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mDNS: source address check added

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RFC6762 section 5.5 and 11 define that we should check that all
packets originated on the local link.
This commit is contained in:
Jasper Verschueren 2018-10-19 13:58:49 +02:00 committed by Dirk Ziegelmeier
parent 331368e3aa
commit 16da67bb21
1 changed files with 17 additions and 0 deletions
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17
src/apps/mdns/mdns.c
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@ -1188,11 +1188,22 @@ mdns_recv(void *arg, struct udp_pcb *pcb, struct pbuf *p, const ip_addr_t *addr,
packet.authoritative = packet.authoritative_left = lwip_ntohs(hdr.numauthrr);
packet.additional = packet.additional_left = lwip_ntohs(hdr.numextrarr);
/* Source address check (RFC6762 section 11) -> for responses.
* Source address check (RFC6762 section 5.5) -> for queries.
* When the dest addr == multicast addr we know the packet originated on that
* link. If not, we need to check the source address. We only accept queries
* that originated on the link. Others are discarded.
*/
#if LWIP_IPV6
if (IP_IS_V6(ip_current_dest_addr())) {
/* instead of having one 'v6group' per netif, just compare zoneless here */
if (!ip_addr_cmp_zoneless(ip_current_dest_addr(), &v6group)) {
packet.recv_unicast = 1;
if (ip6_addr_ismulticast_global(ip_2_ip6(ip_current_src_addr()))
|| ip6_addr_isglobal(ip_2_ip6(ip_current_src_addr()))) {
goto dealloc;
}
}
}
#endif
@ -1200,6 +1211,12 @@ mdns_recv(void *arg, struct udp_pcb *pcb, struct pbuf *p, const ip_addr_t *addr,
if (!IP_IS_V6(ip_current_dest_addr())) {
if (!ip_addr_cmp(ip_current_dest_addr(), &v4group)) {
packet.recv_unicast = 1;
if (!ip4_addr_netcmp(ip_2_ip4(ip_current_src_addr()),
netif_ip4_addr(recv_netif),
netif_ip4_netmask(recv_netif))){
goto dealloc;
}
}
}
#endif