netdev - Re: [PATCH RFC net-next 3/3] netfilter: uapi: Use UAPI definition of INT_MAX and INT

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

Message-Id: <d3554d2d-1344-45f3-a976-188d45415419@app.fastmail.com>
Date: Mon, 05 Jan 2026 14:02:17 +0100
From: "Arnd Bergmann" <arnd@...db.de>
To: Thomas Weißschuh <thomas.weissschuh@...utronix.de>,
 "David S . Miller" <davem@...emloft.net>,
 "Eric Dumazet" <edumazet@...gle.com>, "Jakub Kicinski" <kuba@...nel.org>,
 "Paolo Abeni" <pabeni@...hat.com>, "Simon Horman" <horms@...nel.org>,
 "Andrew Lunn" <andrew@...n.ch>, "Pablo Neira Ayuso" <pablo@...filter.org>,
 "Jozsef Kadlecsik" <kadlec@...filter.org>, "Florian Westphal" <fw@...len.de>,
 "Phil Sutter" <phil@....cc>
Cc: linux-kernel@...r.kernel.org, Netdev <netdev@...r.kernel.org>,
 netfilter-devel@...r.kernel.org, coreteam@...filter.org
Subject: Re: [PATCH RFC net-next 3/3] netfilter: uapi: Use UAPI definition of INT_MAX
 and INT_MIN

On Mon, Jan 5, 2026, at 09:26, Thomas Weißschuh wrote:
> Using <limits.h> to gain access to INT_MAX and INT_MIN introduces a
> dependency on a libc, which UAPI headers should not do.
>
> Use the equivalent UAPI constants.
>
> Signed-off-by: Thomas Weißschuh <thomas.weissschuh@...utronix.de>

I agree with the idea of the patch series, but I think this
introduces a different problem:

>  #include <linux/in.h>
> +#include <linux/limits.h>

linux/limits.h is not always clean against limits.h. In glibc,
you can include both in any order, but in musl, you cannot:

gcc -xc /dev/null -nostdinc -I /usr/include/aarch64-linux-musl -include limits.h -include linux/limits.h  -o - -Wall  -c 
In file included from <command-line>:
/usr/include/aarch64-linux-musl/linux/limits.h:7: warning: "NGROUPS_MAX" redefined
    7 | #define NGROUPS_MAX    65536    /* supplemental group IDs are available */
      | 
In file included from <command-line>:
/usr/include/aarch64-linux-musl/limits.h:48: note: this is the location of the previous definition
   48 | #define NGROUPS_MAX 32

I can think of two alternative approaches here:

- put the __KERNEL_INT_MIN into a different header -- either a new one
  or maybe uapi/linux/types.h
- use the compiler's built-in __INT_MIN__ instead of INT_MIN in
  UAPI headers.

On the other hand, there are a few other uapi headers
that already include linux/limits.h:

include/uapi/linux/auto_fs.h:#include <linux/limits.h>
include/uapi/linux/fs.h:#include <linux/limits.h>
include/uapi/linux/netfilter/xt_bpf.h:#include <linux/limits.h>
include/uapi/linux/netfilter/xt_cgroup.h:#include <linux/limits.h>
include/uapi/linux/netfilter/xt_hashlimit.h:#include <linux/limits.h>

     Arnd