uint16_t tot_len;
uint16_t id;
uint16_t frag_off;
+#define IPHDR_FRAG_OFF ((uint16_t)0x1fff)
+#define IPHDR_FRAG_MORE ((uint16_t)0x2000)
+#define IPHDR_FRAG_DONT ((uint16_t)0x4000)
+/* reserved 0x8000 */
uint8_t ttl;
uint8_t protocol;
uint16_t check;
uint8_t type;
uint8_t code;
uint16_t check;
- union {
+ union icmpinfofield {
uint32_t unused;
struct {
uint8_t pointer;
} echo;
} d;
};
+
+static const union icmpinfofield icmp_noinfo;
static void netlink_packet_deliver(struct netlink *st,
struct netlink_client *client,
struct icmphdr *icmph;
uint32_t source;
+ if (buf->size < (int)sizeof(struct icmphdr)) return False;
iph=(struct iphdr *)buf->start;
icmph=(struct icmphdr *)buf->start;
if (iph->protocol==1) {
switch(icmph->type) {
- case 3: /* Destination unreachable */
- case 11: /* Time Exceeded */
- case 12: /* Parameter Problem */
+ /* Based on http://www.iana.org/assignments/icmp-parameters/icmp-parameters.xhtml#icmp-parameters-types
+ * as retrieved Thu, 20 Mar 2014 00:16:44 +0000.
+ * Deprecated, reserved, unassigned and experimental
+ * options are treated as not safe to reply to.
+ */
+ case 0: /* Echo Reply */
+ case 8: /* Echo */
+ case 13: /* Timestamp */
+ case 14: /* Timestamp Reply */
+ return True;
+ default:
return False;
}
}
/* How do we spot broadcast destination addresses? */
- if (ntohs(iph->frag_off)&0x1fff) return False; /* Non-initial fragment */
+ if (ntohs(iph->frag_off)&IPHDR_FRAG_OFF) return False;
source=ntohl(iph->saddr);
if (source==0) return False;
if ((source&0xff000000)==0x7f000000) return False;
*/
static uint16_t netlink_icmp_reply_len(struct buffer_if *buf)
{
+ if (buf->size < (int)sizeof(struct iphdr)) return 0;
struct iphdr *iph=(struct iphdr *)buf->start;
uint16_t hlen,plen;
comes from. NULL indicates the host. */
static void netlink_icmp_simple(struct netlink *st, struct buffer_if *buf,
struct netlink_client *client,
- uint8_t type, uint8_t code)
+ uint8_t type, uint8_t code,
+ union icmpinfofield info)
{
- struct iphdr *iph=(struct iphdr *)buf->start;
struct icmphdr *h;
uint16_t len;
if (netlink_icmp_may_reply(buf)) {
+ struct iphdr *iph=(struct iphdr *)buf->start;
len=netlink_icmp_reply_len(buf);
h=netlink_icmp_tmpl(st,ntohl(iph->saddr),len);
- h->type=type; h->code=code;
+ h->type=type; h->code=code; h->d=info;
memcpy(buf_append(&st->icmp,len),buf->start,len);
netlink_icmp_csum(h);
netlink_packet_deliver(st,NULL,&st->icmp);
return False; \
}while(0)
+ if (buf->size < (int)sizeof(struct iphdr)) BAD("len %"PRIu32"",buf->size);
struct iphdr *iph=(struct iphdr *)buf->start;
int32_t len;
#undef BAD
}
+/* Deliver a packet _to_ client; used after we have decided
+ * what to do with it (and just to check that the client has
+ * actually registered a delivery function with us). */
+static void netlink_client_deliver(struct netlink *st,
+ struct netlink_client *client,
+ uint32_t source, uint32_t dest,
+ struct buffer_if *buf)
+{
+ if (!client->deliver) {
+ string_t s,d;
+ s=ipaddr_to_string(source);
+ d=ipaddr_to_string(dest);
+ Message(M_ERR,"%s: dropping %s->%s, client not registered\n",
+ st->name,s,d);
+ free(s); free(d);
+ BUF_FREE(buf);
+ return;
+ }
+ client->deliver(client->dst, buf);
+ client->outcount++;
+}
+
/* Deliver a packet. "client" is the _origin_ of the packet, not its
destination, and is NULL for packets from the host and packets
generated internally in secnet. */
struct netlink_client *client,
struct buffer_if *buf)
{
+ if (buf->size < (int)sizeof(struct iphdr)) {
+ Message(M_ERR,"%s: trying to deliver a too-short packet"
+ " from %s!\n",st->name, client?client->name:"(local)");
+ BUF_FREE(buf);
+ return;
+ }
+
struct iphdr *iph=(struct iphdr *)buf->start;
uint32_t dest=ntohl(iph->daddr);
uint32_t source=ntohl(iph->saddr);
"(s=%s, d=%s)\n", st->name, s, d);
free(s); free(d);
netlink_icmp_simple(st,buf,client,ICMP_TYPE_UNREACHABLE,
- ICMP_CODE_NET_UNREACHABLE);
+ ICMP_CODE_NET_UNREACHABLE, icmp_noinfo);
BUF_FREE(buf);
}
} else {
free(s); free(d);
netlink_icmp_simple(st,buf,client,ICMP_TYPE_UNREACHABLE,
- ICMP_CODE_NET_PROHIBITED);
+ ICMP_CODE_NET_PROHIBITED, icmp_noinfo);
BUF_FREE(buf);
} else {
if (best_quality>0) {
/* XXX Fragment if required */
- st->routes[best_match]->deliver(
- st->routes[best_match]->dst, buf);
- st->routes[best_match]->outcount++;
+ netlink_client_deliver(st,st->routes[best_match],
+ source,dest,buf);
BUF_ASSERT_FREE(buf);
} else {
/* Generate ICMP destination unreachable */
- netlink_icmp_simple(st,buf,client,ICMP_TYPE_UNREACHABLE,
- ICMP_CODE_NET_UNREACHABLE); /* client==NULL */
+ netlink_icmp_simple(st,buf,client,/* client==NULL */
+ ICMP_TYPE_UNREACHABLE,
+ ICMP_CODE_NET_UNREACHABLE,
+ icmp_noinfo);
BUF_FREE(buf);
}
}
struct netlink_client *client,
struct buffer_if *buf)
{
+ if (buf->size < (int)sizeof(struct iphdr)) return;
struct iphdr *iph=(struct iphdr *)buf->start;
BUF_ASSERT_USED(buf);
if (iph->ttl<=1) {
/* Generate ICMP time exceeded */
netlink_icmp_simple(st,buf,client,ICMP_TYPE_TIME_EXCEEDED,
- ICMP_CODE_TTL_EXCEEDED);
+ ICMP_CODE_TTL_EXCEEDED,icmp_noinfo);
BUF_FREE(buf);
return;
}
st->localcount++;
+ if (buf->size < (int)sizeof(struct icmphdr)) {
+ Message(M_WARNING,"%s: short packet addressed to secnet; "
+ "ignoring it\n",st->name);
+ BUF_FREE(buf);
+ return;
+ }
h=(struct icmphdr *)buf->start;
- if ((ntohs(h->iph.frag_off)&0xbfff)!=0) {
+ if ((ntohs(h->iph.frag_off)&(IPHDR_FRAG_OFF|IPHDR_FRAG_MORE))!=0) {
Message(M_WARNING,"%s: fragmented packet addressed to secnet; "
"ignoring it\n",st->name);
BUF_FREE(buf);
} else {
/* Send ICMP protocol unreachable */
netlink_icmp_simple(st,buf,client,ICMP_TYPE_UNREACHABLE,
- ICMP_CODE_PROTOCOL_UNREACHABLE);
+ ICMP_CODE_PROTOCOL_UNREACHABLE,icmp_noinfo);
BUF_FREE(buf);
return;
}
BUF_FREE(buf);
return;
}
+ assert(buf->size >= (int)sizeof(struct icmphdr));
iph=(struct iphdr *)buf->start;
source=ntohl(iph->saddr);
if (client) {
st->deliver_to_host(st->dst,buf);
} else {
- st->clients->deliver(st->clients->dst,buf);
+ netlink_client_deliver(st,st->clients,source,dest,buf);
}
BUF_ASSERT_FREE(buf);
return;
if (requested) c=M_WARNING;
if (st->ptp) {
net=ipaddr_to_string(st->secnet_address);
- Message(c,"%s: point-to-point (remote end is %s); routes:\n",
+ Message(c,"%s: point-to-point (remote end is %s); routes: ",
st->name, net);
free(net);
netlink_output_subnets(st,c,st->clients->subnets);
~ian / secnet.git / blobdiff