btrfs-progs: utils: do not expect lo_file_name to be null terminated

The loop_info64::lo_file_name might not be null terminated. Avoid strlen
and trim the length to whatever size of the loop_info buffer.

Signed-off-by: David Sterba <dsterba@suse.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/utils.c b/utils.c
index 4f3fbbae..c9c6394f 100644
--- a/utils.c
+++ b/utils.c
@@ -1188,7 +1188,8 @@ static int resolve_loop_device_with_loopdev(const char* loop_dev, char* loop_fil
 	if (ioctl(fd, LOOP_GET_STATUS64, &lo64) < 0)
 		return -errno;
 
-	memcpy(loop_file, lo64.lo_file_name, strlen(lo64.lo_file_name) + 1);
+	memcpy(loop_file, lo64.lo_file_name, sizeof(lo64.lo_file_name));
+	loop_file[sizeof(lo64.lo_file_name)] = 0;
 	if (close(fd) < 0)
 		return -errno;