linux-kernel - Re: [PATCH] bfs: prevent underflow in bfs_find

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 for Android: free password hash cracker in your pocket

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

Date:   Tue, 10 Mar 2020 18:22:42 +0000
From:   Tigran Aivazian <aivazian.tigran@...il.com>
To:     Walter Harms <wharms@....de>
Cc:     Dan Carpenter <dan.carpenter@...cle.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "kernel-janitors@...r.kernel.org" <kernel-janitors@...r.kernel.org>
Subject: Re: [PATCH] bfs: prevent underflow in bfs_find_entry()

Hello,

On Tue, 10 Mar 2020 at 17:57, Walter Harms <wharms@....de> wrote:
> that raises the question why is there a len paramter in the first place.
> Surely the writer can make sure that there is always a NUL terminated
> string, then it would be possible the use a simple strcmp() and the
> range check is useless and can be removed.
>
> seems a question for the maintainer.

Please have a look at, for example,
fs/ufs/dir.c:ufs_find_entry()/ufs_match() functions --- they do almost
the same thing as the ones in bfs. And, presumably, the line "int
namelen = qstr->len;" in ufs_find_entry() is causing the static
checker warning too, just like the one in bfs which Dan mentioned and
fixed. So, let's not over-complicate things (or make a mountain out of
a molehill) and accept Dan's patch as is.

Kind regards,
Tigran