1. 31 3月, 2018 1 次提交
    • T
      net: Fix untag for vlan packets without ethernet header · ae474573
      Toshiaki Makita 提交于
      In some situation vlan packets do not have ethernet headers. One example
      is packets from tun devices. Users can specify vlan protocol in tun_pi
      field instead of IP protocol, and skb_vlan_untag() attempts to untag such
      packets.
      
      skb_vlan_untag() (more precisely, skb_reorder_vlan_header() called by it)
      however did not expect packets without ethernet headers, so in such a case
      size argument for memmove() underflowed and triggered crash.
      
      ====
      BUG: unable to handle kernel paging request at ffff8801cccb8000
      IP: __memmove+0x24/0x1a0 arch/x86/lib/memmove_64.S:43
      PGD 9cee067 P4D 9cee067 PUD 1d9401063 PMD 1cccb7063 PTE 2810100028101
      Oops: 000b [#1] SMP KASAN
      Dumping ftrace buffer:
         (ftrace buffer empty)
      Modules linked in:
      CPU: 1 PID: 17663 Comm: syz-executor2 Not tainted 4.16.0-rc7+ #368
      Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
      RIP: 0010:__memmove+0x24/0x1a0 arch/x86/lib/memmove_64.S:43
      RSP: 0018:ffff8801cc046e28 EFLAGS: 00010287
      RAX: ffff8801ccc244c4 RBX: fffffffffffffffe RCX: fffffffffff6c4c2
      RDX: fffffffffffffffe RSI: ffff8801cccb7ffc RDI: ffff8801cccb8000
      RBP: ffff8801cc046e48 R08: ffff8801ccc244be R09: ffffed0039984899
      R10: 0000000000000001 R11: ffffed0039984898 R12: ffff8801ccc244c4
      R13: ffff8801ccc244c0 R14: ffff8801d96b7c06 R15: ffff8801d96b7b40
      FS:  00007febd562d700(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000
      CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
      CR2: ffff8801cccb8000 CR3: 00000001ccb2f006 CR4: 00000000001606e0
      DR0: 0000000020000000 DR1: 0000000020000000 DR2: 0000000000000000
      DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
      Call Trace:
       memmove include/linux/string.h:360 [inline]
       skb_reorder_vlan_header net/core/skbuff.c:5031 [inline]
       skb_vlan_untag+0x470/0xc40 net/core/skbuff.c:5061
       __netif_receive_skb_core+0x119c/0x3460 net/core/dev.c:4460
       __netif_receive_skb+0x2c/0x1b0 net/core/dev.c:4627
       netif_receive_skb_internal+0x10b/0x670 net/core/dev.c:4701
       netif_receive_skb+0xae/0x390 net/core/dev.c:4725
       tun_rx_batched.isra.50+0x5ee/0x870 drivers/net/tun.c:1555
       tun_get_user+0x299e/0x3c20 drivers/net/tun.c:1962
       tun_chr_write_iter+0xb9/0x160 drivers/net/tun.c:1990
       call_write_iter include/linux/fs.h:1782 [inline]
       new_sync_write fs/read_write.c:469 [inline]
       __vfs_write+0x684/0x970 fs/read_write.c:482
       vfs_write+0x189/0x510 fs/read_write.c:544
       SYSC_write fs/read_write.c:589 [inline]
       SyS_write+0xef/0x220 fs/read_write.c:581
       do_syscall_64+0x281/0x940 arch/x86/entry/common.c:287
       entry_SYSCALL_64_after_hwframe+0x42/0xb7
      RIP: 0033:0x454879
      RSP: 002b:00007febd562cc68 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
      RAX: ffffffffffffffda RBX: 00007febd562d6d4 RCX: 0000000000454879
      RDX: 0000000000000157 RSI: 0000000020000180 RDI: 0000000000000014
      RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000000
      R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
      R13: 00000000000006b0 R14: 00000000006fc120 R15: 0000000000000000
      Code: 90 90 90 90 90 90 90 48 89 f8 48 83 fa 20 0f 82 03 01 00 00 48 39 fe 7d 0f 49 89 f0 49 01 d0 49 39 f8 0f 8f 9f 00 00 00 48 89 d1 <f3> a4 c3 48 81 fa a8 02 00 00 72 05 40 38 fe 74 3b 48 83 ea 20
      RIP: __memmove+0x24/0x1a0 arch/x86/lib/memmove_64.S:43 RSP: ffff8801cc046e28
      CR2: ffff8801cccb8000
      ====
      
      We don't need to copy headers for packets which do not have preceding
      headers of vlan headers, so skip memmove() in that case.
      
      Fixes: 4bbb3e0e ("net: Fix vlan untag for bridge and vlan_dev with reorder_hdr off")
      Reported-by: NEric Dumazet <eric.dumazet@gmail.com>
      Signed-off-by: NToshiaki Makita <makita.toshiaki@lab.ntt.co.jp>
      Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      ae474573
  2. 30 3月, 2018 4 次提交
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