netdev - Re: UBSAN reports issue in ip_idents

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]

Date:   Tue, 20 Sep 2016 07:11:51 -0700
From:   Eric Dumazet <eric.dumazet@...il.com>
To:     Jiri Pirko <jiri@...nulli.us>
Cc:     netdev@...r.kernel.org
Subject: Re: UBSAN reports issue in ip_idents_reserve

On Tue, 2016-09-20 at 15:39 +0200, Jiri Pirko wrote:

> I see. So how to silent the warning?
> 

We can replace the atomic_add_return() and use a loop around
atomic_read() and atomic_cmpxhg()

This would change the nice property of x86 xadd into a loop.

Or we also could fallback to random generation if the atomic_cmpxchg()
fails.

I'll provide a patch, thanks.