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From: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Date: Sun, 7 Apr 2024 07:24:25 -0700
Message-ID: <CAADnVQJ4BRO_85By7T7bJkxgN8tmzJkS3TvP2JMiFU3WwRT7yA@mail.gmail.com>
Subject: Re: [syzbot] [bpf?] KASAN: stack-out-of-bounds Read in hash
To: Hou Tao <houtao@huaweicloud.com>
Cc: syzbot <syzbot+9459b5d7fab774cf182f@syzkaller.appspotmail.com>, 
	bpf <bpf@vger.kernel.org>, syzkaller-bugs <syzkaller-bugs@googlegroups.com>, 
	Network Development <netdev@vger.kernel.org>, Andrii Nakryiko <andrii@kernel.org>, 
	Alexei Starovoitov <ast@kernel.org>, Daniel Borkmann <daniel@iogearbox.net>, Eddy Z <eddyz87@gmail.com>, 
	Hao Luo <haoluo@google.com>, John Fastabend <john.fastabend@gmail.com>, 
	KP Singh <kpsingh@kernel.org>, Jiri Olsa <jolsa@kernel.org>, 
	Martin KaFai Lau <martin.lau@linux.dev>, Stanislav Fomichev <sdf@google.com>, Song Liu <song@kernel.org>, 
	Yonghong Song <yonghong.song@linux.dev>, LKML <linux-kernel@vger.kernel.org>
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On Sun, Apr 7, 2024 at 2:09=E2=80=AFAM Hou Tao <houtao@huaweicloud.com> wro=
te:
>
> 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 incompati=
bil..
> > git tree:       bpf
> > console+strace: https://syzkaller.appspot.com/x/log.txt?x=3D148ad855180=
000
> > kernel config:  https://syzkaller.appspot.com/x/.config?x=3D6fb1be60a19=
3d440
> > dashboard link: https://syzkaller.appspot.com/bug?extid=3D9459b5d7fab77=
4cf182f
> > compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for D=
ebian) 2.40
> > syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=3D13d867951=
80000
> > C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=3D143eff76180=
000
>
> 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@gmail.com/