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@xxxxxxxxx>
Signed-off-by: Eric Sandeen <sandeen@xxxxxxxxxx>
---
I may have missed some handy macro to work out some of the
math below, if so I'd be perfectly happy to hear about it ;)
diff --git a/db/metadump.c b/db/metadump.c
index 96641e0..6d77d61 100644
--- a/db/metadump.c
+++ b/db/metadump.c
@@ -1459,6 +1459,37 @@ process_dir_data_block(
int wantmagic;
struct xfs_dir2_data_hdr *datahdr;
+ if (offset >= mp->m_dir_geo->freeblk) {
+ /* TODO */
+ return;
+ } else if (offset >= mp->m_dir_geo->leafblk) {
+ struct xfs_dir2_leaf *leaf;
+ struct xfs_dir2_leaf_tail *ltp;
+ struct xfs_dir3_icleaf_hdr leafhdr;
+
+ if (!zero_stale_data)
+ return;
+
+ leaf = (struct xfs_dir2_leaf *)block;
+ ltp = xfs_dir2_leaf_tail_p(mp->m_dir_geo, leaf);
+ 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) {
+ struct xfs_dir2_leaf_entry *ents;
+ __be16 *lbp;
+ char *start; /* end of ents */
+
+ ents = M_DIROPS(mp)->leaf_ents_p(leaf);
+ start = (char *)&ents[leafhdr.count + leafhdr.stale];
+ lbp = xfs_dir2_leaf_bests_p(ltp);
+ memset(start, 0, (char *)lbp - start);
+ iocur_top->need_crc = 1;
+ }
+ return;
+ }
+
+ /* It's a data block. */
datahdr = (struct xfs_dir2_data_hdr *)block;
if (is_block_format) {
@@ -1800,9 +1831,6 @@ process_single_fsb_objects(
dp = iocur_top->data;
switch (btype) {
case TYP_DIR2:
- if (o >= mp->m_dir_geo->leafblk)
- break;
-
process_dir_data_block(dp, o,
last == mp->m_dir_geo->fsbcount);
iocur_top->need_crc = 1;
--
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