linux-kernel - Re: [PATCH bpf-next v1 0/1] Using the right format specifiers for bpftool

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <502d76e9-6933-41ca-9b74-23e339f6244c@kernel.org>
Date: Fri, 7 Feb 2025 15:08:36 +0000
From: Quentin Monnet <qmo@...nel.org>
To: Jiayuan Chen <mrpre@....com>
Cc: bpf@...r.kernel.org, linux-kernel@...r.kernel.org, ast@...nel.org,
 daniel@...earbox.net, davem@...emloft.net, kuba@...nel.org, hawk@...nel.org,
 john.fastabend@...il.com, andrii@...nel.org, martin.lau@...ux.dev,
 eddyz87@...il.com, song@...nel.org, yonghong.song@...ux.dev,
 kpsingh@...nel.org, sdf@...ichev.me, haoluo@...gle.com, jolsa@...nel.org
Subject: Re: [PATCH bpf-next v1 0/1] Using the right format specifiers for
 bpftool

2025-02-07 22:27 UTC+0800 ~ Jiayuan Chen <mrpre@....com>
> On Fri, Feb 07, 2025 at 01:22:19PM +0000, Quentin Monnet wrote:
>> On 07/02/2025 12:37, Jiayuan Chen wrote:
>>> Fixed some incorrect formatting specifiers that were exposed when I added
>>> the "-Wformat" flag to the compiler options.
>>>
>>> This patch doesn't include "-Wformat" in the Makefile for now, as I've
>>> only addressed some obvious semantic issues with the compiler warnings.
>>> There are still other warnings that need to be tackled.
>>>
>>> For example, there's an ifindex that's sometimes defined as a signed type
>>> and sometimes as an unsigned type, which makes formatting a real pain
>>> - sometimes it needs %d and sometimes %u. This might require a more
>>> fundamental fix from the variable definition side.
>>>
>>> If the maintainer is okay with adding "-Wformat" to the
>>> tools/bpf/bpftool/Makefile, please let us know, and we can follow up with
>>> further fixes.
>>
>> No objection from the maintainer, thanks for looking into this. Did you
>> catch these issues with just "-Wformat"? I'm asking because I need to
>> use an additional flag, "-Wformat-signedness", to have my compiler
>> display the %d/%u reports.
>>
>> Thanks,
>> Quentin
> Yes, I previously added '-Wformat -Wformat-signedness', but I just tried
> again and it turns out that only '-Wformat-signedness' takes effect.


I rememeber now that -Wformat is already included in bpftool's Makefile
via tools/scripts/Makefile.include (variable $(EXTRA_WARNINGS)), so it
wouldn't make a difference anyway whether you add it again in bpftool's
Makefile or not.