From: Zqiang qiang.zhang@windriver.com
stable inclusion from stable-v4.19.154 commit cedb0187b8ba929c3f76f28e6bc25804d65f8a54 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I5PB1E CVE: CVE-2020-27784
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[ Upstream commit e8d5f92b8d30bb4ade76494490c3c065e12411b1 ]
Fix this by increase object reference count.
BUG: KASAN: use-after-free in __lock_acquire+0x3fd4/0x4180 kernel/locking/lockdep.c:3831 Read of size 8 at addr ffff8880683b0018 by task syz-executor.0/3377
CPU: 1 PID: 3377 Comm: syz-executor.0 Not tainted 5.6.11 #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0xce/0x128 lib/dump_stack.c:118 print_address_description.constprop.4+0x21/0x3c0 mm/kasan/report.c:374 __kasan_report+0x131/0x1b0 mm/kasan/report.c:506 kasan_report+0x12/0x20 mm/kasan/common.c:641 __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:135 __lock_acquire+0x3fd4/0x4180 kernel/locking/lockdep.c:3831 lock_acquire+0x127/0x350 kernel/locking/lockdep.c:4488 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x35/0x50 kernel/locking/spinlock.c:159 printer_ioctl+0x4a/0x110 drivers/usb/gadget/function/f_printer.c:723 vfs_ioctl fs/ioctl.c:47 [inline] ksys_ioctl+0xfb/0x130 fs/ioctl.c:763 __do_sys_ioctl fs/ioctl.c:772 [inline] __se_sys_ioctl fs/ioctl.c:770 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:770 do_syscall_64+0x9e/0x510 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x4531a9 Code: ed 60 fc ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 bb 60 fc ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fd14ad72c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 000000000073bfa8 RCX: 00000000004531a9 RDX: fffffffffffffff9 RSI: 000000000000009e RDI: 0000000000000003 RBP: 0000000000000003 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000004bbd61 R13: 00000000004d0a98 R14: 00007fd14ad736d4 R15: 00000000ffffffff
Allocated by task 2393: save_stack+0x21/0x90 mm/kasan/common.c:72 set_track mm/kasan/common.c:80 [inline] __kasan_kmalloc.constprop.3+0xa7/0xd0 mm/kasan/common.c:515 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:529 kmem_cache_alloc_trace+0xfa/0x2d0 mm/slub.c:2813 kmalloc include/linux/slab.h:555 [inline] kzalloc include/linux/slab.h:669 [inline] gprinter_alloc+0xa1/0x870 drivers/usb/gadget/function/f_printer.c:1416 usb_get_function+0x58/0xc0 drivers/usb/gadget/functions.c:61 config_usb_cfg_link+0x1ed/0x3e0 drivers/usb/gadget/configfs.c:444 configfs_symlink+0x527/0x11d0 fs/configfs/symlink.c:202 vfs_symlink+0x33d/0x5b0 fs/namei.c:4201 do_symlinkat+0x11b/0x1d0 fs/namei.c:4228 __do_sys_symlinkat fs/namei.c:4242 [inline] __se_sys_symlinkat fs/namei.c:4239 [inline] __x64_sys_symlinkat+0x73/0xb0 fs/namei.c:4239 do_syscall_64+0x9e/0x510 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe
Freed by task 3368: save_stack+0x21/0x90 mm/kasan/common.c:72 set_track mm/kasan/common.c:80 [inline] kasan_set_free_info mm/kasan/common.c:337 [inline] __kasan_slab_free+0x135/0x190 mm/kasan/common.c:476 kasan_slab_free+0xe/0x10 mm/kasan/common.c:485 slab_free_hook mm/slub.c:1444 [inline] slab_free_freelist_hook mm/slub.c:1477 [inline] slab_free mm/slub.c:3034 [inline] kfree+0xf7/0x410 mm/slub.c:3995 gprinter_free+0x49/0xd0 drivers/usb/gadget/function/f_printer.c:1353 usb_put_function+0x38/0x50 drivers/usb/gadget/functions.c:87 config_usb_cfg_unlink+0x2db/0x3b0 drivers/usb/gadget/configfs.c:485 configfs_unlink+0x3b9/0x7f0 fs/configfs/symlink.c:250 vfs_unlink+0x287/0x570 fs/namei.c:4073 do_unlinkat+0x4f9/0x620 fs/namei.c:4137 __do_sys_unlink fs/namei.c:4184 [inline] __se_sys_unlink fs/namei.c:4182 [inline] __x64_sys_unlink+0x42/0x50 fs/namei.c:4182 do_syscall_64+0x9e/0x510 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe
The buggy address belongs to the object at ffff8880683b0000 which belongs to the cache kmalloc-1k of size 1024 The buggy address is located 24 bytes inside of 1024-byte region [ffff8880683b0000, ffff8880683b0400) The buggy address belongs to the page: page:ffffea0001a0ec00 refcount:1 mapcount:0 mapping:ffff88806c00e300 index:0xffff8880683b1800 compound_mapcount: 0 flags: 0x100000000010200(slab|head) raw: 0100000000010200 0000000000000000 0000000600000001 ffff88806c00e300 raw: ffff8880683b1800 000000008010000a 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected
Reported-by: Kyungtae Kim kt0755@gmail.com Signed-off-by: Zqiang qiang.zhang@windriver.com Signed-off-by: Felipe Balbi balbi@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Wei Li liwei391@huawei.com Reviewed-by: Xiongfeng Wang wangxiongfeng2@huawei.com Reviewed-by: Wang Weiyang wangweiyang2@huawei.com Signed-off-by: Yongqiang Liu liuyongqiang13@huawei.com --- drivers/usb/gadget/function/f_printer.c | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-)
diff --git a/drivers/usb/gadget/function/f_printer.c b/drivers/usb/gadget/function/f_printer.c index 9c7ed2539ff7..8ed1295d7e35 100644 --- a/drivers/usb/gadget/function/f_printer.c +++ b/drivers/usb/gadget/function/f_printer.c @@ -31,6 +31,7 @@ #include <linux/types.h> #include <linux/ctype.h> #include <linux/cdev.h> +#include <linux/kref.h>
#include <asm/byteorder.h> #include <linux/io.h> @@ -64,7 +65,7 @@ struct printer_dev { struct usb_gadget *gadget; s8 interface; struct usb_ep *in_ep, *out_ep; - + struct kref kref; struct list_head rx_reqs; /* List of free RX structs */ struct list_head rx_reqs_active; /* List of Active RX xfers */ struct list_head rx_buffers; /* List of completed xfers */ @@ -218,6 +219,13 @@ static inline struct usb_endpoint_descriptor *ep_desc(struct usb_gadget *gadget,
/*-------------------------------------------------------------------------*/
+static void printer_dev_free(struct kref *kref) +{ + struct printer_dev *dev = container_of(kref, struct printer_dev, kref); + + kfree(dev); +} + static struct usb_request * printer_req_alloc(struct usb_ep *ep, unsigned len, gfp_t gfp_flags) { @@ -348,6 +356,7 @@ printer_open(struct inode *inode, struct file *fd)
spin_unlock_irqrestore(&dev->lock, flags);
+ kref_get(&dev->kref); DBG(dev, "printer_open returned %x\n", ret); return ret; } @@ -365,6 +374,7 @@ printer_close(struct inode *inode, struct file *fd) dev->printer_status &= ~PRINTER_SELECTED; spin_unlock_irqrestore(&dev->lock, flags);
+ kref_put(&dev->kref, printer_dev_free); DBG(dev, "printer_close\n");
return 0; @@ -1350,7 +1360,8 @@ static void gprinter_free(struct usb_function *f) struct f_printer_opts *opts;
opts = container_of(f->fi, struct f_printer_opts, func_inst); - kfree(dev); + + kref_put(&dev->kref, printer_dev_free); mutex_lock(&opts->lock); --opts->refcnt; mutex_unlock(&opts->lock); @@ -1419,6 +1430,7 @@ static struct usb_function *gprinter_alloc(struct usb_function_instance *fi) return ERR_PTR(-ENOMEM); }
+ kref_init(&dev->kref); ++opts->refcnt; dev->minor = opts->minor; dev->pnp_string = opts->pnp_string;