Merge tag 'improve-attr-validation-6.10_2024-04-23' of https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux into xfs-6.10-mergeC

xfs: improve extended attribute validation

Prior to introducing parent pointer extended attributes, let's spend
some time cleaning up the attr code and strengthening the validation
that it performs on attrs coming in from the disk.

Signed-off-by: Darrick J. Wong <[email protected]>
Signed-off-by: Chandan Babu R <[email protected]>

* tag 'improve-attr-validation-6.10_2024-04-23' of https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux:
  xfs: enforce one namespace per attribute
  xfs: refactor name/value iovec validation in xlog_recover_attri_commit_pass2
  xfs: refactor name/length checks in xfs_attri_validate
  xfs: use local variables for name and value length in _attri_commit_pass2
  xfs: always set args->value in xfs_attri_item_recover
  xfs: validate recovered name buffers when recovering xattr items
  xfs: use helpers to extract xattr op from opflags
  xfs: restructure xfs_attr_complete_op a bit
  xfs: check shortform attr entry flags specifically
  xfs: fix missing check for invalid attr flags
  xfs: check opcode and iovec count match in xlog_recover_attri_commit_pass2
  xfs: use an XFS_OPSTATE_ flag for detecting if logged xattrs are available
  xfs: require XFS_SB_FEAT_INCOMPAT_LOG_XATTRS for attr log intent item recovery
  xfs: attr fork iext must be loaded before calling xfs_attr_is_leaf

Author: Chandan Babu R

fs/xfs/libxfs/xfs_attr.c

@@ -87,6 +87,8 @@ xfs_attr_is_leaf(
 	struct xfs_iext_cursor	icur;
 	struct xfs_bmbt_irec	imap;
 
+	ASSERT(!xfs_need_iread_extents(ifp));
+
 	if (ifp->if_nextents != 1 || ifp->if_format != XFS_DINODE_FMT_EXTENTS)
 		return false;
 
@@ -224,11 +226,21 @@ int
 xfs_attr_get_ilocked(
 	struct xfs_da_args	*args)
 {
+	int			error;
+
 	xfs_assert_ilocked(args->dp, XFS_ILOCK_SHARED | XFS_ILOCK_EXCL);
 
 	if (!xfs_inode_hasattr(args->dp))
 		return -ENOATTR;
 
+	/*
+	 * The incore attr fork iext tree must be loaded for xfs_attr_is_leaf
+	 * to work correctly.
+	 */
+	error = xfs_iread_extents(args->trans, args->dp, XFS_ATTR_FORK);
+	if (error)
+		return error;
+
 	if (args->dp->i_af.if_format == XFS_DINODE_FMT_LOCAL)
 		return xfs_attr_shortform_getvalue(args);
 	if (xfs_attr_is_leaf(args->dp))
@@ -420,14 +432,13 @@ xfs_attr_complete_op(
 	enum xfs_delattr_state	replace_state)
 {
 	struct xfs_da_args	*args = attr->xattri_da_args;
-	bool			do_replace = args->op_flags & XFS_DA_OP_REPLACE;
+
+	if (!(args->op_flags & XFS_DA_OP_REPLACE))
+		replace_state = XFS_DAS_DONE;
 
 	args->op_flags &= ~XFS_DA_OP_REPLACE;
 	args->attr_filter &= ~XFS_ATTR_INCOMPLETE;
-	if (do_replace)
-		return replace_state;
-
-	return XFS_DAS_DONE;
+	return replace_state;
 }
 
 static int
@@ -870,6 +881,11 @@ xfs_attr_lookup(
 		return -ENOATTR;
 	}
 
+	/* Prerequisite for xfs_attr_is_leaf */
+	error = xfs_iread_extents(args->trans, args->dp, XFS_ATTR_FORK);
+	if (error)
+		return error;
+
 	if (xfs_attr_is_leaf(dp)) {
 		error = xfs_attr_leaf_hasname(args, &bp);
 
@@ -1516,12 +1532,23 @@ xfs_attr_node_get(
 	return error;
 }
 
+/* Enforce that there is at most one namespace bit per attr. */
+inline bool xfs_attr_check_namespace(unsigned int attr_flags)
+{
+	return hweight32(attr_flags & XFS_ATTR_NSP_ONDISK_MASK) < 2;
+}
+
 /* Returns true if the attribute entry name is valid. */
 bool
 xfs_attr_namecheck(
+	unsigned int	attr_flags,
 	const void	*name,
 	size_t		length)
 {
+	/* Only one namespace bit allowed. */
+	if (!xfs_attr_check_namespace(attr_flags))
+		return false;
+
 	/*
 	 * MAXNAMELEN includes the trailing null, but (name/length) leave it
 	 * out, so use >= for the length check.

fs/xfs/libxfs/xfs_attr.h

@@ -529,6 +529,11 @@ struct xfs_attr_intent {
 	struct xfs_bmbt_irec		xattri_map;
 };
 
+static inline unsigned int
+xfs_attr_intent_op(const struct xfs_attr_intent *attr)
+{
+	return attr->xattri_op_flags & XFS_ATTRI_OP_FLAGS_TYPE_MASK;
+}
 
 /*========================================================================
  * Function prototypes for the kernel.
@@ -555,7 +560,9 @@ enum xfs_attr_update {
 int xfs_attr_set(struct xfs_da_args *args, enum xfs_attr_update op);
 int xfs_attr_set_iter(struct xfs_attr_intent *attr);
 int xfs_attr_remove_iter(struct xfs_attr_intent *attr);
-bool xfs_attr_namecheck(const void *name, size_t length);
+bool xfs_attr_check_namespace(unsigned int attr_flags);
+bool xfs_attr_namecheck(unsigned int attr_flags, const void *name,
+		size_t length);
 int xfs_attr_calc_size(struct xfs_da_args *args, int *local);
 void xfs_init_attr_trans(struct xfs_da_args *args, struct xfs_trans_res *tres,
 			 unsigned int *total);

fs/xfs/libxfs/xfs_attr_leaf.c

@@ -950,6 +950,11 @@ xfs_attr_shortform_to_leaf(
 		nargs.hashval = xfs_da_hashname(sfe->nameval,
 						sfe->namelen);
 		nargs.attr_filter = sfe->flags & XFS_ATTR_NSP_ONDISK_MASK;
+		if (!xfs_attr_check_namespace(sfe->flags)) {
+			xfs_da_mark_sick(args);
+			error = -EFSCORRUPTED;
+			goto out;
+		}
 		error = xfs_attr3_leaf_lookup_int(bp, &nargs); /* set a->index */
 		ASSERT(error == -ENOATTR);
 		error = xfs_attr3_leaf_add(bp, &nargs);
@@ -1063,7 +1068,7 @@ xfs_attr_shortform_verify(
 		 * one namespace flag per xattr, so we can just count the
 		 * bits (i.e. hweight) here.
 		 */
-		if (hweight8(sfep->flags & XFS_ATTR_NSP_ONDISK_MASK) > 1)
+		if (!xfs_attr_check_namespace(sfep->flags))
 			return __this_address;
 
 		sfep = next_sfep;

fs/xfs/libxfs/xfs_da_format.h

@@ -719,8 +719,13 @@ struct xfs_attr3_leafblock {
 #define XFS_ATTR_ROOT		(1u << XFS_ATTR_ROOT_BIT)
 #define XFS_ATTR_SECURE		(1u << XFS_ATTR_SECURE_BIT)
 #define XFS_ATTR_INCOMPLETE	(1u << XFS_ATTR_INCOMPLETE_BIT)
+
 #define XFS_ATTR_NSP_ONDISK_MASK	(XFS_ATTR_ROOT | XFS_ATTR_SECURE)
 
+#define XFS_ATTR_ONDISK_MASK	(XFS_ATTR_NSP_ONDISK_MASK | \
+				 XFS_ATTR_LOCAL | \
+				 XFS_ATTR_INCOMPLETE)
+
 #define XFS_ATTR_NAMESPACE_STR \
 	{ XFS_ATTR_LOCAL,	"local" }, \
 	{ XFS_ATTR_ROOT,	"root" }, \

fs/xfs/scrub/attr.c

@@ -192,20 +192,19 @@ xchk_xattr_actor(
 	if (xchk_should_terminate(sc, &error))
 		return error;
 
+	if (attr_flags & ~XFS_ATTR_ONDISK_MASK) {
+		xchk_fblock_set_corrupt(sc, XFS_ATTR_FORK, args.blkno);
+		return -ECANCELED;
+	}
+
 	if (attr_flags & XFS_ATTR_INCOMPLETE) {
 		/* Incomplete attr key, just mark the inode for preening. */
 		xchk_ino_set_preen(sc, ip->i_ino);
 		return 0;
 	}
 
-	/* Only one namespace bit allowed. */
-	if (hweight32(attr_flags & XFS_ATTR_NSP_ONDISK_MASK) > 1) {
-		xchk_fblock_set_corrupt(sc, XFS_ATTR_FORK, args.blkno);
-		return -ECANCELED;
-	}
-
 	/* Does this name make sense? */
-	if (!xfs_attr_namecheck(name, namelen)) {
+	if (!xfs_attr_namecheck(attr_flags, name, namelen)) {
 		xchk_fblock_set_corrupt(sc, XFS_ATTR_FORK, args.blkno);
 		return -ECANCELED;
 	}
@@ -481,7 +480,6 @@ xchk_xattr_rec(
 	xfs_dahash_t			hash;
 	int				nameidx;
 	int				hdrsize;
-	unsigned int			badflags;
 	int				error;
 
 	ASSERT(blk->magic == XFS_ATTR_LEAF_MAGIC);
@@ -511,10 +509,15 @@ xchk_xattr_rec(
 
 	/* Retrieve the entry and check it. */
 	hash = be32_to_cpu(ent->hashval);
-	badflags = ~(XFS_ATTR_LOCAL | XFS_ATTR_ROOT | XFS_ATTR_SECURE |
-			XFS_ATTR_INCOMPLETE);
-	if ((ent->flags & badflags) != 0)
+	if (ent->flags & ~XFS_ATTR_ONDISK_MASK) {
+		xchk_da_set_corrupt(ds, level);
+		return 0;
+	}
+	if (!xfs_attr_check_namespace(ent->flags)) {
 		xchk_da_set_corrupt(ds, level);
+		return 0;
+	}
+
 	if (ent->flags & XFS_ATTR_LOCAL) {
 		lentry = (struct xfs_attr_leaf_name_local *)
 				(((char *)bp->b_addr) + nameidx);
@@ -574,6 +577,15 @@ xchk_xattr_check_sf(
 			break;
 		}
 
+		/*
+		 * Shortform entries do not set LOCAL or INCOMPLETE, so the
+		 * only valid flag bits here are for namespaces.
+		 */
+		if (sfe->flags & ~XFS_ATTR_NSP_ONDISK_MASK) {
+			xchk_fblock_set_corrupt(sc, XFS_ATTR_FORK, 0);
+			break;
+		}
+
 		if (!xchk_xattr_set_map(sc, ab->usedmap,
 				(char *)sfe - (char *)sf,
 				sizeof(struct xfs_attr_sf_entry))) {

fs/xfs/scrub/attr_repair.c

@@ -123,12 +123,10 @@ xrep_xattr_want_salvage(
 		return false;
 	if (namelen > XATTR_NAME_MAX || namelen <= 0)
 		return false;
-	if (!xfs_attr_namecheck(name, namelen))
+	if (!xfs_attr_namecheck(attr_flags, name, namelen))
 		return false;
 	if (valuelen > XATTR_SIZE_MAX || valuelen < 0)
 		return false;
-	if (hweight32(attr_flags & XFS_ATTR_NSP_ONDISK_MASK) > 1)
-		return false;
 	return true;
 }