libfstools: ubi: avoid crash in volume finding function

In case /sys/devices/virtual/ubi/ubi?/ubi?_?/name doesn't exist volname
will be NULL and calling strlen for NULL isn't a good idea.

Signed-off-by: Rafał Miłecki <zajec5@gmail.com>

diff --git a/libfstools/ubi.c b/libfstools/ubi.c
index 866034a7cc84e4d06e495b18d87be85ec658ca8a..ac9eb1b976851e1e4322edace5018cd44265d488 100644 (file)
--- a/libfstools/ubi.c
+++ b/libfstools/ubi.c
@@ -143,6 +143,10 @@ static int ubi_volume_match(struct volume *v, char *name, int ubi_num, int volid
        /* todo: skip existing gluebi device for legacy support */
 
        volname = read_string_from_file(voldir, "name");
+       if (!volname) {
+               fprintf(stderr, "Couldn't read %s/name\n", voldir);
+               return -1;
+       }
 
        if (strncmp(name, volname, strlen(volname) + 1))
                return -1;