fsck.f2fs: fix to check validation of i_xattr_nid

Otherwise, fsck.f2fs will access invalid memory address as below:

- fsck_verify
 - dump_node
  - dump_file
   - dump_inode_blk
    - dump_xattr
     - read_all_xattrs
       - get_node_info
        access &(F2FS_FSCK(sbi)->entries[nid])

Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fsck/dump.c

@@ -309,6 +309,8 @@ static void dump_xattr(struct f2fs_sb_info *sbi, struct f2fs_node *node_blk)
 	int ret;
 
 	xattr = read_all_xattrs(sbi, node_blk);
+	if (!xattr)
+		return;
 
 	list_for_each_xattr(ent, xattr) {
 		char *name = strndup(ent->e_name, ent->e_name_len);

fsck/fsck.c

@@ -487,6 +487,14 @@ static int sanity_check_nid(struct f2fs_sb_info *sbi, u32 nid,
 	return 0;
 }
 
+int fsck_sanity_check_nid(struct f2fs_sb_info *sbi, u32 nid,
+			struct f2fs_node *node_blk,
+			enum FILE_TYPE ftype, enum NODE_TYPE ntype,
+			struct node_info *ni)
+{
+	return sanity_check_nid(sbi, nid, node_blk, ftype, ntype, ni);
+}
+
 static int fsck_chk_xattr_blk(struct f2fs_sb_info *sbi, u32 ino,
 					u32 x_nid, u32 *blk_cnt)
 {

fsck/fsck.h

@@ -144,6 +144,9 @@ static inline bool need_fsync_data_record(struct f2fs_sb_info *sbi)
 extern int fsck_chk_orphan_node(struct f2fs_sb_info *);
 extern int fsck_chk_quota_node(struct f2fs_sb_info *);
 extern int fsck_chk_quota_files(struct f2fs_sb_info *);
+extern int fsck_sanity_check_nid(struct f2fs_sb_info *, u32,
+			struct f2fs_node *, enum FILE_TYPE, enum NODE_TYPE,
+			struct node_info *);
 extern int fsck_chk_node_blk(struct f2fs_sb_info *, struct f2fs_inode *, u32,
 		enum FILE_TYPE, enum NODE_TYPE, u32 *,
 		struct child_info *);

fsck/mount.c

@@ -257,10 +257,12 @@ void print_inode_info(struct f2fs_sb_info *sbi,
 	DISP_u32(inode, i_nid[4]);	/* double indirect */
 
 	xattr_addr = read_all_xattrs(sbi, node);
+	if (xattr_addr) {
 		list_for_each_xattr(ent, xattr_addr) {
 			print_xattr_entry(ent);
 		}
 		free(xattr_addr);
+	}
 
 	printf("\n");
 }

fsck/xattr.c

@@ -22,6 +22,22 @@ void *read_all_xattrs(struct f2fs_sb_info *sbi, struct f2fs_node *inode)
 	struct f2fs_xattr_header *header;
 	void *txattr_addr;
 	u64 inline_size = inline_xattr_size(&inode->i);
+	nid_t xnid = le32_to_cpu(inode->i.i_xattr_nid);
+
+	if (xnid) {
+		struct f2fs_node *node_blk = NULL;
+		struct node_info ni;
+		int ret;
+
+		node_blk = (struct f2fs_node *)calloc(BLOCK_SZ, 1);
+		ASSERT(node_blk != NULL);
+
+		ret = fsck_sanity_check_nid(sbi, xnid, node_blk,
+					F2FS_FT_XATTR, TYPE_XATTR, &ni);
+		free(node_blk);
+		if (ret)
+			return NULL;
+	}
 
 	txattr_addr = calloc(inline_size + BLOCK_SZ, 1);
 	ASSERT(txattr_addr);
@@ -30,11 +46,11 @@ void *read_all_xattrs(struct f2fs_sb_info *sbi, struct f2fs_node *inode)
 		memcpy(txattr_addr, inline_xattr_addr(&inode->i), inline_size);
 
 	/* Read from xattr node block. */
-	if (inode->i.i_xattr_nid) {
+	if (xnid) {
 		struct node_info ni;
 		int ret;
 
-		get_node_info(sbi, le32_to_cpu(inode->i.i_xattr_nid), &ni);
+		get_node_info(sbi, xnid, &ni);
 		ret = dev_read_block(txattr_addr + inline_size, ni.blk_addr);
 		ASSERT(ret >= 0);
 	}