fs/ntfs3: Check if more than chunk-size bytes are written

A incorrectly formatted chunk may decompress into
more than LZNT_CHUNK_SIZE bytes and a index out of bounds
will occur in s_max_off.
Signed-off-by: Andrew Ballance <andrewjballance@gmail.com>
Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>

fs/ntfs3/lznt.c

@@ -236,6 +236,9 @@ static inline ssize_t decompress_chunk(u8 *unc, u8 *unc_end, const u8 *cmpr,
 
 	/* Do decompression until pointers are inside range. */
 	while (up < unc_end && cmpr < cmpr_end) {
+		// return err if more than LZNT_CHUNK_SIZE bytes are written
+		if (up - unc > LZNT_CHUNK_SIZE)
+			return -EINVAL;
 		/* Correct index */
 		while (unc + s_max_off[index] < up)
 			index += 1;