Re: [syzbot] [bpf?] KASAN: stack-out-of-bounds Read in hash

[Alexei Starovoitov]

On Sun, Apr 7, 2024 at 2:09 AM Hou Tao <houtao@xxxxxxxxxxxxxxx> wrote:
>
> Hi,
>
> On 4/6/2024 9:44 PM, syzbot wrote:
> > Hello,
> >
> > syzbot found the following issue on:
> >
> > HEAD commit:    443574b03387 riscv, bpf: Fix kfunc parameters incompatibil..
> > git tree:       bpf
> > console+strace: https://syzkaller.appspot.com/x/log.txt?x=148ad855180000
> > kernel config:  https://syzkaller.appspot.com/x/.config?x=6fb1be60a193d440
> > dashboard link: https://syzkaller.appspot.com/bug?extid=9459b5d7fab774cf182f
> > compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
> > syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=13d86795180000
> > C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=143eff76180000
>
> According to the reproducer, it passes a big value_size (0xfffffe00)
> when creating bloom filter map. The big value_size bypasses the check in
> check_stack_access_within_bounds(). I think a proper fix needs to add
> these following two checks:
> (1) in check_stack_access_within_bounds()  add check for negative
> access_size
> (2) in bloom_map_alloc() limit the max value of bloom_map_alloc().
>
> Will post a patch to fix the syzbot report. Will also check whether or
> not there are similar problems for other bpf maps.

Isn't it fixed by
https://lore.kernel.org/all/20240327024245.318299-2-andreimatei1@xxxxxxxxx/