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>
---
V2:
- factor into new function, process_dir_leaf_block
- add DIR3_LEAF1_MAGIC
- don't add count+stale; count includes stale entries
- move ltp into code block
diff --git a/db/metadump.c b/db/metadump.c
index 3967df6..a8756d6 100644
--- a/db/metadump.c
+++ b/db/metadump.c
@@ -1442,6 +1442,37 @@ process_sf_attr(
}
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,
xfs_fileoff_t offset,
@@ -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:
--
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