvm_spapr_tce_release() and then release_spapr_tce_table() (via call_rcu()) which frees `stt`. Although there are calls to rcu_read_lock() in kvm_spapr_tce_attach_iommu_group() they are not sufficient to prevent the UAF, because `stt` is used outside the locked regions. With an artifcial delay after the fdput() and a userspace program which triggers the race, KASAN detects the UAF: BUG: KASAN: slab-use-after-free in kvm_spapr_tce_attach_iommu_group+0x298/0x720 [kvm] Read of size 4 at addr c000200027552c30 by task kvm-vfio/2505 CPU: 54 PID: 2505 Comm: kvm-vfio Not tainted 6.10.0-rc3-next-20240612-dirty #1 Hardware name: 8335-GTH POWER9 0x4e1202 opal:skiboot-v6.5.3-35-g1851b2a06 PowerNV Call Trace: dump_stack_lvl+0xb4/0x108 (unreliable) print_report+0x2b4/0x6ec kasan_report+0x118/0x2b0 __asan_load4+0xb8/0xd0 kvm_spapr_tce_attach_iommu_group+0x298/0x720 [kvm] kvm_vfio_set_attr+0x524/0xac0 [kvm] kvm_device_ioctl+0x144/0x240 [kvm] sys_ioctl+0x62c/0x1810 system_call_exception+0x190/0x440 system_call_vectored_common+0x15c/0x2ec ... Freed by task 0: ... kfree+0xec/0x3e0 release_spapr_tce_table+0xd4/0x11c [kvm] rcu_core+0x568/0x16a0 handle_softirqs+0x23c/0x920 do_softirq_own_stack+0x6c/0x90 do_softirq_own_stack+0x58/0x90 __irq_exit_rcu+0x218/0x2d0 irq_exit+0x30/0x80 arch_local_irq_restore+0x128/0x230 arch_local_irq_enable+0x1c/0x30 cpuidle_enter_state+0x134/0x5cc cpuidle_enter+0x6c/0xb0 call_cpuidle+0x7c/0x100 do_idle+0x394/0x410 cpu_startup_entry+0x60/0x70 start_secondary+0x3fc/0x410 start_secondary_prolog+0x10/0x14 Fix it by delaying the fdput() until `stt` is no longer in use, which is effectively the entire function. To keep the patch minimal add a call to fdput() at each of the existing return paths. Future work can convert the function to goto or __cleanup style cleanup. With the fix in place the test case no longer triggers the UAF. Reported-by: Al Viro <viro(a)zeniv.linux.org.uk> Closes: https://lore.kernel.org/all/20240610024437.GA1464458@ZenIV/ Signed-off-by: Michael Ellerman <mpe(a)ellerman.id.au> Link: https://msgid.link/20240614122910.3499489-1-mpe@ellerman.id.au Signed-off-by: Sasha Levin <sashal(a)kernel.org> Signed-off-by: Zheng Zucheng <zhengzucheng(a)huawei.com> --- arch/powerpc/kvm/book3s_64_vio.c | 18 +++++++++++++----- 1 file changed, 13 insertions(+), 5 deletions(-) diff --git a/arch/powerpc/kvm/book3s_64_vio.c b/arch/powerpc/kvm/book3s_64_vio.c index 15200d766fc5..c7623fd4d6d9 100644 --- a/arch/powerpc/kvm/book3s_64_vio.c +++ b/arch/powerpc/kvm/book3s_64_vio.c @@ -129,14 +129,16 @@ long kvm_spapr_tce_attach_iommu_group(struct kvm *kvm, int tablefd, } rcu_read_unlock(); - fdput(f); - - if (!found) + if (!found) { + fdput(f); return -EINVAL; + } table_group = iommu_group_get_iommudata(grp); - if (WARN_ON(!table_group)) + if (WARN_ON(!table_group)) { + fdput(f); return -EFAULT; + } for (i = 0; i < IOMMU_TABLE_GROUP_MAX_TABLES; ++i) { struct iommu_table *tbltmp = table_group->tables[i]; @@ -157,8 +159,10 @@ long kvm_spapr_tce_attach_iommu_group(struct kvm *kvm, int tablefd, break; } } - if (!tbl) + if (!tbl) { + fdput(f); return -EINVAL; + } rcu_read_lock(); list_for_each_entry_rcu(stit, &stt->iommu_tables, next) { @@ -169,6 +173,7 @@ long kvm_spapr_tce_attach_iommu_group(struct kvm *kvm, int tablefd, /* stit is being destroyed */ iommu_tce_table_put(tbl); rcu_read_unlock(); + fdput(f); return -ENOTTY; } /* @@ -176,6 +181,7 @@ long kvm_spapr_tce_attach_iommu_group(struct kvm *kvm, int tablefd, * its KVM reference counter and can return. */ rcu_read_unlock(); + fdput(f); return 0; } rcu_read_unlock(); @@ -183,6 +189,7 @@ long kvm_spapr_tce_attach_iommu_group(struct kvm *kvm, int tablefd, stit = kzalloc(sizeof(*stit), GFP_KERNEL); if (!stit) { iommu_tce_table_put(tbl); + fdput(f); return -ENOMEM; } @@ -191,6 +198,7 @@ long kvm_spapr_tce_attach_iommu_group(struct kvm *kvm, int tablefd, list_add_rcu(&stit->next, &stt->iommu_tables); + fdput(f); return 0; } -- 2.34.1

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[PATCH openEuler-1.0-LTS] KVM: PPC: Book3S HV: Prevent UAF in kvm_spapr_tce_attach_iommu_group()
by Zheng Zucheng 04 Aug '24

04 Aug '24

From: Michael Ellerman <mpe(a)ellerman.id.au> stable inclusion from stable-v5.10.222 commit 4cdf6926f443c84f680213c7aafbe6f91a5fcbc0 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IAGEKF CVE: CVE-2024-41070 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id… -------------------------------- [ Upstream commit a986fa57fd81a1430e00b3c6cf8a325d6f894a63 ] Al reported a possible use-after-free (UAF) in kvm_spapr_tce_attach_iommu_group(). It looks up `stt` from tablefd, but then continues to use it after doing fdput() on the returned fd. After the fdput() the tablefd is free to be closed by another thread. The close calls kvm_spapr_tce_release() and then release_spapr_tce_table() (via call_rcu()) which frees `stt`. Although there are calls to rcu_read_lock() in kvm_spapr_tce_attach_iommu_group() they are not sufficient to prevent the UAF, because `stt` is used outside the locked regions. With an artifcial delay after the fdput() and a userspace program which triggers the race, KASAN detects the UAF: BUG: KASAN: slab-use-after-free in kvm_spapr_tce_attach_iommu_group+0x298/0x720 [kvm] Read of size 4 at addr c000200027552c30 by task kvm-vfio/2505 CPU: 54 PID: 2505 Comm: kvm-vfio Not tainted 6.10.0-rc3-next-20240612-dirty #1 Hardware name: 8335-GTH POWER9 0x4e1202 opal:skiboot-v6.5.3-35-g1851b2a06 PowerNV Call Trace: dump_stack_lvl+0xb4/0x108 (unreliable) print_report+0x2b4/0x6ec kasan_report+0x118/0x2b0 __asan_load4+0xb8/0xd0 kvm_spapr_tce_attach_iommu_group+0x298/0x720 [kvm] kvm_vfio_set_attr+0x524/0xac0 [kvm] kvm_device_ioctl+0x144/0x240 [kvm] sys_ioctl+0x62c/0x1810 system_call_exception+0x190/0x440 system_call_vectored_common+0x15c/0x2ec ... Freed by task 0: ... kfree+0xec/0x3e0 release_spapr_tce_table+0xd4/0x11c [kvm] rcu_core+0x568/0x16a0 handle_softirqs+0x23c/0x920 do_softirq_own_stack+0x6c/0x90 do_softirq_own_stack+0x58/0x90 __irq_exit_rcu+0x218/0x2d0 irq_exit+0x30/0x80 arch_local_irq_restore+0x128/0x230 arch_local_irq_enable+0x1c/0x30 cpuidle_enter_state+0x134/0x5cc cpuidle_enter+0x6c/0xb0 call_cpuidle+0x7c/0x100 do_idle+0x394/0x410 cpu_startup_entry+0x60/0x70 start_secondary+0x3fc/0x410 start_secondary_prolog+0x10/0x14 Fix it by delaying the fdput() until `stt` is no longer in use, which is effectively the entire function. To keep the patch minimal add a call to fdput() at each of the existing return paths. Future work can convert the function to goto or __cleanup style cleanup. With the fix in place the test case no longer triggers the UAF. Reported-by: Al Viro <viro(a)zeniv.linux.org.uk> Closes: https://lore.kernel.org/all/20240610024437.GA1464458@ZenIV/ Signed-off-by: Michael Ellerman <mpe(a)ellerman.id.au> Link: https://msgid.link/20240614122910.3499489-1-mpe@ellerman.id.au Signed-off-by: Sasha Levin <sashal(a)kernel.org> Signed-off-by: Zheng Zucheng <zhengzucheng(a)huawei.com> --- arch/powerpc/kvm/book3s_64_vio.c | 18 +++++++++++++----- 1 file changed, 13 insertions(+), 5 deletions(-) diff --git a/arch/powerpc/kvm/book3s_64_vio.c b/arch/powerpc/kvm/book3s_64_vio.c index 3cb2e05a7ee8..a8e5eefee794 100644 --- a/arch/powerpc/kvm/book3s_64_vio.c +++ b/arch/powerpc/kvm/book3s_64_vio.c @@ -117,14 +117,16 @@ extern long kvm_spapr_tce_attach_iommu_group(struct kvm *kvm, int tablefd, } rcu_read_unlock(); - fdput(f); - - if (!found) + if (!found) { + fdput(f); return -EINVAL; + } table_group = iommu_group_get_iommudata(grp); - if (WARN_ON(!table_group)) + if (WARN_ON(!table_group)) { + fdput(f); return -EFAULT; + } for (i = 0; i < IOMMU_TABLE_GROUP_MAX_TABLES; ++i) { struct iommu_table *tbltmp = table_group->tables[i]; @@ -145,8 +147,10 @@ extern long kvm_spapr_tce_attach_iommu_group(struct kvm *kvm, int tablefd, break; } } - if (!tbl) + if (!tbl) { + fdput(f); return -EINVAL; + } rcu_read_lock(); list_for_each_entry_rcu(stit, &stt->iommu_tables, next) { @@ -157,6 +161,7 @@ extern long kvm_spapr_tce_attach_iommu_group(struct kvm *kvm, int tablefd, /* stit is being destroyed */ iommu_tce_table_put(tbl); rcu_read_unlock(); + fdput(f); return -ENOTTY; } /* @@ -164,6 +169,7 @@ extern long kvm_spapr_tce_attach_iommu_group(struct kvm *kvm, int tablefd, * its KVM reference counter and can return. */ rcu_read_unlock(); + fdput(f); return 0; } rcu_read_unlock(); @@ -171,6 +177,7 @@ extern long kvm_spapr_tce_attach_iommu_group(struct kvm *kvm, int tablefd, stit = kzalloc(sizeof(*stit), GFP_KERNEL); if (!stit) { iommu_tce_table_put(tbl); + fdput(f); return -ENOMEM; } @@ -179,6 +186,7 @@ extern long kvm_spapr_tce_attach_iommu_group(struct kvm *kvm, int tablefd, list_add_rcu(&stit->next, &stt->iommu_tables); + fdput(f); return 0; } -- 2.34.1

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[PATCH openEuler-22.03-LTS-SP1] KVM: PPC: Book3S HV: Prevent UAF in kvm_spapr_tce_attach_iommu_group()
by Zheng Zucheng 04 Aug '24

04 Aug '24

From: Michael Ellerman <mpe(a)ellerman.id.au> stable inclusion from stable-v5.10.222 commit 4cdf6926f443c84f680213c7aafbe6f91a5fcbc0 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IAGEKF CVE: CVE-2024-41070 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id… -------------------------------- [ Upstream commit a986fa57fd81a1430e00b3c6cf8a325d6f894a63 ] Al reported a possible use-after-free (UAF) in kvm_spapr_tce_attach_iommu_group(). It looks up `stt` from tablefd, but then continues to use it after doing fdput() on the returned fd. After the fdput() the tablefd is free to be closed by another thread. The close calls kvm_spapr_tce_release() and then release_spapr_tce_table() (via call_rcu()) which frees `stt`. Although there are calls to rcu_read_lock() in kvm_spapr_tce_attach_iommu_group() they are not sufficient to prevent the UAF, because `stt` is used outside the locked regions. With an artifcial delay after the fdput() and a userspace program which triggers the race, KASAN detects the UAF: BUG: KASAN: slab-use-after-free in kvm_spapr_tce_attach_iommu_group+0x298/0x720 [kvm] Read of size 4 at addr c000200027552c30 by task kvm-vfio/2505 CPU: 54 PID: 2505 Comm: kvm-vfio Not tainted 6.10.0-rc3-next-20240612-dirty #1 Hardware name: 8335-GTH POWER9 0x4e1202 opal:skiboot-v6.5.3-35-g1851b2a06 PowerNV Call Trace: dump_stack_lvl+0xb4/0x108 (unreliable) print_report+0x2b4/0x6ec kasan_report+0x118/0x2b0 __asan_load4+0xb8/0xd0 kvm_spapr_tce_attach_iommu_group+0x298/0x720 [kvm] kvm_vfio_set_attr+0x524/0xac0 [kvm] kvm_device_ioctl+0x144/0x240 [kvm] sys_ioctl+0x62c/0x1810 system_call_exception+0x190/0x440 system_call_vectored_common+0x15c/0x2ec ... Freed by task 0: ... kfree+0xec/0x3e0 release_spapr_tce_table+0xd4/0x11c [kvm] rcu_core+0x568/0x16a0 handle_softirqs+0x23c/0x920 do_softirq_own_stack+0x6c/0x90 do_softirq_own_stack+0x58/0x90 __irq_exit_rcu+0x218/0x2d0 irq_exit+0x30/0x80 arch_local_irq_restore+0x128/0x230 arch_local_irq_enable+0x1c/0x30 cpuidle_enter_state+0x134/0x5cc cpuidle_enter+0x6c/0xb0 call_cpuidle+0x7c/0x100 do_idle+0x394/0x410 cpu_startup_entry+0x60/0x70 start_secondary+0x3fc/0x410 start_secondary_prolog+0x10/0x14 Fix it by delaying the fdput() until `stt` is no longer in use, which is effectively the entire function. To keep the patch minimal add a call to fdput() at each of the existing return paths. Future work can convert the function to goto or __cleanup style cleanup. With the fix in place the test case no longer triggers the UAF. Reported-by: Al Viro <viro(a)zeniv.linux.org.uk> Closes: https://lore.kernel.org/all/20240610024437.GA1464458@ZenIV/ Signed-off-by: Michael Ellerman <mpe(a)ellerman.id.au> Link: https://msgid.link/20240614122910.3499489-1-mpe@ellerman.id.au Signed-off-by: Sasha Levin <sashal(a)kernel.org> Signed-off-by: Zheng Zucheng <zhengzucheng(a)huawei.com> --- arch/powerpc/kvm/book3s_64_vio.c | 18 +++++++++++++----- 1 file changed, 13 insertions(+), 5 deletions(-) diff --git a/arch/powerpc/kvm/book3s_64_vio.c b/arch/powerpc/kvm/book3s_64_vio.c index 3cb2e05a7ee8..a8e5eefee794 100644 --- a/arch/powerpc/kvm/book3s_64_vio.c +++ b/arch/powerpc/kvm/book3s_64_vio.c @@ -117,14 +117,16 @@ extern long kvm_spapr_tce_attach_iommu_group(struct kvm *kvm, int tablefd, } rcu_read_unlock(); - fdput(f); - - if (!found) + if (!found) { + fdput(f); return -EINVAL; + } table_group = iommu_group_get_iommudata(grp); - if (WARN_ON(!table_group)) + if (WARN_ON(!table_group)) { + fdput(f); return -EFAULT; + } for (i = 0; i < IOMMU_TABLE_GROUP_MAX_TABLES; ++i) { struct iommu_table *tbltmp = table_group->tables[i]; @@ -145,8 +147,10 @@ extern long kvm_spapr_tce_attach_iommu_group(struct kvm *kvm, int tablefd, break; } } - if (!tbl) + if (!tbl) { + fdput(f); return -EINVAL; + } rcu_read_lock(); list_for_each_entry_rcu(stit, &stt->iommu_tables, next) { @@ -157,6 +161,7 @@ extern long kvm_spapr_tce_attach_iommu_group(struct kvm *kvm, int tablefd, /* stit is being destroyed */ iommu_tce_table_put(tbl); rcu_read_unlock(); + fdput(f); return -ENOTTY; } /* @@ -164,6 +169,7 @@ extern long kvm_spapr_tce_attach_iommu_group(struct kvm *kvm, int tablefd, * its KVM reference counter and can return. */ rcu_read_unlock(); + fdput(f); return 0; } rcu_read_unlock(); @@ -171,6 +177,7 @@ extern long kvm_spapr_tce_attach_iommu_group(struct kvm *kvm, int tablefd, stit = kzalloc(sizeof(*stit), GFP_KERNEL); if (!stit) { iommu_tce_table_put(tbl); + fdput(f); return -ENOMEM; } @@ -179,6 +186,7 @@ extern long kvm_spapr_tce_attach_iommu_group(struct kvm *kvm, int tablefd, list_add_rcu(&stit->next, &stt->iommu_tables); + fdput(f); return 0; } -- 2.34.1

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