Brad Bishop | 1932369 | 2019-04-05 15:28:33 -0400 | [diff] [blame] | 1 | Upstream-Status: Backport [https://github.com/lathiat/avahi/commit/e111def] |
| 2 | |
| 3 | CVE: CVE-2017-6519 |
| 4 | |
| 5 | Signed-off-by: Kai Kang <kai.kang@windriver.com> |
| 6 | |
| 7 | From e111def44a7df4624a4aa3f85fe98054bffb6b4f Mon Sep 17 00:00:00 2001 |
| 8 | From: Trent Lloyd <trent@lloyd.id.au> |
| 9 | Date: Sat, 22 Dec 2018 09:06:07 +0800 |
| 10 | Subject: [PATCH] Drop legacy unicast queries from address not on local link |
| 11 | |
| 12 | When handling legacy unicast queries, ensure that the source IP is |
| 13 | inside a subnet on the local link, otherwise drop the packet. |
| 14 | |
| 15 | Fixes #145 |
| 16 | Fixes #203 |
| 17 | CVE-2017-6519 |
| 18 | CVE-2018-1000845 |
| 19 | --- |
| 20 | avahi-core/server.c | 8 ++++++++ |
| 21 | 1 file changed, 8 insertions(+) |
| 22 | |
| 23 | diff --git a/avahi-core/server.c b/avahi-core/server.c |
| 24 | index a2cb19a8..a2580e38 100644 |
| 25 | --- a/avahi-core/server.c |
| 26 | +++ b/avahi-core/server.c |
| 27 | @@ -930,6 +930,7 @@ static void dispatch_packet(AvahiServer *s, AvahiDnsPacket *p, const AvahiAddres |
| 28 | |
| 29 | if (avahi_dns_packet_is_query(p)) { |
| 30 | int legacy_unicast = 0; |
| 31 | + char t[AVAHI_ADDRESS_STR_MAX]; |
| 32 | |
| 33 | /* For queries EDNS0 might allow ARCOUNT != 0. We ignore the |
| 34 | * AR section completely here, so far. Until the day we add |
| 35 | @@ -947,6 +948,13 @@ static void dispatch_packet(AvahiServer *s, AvahiDnsPacket *p, const AvahiAddres |
| 36 | legacy_unicast = 1; |
| 37 | } |
| 38 | |
| 39 | + if (!is_mdns_mcast_address(dst_address) && |
| 40 | + !avahi_interface_address_on_link(i, src_address)) { |
| 41 | + |
| 42 | + avahi_log_debug("Received non-local unicast query from host %s on interface '%s.%i'.", avahi_address_snprint(t, sizeof(t), src_address), i->hardware->name, i->protocol); |
| 43 | + return; |
| 44 | + } |
| 45 | + |
| 46 | if (legacy_unicast) |
| 47 | reflect_legacy_unicast_query_packet(s, p, i, src_address, port); |
| 48 | |