Revert "Fix Router Advertisement/Solicitation option parsing"

[project/odhcpd.git] / src / router.c

diff --git a/src/router.c b/src/router.c
index 9258acf..fffdc4c 100644 (file)
--- a/src/router.c
+++ b/src/router.c
@@ -130,12 +130,66 @@ static void sigusr1_refresh(_unused int signal)
                        uloop_timeout_set(&iface->timer_rs, 1000);
 }
 
+static int router_icmpv6_valid(struct sockaddr_in6 *source, uint8_t *data, size_t len)
+{
+       struct icmp6_hdr *hdr = (struct icmp6_hdr *)data;
+       struct icmpv6_opt *opt;
+       size_t optlen = len - sizeof(*hdr);
+
+       /* Hoplimit is already checked in odhcpd_receive_packets */
+       if (len < sizeof(*hdr))
+               return 0;
+
+       if (hdr->icmp6_code)
+               return 0;
+
+       switch (hdr->icmp6_type) {
+       case ND_ROUTER_ADVERT:
+               if (!IN6_IS_ADDR_LINKLOCAL(&source->sin6_addr))
+                       return 0;
+
+               opt = (struct icmpv6_opt *)((struct nd_router_advert *)data + 1);
+               break;
+
+       case ND_ROUTER_SOLICIT:
+               opt = (struct icmpv6_opt *)((struct nd_router_solicit *)data + 1);
+               break;
+
+       default:
+               return 0;
+       }
+
+       while (optlen > 0) {
+               size_t l = opt->len << 3;
+
+               if (optlen < sizeof(*opt))
+                       return 0;
+
+               if (l > optlen || l == 0)
+                       return 0;
+
+               if (opt->type == ND_OPT_SOURCE_LINKADDR && IN6_IS_ADDR_UNSPECIFIED(&source->sin6_addr) &&
+                       hdr->icmp6_type == ND_ROUTER_SOLICIT) {
+                       return 0;
+               }
+
+               opt = (struct icmpv6_opt *)(((uint8_t *)opt) + l);
+
+               optlen -= l;
+       }
+
+       return 1;
+}
 
 // Event handler for incoming ICMPv6 packets
-static void handle_icmpv6(_unused void *addr, void *data, size_t len,
+static void handle_icmpv6(void *addr, void *data, size_t len,
                struct interface *iface)
 {
        struct icmp6_hdr *hdr = data;
+       
+       if (!router_icmpv6_valid(addr, data, len))
+               return;
+
        if ((iface->ra == RELAYD_SERVER && !iface->master)) { // Server mode
                if (hdr->icmp6_type == ND_ROUTER_SOLICIT)
                        send_router_advert(&iface->timer_rs);
@@ -169,7 +223,7 @@ static bool parse_routes(struct odhcpd_ipaddr *n, ssize_t len)
 
        char line[512], ifname[16];
        bool found_default = false;
-       struct odhcpd_ipaddr p = {IN6ADDR_ANY_INIT, 0, 0, 0};
+       struct odhcpd_ipaddr p = {IN6ADDR_ANY_INIT, 0, false, 0, 0, 0};
        while (fgets(line, sizeof(line), fp_route)) {
                uint32_t rflags;
                if (sscanf(line, "00000000000000000000000000000000 00 "
@@ -219,7 +273,10 @@ static void send_router_advert(struct uloop_timeout *event)
                .lladdr = {ND_OPT_SOURCE_LINKADDR, 1, {0}},
                .mtu = {ND_OPT_MTU, 1, 0, htonl(mtu)},
        };
-       adv.h.nd_ra_flags_reserved = ND_RA_FLAG_OTHER;
+
+       if (iface->dhcpv6)
+               adv.h.nd_ra_flags_reserved = ND_RA_FLAG_OTHER;
+
        if (iface->managed >= RELAYD_MANAGED_MFLAG)
                adv.h.nd_ra_flags_reserved |= ND_RA_FLAG_MANAGED;
 
@@ -254,7 +311,7 @@ static void send_router_advert(struct uloop_timeout *event)
 
        for (ssize_t i = 0; i < ipcnt; ++i) {
                struct odhcpd_ipaddr *addr = &addrs[i];
-               if (addr->prefix > 64)
+               if (addr->prefix > 64 || addr->has_class)
                        continue; // Address not suitable
 
                if (addr->preferred > MaxPreferredTime)
@@ -353,6 +410,11 @@ static void send_router_advert(struct uloop_timeout *event)
                uint32_t lifetime;
                uint8_t name[];
        } *search = alloca(sizeof(*search) + search_padded);
+
+       if (!search) {
+               syslog(LOG_ERR, "Alloca failed for dns search on interface %s", iface->ifname);
+               return;
+       }
        search->type = ND_OPT_DNS_SEARCH;
        search->len = search_len ? ((sizeof(*search) + search_padded) / 8) : 0;
        search->pad = 0;