releases/4.9.164/net-x25-fix-use-after-free-in-x25_device_event.patch

   1 From foo@baz Fri Mar 15 21:00:09 PDT 2019
   2 From: Eric Dumazet <edumazet@google.com>
   3 Date: Sun, 10 Mar 2019 09:07:14 -0700
   4 Subject: net/x25: fix use-after-free in x25_device_event()
   5
   6 From: Eric Dumazet <edumazet@google.com>
   7
   8 [ Upstream commit 95d6ebd53c79522bf9502dbc7e89e0d63f94dae4 ]
   9
  10 In case of failure x25_connect() does a x25_neigh_put(x25->neighbour)
  11 but forgets to clear x25->neighbour pointer, thus triggering use-after-free.
  12
  13 Since the socket is visible in x25_list, we need to hold x25_list_lock
  14 to protect the operation.
  15
  16 syzbot report :
  17
  18 BUG: KASAN: use-after-free in x25_kill_by_device net/x25/af_x25.c:217 [inline]
  19 BUG: KASAN: use-after-free in x25_device_event+0x296/0x2b0 net/x25/af_x25.c:252
  20 Read of size 8 at addr ffff8880a030edd0 by task syz-executor003/7854
  21
  22 CPU: 0 PID: 7854 Comm: syz-executor003 Not tainted 5.0.0+ #97
  23 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
  24 Call Trace:
  25  __dump_stack lib/dump_stack.c:77 [inline]
  26  dump_stack+0x172/0x1f0 lib/dump_stack.c:113
  27  print_address_description.cold+0x7c/0x20d mm/kasan/report.c:187
  28  kasan_report.cold+0x1b/0x40 mm/kasan/report.c:317
  29  __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:135
  30  x25_kill_by_device net/x25/af_x25.c:217 [inline]
  31  x25_device_event+0x296/0x2b0 net/x25/af_x25.c:252
  32  notifier_call_chain+0xc7/0x240 kernel/notifier.c:93
  33  __raw_notifier_call_chain kernel/notifier.c:394 [inline]
  34  raw_notifier_call_chain+0x2e/0x40 kernel/notifier.c:401
  35  call_netdevice_notifiers_info+0x3f/0x90 net/core/dev.c:1739
  36  call_netdevice_notifiers_extack net/core/dev.c:1751 [inline]
  37  call_netdevice_notifiers net/core/dev.c:1765 [inline]
  38  __dev_notify_flags+0x1e9/0x2c0 net/core/dev.c:7607
  39  dev_change_flags+0x10d/0x170 net/core/dev.c:7643
  40  dev_ifsioc+0x2b0/0x940 net/core/dev_ioctl.c:237
  41  dev_ioctl+0x1b8/0xc70 net/core/dev_ioctl.c:488
  42  sock_do_ioctl+0x1bd/0x300 net/socket.c:995
  43  sock_ioctl+0x32b/0x610 net/socket.c:1096
  44  vfs_ioctl fs/ioctl.c:46 [inline]
  45  file_ioctl fs/ioctl.c:509 [inline]
  46  do_vfs_ioctl+0xd6e/0x1390 fs/ioctl.c:696
  47  ksys_ioctl+0xab/0xd0 fs/ioctl.c:713
  48  __do_sys_ioctl fs/ioctl.c:720 [inline]
  49  __se_sys_ioctl fs/ioctl.c:718 [inline]
  50  __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718
  51  do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
  52  entry_SYSCALL_64_after_hwframe+0x49/0xbe
  53 RIP: 0033:0x4467c9
  54 Code: e8 0c e8 ff ff 48 83 c4 18 c3 0f 1f 80 00 00 00 00 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 5b 07 fc ff c3 66 2e 0f 1f 84 00 00 00 00
  55 RSP: 002b:00007fdbea222d98 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
  56 RAX: ffffffffffffffda RBX: 00000000006dbc58 RCX: 00000000004467c9
  57 RDX: 0000000020000340 RSI: 0000000000008914 RDI: 0000000000000003
  58 RBP: 00000000006dbc50 R08: 00007fdbea223700 R09: 0000000000000000
  59 R10: 00007fdbea223700 R11: 0000000000000246 R12: 00000000006dbc5c
  60 R13: 6000030030626669 R14: 0000000000000000 R15: 0000000030626669
  61
  62 Allocated by task 7843:
  63  save_stack+0x45/0xd0 mm/kasan/common.c:73
  64  set_track mm/kasan/common.c:85 [inline]
  65  __kasan_kmalloc mm/kasan/common.c:495 [inline]
  66  __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:468
  67  kasan_kmalloc+0x9/0x10 mm/kasan/common.c:509
  68  kmem_cache_alloc_trace+0x151/0x760 mm/slab.c:3615
  69  kmalloc include/linux/slab.h:545 [inline]
  70  x25_link_device_up+0x46/0x3f0 net/x25/x25_link.c:249
  71  x25_device_event+0x116/0x2b0 net/x25/af_x25.c:242
  72  notifier_call_chain+0xc7/0x240 kernel/notifier.c:93
  73  __raw_notifier_call_chain kernel/notifier.c:394 [inline]
  74  raw_notifier_call_chain+0x2e/0x40 kernel/notifier.c:401
  75  call_netdevice_notifiers_info+0x3f/0x90 net/core/dev.c:1739
  76  call_netdevice_notifiers_extack net/core/dev.c:1751 [inline]
  77  call_netdevice_notifiers net/core/dev.c:1765 [inline]
  78  __dev_notify_flags+0x121/0x2c0 net/core/dev.c:7605
  79  dev_change_flags+0x10d/0x170 net/core/dev.c:7643
  80  dev_ifsioc+0x2b0/0x940 net/core/dev_ioctl.c:237
  81  dev_ioctl+0x1b8/0xc70 net/core/dev_ioctl.c:488
  82  sock_do_ioctl+0x1bd/0x300 net/socket.c:995
  83  sock_ioctl+0x32b/0x610 net/socket.c:1096
  84  vfs_ioctl fs/ioctl.c:46 [inline]
  85  file_ioctl fs/ioctl.c:509 [inline]
  86  do_vfs_ioctl+0xd6e/0x1390 fs/ioctl.c:696
  87  ksys_ioctl+0xab/0xd0 fs/ioctl.c:713
  88  __do_sys_ioctl fs/ioctl.c:720 [inline]
  89  __se_sys_ioctl fs/ioctl.c:718 [inline]
  90  __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718
  91  do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
  92  entry_SYSCALL_64_after_hwframe+0x49/0xbe
  93
  94 Freed by task 7865:
  95  save_stack+0x45/0xd0 mm/kasan/common.c:73
  96  set_track mm/kasan/common.c:85 [inline]
  97  __kasan_slab_free+0x102/0x150 mm/kasan/common.c:457
  98  kasan_slab_free+0xe/0x10 mm/kasan/common.c:465
  99  __cache_free mm/slab.c:3494 [inline]
 100  kfree+0xcf/0x230 mm/slab.c:3811
 101  x25_neigh_put include/net/x25.h:253 [inline]
 102  x25_connect+0x8d8/0xde0 net/x25/af_x25.c:824
 103  __sys_connect+0x266/0x330 net/socket.c:1685
 104  __do_sys_connect net/socket.c:1696 [inline]
 105  __se_sys_connect net/socket.c:1693 [inline]
 106  __x64_sys_connect+0x73/0xb0 net/socket.c:1693
 107  do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
 108  entry_SYSCALL_64_after_hwframe+0x49/0xbe
 109
 110 The buggy address belongs to the object at ffff8880a030edc0
 111  which belongs to the cache kmalloc-256 of size 256
 112 The buggy address is located 16 bytes inside of
 113  256-byte region [ffff8880a030edc0, ffff8880a030eec0)
 114 The buggy address belongs to the page:
 115 page:ffffea000280c380 count:1 mapcount:0 mapping:ffff88812c3f07c0 index:0x0
 116 flags: 0x1fffc0000000200(slab)
 117 raw: 01fffc0000000200 ffffea0002806788 ffffea00027f0188 ffff88812c3f07c0
 118 raw: 0000000000000000 ffff8880a030e000 000000010000000c 0000000000000000
 119 page dumped because: kasan: bad access detected
 120
 121 Signed-off-by: Eric Dumazet <edumazet@google.com>
 122 Reported-by: syzbot+04babcefcd396fabec37@syzkaller.appspotmail.com
 123 Cc: andrew hendry <andrew.hendry@gmail.com>
 124 Signed-off-by: David S. Miller <davem@davemloft.net>
 125 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
 126 ---
 127  net/x25/af_x25.c |    6 +++++-
 128  1 file changed, 5 insertions(+), 1 deletion(-)
 129
 130 --- a/net/x25/af_x25.c
 131 +++ b/net/x25/af_x25.c
 132 @@ -812,8 +812,12 @@ static int x25_connect(struct socket *so
 133         sock->state = SS_CONNECTED;
 134         rc = 0;
 135  out_put_neigh:
 136 -       if (rc)
 137 +       if (rc) {
 138 +               read_lock_bh(&x25_list_lock);
 139                 x25_neigh_put(x25->neighbour);
 140 +               x25->neighbour = NULL;
 141 +               read_unlock_bh(&x25_list_lock);
 142 +       }
 143  out_put_route:
 144         x25_route_put(rt);
 145  out: