ntfs_fill_super() loads the on-disk volume label with utf16s_to_utf8s()
and stores the result in sbi->volume.label. The converted label is later
exposed through ntfs3_label_show() using %s, but utf16s_to_utf8s() only
returns the number of bytes written and does not add a trailing NUL.
If the converted label fills the entire fixed buffer,
ntfs3_label_show() can read past the end of sbi->volume.label while
looking for a terminator.
Terminate the cached label explicitly after a successful conversion and
clamp the exact-full case to the last byte of the buffer.
Fixes: 82cae269cfa9 ("fs/ntfs3: Add initialization of super block")
Signed-off-by: Pengpeng Hou <pengpeng@iscas.ac.cn>
---
fs/ntfs3/super.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/fs/ntfs3/super.c b/fs/ntfs3/super.c
index 174a7cb202a0..9ed485f9efba 100644
--- a/fs/ntfs3/super.c
+++ b/fs/ntfs3/super.c
@@ -1339,8 +1339,13 @@ static int ntfs_fill_super(struct super_block *sb, struct fs_context *fc)
le32_to_cpu(attr->res.data_size) >> 1,
UTF16_LITTLE_ENDIAN, sbi->volume.label,
sizeof(sbi->volume.label));
- if (err < 0)
+ if (err < 0) {
sbi->volume.label[0] = 0;
+ } else if (err >= sizeof(sbi->volume.label)) {
+ sbi->volume.label[sizeof(sbi->volume.label) - 1] = 0;
+ } else {
+ sbi->volume.label[err] = 0;
+ }
} else {
/* Should we break mounting here? */
//err = -EINVAL;
--
2.50.1 (Apple Git-155)