From: Yonghong Song <yhs@fb.com>
To: Eugene Syromiatnikov <esyr@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>,
Masami Hiramatsu <mhiramat@kernel.org>,
Steven Rostedt <rostedt@goodmis.org>,
Ingo Molnar <mingo@redhat.com>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Andrii Nakryiko <andrii@kernel.org>,
Martin KaFai Lau <kafai@fb.com>, Song Liu <songliubraving@fb.com>,
John Fastabend <john.fastabend@gmail.com>,
KP Singh <kpsingh@kernel.org>,
netdev@vger.kernel.org, bpf@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH bpf v3 1/2] bpf_trace: check size for overflow in bpf_kprobe_multi_link_attach
Date: Wed, 18 May 2022 13:41:59 -0700 [thread overview]
Message-ID: <cfe6abea-8d00-8f8c-f84c-e6f27753b5d1@fb.com> (raw)
In-Reply-To: <20220518200010.GA29226@asgard.redhat.com>
On 5/18/22 1:00 PM, Eugene Syromiatnikov wrote:
> On Wed, May 18, 2022 at 09:34:22AM -0700, Yonghong Song wrote:
>> On 5/18/22 5:22 AM, Eugene Syromiatnikov wrote:
>>> - size = cnt * sizeof(*syms);
>>> + if (check_mul_overflow(cnt, (u32)sizeof(*syms), &size))
>>> + return -EOVERFLOW;
>>
>> In mm/util.c kvmalloc_node(), we have
>>
>> /* Don't even allow crazy sizes */
>> if (unlikely(size > INT_MAX)) {
>> WARN_ON_ONCE(!(flags & __GFP_NOWARN));
>> return NULL;
>> }
>>
>> Basically the maximum size to be allocated in INT_MAX.
>>
>> Here, we have 'size' as u32, which means if the size is 0xffff0000,
>> the check_mul_overflow will return false (no overflow) but
>> kvzalloc will still have a warning.
>>
>> I think we should change the type of 'size' to be 'int' which
>> should catch the above case and be consistent with
>> what kvmalloc_node() intends to warn.
>
> Huh, it's a bitmore complicated as check_mul_overflow requires types to
> match; what do you think about
>
> + if (check_mul_overflow(cnt, (u32)sizeof(*syms), &size) || size > INT_MAX)
>
> ?
This works for me.
next prev parent reply other threads:[~2022-05-18 20:42 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-18 12:22 [PATCH bpf v3 0/2] Fix kprobe_multi interface issues for 5.18 Eugene Syromiatnikov
2022-05-18 12:22 ` [PATCH bpf v3 1/2] bpf_trace: check size for overflow in bpf_kprobe_multi_link_attach Eugene Syromiatnikov
2022-05-18 16:34 ` Yonghong Song
2022-05-18 20:00 ` Eugene Syromiatnikov
2022-05-18 20:41 ` Yonghong Song [this message]
2022-05-18 12:22 ` [PATCH bpf v3 2/2] bpf_trace: bail out from bpf_kprobe_multi_link_attach when in compat Eugene Syromiatnikov
2022-05-18 16:55 ` Yonghong Song
2022-05-18 20:03 ` Eugene Syromiatnikov
2022-05-18 20:57 ` Yonghong Song
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=cfe6abea-8d00-8f8c-f84c-e6f27753b5d1@fb.com \
--to=yhs@fb.com \
--cc=andrii@kernel.org \
--cc=ast@kernel.org \
--cc=bpf@vger.kernel.org \
--cc=daniel@iogearbox.net \
--cc=esyr@redhat.com \
--cc=john.fastabend@gmail.com \
--cc=jolsa@kernel.org \
--cc=kafai@fb.com \
--cc=kpsingh@kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mhiramat@kernel.org \
--cc=mingo@redhat.com \
--cc=netdev@vger.kernel.org \
--cc=rostedt@goodmis.org \
--cc=songliubraving@fb.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).