1. 27 Feb, 2019 38 commits
  2. 23 Feb, 2019 2 commits
    • Greg Kroah-Hartman's avatar
      Linux 4.14.103 · c793fa33
      Greg Kroah-Hartman authored
      c793fa33
    • Eric Dumazet's avatar
      ax25: fix possible use-after-free · d283ed95
      Eric Dumazet authored
      commit 63530aba
      
       upstream.
      
      syzbot found that ax25 routes where not properly protected
      against concurrent use [1].
      
      In this particular report the bug happened while
      copying ax25->digipeat.
      
      Fix this problem by making sure we call ax25_get_route()
      while ax25_route_lock is held, so that no modification
      could happen while using the route.
      
      The current two ax25_get_route() callers do not sleep,
      so this change should be fine.
      
      Once we do that, ax25_get_route() no longer needs to
      grab a reference on the found route.
      
      [1]
      ax25_connect(): syz-executor0 uses autobind, please contact jreuter@yaina.de
      BUG: KASAN: use-after-free in memcpy include/linux/string.h:352 [inline]
      BUG: KASAN: use-after-free in kmemdup+0x42/0x60 mm/util.c:113
      Read of size 66 at addr ffff888066641a80 by task syz-executor2/531
      
      ax25_connect(): syz-executor0 uses autobind, please contact jreuter@yaina.de
      CPU: 1 PID: 531 Comm: syz-executor2 Not tainted 5.0.0-rc2+ #10
      Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
      Call Trace:
       __dump_stack lib/dump_stack.c:77 [inline]
       dump_stack+0x1db/0x2d0 lib/dump_stack.c:113
       print_address_description.cold+0x7c/0x20d mm/kasan/report.c:187
       kasan_report.cold+0x1b/0x40 mm/kasan/report.c:317
       check_memory_region_inline mm/kasan/generic.c:185 [inline]
       check_memory_region+0x123/0x190 mm/kasan/generic.c:191
       memcpy+0x24/0x50 mm/kasan/common.c:130
       memcpy include/linux/string.h:352 [inline]
       kmemdup+0x42/0x60 mm/util.c:113
       kmemdup include/linux/string.h:425 [inline]
       ax25_rt_autobind+0x25d/0x750 net/ax25/ax25_route.c:424
       ax25_connect.cold+0x30/0xa4 net/ax25/af_ax25.c:1224
       __sys_connect+0x357/0x490 net/socket.c:1664
       __do_sys_connect net/socket.c:1675 [inline]
       __se_sys_connect net/socket.c:1672 [inline]
       __x64_sys_connect+0x73/0xb0 net/socket.c:1672
       do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290
       entry_SYSCALL_64_after_hwframe+0x49/0xbe
      RIP: 0033:0x458099
      Code: 6d b7 fb 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 3b b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00
      RSP: 002b:00007f870ee22c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
      RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000458099
      RDX: 0000000000000048 RSI: 0000000020000080 RDI: 0000000000000005
      RBP: 000000000073bf00 R08: 0000000000000000 R09: 0000000000000000
      ax25_connect(): syz-executor4 uses autobind, please contact jreuter@yaina.de
      R10: 0000000000000000 R11: 0000000000000246 R12: 00007f870ee236d4
      R13: 00000000004be48e R14: 00000000004ce9a8 R15: 00000000ffffffff
      
      Allocated by task 526:
       save_stack+0x45/0xd0 mm/kasan/common.c:73
       set_track mm/kasan/common.c:85 [inline]
       __kasan_kmalloc mm/kasan/common.c:496 [inline]
       __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:469
       kasan_kmalloc+0x9/0x10 mm/kasan/common.c:504
      ax25_connect(): syz-executor5 uses autobind, please contact jreuter@yaina.de
       kmem_cache_alloc_trace+0x151/0x760 mm/slab.c:3609
       kmalloc include/linux/slab.h:545 [inline]
       ax25_rt_add net/ax25/ax25_route.c:95 [inline]
       ax25_rt_ioctl+0x3b9/0x1270 net/ax25/ax25_route.c:233
       ax25_ioctl+0x322/0x10b0 net/ax25/af_ax25.c:1763
       sock_do_ioctl+0xe2/0x400 net/socket.c:950
       sock_ioctl+0x32f/0x6c0 net/socket.c:1074
       vfs_ioctl fs/ioctl.c:46 [inline]
       file_ioctl fs/ioctl.c:509 [inline]
       do_vfs_ioctl+0x107b/0x17d0 fs/ioctl.c:696
       ksys_ioctl+0xab/0xd0 fs/ioctl.c:713
       __do_sys_ioctl fs/ioctl.c:720 [inline]
       __se_sys_ioctl fs/ioctl.c:718 [inline]
       __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718
       do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290
       entry_SYSCALL_64_after_hwframe+0x49/0xbe
      
      ax25_connect(): syz-executor5 uses autobind, please contact jreuter@yaina.de
      Freed by task 550:
       save_stack+0x45/0xd0 mm/kasan/common.c:73
       set_track mm/kasan/common.c:85 [inline]
       __kasan_slab_free+0x102/0x150 mm/kasan/common.c:458
       kasan_slab_free+0xe/0x10 mm/kasan/common.c:466
       __cache_free mm/slab.c:3487 [inline]
       kfree+0xcf/0x230 mm/slab.c:3806
       ax25_rt_add net/ax25/ax25_route.c:92 [inline]
       ax25_rt_ioctl+0x304/0x1270 net/ax25/ax25_route.c:233
       ax25_ioctl+0x322/0x10b0 net/ax25/af_ax25.c:1763
       sock_do_ioctl+0xe2/0x400 net/socket.c:950
       sock_ioctl+0x32f/0x6c0 net/socket.c:1074
       vfs_ioctl fs/ioctl.c:46 [inline]
       file_ioctl fs/ioctl.c:509 [inline]
       do_vfs_ioctl+0x107b/0x17d0 fs/ioctl.c:696
       ksys_ioctl+0xab/0xd0 fs/ioctl.c:713
       __do_sys_ioctl fs/ioctl.c:720 [inline]
       __se_sys_ioctl fs/ioctl.c:718 [inline]
       __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718
       do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290
       entry_SYSCALL_64_after_hwframe+0x49/0xbe
      
      The buggy address belongs to the object at ffff888066641a80
       which belongs to the cache kmalloc-96 of size 96
      The buggy address is located 0 bytes inside of
       96-byte region [ffff888066641a80, ffff888066641ae0)
      The buggy address belongs to the page:
      page:ffffea0001999040 count:1 mapcount:0 mapping:ffff88812c3f04c0 index:0x0
      flags: 0x1fffc0000000200(slab)
      ax25_connect(): syz-executor4 uses autobind, please contact jreuter@yaina.de
      raw: 01fffc0000000200 ffffea0001817948 ffffea0002341dc8 ffff88812c3f04c0
      raw: 0000000000000000 ffff888066641000 0000000100000020 0000000000000000
      page dumped because: kasan: bad access detected
      
      Memory state around the buggy address:
       ffff888066641980: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
       ffff888066641a00: 00 00 00 00 00 00 00 00 02 fc fc fc fc fc fc fc
      >ffff888066641a80: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
                         ^
       ffff888066641b00: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
       ffff888066641b80: 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc fc
      Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
      Cc: Ralf Baechle <ralf@linux-mips.org>
      Reported-by: default avatarsyzbot <syzkaller@googlegroups.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      d283ed95