Unverified Commit a6cd43fe authored Mar 27, 2026 by Pengpeng Hou Committed by Konstantin Komarov Apr 07, 2026

fs/ntfs3: terminate the cached volume label after UTF-8 conversion

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: 82cae269 ("fs/ntfs3: Add initialization of super block")
Signed-off-by: Pengpeng Hou <pengpeng@iscas.ac.cn>
Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>

parent d1062683

fs/ntfs3/super.c

+6 −1

Original line number	Diff line number	Diff line
		@@ -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;