[PATCH] f2fs: fix to disallow getting inner inode via f2fs_iget()

[Chao Yu]

From: Chao Yu <chao.yu@xxxxxxxx>

Introduce f2fs_iget_inner() for f2fs_fill_super() to get inner inode:
meta inode, node inode or compressed inode, and add f2fs_check_nid_range()
in f2fs_iget() to avoid getting inner inode from external interfaces.

Signed-off-by: Chao Yu <chao.yu@xxxxxxxx>
---
 fs/f2fs/compress.c |  2 +-
 fs/f2fs/f2fs.h     |  1 +
 fs/f2fs/inode.c    | 10 +++++++++-
 fs/f2fs/super.c    |  4 ++--
 4 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/fs/f2fs/compress.c b/fs/f2fs/compress.c
index 730256732a9e..c38b22bb6432 100644
--- a/fs/f2fs/compress.c
+++ b/fs/f2fs/compress.c
@@ -1947,7 +1947,7 @@ int f2fs_init_compress_inode(struct f2fs_sb_info *sbi)
 	if (!test_opt(sbi, COMPRESS_CACHE))
 		return 0;
 
-	inode = f2fs_iget(sbi->sb, F2FS_COMPRESS_INO(sbi));
+	inode = f2fs_iget_inner(sbi->sb, F2FS_COMPRESS_INO(sbi));
 	if (IS_ERR(inode))
 		return PTR_ERR(inode);
 	sbi->compress_inode = inode;
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 408d8034ed74..35f9e1a6a1bf 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -3467,6 +3467,7 @@ int f2fs_pin_file_control(struct inode *inode, bool inc);
 void f2fs_set_inode_flags(struct inode *inode);
 bool f2fs_inode_chksum_verify(struct f2fs_sb_info *sbi, struct page *page);
 void f2fs_inode_chksum_set(struct f2fs_sb_info *sbi, struct page *page);
+struct inode *f2fs_iget_inner(struct super_block *sb, unsigned long ino);
 struct inode *f2fs_iget(struct super_block *sb, unsigned long ino);
 struct inode *f2fs_iget_retry(struct super_block *sb, unsigned long ino);
 int f2fs_try_to_free_nats(struct f2fs_sb_info *sbi, int nr_shrink);
diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c
index 6d11c365d7b4..0ab3ae9b2110 100644
--- a/fs/f2fs/inode.c
+++ b/fs/f2fs/inode.c
@@ -480,7 +480,7 @@ static int do_read_inode(struct inode *inode)
 	return 0;
 }
 
-struct inode *f2fs_iget(struct super_block *sb, unsigned long ino)
+struct inode *f2fs_iget_inner(struct super_block *sb, unsigned long ino)
 {
 	struct f2fs_sb_info *sbi = F2FS_SB(sb);
 	struct inode *inode;
@@ -568,6 +568,14 @@ struct inode *f2fs_iget(struct super_block *sb, unsigned long ino)
 	return ERR_PTR(ret);
 }
 
+struct inode *f2fs_iget(struct super_block *sb, unsigned long ino)
+{
+	if (f2fs_check_nid_range(F2FS_SB(sb), ino))
+		return -EINVAL;
+
+	return f2fs_iget_inner(sb, ino);
+}
+
 struct inode *f2fs_iget_retry(struct super_block *sb, unsigned long ino)
 {
 	struct inode *inode;
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index b8e5fe244596..a5f5e7483791 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -4157,7 +4157,7 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
 		goto free_xattr_cache;
 
 	/* get an inode for meta space */
-	sbi->meta_inode = f2fs_iget(sb, F2FS_META_INO(sbi));
+	sbi->meta_inode = f2fs_iget_inner(sb, F2FS_META_INO(sbi));
 	if (IS_ERR(sbi->meta_inode)) {
 		f2fs_err(sbi, "Failed to read F2FS meta data inode");
 		err = PTR_ERR(sbi->meta_inode);
@@ -4265,7 +4265,7 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
 		goto free_nm;
 
 	/* get an inode for node space */
-	sbi->node_inode = f2fs_iget(sb, F2FS_NODE_INO(sbi));
+	sbi->node_inode = f2fs_iget_inner(sb, F2FS_NODE_INO(sbi));
 	if (IS_ERR(sbi->node_inode)) {
 		f2fs_err(sbi, "Failed to read node inode");
 		err = PTR_ERR(sbi->node_inode);
-- 
2.25.1