xfs: validate explicit directory block buffer owners

Port the existing directory block header checking function to accept an
owner number instead of an xfs_inode, then update the callsites to use
xfs_da_args.owner when possible.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

fs/xfs/libxfs/xfs_dir2.h

@@ -103,6 +103,7 @@ extern int xfs_dir_ino_validate(struct xfs_mount *mp, xfs_ino_t ino);
 
 xfs_failaddr_t xfs_dir3_leaf_header_check(struct xfs_buf *bp, xfs_ino_t owner);
 xfs_failaddr_t xfs_dir3_data_header_check(struct xfs_buf *bp, xfs_ino_t owner);
+xfs_failaddr_t xfs_dir3_block_header_check(struct xfs_buf *bp, xfs_ino_t owner);
 
 extern const struct xfs_buf_ops xfs_dir3_block_buf_ops;
 extern const struct xfs_buf_ops xfs_dir3_leafn_buf_ops;

fs/xfs/libxfs/xfs_dir2_block.c

@@ -115,17 +115,20 @@ const struct xfs_buf_ops xfs_dir3_block_buf_ops = {
 	.verify_struct = xfs_dir3_block_verify,
 };
 
-static xfs_failaddr_t
+xfs_failaddr_t
 xfs_dir3_block_header_check(
-	struct xfs_inode	*dp,
-	struct xfs_buf		*bp)
+	struct xfs_buf		*bp,
+	xfs_ino_t		owner)
 {
-	struct xfs_mount	*mp = dp->i_mount;
+	struct xfs_mount	*mp = bp->b_mount;
 
 	if (xfs_has_crc(mp)) {
 		struct xfs_dir3_blk_hdr *hdr3 = bp->b_addr;
 
-		if (be64_to_cpu(hdr3->owner) != dp->i_ino)
+		if (hdr3->magic != cpu_to_be32(XFS_DIR3_BLOCK_MAGIC))
+			return __this_address;
+
+		if (be64_to_cpu(hdr3->owner) != owner)
 			return __this_address;
 	}
 
@@ -136,6 +139,7 @@ int
 xfs_dir3_block_read(
 	struct xfs_trans	*tp,
 	struct xfs_inode	*dp,
+	xfs_ino_t		owner,
 	struct xfs_buf		**bpp)
 {
 	struct xfs_mount	*mp = dp->i_mount;
@@ -148,7 +152,7 @@ xfs_dir3_block_read(
 		return err;
 
 	/* Check things that we can't do in the verifier. */
-	fa = xfs_dir3_block_header_check(dp, *bpp);
+	fa = xfs_dir3_block_header_check(*bpp, owner);
 	if (fa) {
 		__xfs_buf_mark_corrupt(*bpp, fa);
 		xfs_trans_brelse(tp, *bpp);
@@ -383,7 +387,7 @@ xfs_dir2_block_addname(
 	tp = args->trans;
 
 	/* Read the (one and only) directory block into bp. */
-	error = xfs_dir3_block_read(tp, dp, &bp);
+	error = xfs_dir3_block_read(tp, dp, args->owner, &bp);
 	if (error)
 		return error;
 
@@ -698,7 +702,7 @@ xfs_dir2_block_lookup_int(
 	dp = args->dp;
 	tp = args->trans;
 
-	error = xfs_dir3_block_read(tp, dp, &bp);
+	error = xfs_dir3_block_read(tp, dp, args->owner, &bp);
 	if (error)
 		return error;
 

fs/xfs/libxfs/xfs_dir2_priv.h

@@ -50,8 +50,8 @@ extern int xfs_dir_cilookup_result(struct xfs_da_args *args,
 
 
 /* xfs_dir2_block.c */
-extern int xfs_dir3_block_read(struct xfs_trans *tp, struct xfs_inode *dp,
-			       struct xfs_buf **bpp);
+int xfs_dir3_block_read(struct xfs_trans *tp, struct xfs_inode *dp,
+		xfs_ino_t owner, struct xfs_buf **bpp);
 extern int xfs_dir2_block_addname(struct xfs_da_args *args);
 extern int xfs_dir2_block_lookup(struct xfs_da_args *args);
 extern int xfs_dir2_block_removename(struct xfs_da_args *args);

fs/xfs/libxfs/xfs_exchmaps.c

@@ -476,7 +476,7 @@ xfs_exchmaps_dir_to_sf(
 	if (!isblock)
 		return 0;
 
-	error = xfs_dir3_block_read(tp, xmi->xmi_ip2, &bp);
+	error = xfs_dir3_block_read(tp, xmi->xmi_ip2, xmi->xmi_ip2->i_ino, &bp);
 	if (error)
 		return error;
 

fs/xfs/scrub/dir.c

@@ -315,7 +315,7 @@ xchk_directory_data_bestfree(
 		/* dir block format */
 		if (lblk != XFS_B_TO_FSBT(mp, XFS_DIR2_DATA_OFFSET))
 			xchk_fblock_set_corrupt(sc, XFS_DATA_FORK, lblk);
-		error = xfs_dir3_block_read(sc->tp, sc->ip, &bp);
+		error = xfs_dir3_block_read(sc->tp, sc->ip, sc->ip->i_ino, &bp);
 	} else {
 		/* dir data format */
 		error = xfs_dir3_data_read(sc->tp, sc->ip, sc->ip->i_ino, lblk,

fs/xfs/scrub/readdir.c

@@ -99,7 +99,7 @@ xchk_dir_walk_block(
 	unsigned int		off, next_off, end;
 	int			error;
 
-	error = xfs_dir3_block_read(sc->tp, dp, &bp);
+	error = xfs_dir3_block_read(sc->tp, dp, dp->i_ino, &bp);
 	if (error)
 		return error;
 

fs/xfs/xfs_dir2_readdir.c

@@ -157,7 +157,7 @@ xfs_dir2_block_getdents(
 	if (xfs_dir2_dataptr_to_db(geo, ctx->pos) > geo->datablk)
 		return 0;
 
-	error = xfs_dir3_block_read(args->trans, dp, &bp);
+	error = xfs_dir3_block_read(args->trans, dp, args->owner, &bp);
 	if (error)
 		return error;