Hello, syzbot found the following issue on: HEAD commit: b77ffb30cfc5 libbpf: fix an snprintf() overflow check git tree: bpf-next console+strace: https://syzkaller.appspot.com/x/log.txt?x=11ef3226080000 kernel config: https://syzkaller.appspot.com/x/.config?x=386b986585586629 dashboard link: https://syzkaller.appspot.com/bug?extid=5ea725c25d06fb9114c4 compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=11004e64080000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1009bfd0080000 The issue was bisected to: commit fd1894224407c484f652ad456e1ce423e89bb3eb Author: Zhengchao Shao <shaozhengchao@xxxxxxxxxx> Date: Fri Jul 15 11:55:59 2022 +0000 bpf: Don't redirect packets with invalid pkt_len bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=1749bfd0080000 final oops: https://syzkaller.appspot.com/x/report.txt?x=14c9bfd0080000 console output: https://syzkaller.appspot.com/x/log.txt?x=10c9bfd0080000 IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+5ea725c25d06fb9114c4@xxxxxxxxxxxxxxxxxxxxxxxxx Fixes: fd1894224407 ("bpf: Don't redirect packets with invalid pkt_len") ------------[ cut here ]------------ skb_assert_len WARNING: CPU: 0 PID: 3608 at include/linux/skbuff.h:2465 skb_assert_len include/linux/skbuff.h:2465 [inline] WARNING: CPU: 0 PID: 3608 at include/linux/skbuff.h:2465 __dev_queue_xmit+0x313c/0x3ad0 net/core/dev.c:4171 Modules linked in: CPU: 0 PID: 3608 Comm: syz-executor357 Not tainted 5.19.0-rc5-syzkaller-01146-gb77ffb30cfc5 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/29/2022 RIP: 0010:skb_assert_len include/linux/skbuff.h:2465 [inline] RIP: 0010:__dev_queue_xmit+0x313c/0x3ad0 net/core/dev.c:4171 Code: 10 e8 18 6c 73 fa e9 b4 f2 ff ff e8 4e 18 26 fa 48 c7 c6 a0 81 d3 8a 48 c7 c7 a0 55 d3 8a c6 05 89 33 52 06 01 e8 45 75 de 01 <0f> 0b e9 4f f2 ff ff e8 28 18 26 fa e8 a3 17 10 fa 31 ff 89 c3 89 RSP: 0018:ffffc900031af748 EFLAGS: 00010286 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: ffff88801b9bbb00 RSI: ffffffff8160d618 RDI: fffff52000635edb RBP: ffff888020059aba R08: 0000000000000005 R09: 0000000000000000 R10: 0000000080000000 R11: 0000000000000001 R12: ffff888020059a00 R13: 0000000000000000 R14: ffff888020059a10 R15: ffff888020059a00 FS: 0000555556f80300(0000) GS:ffff8880b9a00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000561be8192048 CR3: 0000000020721000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> packet_snd net/packet/af_packet.c:3073 [inline] packet_sendmsg+0x21f4/0x55d0 net/packet/af_packet.c:3104 sock_sendmsg_nosec net/socket.c:714 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:734 ____sys_sendmsg+0x6eb/0x810 net/socket.c:2485 ___sys_sendmsg+0xf3/0x170 net/socket.c:2539 __sys_sendmsg net/socket.c:2568 [inline] __do_sys_sendmsg net/socket.c:2577 [inline] __se_sys_sendmsg net/socket.c:2575 [inline] __x64_sys_sendmsg+0x132/0x220 net/socket.c:2575 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x46/0xb0 RIP: 0033:0x7f4882617369 Code: 28 c3 e8 4a 15 00 00 66 2e 0f 1f 84 00 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 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fff94d23dd8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f4882617369 RDX: 0000000000000000 RSI: 0000000020000100 RDI: 0000000000000003 RBP: 0000000000000003 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fff94d23df0 R13: 00007fff94d23e10 R14: 0000000000000000 R15: 0000000000000000 </TASK> --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. For information about bisection process see: https://goo.gl/tpsmEJ#bisection syzbot can test patches for this issue, for details see: https://goo.gl/tpsmEJ#testing-patches
