syzbot


general protection fault in subflow_v6_route_req

Status: fixed on 2024/06/05 19:57
Subsystems: mptcp
[Documentation on labels]
Fix commit: 445c0b69c729 mptcp: fix possible NULL dereferences
First crash: 47d, last: 47d
Cause bisection: introduced by (bisect log) :
commit 3e140491dd80d8643261a21efde3ce2ff6fb9fdf
Author: Jason Xing <kernelxing@tencent.com>
Date: Thu Apr 25 03:13:38 2024 +0000

  mptcp: support rstreason for passive reset

Crash: BUG: unable to handle kernel NULL pointer dereference in subflow_v6_route_req (log)
Repro: C syz .config
  

Sample crash report:
RBP: 0000000000000001 R08: 0000000000000001 R09: 00007ffff9a72d67
R10: 0000000000000000 R11: 0000000000000202 R12: 000000000001281f
R13: 00007ffff9a72fd8 R14: 00007ffff9a73010 R15: 00007ffff9a73000
 </TASK>
general protection fault, probably for non-canonical address 0xdffffc0000000003: 0000 [#1] PREEMPT SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000018-0x000000000000001f]
CPU: 0 PID: 5098 Comm: syz-executor132 Not tainted 6.9.0-rc6-syzkaller-01478-gcdc74c9d06e7 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
RIP: 0010:subflow_v6_route_req+0x2c7/0x490 net/mptcp/subflow.c:388
Code: 8d 7b 07 48 89 f8 48 c1 e8 03 42 0f b6 04 20 84 c0 0f 85 c0 01 00 00 0f b6 43 07 48 8d 1c c3 48 83 c3 18 48 89 d8 48 c1 e8 03 <42> 0f b6 04 20 84 c0 0f 85 84 01 00 00 0f b6 5b 01 83 e3 0f 48 89
RSP: 0018:ffffc9000362eb68 EFLAGS: 00010206
RAX: 0000000000000003 RBX: 0000000000000018 RCX: ffff888022039e00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffff88807d961140 R08: ffffffff8b6cb76b R09: 1ffff1100fb2c230
R10: dffffc0000000000 R11: ffffed100fb2c231 R12: dffffc0000000000
R13: ffff888022bfe273 R14: ffff88802cf9cc80 R15: ffff88802ad5a700
FS:  0000555587ad2380(0000) GS:ffff8880b9400000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f420c3f9720 CR3: 0000000022bfc000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 tcp_conn_request+0xf07/0x32c0 net/ipv4/tcp_input.c:7180
 tcp_rcv_state_process+0x183c/0x4500 net/ipv4/tcp_input.c:6663
 tcp_v6_do_rcv+0x8b2/0x1310 net/ipv6/tcp_ipv6.c:1673
 tcp_v6_rcv+0x22b4/0x30b0 net/ipv6/tcp_ipv6.c:1910
 ip6_protocol_deliver_rcu+0xc76/0x1570 net/ipv6/ip6_input.c:438
 ip6_input_finish+0x186/0x2d0 net/ipv6/ip6_input.c:483
 NF_HOOK+0x3a4/0x450 include/linux/netfilter.h:314
 NF_HOOK+0x3a4/0x450 include/linux/netfilter.h:314
 __netif_receive_skb_one_core net/core/dev.c:5625 [inline]
 __netif_receive_skb+0x1ea/0x650 net/core/dev.c:5739
 netif_receive_skb_internal net/core/dev.c:5825 [inline]
 netif_receive_skb+0x1e8/0x890 net/core/dev.c:5885
 tun_rx_batched+0x1b7/0x8f0 drivers/net/tun.c:1549
 tun_get_user+0x2f35/0x4560 drivers/net/tun.c:2002
 tun_chr_write_iter+0x113/0x1f0 drivers/net/tun.c:2048
 call_write_iter include/linux/fs.h:2110 [inline]
 new_sync_write fs/read_write.c:497 [inline]
 vfs_write+0xa84/0xcb0 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+0xf5/0x240 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f420c3c0c90
Code: 40 00 48 c7 c2 b8 ff ff ff f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b7 0f 1f 00 80 3d 11 e4 07 00 00 74 17 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 58 c3 0f 1f 80 00 00 00 00 48 83 ec 28 48 89
RSP: 002b:00007ffff9a72fc8 EFLAGS: 00000202 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007ffff9a72ff0 RCX: 00007f420c3c0c90
RDX: 0000000000000056 RSI: 0000000020000040 RDI: 00000000000000c8
RBP: 0000000000000001 R08: 0000000000000001 R09: 00007ffff9a72d67
R10: 0000000000000000 R11: 0000000000000202 R12: 000000000001281f
R13: 00007ffff9a72fd8 R14: 00007ffff9a73010 R15: 00007ffff9a73000
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:subflow_v6_route_req+0x2c7/0x490 net/mptcp/subflow.c:388
Code: 8d 7b 07 48 89 f8 48 c1 e8 03 42 0f b6 04 20 84 c0 0f 85 c0 01 00 00 0f b6 43 07 48 8d 1c c3 48 83 c3 18 48 89 d8 48 c1 e8 03 <42> 0f b6 04 20 84 c0 0f 85 84 01 00 00 0f b6 5b 01 83 e3 0f 48 89
RSP: 0018:ffffc9000362eb68 EFLAGS: 00010206
RAX: 0000000000000003 RBX: 0000000000000018 RCX: ffff888022039e00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffff88807d961140 R08: ffffffff8b6cb76b R09: 1ffff1100fb2c230
R10: dffffc0000000000 R11: ffffed100fb2c231 R12: dffffc0000000000
R13: ffff888022bfe273 R14: ffff88802cf9cc80 R15: ffff88802ad5a700
FS:  0000555587ad2380(0000) GS:ffff8880b9400000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f420c3f9720 CR3: 0000000022bfc000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	8d 7b 07             	lea    0x7(%rbx),%edi
   3:	48 89 f8             	mov    %rdi,%rax
   6:	48 c1 e8 03          	shr    $0x3,%rax
   a:	42 0f b6 04 20       	movzbl (%rax,%r12,1),%eax
   f:	84 c0                	test   %al,%al
  11:	0f 85 c0 01 00 00    	jne    0x1d7
  17:	0f b6 43 07          	movzbl 0x7(%rbx),%eax
  1b:	48 8d 1c c3          	lea    (%rbx,%rax,8),%rbx
  1f:	48 83 c3 18          	add    $0x18,%rbx
  23:	48 89 d8             	mov    %rbx,%rax
  26:	48 c1 e8 03          	shr    $0x3,%rax
* 2a:	42 0f b6 04 20       	movzbl (%rax,%r12,1),%eax <-- trapping instruction
  2f:	84 c0                	test   %al,%al
  31:	0f 85 84 01 00 00    	jne    0x1bb
  37:	0f b6 5b 01          	movzbl 0x1(%rbx),%ebx
  3b:	83 e3 0f             	and    $0xf,%ebx
  3e:	48                   	rex.W
  3f:	89                   	.byte 0x89

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/05/06 09:48 net-next cdc74c9d06e7 610f2a54 .config strace log report syz C [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce general protection fault in subflow_v6_route_req
2024/05/06 09:21 net-next cdc74c9d06e7 610f2a54 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce general protection fault in subflow_v6_route_req
* Struck through repros no longer work on HEAD.