Guard against failure in if_discover. Thanks to Will Miles.

diff --git a/dhcpcd.c b/dhcpcd.c
index b4644ed0834c99539a8553d7deed33603652fd52..47eb9c2ad72cabeb819a2c52a56dbafb4b88324e 100644 (file)
--- a/dhcpcd.c
+++ b/dhcpcd.c
@@ -903,6 +903,10 @@ dhcpcd_handleinterface(void *arg, int action, const char *ifname)
 
        i = -1;
        ifs = if_discover(ctx, -1, UNCONST(argv));
+       if (ifs == NULL) {
+               syslog(LOG_ERR, "%s: if_discover: %m", __func__);
+               return -1;
+       }
        TAILQ_FOREACH_SAFE(ifp, ifs, next, ifn) {
                if (strcmp(ifp->name, ifname) != 0)
                        continue;
@@ -1003,8 +1007,10 @@ reconf_reboot(struct dhcpcd_ctx *ctx, int action, int argc, char **argv, int oi)
        struct interface *ifn, *ifp;
 
        ifs = if_discover(ctx, argc - oi, argv + oi);
-       if (ifs == NULL)
+       if (ifs == NULL) {
+               syslog(LOG_ERR, "%s: if_discover: %m", __func__);
                return;
+       }
 
        while ((ifp = TAILQ_FIRST(ifs))) {
                TAILQ_REMOVE(ifs, ifp, next);
@@ -1510,8 +1516,10 @@ main(int argc, char **argv)
                /* We need to try and find the interface so we can
                 * load the hardware address to compare automated IAID */
                ctx.ifaces = if_discover(&ctx, 1, argv + optind);
-               if (ctx.ifaces == NULL)
+               if (ctx.ifaces == NULL) {
+                       syslog(LOG_ERR, "if_discover: %m");
                        goto exit_failure;
+               }
                ifp = TAILQ_FIRST(ctx.ifaces);
                if (ifp == NULL) {
                        ifp = calloc(1, sizeof(*ifp));
@@ -1703,12 +1711,16 @@ main(int argc, char **argv)
                dev_start(&ctx);
 
        ctx.ifaces = if_discover(&ctx, ctx.ifc, ctx.ifv);
+       if (ctx.ifaces == NULL) {
+               syslog(LOG_ERR, "if_discover: %m");
+               goto exit_failure;
+       }
        for (i = 0; i < ctx.ifc; i++) {
                if (if_find(&ctx, ctx.ifv[i]) == NULL)
                        syslog(LOG_ERR, "%s: interface not found or invalid",
                            ctx.ifv[i]);
        }
-       if (ctx.ifaces == NULL || TAILQ_FIRST(ctx.ifaces) == NULL) {
+       if (TAILQ_FIRST(ctx.ifaces) == NULL) {
                if (ctx.ifc == 0)
                        syslog(LOG_ERR, "no valid interfaces found");
                else