[PATCH 4.14 17/51] f2fs: check if file namelen exceeds max value

[Greg Kroah-Hartman]

From: Sheng Yong <shengyong1@xxxxxxxxxx>

[ Upstream commit 720db068634c91553a8e1d9a0fcd8c7050e06d2b ]

Dentry bitmap is not enough to detect incorrect dentries. So this patch
also checks the namelen value of a dentry.

Signed-off-by: Gong Chen <gongchen4@xxxxxxxxxx>
Signed-off-by: Sheng Yong <shengyong1@xxxxxxxxxx>
Reviewed-by: Chao Yu <yuchao0@xxxxxxxxxx>
Signed-off-by: Jaegeuk Kim <jaegeuk@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 fs/f2fs/dir.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
index 7a177b8f227d2..ff519f7a87847 100644
--- a/fs/f2fs/dir.c
+++ b/fs/f2fs/dir.c
@@ -819,7 +819,8 @@ int f2fs_fill_dentries(struct dir_context *ctx, struct f2fs_dentry_ptr *d,
 
 		/* check memory boundary before moving forward */
 		bit_pos += GET_DENTRY_SLOTS(le16_to_cpu(de->name_len));
-		if (unlikely(bit_pos > d->max)) {
+		if (unlikely(bit_pos > d->max ||
+				le16_to_cpu(de->name_len) > F2FS_NAME_LEN)) {
 			f2fs_msg(F2FS_I_SB(d->inode)->sb, KERN_WARNING,
 				"%s: corrupted namelen=%d, run fsck to fix.",
 				__func__, le16_to_cpu(de->name_len));
-- 
2.25.1