Merge pull request #4 from dedeckeh/master

Bugfixes

3 files changed, 77 insertions, 20 deletions

diff --git a/src/odhcpd.c b/src/odhcpd.c
index d6ca298..cb84513 100644
--- a/src/odhcpd.c
+++ b/src/odhcpd.c
@@ -320,8 +320,7 @@ static void odhcpd_receive_packets(struct uloop_fd *u, _unused unsigned int even
 		int *hlim = NULL;
 		struct in6_pktinfo *pktinfo;
 		struct in_pktinfo *pkt4info;
-		for (struct cmsghdr *ch = CMSG_FIRSTHDR(&msg); ch != NULL &&
-				destiface == 0; ch = CMSG_NXTHDR(&msg, ch)) {
+		for (struct cmsghdr *ch = CMSG_FIRSTHDR(&msg); ch != NULL; ch = CMSG_NXTHDR(&msg, ch)) {
 			if (ch->cmsg_level == IPPROTO_IPV6 &&
 					ch->cmsg_type == IPV6_PKTINFO) {
 				pktinfo = (struct in6_pktinfo*)CMSG_DATA(ch);
diff --git a/src/router.c b/src/router.c
index 83da938..a213c84 100644
--- 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);
@@ -211,7 +265,7 @@ static void send_router_advert(struct uloop_timeout *event)
 
 	struct {
 		struct nd_router_advert h;
-		struct icmpv6_opt lladdr;
+		struct nd_opt_slla lladdr;
 		struct nd_opt_mtu mtu;
 		struct nd_opt_prefix_info prefix[RELAYD_MAX_PREFIXES];
 	} adv = {
@@ -227,7 +281,7 @@ static void send_router_advert(struct uloop_timeout *event)
 		adv.h.nd_ra_flags_reserved |= ND_RA_PREF_LOW;
 	else if (iface->route_preference > 0)
 		adv.h.nd_ra_flags_reserved |= ND_RA_PREF_HIGH;
-	odhcpd_get_mac(iface, adv.lladdr.data);
+	odhcpd_get_mac(iface, adv.lladdr.addr);
 
 	// If not currently shutting down
 	struct odhcpd_ipaddr addrs[RELAYD_MAX_PREFIXES];
@@ -319,14 +373,7 @@ static void send_router_advert(struct uloop_timeout *event)
 	if (!dns_addr)
 		dns_cnt = 0;
 
-	struct {
-		uint8_t type;
-		uint8_t len;
-		uint8_t pad;
-		uint8_t pad2;
-		uint32_t lifetime;
-	} dns = {ND_OPT_RECURSIVE_DNS, (1 + (2 * dns_cnt)), 0, 0, htonl(dns_time)};
-
+	struct nd_opt_recursive_dns dns = {ND_OPT_RECURSIVE_DNS, (1 + (2 * dns_cnt)), 0, 0, htonl(dns_time)};
 
 
 	// DNS Search options
@@ -455,11 +502,12 @@ static void forward_router_advertisement(uint8_t *data, size_t len)
 	icmpv6_for_each_option(opt, &adv[1], end) {
 		if (opt->type == ND_OPT_SOURCE_LINKADDR) {
 			// Store address of source MAC-address
-			mac_ptr = opt->data;
+			mac_ptr = ((struct nd_opt_slla *)opt)->addr;
 		} else if (opt->type == ND_OPT_RECURSIVE_DNS && opt->len > 1) {
+			struct nd_opt_recursive_dns *dns = (struct nd_opt_recursive_dns *)opt;
 			// Check if we have to rewrite DNS
-			dns_ptr = (struct in6_addr*)&opt->data[6];
-			dns_count = (opt->len - 1) / 2;
+			dns_ptr = (struct in6_addr *)&dns[1];
+			dns_count = (dns->len - 1) / 2;
 		}
 	}
 
diff --git a/src/router.h b/src/router.h
index 1e8649c..8d74967 100644
--- a/src/router.h
+++ b/src/router.h
@@ -20,15 +20,25 @@
 struct icmpv6_opt {
 	uint8_t type;
 	uint8_t len;
-	uint8_t data[6];
 };
 
+struct nd_opt_slla {
+	uint8_t type;
+	uint8_t len;
+	uint8_t addr[6];
+};
+
+struct nd_opt_recursive_dns {
+	uint8_t type;
+	uint8_t len;
+	uint8_t pad;
+	uint8_t pad2;
+	uint32_t lifetime;
+};
 
 #define icmpv6_for_each_option(opt, start, end)\
 	for (opt = (struct icmpv6_opt*)(start);\
-	(void*)(opt + 1) <= (void*)(end) && opt->len > 0 &&\
-	(void*)(opt + opt->len) <= (void*)(end); opt += opt->len)
-
+	(void*)(opt + (opt->len << 3)) <= (void*)(end); opt += (opt->len << 3))
 
 #define MaxRtrAdvInterval 600
 #define MinRtrAdvInterval (MaxRtrAdvInterval / 3)