Add check for more than one RTA_OIF, even though this is rather unlikely. Get rid of the buggy switch / break as this code won't need to handle more attributes. Use VIR_WARNINGS_NO_CAST_ALIGN to fix impossible to fix util/virnetdevip.c:560:17: error: cast increases required alignment of target type [-Werror=cast-align] ---  Diff to v1:    * Add error message    * Use VIR_WARNINGS_NO_CAST_ALIGN  src/util/virnetdevip.c | 17 +++++++++++++----  1 file changed, 13 insertions(+), 4 deletions(-) diff --git a/src/util/virnetdevip.c b/src/util/virnetdevip.c index c9ac6baf7..726fa6c3e 100644 --- a/src/util/virnetdevip.c +++ b/src/util/virnetdevip.c @@ -556,15 +556,24 @@ virNetDevIPCheckIPv6ForwardingCallback(const struct nlmsghdr *resp,      if (resp->nlmsg_type != RTM_NEWROUTE)          return ret;   -    /* Extract a few attributes */ +    /* Extract a device ID attribute */ +    VIR_WARNINGS_NO_CAST_ALIGN      for (rta = RTM_RTA(rtmsg); RTA_OK(rta, len); rta = RTA_NEXT(rta, len)) { -        switch (rta->rta_type) { -        case RTA_OIF: +        VIR_WARNINGS_RESET +        if (rta->rta_type == RTA_OIF) {              oif = *(int *)RTA_DATA(rta);   +            /* Should never happen: netlink message would be broken */ +            if (ifname) { +                char *ifname2 = virNetDevGetName(oif); +                VIR_WARN("Single route has unexpected 2nd interface " +                         "- '%s' and '%s'", ifname, ifname2); +                VIR_FREE(ifname2); +                break; +            } +              if (!(ifname = virNetDevGetName(oif)))                  goto error; -            break;          }      }