general protection fault in __fib6_update_sernum_upto_root

[Ubisectech Sirius]

Hello.
We are Ubisectech Sirius Team, the vulnerability lab of China ValiantSec. Recently, our team has discovered a issue in Linux kernel 6.7. Attached to the email were a PoC file of the issue.

Stack dump:
general protection fault, probably for non-canonical address 0xff1f1b1f1f1f1f24: 0000 [#1] PREEMPT SMP KASAN NOPTI
KASAN: maybe wild-memory-access in range [0xf8f8f8f8f8f8f920-0xf8f8f8f8f8f8f927]
CPU: 1 PID: 9367 Comm: kworker/1:5 Not tainted 6.7.0 #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014
Workqueue: ipv6_addrconf addrconf_dad_work
RIP: 0010:__fib6_update_sernum_upto_root+0xa7/0x270 net/ipv6/ip6_fib.c:1358
Code: c1 e8 03 42 80 3c 20 00 0f 85 9b 01 00 00 48 8b 1b 48 85 db 0f 84 d9 00 00 00 e8 74 70 39 f8 48 8d 7b 2c 48 89 f8 48 c1 e8 03 <42> 0f b6 14 20 48 89 f8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85
RSP: 0018:ffffc9000631f7c8 EFLAGS: 00010a07
RAX: 1f1f1f1f1f1f1f24 RBX: f8f8f8f8f8f8f8f8 RCX: ffffffff89508644
RDX: ffff888051d78000 RSI: ffffffff895085dc RDI: f8f8f8f8f8f8f924
RBP: 0000000000000001 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: dffffc0000000000
R13: 0000000000000186 R14: ffff888052396c00 R15: ffffed100a472d80
FS:  0000000000000000(0000) GS:ffff88807ec00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f42c8487d00 CR3: 000000004b42c000 CR4: 0000000000750ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
PKRU: 55555554
Call Trace:
 <TASK>
 __list_add include/linux/list.h:153 [inline]
 list_add include/linux/list.h:169 [inline]
 fib6_add+0x16c4/0x4410 net/ipv6/ip6_fib.c:1490
 __ip6_ins_rt net/ipv6/route.c:1313 [inline]
 ip6_ins_rt+0xb6/0x110 net/ipv6/route.c:1323
 __ipv6_ifa_notify+0xab3/0xd30 net/ipv6/addrconf.c:6266
 ipv6_ifa_notify net/ipv6/addrconf.c:6303 [inline]
 addrconf_dad_completed+0x15f/0xef0 net/ipv6/addrconf.c:4317
 addrconf_dad_work+0x785/0x14e0 net/ipv6/addrconf.c:4260
 process_one_work+0x87b/0x15c0 kernel/workqueue.c:3226
 worker_thread+0x855/0x1200 kernel/workqueue.c:3380
 kthread+0x2cc/0x3b0 kernel/kthread.c:388
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1b/0x30 arch/x86/entry/entry_64.S:256
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:__fib6_update_sernum_upto_root+0xa7/0x270 net/ipv6/ip6_fib.c:1358
Code: c1 e8 03 42 80 3c 20 00 0f 85 9b 01 00 00 48 8b 1b 48 85 db 0f 84 d9 00 00 00 e8 74 70 39 f8 48 8d 7b 2c 48 89 f8 48 c1 e8 03 <42> 0f b6 14 20 48 89 f8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85
RSP: 0018:ffffc9000631f7c8 EFLAGS: 00010a07
RAX: 1f1f1f1f1f1f1f24 RBX: f8f8f8f8f8f8f8f8 RCX: ffffffff89508644
RDX: ffff888051d78000 RSI: ffffffff895085dc RDI: f8f8f8f8f8f8f924
RBP: 0000000000000001 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: dffffc0000000000
R13: 0000000000000186 R14: ffff888052396c00 R15: ffffed100a472d80
FS:  0000000000000000(0000) GS:ffff88807ec00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f42c8487d00 CR3: 000000004b42c000 CR4: 0000000000750ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
PKRU: 55555554
----------------
Code disassembly (best guess):
   0:   c1 e8 03                shr    $0x3,%eax
   3:   42 80 3c 20 00          cmpb   $0x0,(%rax,%r12,1)
   8:   0f 85 9b 01 00 00       jne    0x1a9
   e:   48 8b 1b                mov    (%rbx),%rbx
  11:   48 85 db                test   %rbx,%rbx
  14:   0f 84 d9 00 00 00       je     0xf3
  1a:   e8 74 70 39 f8          call   0xf8397093
  1f:   48 8d 7b 2c             lea    0x2c(%rbx),%rdi
  23:   48 89 f8                mov    %rdi,%rax
  26:   48 c1 e8 03             shr    $0x3,%rax
* 2a:   42 0f b6 14 20          movzbl (%rax,%r12,1),%edx <-- trapping instruction
  2f:   48 89 f8                mov    %rdi,%rax
  32:   83 e0 07                and    $0x7,%eax
  35:   83 c0 03                add    $0x3,%eax
  38:   38 d0                   cmp    %dl,%al
  3a:   7c 08                   jl     0x44
  3c:   84 d2                   test   %dl,%dl
  3e:   0f                      .byte 0xf
  3f:   85                      .byte 0x85

Thank you for taking the time to read this email and we look forward to working with you further.

Attachment: poc.c
Description: Binary data