treewide: use if_nametoindex to avoid overflows

[can-utils.git] / isotptun.c

diff --git a/isotptun.c b/isotptun.c
index c793f42015fb080c84fc88ed35fb1dbf1d04cfe7..fc2a8d57bf2fc81201c2c06d895d439667946c5b 100644 (file)
--- a/isotptun.c
+++ b/isotptun.c
@@ -265,9 +265,15 @@ int main(int argc, char **argv)
                }
        }
 
+       strncpy(ifr.ifr_name, argv[optind], IFNAMSIZ);
+       ifr.ifr_ifindex = if_nametoindex(ifr.ifr_name);
+       if (!ifr.ifr_ifindex) {
+               perror("if_nametoindex");
+               close(s);
+               exit(1);
+       }
+
        addr.can_family = AF_CAN;
-       strcpy(ifr.ifr_name, argv[optind]);
-       ioctl(s, SIOCGIFINDEX, &ifr);
        addr.can_ifindex = ifr.ifr_ifindex;
 
        if (bind(s, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
@@ -285,7 +291,8 @@ int main(int argc, char **argv)
 
        memset(&ifr, 0, sizeof(ifr));
        ifr.ifr_flags = IFF_TUN | IFF_NO_PI;
-       strncpy(ifr.ifr_name, name, IFNAMSIZ);
+       strncpy(ifr.ifr_name, name, IFNAMSIZ - 1);
+       ifr.ifr_name[IFNAMSIZ - 1] = '\0';
 
        if (ioctl(t, TUNSETIFF, (void *) &ifr) < 0) {
                perror("ioctl tunfd");