Allow options with zero data, for example Accept Reconf (20).

Assume if no status option is present it is OK.
Based on an initial patch by pmarks@google.com

diff --git a/dhcp6.c b/dhcp6.c
index 795d2f8b97372f4ca68347087939130b49f7065c..1e19c3662421a0ac654d4ae734f5f3bb34f64c3b 100644 (file)
--- a/dhcp6.c
+++ b/dhcp6.c
@@ -80,6 +80,7 @@ static unsigned char *duid;
 static uint16_t duid_len;
 static char ntopbuf[INET6_ADDRSTRLEN];
 static char *status;
+static size_t status_len;
 
 struct dhcp6_op {
        uint16_t type;
@@ -287,8 +288,6 @@ dhcp6_findoption(int code, const uint8_t *d, ssize_t len)
            len > (ssize_t)sizeof(*o);
            o = D6_CNEXT_OPTION(o))
        {
-               if (o->len == 0)
-                       break;
                len -= sizeof(*o) + ntohs(o->len);
                if (len < 0) {
                        errno = EINVAL;
@@ -1004,6 +1003,7 @@ dhcp6_startrelease(struct interface *ifp)
 
 static int dhcp6_getstatus(const struct dhcp6_option *o)
 {
+       char *nstatus;
        const struct dhcp6_status *s;
        size_t len;
 
@@ -1019,15 +1019,39 @@ static int dhcp6_getstatus(const struct dhcp6_option *o)
        }
        s = (const struct dhcp6_status *)o;
        len = ntohs(s->len) - sizeof(s->len);
-       if (status == NULL || len > strlen(status)) {
-               free(status);
-               status = malloc(len + 1);
+       if (status == NULL || len + 1 > status_len) {
+               status_len = len;
+               nstatus = realloc(status, status_len + 1);
+               if (nstatus == NULL) {
+                       syslog(LOG_ERR, "%s: %m", __func__);
+                       free(status);
+               }
+               status = nstatus;
+       }
+       if (status) {
+               memcpy(status, (const char *)s + sizeof(*s), len);
+               status[len] = '\0';
        }
-       memcpy(status, (const char *)s + sizeof(*s), len);
-       status[len] = '\0';
        return ntohs(s->status);
 }
 
+static int
+dhcp6_checkstatusok(const struct interface *ifp,
+    const struct dhcp6_message *m, const uint8_t *p, size_t len)
+{
+       const struct dhcp6_option *o;
+
+       if (p)
+               o = dhcp6_findoption(D6_OPTION_STATUS_CODE, p, len);
+       else
+               o = dhcp6_getoption(D6_OPTION_STATUS_CODE, m, len);
+       if (o && dhcp6_getstatus(o) != D6_STATUS_OK) {
+               syslog(LOG_ERR, "%s: DHCPv6 REPLY: %s", ifp->name, status);
+               return -1;
+       }
+       return 0;
+}
+
 static struct ipv6_addr *
 dhcp6_findaddr(const struct in6_addr *a, struct interface *ifp)
 {
@@ -1304,12 +1328,8 @@ dhcp6_findia(struct interface *ifp, const uint8_t *d, size_t l,
                            (rebind < state->rebind || state->rebind == 0))
                                state->rebind = rebind;
                }
-               o = dhcp6_findoption(D6_OPTION_STATUS_CODE, p, ol);
-               if (o && dhcp6_getstatus(o) != D6_STATUS_OK) {
-                       syslog(LOG_ERR, "%s: DHCPv6 REPLY: %s",
-                           ifp->name, status);
+               if (dhcp6_checkstatusok(ifp, NULL, p, ol) == -1)
                        return -1;
-               }
                if (ifo->ia_type == D6_OPTION_IA_PD) {
                        dhcp6_freedrop_addrs(ifp, 0);
                        if (dhcp6_findpd(ifp, iaid, p, ol) == 0) {
@@ -1754,16 +1774,7 @@ dhcp6_handledata(__unused void *arg)
                        break;
                switch(state->state) {
                case DH6S_CONFIRM:
-                       o = dhcp6_getoption(D6_OPTION_STATUS_CODE, r, len);
-                       if (o == NULL) {
-                               syslog(LOG_ERR,
-                                   "%s: no status code in reply from %s",
-                                   ifp->name, sfrom);
-                               return;
-                       }
-                       if (dhcp6_getstatus(o) != D6_STATUS_OK) {
-                               syslog(LOG_ERR, "%s: DHCPv6 REPLY: %s",
-                                   ifp->name, status);
+                       if (dhcp6_checkstatusok(ifp, r, NULL, len) == -1) {
                                dhcp6_startdiscover(ifp);
                                return;
                        }