xfs: check log iovec size to make sure it's plausibly a buffer log format
When log recovery is processing buffer log items, we should check that
the incoming iovec actually describes a region of memory large enough to
contain the log format and the dirty map.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
diff --git a/fs/xfs/xfs_buf_item.c b/fs/xfs/xfs_buf_item.c
index be691d1..5be8973 100644
--- a/fs/xfs/xfs_buf_item.c
+++ b/fs/xfs/xfs_buf_item.c
@@ -27,6 +27,23 @@ static inline struct xfs_buf_log_item *BUF_ITEM(struct xfs_log_item *lip)
STATIC void xfs_buf_do_callbacks(struct xfs_buf *bp);
+/* Is this log iovec plausibly large enough to contain the buffer log format? */
+bool
+xfs_buf_log_check_iovec(
+ struct xfs_log_iovec *iovec)
+{
+ struct xfs_buf_log_format *blfp = iovec->i_addr;
+ char *bmp_end;
+ char *item_end;
+
+ if (offsetof(struct xfs_buf_log_format, blf_data_map) > iovec->i_len)
+ return false;
+
+ item_end = (char *)iovec->i_addr + iovec->i_len;
+ bmp_end = (char *)&blfp->blf_data_map[blfp->blf_map_size];
+ return bmp_end <= item_end;
+}
+
static inline int
xfs_buf_log_format_size(
struct xfs_buf_log_format *blfp)