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From: Dave Chinner <david@fromorbit.com>
To: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Fabian Yamaguchi <fabs@goesec.de>,
	security@kernel.org, Alex Elder <elder@kernel.org>,
	xfs@oss.sgi.com, Ben Myers <bpm@sgi.com>,
	Nico Golde <nico@ngolde.de>
Subject: Re: [patch] xfs: underflow bug in xfs_attrlist_by_handle()
Date: Fri, 1 Nov 2013 08:34:56 +1100	[thread overview]
Message-ID: <20131031213456.GM4446@dastard> (raw)
In-Reply-To: <20131031180010.GA24839@longonot.mountain>

On Thu, Oct 31, 2013 at 09:00:10PM +0300, Dan Carpenter wrote:
> If we allocate less than sizeof(struct attrlist) then we end up
> corrupting memory or doing a ZERO_PTR_SIZE dereference.
> 
> This can only be triggered with CAP_SYS_ADMIN.
> 
> Reported-by: Nico Golde <nico@ngolde.de>
> Reported-by: Fabian Yamaguchi <fabs@goesec.de>
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> 
> diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
> index 4d61340..33ad9a7 100644
> --- a/fs/xfs/xfs_ioctl.c
> +++ b/fs/xfs/xfs_ioctl.c
> @@ -442,7 +442,8 @@ xfs_attrlist_by_handle(
>  		return -XFS_ERROR(EPERM);
>  	if (copy_from_user(&al_hreq, arg, sizeof(xfs_fsop_attrlist_handlereq_t)))
>  		return -XFS_ERROR(EFAULT);
> -	if (al_hreq.buflen > XATTR_LIST_MAX)
> +	if (al_hreq.buflen < sizeof(struct attrlist) ||
> +	    al_hreq.buflen > XATTR_LIST_MAX)
>  		return -XFS_ERROR(EINVAL);

Yup, that's not checked in xfs_attr_list(). Looks like these are the
only direct callers of xfs_attr_list(), and the other callers of
xfs_attr_list_int() don't appear to have the same issue. Good find!

Reviewed-by: Dave Chinner <dchinner@redhat.com>

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com

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  reply	other threads:[~2013-10-31 21:35 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20131025144452.GA28451@ngolde.de>
2013-10-29 19:06 ` [uml-devel] [patch] uml: check length in exitcode_proc_write() Dan Carpenter
2013-11-01  9:22   ` Richard Weinberger
2013-10-29 19:06 ` [patch] libertas: potential oops in debugfs Dan Carpenter
2013-10-29 20:09   ` Dan Carpenter
2013-10-29 19:10 ` [patch] [SCSI] aacraid: prevent ZERO_SIZE_PTR dereference Dan Carpenter
2013-10-29 19:36   ` James Bottomley
2013-10-29 19:59   ` Linus Torvalds
2013-10-29 20:06     ` Dan Carpenter
2013-10-29 20:17       ` Linus Torvalds
2013-10-30  7:47   ` Dan Carpenter
2013-10-29 19:11 ` [patch] [SCSI] aacraid: missing capable() check in compat ioctl Dan Carpenter
2013-10-30 17:12 ` [patch v2] libertas: potential oops in debugfs Dan Carpenter
2013-10-30 17:12   ` Dan Carpenter
2013-10-30 19:51   ` Dan Williams
2013-10-30 19:51     ` Dan Williams
2013-10-30 17:13 ` [patch] [SCSI] megaraid: missing bounds check in mimd_to_kioc() Dan Carpenter
2013-11-21  0:40   ` Kees Cook
2014-01-08 12:27   ` Saxena, Sumit
2014-01-09 18:34     ` Kees Cook
2014-01-09 19:53       ` Saxena, Sumit
2014-01-09 20:03         ` Kees Cook
2013-10-31 18:00 ` [patch] xfs: underflow bug in xfs_attrlist_by_handle() Dan Carpenter
2013-10-31 21:34   ` Dave Chinner [this message]
2013-12-04 21:53   ` Ben Myers

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