1. 13 Apr, 2021 6 commits
  2. 12 Apr, 2021 10 commits
  3. 05 Apr, 2021 14 commits
  4. 04 Apr, 2021 2 commits
    • Linus Torvalds's avatar
      Linux 5.12-rc6 · e49d033b
      Linus Torvalds authored
      e49d033b
    • Zheyu Ma's avatar
      firewire: nosy: Fix a use-after-free bug in nosy_ioctl() · 829933ef
      Zheyu Ma authored
      For each device, the nosy driver allocates a pcilynx structure.
      A use-after-free might happen in the following scenario:
      
       1. Open nosy device for the first time and call ioctl with command
          NOSY_IOC_START, then a new client A will be malloced and added to
          doubly linked list.
       2. Open nosy device for the second time and call ioctl with command
          NOSY_IOC_START, then a new client B will be malloced and added to
          doubly linked list.
       3. Call ioctl with command NOSY_IOC_START for client A, then client A
          will be readded to the doubly linked list. Now the doubly linked
          list is messed up.
       4. Close the first nosy device and nosy_release will be called. In
          nosy_release, client A will be unlinked and freed.
       5. Close the second nosy device, and client A will be referenced,
          resulting in UAF.
      
      The root cause of this bug is that the element in the doubly linked list
      is reentered into the list.
      
      Fix this bug by adding a check before inserting a client.  If a client
      is already in the linked list, don't insert it.
      
      The following KASAN report reveals it:
      
         BUG: KASAN: use-after-free in nosy_release+0x1ea/0x210
         Write of size 8 at addr ffff888102ad7360 by task poc
         CPU: 3 PID: 337 Comm: poc Not tainted 5.12.0-rc5+ #6
         Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/01/2014
         Call Trace:
           nosy_release+0x1ea/0x210
           __fput+0x1e2/0x840
           task_work_run+0xe8/0x180
           exit_to_user_mode_prepare+0x114/0x120
           syscall_exit_to_user_mode+0x1d/0x40
           entry_SYSCALL_64_after_hwframe+0x44/0xae
      
         Allocated by task 337:
           nosy_open+0x154/0x4d0
           misc_open+0x2ec/0x410
           chrdev_open+0x20d/0x5a0
           do_dentry_open+0x40f/0xe80
           path_openat+0x1cf9/0x37b0
           do_filp_open+0x16d/0x390
           do_sys_openat2+0x11d/0x360
           __x64_sys_open+0xfd/0x1a0
           do_syscall_64+0x33/0x40
           entry_SYSCALL_64_after_hwframe+0x44/0xae
      
         Freed by task 337:
           kfree+0x8f/0x210
           nosy_release+0x158/0x210
           __fput+0x1e2/0x840
           task_work_run+0xe8/0x180
           exit_to_user_mode_prepare+0x114/0x120
           syscall_exit_to_user_mode+0x1d/0x40
           entry_SYSCALL_64_after_hwframe+0x44/0xae
      
         The buggy address belongs to the object at ffff888102ad7300 which belongs to the cache kmalloc-128 of size 128
         The buggy address is located 96 bytes inside of 128-byte region [ffff888102ad7300, ffff888102ad7380)
      
      [ Modified to use 'list_empty()' inside proper lock  - Linus ]
      
      Link: https://lore.kernel.org/lkml/1617433116-5930-1-git-send-email-zheyuma97@gmail.com/Reported-and-tested-by: default avatar马哲宇 (Zheyu Ma) <zheyuma97@gmail.com>
      Signed-off-by: default avatarZheyu Ma <zheyuma97@gmail.com>
      Cc: Greg Kroah-Hartman <greg@kroah.com>
      Cc: Stefan Richter <stefanr@s5r6.in-berlin.de>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      829933ef
  5. 03 Apr, 2021 8 commits