Re: [syzbot] KASAN: vmalloc-out-of-bounds Write in ringbuf_map_alloc

Daniel Borkmann
2022-02-02T14:55:53Z

On 2/2/22 3:49 PM, Marco Elver wrote:
> On Wed, 2 Feb 2022 at 15:36, syzbot
> <syzbot+5ad567a418794b9b5983@syzkaller.appspotmail.com> wrote:
>>
>> syzbot has bisected this issue to:
>>
>> commit c34cdf846c1298de1c0f7fbe04820fe96c45068c
>> Author: Andrey Konovalov <andreyknvl@google.com>
>> Date: Wed Feb 2 01:04:27 2022 +0000
>>
>> kasan, vmalloc: unpoison VM_ALLOC pages after mapping
>
> Is this a case of a new bug surfacing due to KASAN improvements? But
> it's not quite clear to me why this commit.
>
> Andrey, any thoughts?

Marco / Andrey, fix should be this one:

https://patchwork.kernel.org/project/netdevbpf/patch/20220202060158.6260-1-houtao1@huawei.com/

>> bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=128cb900700000
>> start commit: 6abab1b81b65 Add linux-next specific files for 20220202
>> git tree: linux-next
>> final oops: https://syzkaller.appspot.com/x/report.txt?x=118cb900700000
>> console output: https://syzkaller.appspot.com/x/log.txt?x=168cb900700000
>> kernel config: https://syzkaller.appspot.com/x/.config?x=b8d8750556896349
>> dashboard link: https://syzkaller.appspot.com/bug?extid=5ad567a418794b9b5983
>> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1450d9f0700000
>> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=130ef35bb00000
>>
>> Reported-by: syzbot+5ad567a418794b9b5983@syzkaller.appspotmail.com
>> Fixes: c34cdf846c12 ("kasan, vmalloc: unpoison VM_ALLOC pages after mapping")
>>
>> For information about bisection process see: https://goo.gl/tpsmEJ#bisection