linux-kernel - Re: [PATCH v2] xfs: check for possible overflow in xfs_ioc

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:	Wed, 8 Aug 2012 09:22:01 +0200 (CEST)
From:	Lukáš Czerner <lczerner@...hat.com>
To:	Tomas Racek <tracek@...hat.com>
cc:	linux-xfs@...r.kernel.org, lczerner@...hat.com,
	Ben Myers <bpm@....com>, Alex Elder <elder@...nel.org>,
	"supporter:XFS FILESYSTEM" <xfs@....sgi.com>,
	open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2] xfs: check for possible overflow in xfs_ioc_trim

On Wed, 1 Aug 2012, Tomas Racek wrote:

> Date: Wed,  1 Aug 2012 15:45:37 +0200
> From: Tomas Racek <tracek@...hat.com>
> To: linux-xfs@...r.kernel.org
> Cc: lczerner@...hat.com, Tomas Racek <tracek@...hat.com>,
>     Ben Myers <bpm@....com>, Alex Elder <elder@...nel.org>,
>     "supporter:XFS FILESYSTEM" <xfs@....sgi.com>,
>     open list <linux-kernel@...r.kernel.org>
> Subject: [PATCH v2] xfs: check for possible overflow in xfs_ioc_trim
> 
> If range.start points behind the filesystem, return invalid value error.
> This fixes possible overflow in
> 
> start = BTOBB(range.start)
> 
> when range.start is nearly ULLONG_MAX.
> 
> Signed-off-by: Tomas Racek <tracek@...hat.com>

The fix looks good to me, but I have one comment bellow.

> ---
>  fs/xfs/xfs_discard.c |    5 +++--
>  1 files changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/fs/xfs/xfs_discard.c b/fs/xfs/xfs_discard.c
> index f9c3fe3..33d367f 100644
> --- a/fs/xfs/xfs_discard.c
> +++ b/fs/xfs/xfs_discard.c
> @@ -179,12 +179,13 @@ xfs_ioc_trim(
>  	 * used by the fstrim application.  In the end it really doesn't
>  	 * matter as trimming blocks is an advisory interface.
>  	 */
> +	if (range.start >= XFS_FSB_TO_B(mp, mp->m_sb.sb_dblocks))
> +		return -XFS_ERROR(EINVAL);
> +
>  	start = BTOBB(range.start);
>  	end = start + BTOBBT(range.len) - 1;
>  	minlen = BTOBB(max_t(u64, granularity, range.minlen));

It seems that we have the same problem here with range.minlen. It
is highly unlikely and stupid from the user space to send minlen of
such size, but it is possible.

Thanks!
-Lukas

>  
> -	if (XFS_BB_TO_FSB(mp, start) >= mp->m_sb.sb_dblocks)
> -		return -XFS_ERROR(EINVAL);
>  	if (end > XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks) - 1)
>  		end = XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks)- 1;
>  
> 
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/