[syzbot] [bpf?] [net?] stack segment fault in bpf_xdp_redirect

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 1c5fc27bc48a Merge tag 'nf-next-24-06-28' of git://git.ker..
git tree: net-next
console output: https://syzkaller.appspot.com/x/log.txt?x=11aa6fa6980000
kernel config: https://syzkaller.appspot.com/x/.config?x=5264b58fdff6e881
dashboard link: https://syzkaller.appspot.com/bug?extid=5ae46b237278e2369cac
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/9672225af907/disk-1c5fc27b.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/0f14d163a914/vmlinux-1c5fc27b.xz
kernel image: https://storage.googleapis.com/syzbot-assets/ec6c331e6a6e/bzImage-1c5fc27b.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+5ae46b...@syzkaller.appspotmail.com

Oops: stack segment: 0000 [#1] PREEMPT SMP KASAN PTI
CPU: 1 PID: 10179 Comm: syz.0.1527 Not tainted 6.10.0-rc5-syzkaller-01137-g1c5fc27bc48a #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
RIP: 0010:bpf_net_ctx_get_ri include/linux/filter.h:788 [inline]
RIP: 0010:____bpf_xdp_redirect net/core/filter.c:4544 [inline]
RIP: 0010:bpf_xdp_redirect+0x59/0x1a0 net/core/filter.c:4542
Code: 81 c3 08 18 00 00 48 89 d8 48 c1 e8 03 42 80 3c 28 00 74 08 48 89 df e8 55 1a 99 f8 48 8b 1b 4c 8d 63 38 4c 89 e5 48 c1 ed 03 <42> 0f b6 44 2d 00 84 c0 0f 85 d0 00 00 00 45 8b 34 24 44 89 f6 83
RSP: 0018:ffffc9000d537970 EFLAGS: 00010202
RAX: 1ffff1100c81ca81 RBX: 0000000000000000 RCX: ffff8880640e3c00
RDX: 0000000000000000 RSI: 000000000000a020 RDI: ffffc9000d537af0
RBP: 0000000000000007 R08: ffffffff8665e84f R09: 1ffffffff25f78b0
R10: dffffc0000000000 R11: fffffbfff25f78b1 R12: 0000000000000038
R13: dffffc0000000000 R14: ffffc90012a31048 R15: 000000000000a020
FS: 00007f04c1ac26c0(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f04c1aa1d58 CR3: 000000002ccf6000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
bpf_prog_bc55b47b7a2429cd+0x1d/0x1f
__bpf_prog_run include/linux/filter.h:691 [inline]
bpf_prog_run_xdp include/net/xdp.h:514 [inline]
tun_build_skb drivers/net/tun.c:1711 [inline]
tun_get_user+0x3321/0x4560 drivers/net/tun.c:1819
tun_chr_write_iter+0x113/0x1f0 drivers/net/tun.c:2048
new_sync_write fs/read_write.c:497 [inline]
vfs_write+0xa72/0xc90 fs/read_write.c:590
ksys_write+0x1a0/0x2c0 fs/read_write.c:643
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f04c0d7471f
Code: 89 54 24 18 48 89 74 24 10 89 7c 24 08 e8 29 8c 02 00 48 8b 54 24 18 48 8b 74 24 10 41 89 c0 8b 7c 24 08 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 31 44 89 c7 48 89 44 24 08 e8 7c 8c 02 00 48
RSP: 002b:00007f04c1ac2010 EFLAGS: 00000293 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f04c0f04150 RCX: 00007f04c0d7471f
RDX: 0000000000000032 RSI: 0000000020001500 RDI: 00000000000000c8
RBP: 00007f04c0df677e R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000032 R11: 0000000000000293 R12: 0000000000000000
R13: 000000000000000b R14: 00007f04c0f04150 R15: 00007ffffb5272c8
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:bpf_net_ctx_get_ri include/linux/filter.h:788 [inline]
RIP: 0010:____bpf_xdp_redirect net/core/filter.c:4544 [inline]
RIP: 0010:bpf_xdp_redirect+0x59/0x1a0 net/core/filter.c:4542
Code: 81 c3 08 18 00 00 48 89 d8 48 c1 e8 03 42 80 3c 28 00 74 08 48 89 df e8 55 1a 99 f8 48 8b 1b 4c 8d 63 38 4c 89 e5 48 c1 ed 03 <42> 0f b6 44 2d 00 84 c0 0f 85 d0 00 00 00 45 8b 34 24 44 89 f6 83
RSP: 0018:ffffc9000d537970 EFLAGS: 00010202
RAX: 1ffff1100c81ca81 RBX: 0000000000000000 RCX: ffff8880640e3c00
RDX: 0000000000000000 RSI: 000000000000a020 RDI: ffffc9000d537af0
RBP: 0000000000000007 R08: ffffffff8665e84f R09: 1ffffffff25f78b0
R10: dffffc0000000000 R11: fffffbfff25f78b1 R12: 0000000000000038
R13: dffffc0000000000 R14: ffffc90012a31048 R15: 000000000000a020
FS: 00007f04c1ac26c0(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f04c1aa1d58 CR3: 000000002ccf6000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
0: 81 c3 08 18 00 00 add $0x1808,%ebx
6: 48 89 d8 mov %rbx,%rax
9: 48 c1 e8 03 shr $0x3,%rax
d: 42 80 3c 28 00 cmpb $0x0,(%rax,%r13,1)
12: 74 08 je 0x1c
14: 48 89 df mov %rbx,%rdi
17: e8 55 1a 99 f8 call 0xf8991a71
1c: 48 8b 1b mov (%rbx),%rbx
1f: 4c 8d 63 38 lea 0x38(%rbx),%r12
23: 4c 89 e5 mov %r12,%rbp
26: 48 c1 ed 03 shr $0x3,%rbp
* 2a: 42 0f b6 44 2d 00 movzbl 0x0(%rbp,%r13,1),%eax <-- trapping instruction
30: 84 c0 test %al,%al
32: 0f 85 d0 00 00 00 jne 0x108
38: 45 8b 34 24 mov (%r12),%r14d
3c: 44 89 f6 mov %r14d,%esi
3f: 83 .byte 0x83


---
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[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit: 1c5fc27bc48a Merge tag 'nf-next-24-06-28' of git://git.ker..
git tree: net-next

console output: https://syzkaller.appspot.com/x/log.txt?x=14aeab3e980000

kernel config: https://syzkaller.appspot.com/x/.config?x=5264b58fdff6e881
dashboard link: https://syzkaller.appspot.com/bug?extid=5ae46b237278e2369cac
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1673738e980000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/9672225af907/disk-1c5fc27b.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/0f14d163a914/vmlinux-1c5fc27b.xz
kernel image: https://storage.googleapis.com/syzbot-assets/ec6c331e6a6e/bzImage-1c5fc27b.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+5ae46b...@syzkaller.appspotmail.com

Oops: stack segment: 0000 [#1] PREEMPT SMP KASAN PTI

CPU: 1 PID: 14042 Comm: syz.0.2930 Not tainted 6.10.0-rc5-syzkaller-01137-g1c5fc27bc48a #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
RIP: 0010:bpf_net_ctx_get_ri include/linux/filter.h:788 [inline]
RIP: 0010:____bpf_xdp_redirect net/core/filter.c:4544 [inline]
RIP: 0010:bpf_xdp_redirect+0x59/0x1a0 net/core/filter.c:4542
Code: 81 c3 08 18 00 00 48 89 d8 48 c1 e8 03 42 80 3c 28 00 74 08 48 89 df e8 55 1a 99 f8 48 8b 1b 4c 8d 63 38 4c 89 e5 48 c1 ed 03 <42> 0f b6 44 2d 00 84 c0 0f 85 d0 00 00 00 45 8b 34 24 44 89 f6 83

RSP: 0018:ffffc9000aaf7970 EFLAGS: 00010202
RAX: 1ffff1100536be41 RBX: 0000000000000000 RCX: ffff888029b5da00
RDX: 0000000000000000 RSI: 000000000000a020 RDI: ffffc9000aaf7af0

RBP: 0000000000000007 R08: ffffffff8665e84f R09: 1ffffffff25f78b0
R10: dffffc0000000000 R11: fffffbfff25f78b1 R12: 0000000000000038

R13: dffffc0000000000 R14: ffffc90009f63048 R15: 000000000000a020
FS: 00007f2c699ff6c0(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000

CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033

CR2: 00007fa0bea356dd CR3: 000000007a9bc000 CR4: 00000000003506f0

DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
bpf_prog_bc55b47b7a2429cd+0x1d/0x1f
__bpf_prog_run include/linux/filter.h:691 [inline]
bpf_prog_run_xdp include/net/xdp.h:514 [inline]
tun_build_skb drivers/net/tun.c:1711 [inline]
tun_get_user+0x3321/0x4560 drivers/net/tun.c:1819
tun_chr_write_iter+0x113/0x1f0 drivers/net/tun.c:2048
new_sync_write fs/read_write.c:497 [inline]
vfs_write+0xa72/0xc90 fs/read_write.c:590
ksys_write+0x1a0/0x2c0 fs/read_write.c:643
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

RIP: 0033:0x7f2c69f7471f

Code: 89 54 24 18 48 89 74 24 10 89 7c 24 08 e8 29 8c 02 00 48 8b 54 24 18 48 8b 74 24 10 41 89 c0 8b 7c 24 08 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 31 44 89 c7 48 89 44 24 08 e8 7c 8c 02 00 48

RSP: 002b:00007f2c699ff010 EFLAGS: 00000293 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f2c6a103fa0 RCX: 00007f2c69f7471f

RDX: 0000000000000032 RSI: 0000000020001500 RDI: 00000000000000c8

RBP: 00007f2c69ff677e R08: 0000000000000000 R09: 0000000000000000

R10: 0000000000000032 R11: 0000000000000293 R12: 0000000000000000

R13: 000000000000000b R14: 00007f2c6a103fa0 R15: 00007ffd4d9d6998

</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:bpf_net_ctx_get_ri include/linux/filter.h:788 [inline]
RIP: 0010:____bpf_xdp_redirect net/core/filter.c:4544 [inline]
RIP: 0010:bpf_xdp_redirect+0x59/0x1a0 net/core/filter.c:4542
Code: 81 c3 08 18 00 00 48 89 d8 48 c1 e8 03 42 80 3c 28 00 74 08 48 89 df e8 55 1a 99 f8 48 8b 1b 4c 8d 63 38 4c 89 e5 48 c1 ed 03 <42> 0f b6 44 2d 00 84 c0 0f 85 d0 00 00 00 45 8b 34 24 44 89 f6 83

RSP: 0018:ffffc9000aaf7970 EFLAGS: 00010202
RAX: 1ffff1100536be41 RBX: 0000000000000000 RCX: ffff888029b5da00
RDX: 0000000000000000 RSI: 000000000000a020 RDI: ffffc9000aaf7af0

RBP: 0000000000000007 R08: ffffffff8665e84f R09: 1ffffffff25f78b0
R10: dffffc0000000000 R11: fffffbfff25f78b1 R12: 0000000000000038

R13: dffffc0000000000 R14: ffffc90009f63048 R15: 000000000000a020
FS: 00007f2c699ff6c0(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000

CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033

CR2: 00007fa0bea356dd CR3: 000000007a9bc000 CR4: 00000000003506f0

DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
0: 81 c3 08 18 00 00 add $0x1808,%ebx
6: 48 89 d8 mov %rbx,%rax
9: 48 c1 e8 03 shr $0x3,%rax
d: 42 80 3c 28 00 cmpb $0x0,(%rax,%r13,1)
12: 74 08 je 0x1c
14: 48 89 df mov %rbx,%rdi
17: e8 55 1a 99 f8 call 0xf8991a71
1c: 48 8b 1b mov (%rbx),%rbx
1f: 4c 8d 63 38 lea 0x38(%rbx),%r12
23: 4c 89 e5 mov %r12,%rbp
26: 48 c1 ed 03 shr $0x3,%rbp
* 2a: 42 0f b6 44 2d 00 movzbl 0x0(%rbp,%r13,1),%eax <-- trapping instruction
30: 84 c0 test %al,%al
32: 0f 85 d0 00 00 00 jne 0x108
38: 45 8b 34 24 mov (%r12),%r14d
3c: 44 89 f6 mov %r14d,%esi
3f: 83 .byte 0x83


---

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