xfs_metadump: zap stale data in DIR2_LEAF1 dirs

xfs_metadump attempts to zero out unused regions of metadata
blocks to prevent data leaks when sharing metadata images.

However, Stefan Ring reported a significant number of leaked
strings when dumping his 1T filesystem.  Based on a reduced
metadata set, I was able to identify "leaf" directories
(with XFS_DIR2_LEAF1_MAGIC magic) as the primary culprit;
the region between the end of the entries array and the start
of the bests array was not getting zeroed out.  This patch
seems to remedy that problem.

Reported-by: Stefan Ring <stefanrin@gmail.com>
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Eric Sandeen <sandeen@sandeen.net>

diff --git a/db/metadump.c b/db/metadump.c
index 6dd06c302a6666e4b06982656a1afbb6850358c1..dd6bef0d671a2f05c706b4969bcf7d5271297e8a 100644 (file)
--- a/db/metadump.c
+++ b/db/metadump.c
@@ -1441,6 +1441,37 @@ process_sf_attr(
                memset(asfep, 0, XFS_DFORK_ASIZE(dip, mp) - ino_attr_size);
 }
 
+static void
+process_dir_leaf_block(
+       char                            *block)
+{
+       struct xfs_dir2_leaf            *leaf;
+       struct xfs_dir3_icleaf_hdr      leafhdr;
+
+       if (!zero_stale_data)
+               return;
+
+       /* Yes, this works for dir2 & dir3.  Difference is padding. */
+       leaf = (struct xfs_dir2_leaf *)block;
+       M_DIROPS(mp)->leaf_hdr_from_disk(&leafhdr, leaf);
+
+       /* Zero out space from end of ents[] to bests */
+       if (leafhdr.magic == XFS_DIR2_LEAF1_MAGIC ||
+           leafhdr.magic == XFS_DIR3_LEAF1_MAGIC) {
+               struct xfs_dir2_leaf_tail       *ltp;
+               __be16                          *lbp;
+               struct xfs_dir2_leaf_entry      *ents;
+               char                            *free; /* end of ents */
+
+               ents = M_DIROPS(mp)->leaf_ents_p(leaf);
+               free = (char *)&ents[leafhdr.count];
+               ltp = xfs_dir2_leaf_tail_p(mp->m_dir_geo, leaf);
+               lbp = xfs_dir2_leaf_bests_p(ltp);
+               memset(free, 0, (char *)lbp - free);
+               iocur_top->need_crc = 1;
+       }
+}
+
 static void
 process_dir_data_block(
        char            *block,
@@ -1801,11 +1832,15 @@ process_single_fsb_objects(
                dp = iocur_top->data;
                switch (btype) {
                case TYP_DIR2:
-                       if (o >= mp->m_dir_geo->leafblk)
+                       if (o >= mp->m_dir_geo->freeblk) {
+                               /* TODO, zap any stale data */
                                break;
-
-                       process_dir_data_block(dp, o,
+                       } else if (o >= mp->m_dir_geo->leafblk) {
+                               process_dir_leaf_block(dp);
+                       } else {
+                               process_dir_data_block(dp, o,
                                         last == mp->m_dir_geo->fsbcount);
+                       }
                        iocur_top->need_crc = 1;
                        break;
                case TYP_SYMLINK: