Re: [syzbot] [net?] KMSAN: uninit-value in xfrm_state_find (4)

[Sabrina Dubroca <sd@queasysnail.net>]

2025-05-21, 12:14:27 -0700, syzbot wrote:
> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    172a9d94339c Merge tag '6.15-rc6-smb3-client-fixes' of git..
> git tree:       upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=17b062d4580000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=56e29fa09e87dea7
> dashboard link: https://syzkaller.appspot.com/bug?extid=7ed9d47e15e88581dc5b
> compiler:       Debian clang version 20.1.2 (++20250402124445+58df0ef89dd6-1~exp1~20250402004600.97), Debian LLD 20.1.2
> 
> Unfortunately, I don't have any reproducer for this issue yet.
> 
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/da9615d2ee0b/disk-172a9d94.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/997b6c928374/vmlinux-172a9d94.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/30f01bdce820/bzImage-172a9d94.xz
> 
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+7ed9d47e15e88581dc5b@syzkaller.appspotmail.com
> 
> =====================================================
> BUG: KMSAN: uninit-value in xfrm_state_find+0x2423/0xaae0 net/xfrm/xfrm_state.c:1438

I was looking into possible uninitialized uses of state_ptrs a while
ago, this report probably is the same thing. I'll post the patch later
today.

>  xfrm_state_find+0x2423/0xaae0 net/xfrm/xfrm_state.c:1438
>  xfrm_tmpl_resolve_one net/xfrm/xfrm_policy.c:2519 [inline]
>  xfrm_tmpl_resolve net/xfrm/xfrm_policy.c:2570 [inline]
>  xfrm_resolve_and_create_bundle+0xabc/0x58b0 net/xfrm/xfrm_policy.c:2868
>  xfrm_lookup_with_ifid+0x48c/0x3ac0 net/xfrm/xfrm_policy.c:3202
>  xfrm_lookup net/xfrm/xfrm_policy.c:3333 [inline]
>  xfrm_lookup_route+0x63/0x2b0 net/xfrm/xfrm_policy.c:3344
>  ip_route_output_flow+0x20d/0x2b0 net/ipv4/route.c:2918
>  ip_route_connect include/net/route.h:352 [inline]
>  tcp_v4_connect+0xa43/0x1cd0 net/ipv4/tcp_ipv4.c:252
>  tcp_v6_connect+0x134a/0x1d40 net/ipv6/tcp_ipv6.c:240
>  __inet_stream_connect+0x2d3/0x1760 net/ipv4/af_inet.c:677
>  inet_stream_connect+0x69/0xd0 net/ipv4/af_inet.c:748
>  __sys_connect_file net/socket.c:2038 [inline]
>  __sys_connect+0x523/0x680 net/socket.c:2057
>  __do_sys_connect net/socket.c:2063 [inline]
>  __se_sys_connect net/socket.c:2060 [inline]
>  __x64_sys_connect+0x95/0x100 net/socket.c:2060
>  x64_sys_call+0x23bb/0x3db0 arch/x86/include/generated/asm/syscalls_64.h:43
>  do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
>  do_syscall_64+0xd9/0x1b0 arch/x86/entry/syscall_64.c:94
>  entry_SYSCALL_64_after_hwframe+0x77/0x7f
>
> Local variable tmp.i.i created at:
>  xfrm_tmpl_resolve_one net/xfrm/xfrm_policy.c:2491 [inline]
>  xfrm_tmpl_resolve net/xfrm/xfrm_policy.c:2570 [inline]
>  xfrm_resolve_and_create_bundle+0x3a7/0x58b0 net/xfrm/xfrm_policy.c:2868
>  xfrm_lookup_with_ifid+0x48c/0x3ac0 net/xfrm/xfrm_policy.c:3202

-- 
Sabrina