syzbot


kernel BUG at net/core/dev.c:LINE!

Status: fixed on 2021/01/17 13:53
Reported-by: syzbot+7010af67ced6105e5ab6@syzkaller.appspotmail.com
Fix commit: 8f9a69a92fc6 net: drop bogus skb with CHECKSUM_PARTIAL and offset beyond end of trimmed packet
First crash: 974d, last: 705d

Fix bisection: the fix commit could be any of (bisect log):
  4520f06b03ae Linux 4.14.175
  4139fb08c05f Linux 4.14.187
similar bugs (8):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.19 kernel BUG at net/core/dev.c:LINE! (2) C error 90 51d 723d 0/1 upstream: reported C repro on 2020/12/11 13:29
linux-4.14 kernel BUG in validate_xmit_skb 1 662d 662d 0/1 auto-closed as invalid on 2021/06/10 04:03
upstream kernel BUG at net/core/dev.c:LINE! (2) syz 2 1516d 1516d 12/24 fixed on 2018/10/18 14:43
upstream kernel BUG in netem_enqueue 8 19d 214d 23/24 internal: reported on 2022/05/04 17:12
linux-4.19 kernel BUG at net/core/dev.c:LINE! 4 953d 955d 0/1 auto-closed as invalid on 2020/08/23 07:17
upstream kernel BUG at net/core/dev.c:LINE! (4) C done done 432 354d 741d 22/24 fixed on 2022/03/08 16:11
upstream kernel BUG at net/core/dev.c:LINE! C 5 1833d 1838d 3/24 fixed on 2017/12/08 02:32
upstream kernel BUG at net/core/dev.c:LINE! (3) C done 979 823d 967d 17/24 fixed on 2020/09/16 22:51

Sample crash report:
ip_tables: iptables: counters copy to user failed while replacing table
------------[ cut here ]------------
kernel BUG at net/core/dev.c:2648!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
Modules linked in:
CPU: 0 PID: 6341 Comm: syz-executor763 Not tainted 4.14.175-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8880846780c0 task.stack: ffff888097cd8000
RIP: 0010:skb_checksum_help+0x5fd/0x830 net/core/dev.c:2648
RSP: 0018:ffff888097cdf468 EFLAGS: 00010297
RAX: ffff8880846780c0 RBX: 00000000000000e0 RCX: 0000000000000120
RDX: 0000000000000000 RSI: 000000000000001c RDI: 0000000000000000
RBP: ffff88809dd2cb40 R08: ffff88809dd2cbc0 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff88809dd2cbc4
R13: ffff88809dd2cc0c R14: ffff88809dd2cbd0 R15: 0000000000000000
FS:  0000000000f03880(0000) GS:ffff8880aea00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000008d0ca000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 checksum_tg+0x52/0x65 net/netfilter/xt_CHECKSUM.c:29
 ipt_do_table+0xaaf/0x16d0 net/ipv4/netfilter/ip_tables.c:353
 iptable_mangle_hook+0x9c/0x560 net/ipv4/netfilter/iptable_mangle.c:90
 nf_hook_entry_hookfn include/linux/netfilter.h:108 [inline]
 nf_hook_slow+0xa5/0x1a0 net/netfilter/core.c:467
 nf_hook include/linux/netfilter.h:205 [inline]
 NF_HOOK include/linux/netfilter.h:248 [inline]
 ip_rcv+0xb9e/0xfec net/ipv4/ip_input.c:493
 __netif_receive_skb_core+0x1e50/0x2c00 net/core/dev.c:4477
 __netif_receive_skb+0x27/0x1a0 net/core/dev.c:4515
 netif_receive_skb_internal+0xd7/0x580 net/core/dev.c:4588
 tun_rx_batched.isra.0+0x46c/0x7a0 drivers/net/tun.c:1221
 tun_get_user+0xcde/0x3880 drivers/net/tun.c:1581
 tun_chr_write_iter+0xcf/0x179 drivers/net/tun.c:1608
 call_write_iter include/linux/fs.h:1778 [inline]
 new_sync_write fs/read_write.c:469 [inline]
 __vfs_write+0x44e/0x630 fs/read_write.c:482
 vfs_write+0x192/0x4e0 fs/read_write.c:544
 SYSC_write fs/read_write.c:590 [inline]
 SyS_write+0xf2/0x210 fs/read_write.c:582
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x441729
RSP: 002b:00007fffbaae6ae8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000441729
RDX: 000000000000fdef RSI: 00000000200000c0 RDI: 0000000000000003
RBP: 656c6c616b7a7973 R08: 0000000000001c00 R09: 0000000000402fb0
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000402fb0
R13: 0000000000403040 R14: 0000000000000000 R15: 0000000000000000
Code: 8b 7c 24 28 e8 75 e0 85 fc e9 0d fe ff ff e8 4b 8e 5c fc 48 89 ef 41 bc ea ff ff ff e8 9d b3 ff ff e9 94 fe ff ff e8 33 8e 5c fc <0f> 0b e8 2c 8e 5c fc 0f 0b e8 25 8e 5c fc 48 8b 54 24 28 48 b8 
RIP: skb_checksum_help+0x5fd/0x830 net/core/dev.c:2648 RSP: ffff888097cdf468
---[ end trace dd20dd799c821843 ]---

Crashes (3):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-linux-4-14 2020/04/04 03:36 linux-4.14.y 4520f06b03ae ef26b610 .config log report syz C
ci2-linux-4-14 2020/12/29 08:11 linux-4.14.y 3f2ecb86cb90 8259d56c .config log report info
ci2-linux-4-14 2020/12/08 15:04 linux-4.14.y 47cbf4cc32db 9af51e31 .config log report info
* Struck through repros no longer work on HEAD.