Fix advertised IPv6 addresses

[oweals/mdnsd.git] / dns.c

diff --git a/dns.c b/dns.c
index aadfdd8f6927806cbdb7108d81c1031559100308..3e902d019df417fd5443d436c956992cf99fdc5a 100644 (file)
--- a/dns.c
+++ b/dns.c
@@ -200,10 +200,8 @@ dns_reply_a(struct interface *iface, struct sockaddr *to, int ttl)
                        dns_add_answer(TYPE_A, (uint8_t *) &sa->sin_addr, 4, ttl);
                }
                if (ifa->ifa_addr->sa_family == AF_INET6) {
-                       uint8_t ll_prefix[] = {0xfe, 0x80 };
                        sa6 = (struct sockaddr_in6 *) ifa->ifa_addr;
-                       if (!memcmp(&sa6->sin6_addr, &ll_prefix, 2))
-                               dns_add_answer(TYPE_AAAA, (uint8_t *) &sa6->sin6_addr, 16, ttl);
+                       dns_add_answer(TYPE_AAAA, (uint8_t *) &sa6->sin6_addr, 16, ttl);
                }
        }
        dns_send_answer(iface, to, mdns_hostname_local);
@@ -222,6 +220,7 @@ scan_name(const uint8_t *buffer, int len)
                if (IS_COMPRESSED(l))
                        return offset + 2;
 
+               if (l + 1 > len) return -1;
                len -= l + 1;
                offset += l + 1;
                buffer += l + 1;
@@ -237,16 +236,16 @@ static struct dns_header*
 dns_consume_header(uint8_t **data, int *len)
 {
        struct dns_header *h = (struct dns_header *) *data;
-       uint16_t *swap = (uint16_t *) h;
-       int endianess = 6;
 
        if (*len < sizeof(struct dns_header))
                return NULL;
 
-       while (endianess--) {
-               *swap = be16_to_cpu(*swap);
-               swap++;
-       }
+       h->id = be16_to_cpu(h->id);
+       h->flags = be16_to_cpu(h->flags);
+       h->questions = be16_to_cpu(h->questions);
+       h->answers = be16_to_cpu(h->answers);
+       h->authority = be16_to_cpu(h->authority);
+       h->additional = be16_to_cpu(h->additional);
 
        *len -= sizeof(struct dns_header);
        *data += sizeof(struct dns_header);
@@ -258,16 +257,12 @@ static struct dns_question*
 dns_consume_question(uint8_t **data, int *len)
 {
        struct dns_question *q = (struct dns_question *) *data;
-       uint16_t *swap = (uint16_t *) q;
-       int endianess = 2;
 
        if (*len < sizeof(struct dns_question))
                return NULL;
 
-       while (endianess--) {
-               *swap = be16_to_cpu(*swap);
-               swap++;
-       }
+       q->type = be16_to_cpu(q->type);
+       q->class = be16_to_cpu(q->class);
 
        *len -= sizeof(struct dns_question);
        *data += sizeof(struct dns_question);
@@ -321,7 +316,7 @@ static int parse_answer(struct interface *iface, struct sockaddr *from,
        struct dns_answer *a;
        uint8_t *rdata;
 
-       if (!name) {
+       if (!name || *rlen < 0) {
                fprintf(stderr, "dropping: bad question\n");
                return -1;
        }
@@ -425,7 +420,7 @@ dns_handle_packet(struct interface *iface, struct sockaddr *from, uint16_t port,
                char *name = dns_consume_name(buffer, len, &b, &rlen);
                struct dns_question *q;
 
-               if (!name) {
+               if (!name || rlen < 0) {
                        fprintf(stderr, "dropping: bad name\n");
                        return;
                }