On Fri, Oct 04, 2013 at 10:51:50AM -0700, Viet Nguyen wrote: > Hi, > > I was wondering if you got a chance to look at this and if one's available, > where can I get a patch? Can you try the patch below? Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx libxfs: validity check the directory block leaf entry count From: Dave Chinner <dchinner@xxxxxxxxxx> The directory block format verifier fails to check that the leaf entry count is in a valid range, and so if it is corrupted then it can lead to derefencing a pointer outside the block buffer. While we can't exactly validate the count without first walking the directory block, we can ensure the count lands in the valid area within the directory block and hence avoid out-of-block references. Signed-off-by: Dave Chinner <dchinner@xxxxxxxxxx> --- libxfs/xfs_dir2_data.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/libxfs/xfs_dir2_data.c b/libxfs/xfs_dir2_data.c index 189699f..1b5196b 100644 --- a/libxfs/xfs_dir2_data.c +++ b/libxfs/xfs_dir2_data.c @@ -59,6 +59,18 @@ __xfs_dir3_data_check( btp = xfs_dir2_block_tail_p(mp, hdr); lep = xfs_dir2_block_leaf_p(btp); endp = (char *)lep; + + /* + * The number of leaf entries is limited by the size of the + * block and the amount of space used by the data entries. + * We don't know how much space is used by the data entries yet, + * so just ensure that the count falls somewhere inside the + * block right now. + */ + XFS_WANT_CORRUPTED_RETURN(be32_to_cpu(btp->count) > + ((char *)btp - (char *)p) / + sizeof(struct xfs_dir2_leaf_entry)); + break; case cpu_to_be32(XFS_DIR3_DATA_MAGIC): case cpu_to_be32(XFS_DIR2_DATA_MAGIC): _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
