Re: [syzbot] KMSAN: kernel-infoleak in move_addr_to_user (6)

[Pavel Skripkin]

On 12/20/21 19:33, syzbot wrote:
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit:    b0a8b5053e8b kmsan: core: add dependency on DEBUG_KERNEL
> git tree:       https://github.com/google/kmsan.git master
> console output: https://syzkaller.appspot.com/x/log.txt?x=14a45071b00000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=46a956fc7a887c60
> dashboard link: https://syzkaller.appspot.com/bug?extid=cdbd40e0c3ca02cae3b7
> compiler:       clang version 14.0.0 (/usr/local/google/src/llvm-git-monorepo 2b554920f11c8b763cd9ed9003f4e19b919b8e1f), GNU ld (GNU Binutils for Debian) 2.35.2
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1343f443b00000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=16efa493b00000
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+cdbd40e0c3ca02cae3b7@xxxxxxxxxxxxxxxxxxxxxxxxx

Looks like missing memset(0). tipc_nametbl_lookup_anycast() may return 
before initializing sk.ref

>  * On exit:
>  *
>  * - If lookup is deferred to another node, leave 'sk->node' unchanged and
>  *   return 'true'.

And then sk.ref is passed to msg_set_destport().

There is also one more place with similar possible uninit-value in 
tipc_msg_lookup_dest().



With regards,
Pavel Skripkin