On 2018/03/28 15:11, Eric Dumazet wrote: > On 03/16/2018 07:05 AM, David Miller wrote: >> From: Toshiaki Makita <makita.toshi...@lab.ntt.co.jp> >> Date: Tue, 13 Mar 2018 14:51:26 +0900 >> >>> As Brandon Carpenter reported[1], sending non-vlan-offloaded packets from >>> bridge devices ends up with corrupted packets. He narrowed down this problem >>> and found that the root cause is in skb_reorder_vlan_header(). >>> >>> While I was working on fixing this problem, I found that the function does >>> not work properly for double tagged packets with reorder_hdr off as well. >>> >>> Patch 1 fixes these 2 problems in skb_reorder_vlan_header(). >>> >>> And it turned out that fixing skb_reorder_vlan_header() is not sufficient >>> to receive double tagged packets with reorder_hdr off while I was testing >>> the >>> fix. Vlan tags got out of order when vlan devices with reorder_hdr disabled >>> were stacked. Patch 2 fixes this problem. >>> >>> [1] https://www.spinics.net/lists/linux-ethernet-bridging/msg07039.html >> >> Series applied and queued up for -stable, thanks. >> >> I was thinking of pushing back on the addition of the ETH_TLEN UAPI visible >> macro, because I don't see any other system providing that define. But in >> the end I decided that it's harmless and really that header file is the >> correct location for such a definition. >> >> Thank you. >> > > syzbot reported some crashes caused by a memmove(..., ..., count=-2)
Thank you for your report. Interesting, tun device can make vlan packets which does not have ethernet header. > > So something needs to be refined I guess. Probably we can skip memmove() for such packets, since there is no header to copy. I'll make a fix. Thanks. > > 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 > ---[ end trace b21c0866ee797d6d ]--- > BUG: unable to handle kernel > > > -- Toshiaki Makita
