syzbot


general protection fault in fib6_rule_action

Status: fixed on 2024/06/05 13:52
Subsystems: net
[Documentation on labels]
Fix commit: d101291b2681 ipv6: fib6_rules: avoid possible NULL dereference in fib6_rule_action()
First crash: 61d, last: 61d

Sample crash report:
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 0 PID: 31648 Comm: syz-executor.0 Not tainted 6.9.0-rc4-next-20240417-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
RIP: 0010:__fib6_rule_action net/ipv6/fib6_rules.c:237 [inline]
RIP: 0010:fib6_rule_action+0x241/0x7b0 net/ipv6/fib6_rules.c:267
Code: 02 00 00 49 8d 9f d8 00 00 00 48 89 d8 48 c1 e8 03 42 80 3c 20 00 74 08 48 89 df e8 f9 32 bf f7 48 8b 1b 48 89 d8 48 c1 e8 03 <42> 80 3c 20 00 74 08 48 89 df e8 e0 32 bf f7 4c 8b 03 48 89 ef 4c
RSP: 0018:ffffc9000fc1f2f0 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 1a772f98c8186700
RDX: 0000000000000003 RSI: ffffffff8bcac4e0 RDI: ffffffff8c1f9760
RBP: ffff8880673fb980 R08: ffffffff8fac15ef R09: 1ffffffff1f582bd
R10: dffffc0000000000 R11: fffffbfff1f582be R12: dffffc0000000000
R13: 0000000000000080 R14: ffff888076509000 R15: ffff88807a029a00
FS:  00007f55e82ca6c0(0000) GS:ffff8880b9400000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b31d23000 CR3: 0000000022b66000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 fib_rules_lookup+0x62c/0xdb0 net/core/fib_rules.c:317
 fib6_rule_lookup+0x1fd/0x790 net/ipv6/fib6_rules.c:108
 ip6_route_output_flags_noref net/ipv6/route.c:2637 [inline]
 ip6_route_output_flags+0x38e/0x610 net/ipv6/route.c:2649
 ip6_route_output include/net/ip6_route.h:93 [inline]
 ip6_dst_lookup_tail+0x189/0x11a0 net/ipv6/ip6_output.c:1120
 ip6_dst_lookup_flow+0xb9/0x180 net/ipv6/ip6_output.c:1250
 sctp_v6_get_dst+0x792/0x1e20 net/sctp/ipv6.c:326
 sctp_transport_route+0x12c/0x2e0 net/sctp/transport.c:455
 sctp_assoc_add_peer+0x614/0x15c0 net/sctp/associola.c:662
 sctp_connect_new_asoc+0x31d/0x6c0 net/sctp/socket.c:1099
 __sctp_connect+0x66d/0xe30 net/sctp/socket.c:1197
 sctp_connect net/sctp/socket.c:4819 [inline]
 sctp_inet_connect+0x149/0x1f0 net/sctp/socket.c:4834
 __sys_connect_file net/socket.c:2048 [inline]
 __sys_connect+0x2df/0x310 net/socket.c:2065
 __do_sys_connect net/socket.c:2075 [inline]
 __se_sys_connect net/socket.c:2072 [inline]
 __x64_sys_connect+0x7a/0x90 net/socket.c:2072
 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: 0033:0x7f55e747dea9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f55e82ca0c8 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
RAX: ffffffffffffffda RBX: 00007f55e75abf80 RCX: 00007f55e747dea9
RDX: 000000000000001c RSI: 0000000020000080 RDI: 0000000000000003
RBP: 00007f55e74ca4a4 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007f55e75abf80 R15: 00007ffeaabb0e08
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:__fib6_rule_action net/ipv6/fib6_rules.c:237 [inline]
RIP: 0010:fib6_rule_action+0x241/0x7b0 net/ipv6/fib6_rules.c:267
Code: 02 00 00 49 8d 9f d8 00 00 00 48 89 d8 48 c1 e8 03 42 80 3c 20 00 74 08 48 89 df e8 f9 32 bf f7 48 8b 1b 48 89 d8 48 c1 e8 03 <42> 80 3c 20 00 74 08 48 89 df e8 e0 32 bf f7 4c 8b 03 48 89 ef 4c
RSP: 0018:ffffc9000fc1f2f0 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 1a772f98c8186700
RDX: 0000000000000003 RSI: ffffffff8bcac4e0 RDI: ffffffff8c1f9760
RBP: ffff8880673fb980 R08: ffffffff8fac15ef R09: 1ffffffff1f582bd
R10: dffffc0000000000 R11: fffffbfff1f582be R12: dffffc0000000000
R13: 0000000000000080 R14: ffff888076509000 R15: ffff88807a029a00
FS:  00007f55e82ca6c0(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b30322000 CR3: 0000000022b66000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	02 00                	add    (%rax),%al
   2:	00 49 8d             	add    %cl,-0x73(%rcx)
   5:	9f                   	lahf
   6:	d8 00                	fadds  (%rax)
   8:	00 00                	add    %al,(%rax)
   a:	48 89 d8             	mov    %rbx,%rax
   d:	48 c1 e8 03          	shr    $0x3,%rax
  11:	42 80 3c 20 00       	cmpb   $0x0,(%rax,%r12,1)
  16:	74 08                	je     0x20
  18:	48 89 df             	mov    %rbx,%rdi
  1b:	e8 f9 32 bf f7       	call   0xf7bf3319
  20:	48 8b 1b             	mov    (%rbx),%rbx
  23:	48 89 d8             	mov    %rbx,%rax
  26:	48 c1 e8 03          	shr    $0x3,%rax
* 2a:	42 80 3c 20 00       	cmpb   $0x0,(%rax,%r12,1) <-- trapping instruction
  2f:	74 08                	je     0x39
  31:	48 89 df             	mov    %rbx,%rdi
  34:	e8 e0 32 bf f7       	call   0xf7bf3319
  39:	4c 8b 03             	mov    (%rbx),%r8
  3c:	48 89 ef             	mov    %rbp,%rdi
  3f:	4c                   	rex.WR

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/04/17 19:20 linux-next 4eab35893071 bd38b692 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root general protection fault in fib6_rule_action
* Struck through repros no longer work on HEAD.