Commit a70f9fe52daa ("xfs: detect and handle invalid iclog size set by
mkfs") added a fixup for incorrect h_size values used for the initial
umount record in old xfsprogs versions. Later commit 0c771b99d6c9
("xfs: clean up calculation of LR header blocks") cleaned up the log
reover buffer calculation, but stoped using the fixed up h_size value
to size the log recovery buffer, which can lead to an out of bounds
access when the incorrect h_size does not come from the old mkfs
tool, but a fuzzer.
Fix this by open coding xlog_logrec_hblks and taking the fixed h_size
into account for this calculation.
Fixes: 0c771b99d6c9 ("xfs: clean up calculation of LR header blocks")
Reported-by: Sam Sun <samsun1006219@xxxxxxxxx>
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Reviewed-by: Brian Foster <bfoster@xxxxxxxxxx>
Reviewed-by: Darrick J. Wong <djwong@xxxxxxxxxx>
---
fs/xfs/xfs_log_recover.c | 20 ++++++++++++++------
1 file changed, 14 insertions(+), 6 deletions(-)
diff --git a/fs/xfs/xfs_log_recover.c b/fs/xfs/xfs_log_recover.c
index b445e8ce4a7d21..bb8957927c3c2e 100644
--- a/fs/xfs/xfs_log_recover.c
+++ b/fs/xfs/xfs_log_recover.c
@@ -2999,7 +2999,7 @@ xlog_do_recovery_pass(
int error = 0, h_size, h_len;
int error2 = 0;
int bblks, split_bblks;
- int hblks, split_hblks, wrapped_hblks;
+ int hblks = 1, split_hblks, wrapped_hblks;
int i;
struct hlist_head rhash[XLOG_RHASH_SIZE];
LIST_HEAD (buffer_list);
@@ -3055,14 +3055,22 @@ xlog_do_recovery_pass(
if (error)
goto bread_err1;
- hblks = xlog_logrec_hblks(log, rhead);
- if (hblks != 1) {
- kvfree(hbp);
- hbp = xlog_alloc_buffer(log, hblks);
+ /*
+ * This open codes xlog_logrec_hblks so that we can reuse the
+ * fixed up h_size value calculated above. Without that we'd
+ * still allocate the buffer based on the incorrect on-disk
+ * size.
+ */
+ if (h_size > XLOG_HEADER_CYCLE_SIZE &&
+ (rhead->h_version & cpu_to_be32(XLOG_VERSION_2))) {
+ hblks = DIV_ROUND_UP(h_size, XLOG_HEADER_CYCLE_SIZE);
+ if (hblks > 1) {
+ kvfree(hbp);
+ hbp = xlog_alloc_buffer(log, hblks);
+ }
}
} else {
ASSERT(log->l_sectBBsize == 1);
- hblks = 1;
hbp = xlog_alloc_buffer(log, 1);
h_size = XLOG_BIG_RECORD_BSIZE;
}
--
2.39.2
