btrfs: tree-checker: add inode extref checks

[ Upstream commit aab9458 ]

Like inode refs, inode extrefs have a variable length name, which means
we have to do a proper check to make sure no header nor name can exceed
the item limits.

The check itself is very similar to check_inode_ref(), just a different
structure (btrfs_inode_extref vs btrfs_inode_ref).

Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

Author: adam900710

fs/btrfs/tree-checker.c

@@ -183,6 +183,7 @@ static bool check_prev_ino(struct extent_buffer *leaf,
 	/* Only these key->types needs to be checked */
 	ASSERT(key->type == BTRFS_XATTR_ITEM_KEY ||
 	       key->type == BTRFS_INODE_REF_KEY ||
+	       key->type == BTRFS_INODE_EXTREF_KEY ||
 	       key->type == BTRFS_DIR_INDEX_KEY ||
 	       key->type == BTRFS_DIR_ITEM_KEY ||
 	       key->type == BTRFS_EXTENT_DATA_KEY);
@@ -1770,6 +1771,39 @@ static int check_inode_ref(struct extent_buffer *leaf,
 	return 0;
 }
 
+static int check_inode_extref(struct extent_buffer *leaf,
+			      struct btrfs_key *key, struct btrfs_key *prev_key,
+			      int slot)
+{
+	unsigned long ptr = btrfs_item_ptr_offset(leaf, slot);
+	unsigned long end = ptr + btrfs_item_size(leaf, slot);
+
+	if (unlikely(!check_prev_ino(leaf, key, slot, prev_key)))
+		return -EUCLEAN;
+
+	while (ptr < end) {
+		struct btrfs_inode_extref *extref = (struct btrfs_inode_extref *)ptr;
+		u16 namelen;
+
+		if (unlikely(ptr + sizeof(*extref)) > end) {
+			inode_ref_err(leaf, slot,
+			"inode extref overflow, ptr %lu end %lu inode_extref size %zu",
+				      ptr, end, sizeof(*extref));
+			return -EUCLEAN;
+		}
+
+		namelen = btrfs_inode_extref_name_len(leaf, extref);
+		if (unlikely(ptr + sizeof(*extref) + namelen > end)) {
+			inode_ref_err(leaf, slot,
+				"inode extref overflow, ptr %lu end %lu namelen %u",
+				ptr, end, namelen);
+			return -EUCLEAN;
+		}
+		ptr += sizeof(*extref) + namelen;
+	}
+	return 0;
+}
+
 static int check_raid_stripe_extent(const struct extent_buffer *leaf,
 				    const struct btrfs_key *key, int slot)
 {
@@ -1881,6 +1915,9 @@ static enum btrfs_tree_block_status check_leaf_item(struct extent_buffer *leaf,
 	case BTRFS_INODE_REF_KEY:
 		ret = check_inode_ref(leaf, key, prev_key, slot);
 		break;
+	case BTRFS_INODE_EXTREF_KEY:
+		ret = check_inode_extref(leaf, key, prev_key, slot);
+		break;
 	case BTRFS_BLOCK_GROUP_ITEM_KEY:
 		ret = check_block_group_item(leaf, key, slot);
 		break;