[PATCH] Fix possible memory corruption in xfs_readlink

Dave Chinner david at fromorbit.com
Mon Oct 17 17:43:09 CDT 2011


On Mon, Oct 17, 2011 at 07:05:28PM -0200, Carlos Maiolino wrote:
> Fixes a possible memory corruption when the link is larger than
> MAXPATHLEN and XFS_DEBUG is not enabled. This also remove the
> S_ISLNK assert, since the inode mode is checked previously in
> xfs_readlink_by_handle() and via VFS.
> 
> Signed-off-by: Carlos Maiolino <cmaiolino at redhat.com>

Looks good. One minor thing for consistency, but consider it:

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

> ---
>  fs/xfs/xfs_vnodeops.c |   11 ++++++++---
>  1 files changed, 8 insertions(+), 3 deletions(-)
> 
> diff --git a/fs/xfs/xfs_vnodeops.c b/fs/xfs/xfs_vnodeops.c
> index 51fc429..9ca6676 100644
> --- a/fs/xfs/xfs_vnodeops.c
> +++ b/fs/xfs/xfs_vnodeops.c
> @@ -123,13 +123,18 @@ xfs_readlink(
>  
>  	xfs_ilock(ip, XFS_ILOCK_SHARED);
>  
> -	ASSERT(S_ISLNK(ip->i_d.di_mode));
> -	ASSERT(ip->i_d.di_size <= MAXPATHLEN);
> -
>  	pathlen = ip->i_d.di_size;
>  	if (!pathlen)
>  		goto out;
>  
> +	if (pathlen > MAXPATHLEN) {
> +		xfs_emerg(mp, "%s: inode (%lld) symlink length (%d) too long",
> +			 __func__, (unsigned long long)ip->i_ino, pathlen);

xfs_alert() is generally used for such messages - it's not a fatal
error (yet)....

Cheers,

Dave.
-- 
Dave Chinner
david at fromorbit.com




More information about the xfs mailing list