linux-ext4 - Re: [PATCH] jbd2: Fix block tag checksum verification brokenness

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]

Date:	Thu, 9 May 2013 00:03:39 +0100
From:	Al Viro <viro@...IV.linux.org.uk>
To:	"Darrick J. Wong" <darrick.wong@...cle.com>
Cc:	Andreas Dilger <adilger@...ger.ca>, Theodore Ts'o <tytso@....edu>,
	"linux-fsdevel@...r.kernel.org" <linux-fsdevel@...r.kernel.org>,
	linux-ext4 <linux-ext4@...r.kernel.org>
Subject: Re: [PATCH] jbd2: Fix block tag checksum verification brokenness

On Wed, May 08, 2013 at 03:00:27PM -0700, Darrick J. Wong wrote:
> +	crc = csum32 & 0xFFFF;
>  
> -	tag->t_checksum = cpu_to_be32(csum);
> +	tag->t_checksum = cpu_to_be16(crc);

Simple cpu_to_be16(csum) will do - it'll convert the argument to __u16,
which will do exactly the same thing your & 0xFFFF is doing.  Matter of
taste...

> +	crc = csum32 & 0xFFFF;
> +	provided = be16_to_cpu(tag->t_checksum);
>  
> -	return provided == cpu_to_be32(calculated);
> +	return provided == crc;

I'd go for tag->t_checksum == cpu_to_be16(calculated) - less cluttered that
way, IMO.  Again, a matter of taste.  ACK, as far as correctness is concerned.
--
To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html