gnu: avahi: Fix CVE-2018-1000845 and duplicate CVE-2017-6519.

* gnu/packages/avahi.scm (avahi/fixed): New variable.
(avahi)[replacement]: Use it.
* gnu/packages/patches/avahi-CVE-2018-1000845.patch: New file.
* gnu/local.mk (dist_patch_DATA): Add it.

1 files changed, 42 insertions, 0 deletions

diff --git a/gnu/packages/patches/avahi-CVE-2018-1000845.patch b/gnu/packages/patches/avahi-CVE-2018-1000845.patch
new file mode 100644
index 0000000000..e5b13e0bee
--- /dev/null
+++ b/gnu/packages/patches/avahi-CVE-2018-1000845.patch
@@ -0,0 +1,42 @@
+From e111def44a7df4624a4aa3f85fe98054bffb6b4f Mon Sep 17 00:00:00 2001
+From: Trent Lloyd <trent@lloyd.id.au>
+Date: Sat, 22 Dec 2018 09:06:07 +0800
+Subject: [PATCH] Drop legacy unicast queries from address not on local link
+
+When handling legacy unicast queries, ensure that the source IP is
+inside a subnet on the local link, otherwise drop the packet.
+
+Fixes #145
+Fixes #203
+CVE-2017-6519
+CVE-2018-100084
+---
+ avahi-core/server.c | 8 ++++++++
+ 1 file changed, 8 insertions(+)
+
+diff --git a/avahi-core/server.c b/avahi-core/server.c
+index a2cb19a8..a2580e38 100644
+--- a/avahi-core/server.c
++++ b/avahi-core/server.c
+@@ -930,6 +930,7 @@ static void dispatch_packet(AvahiServer *s, AvahiDnsPacket *p, const AvahiAddres
+ 
+     if (avahi_dns_packet_is_query(p)) {
+         int legacy_unicast = 0;
++        char t[AVAHI_ADDRESS_STR_MAX];
+ 
+         /* For queries EDNS0 might allow ARCOUNT != 0. We ignore the
+          * AR section completely here, so far. Until the day we add
+@@ -947,6 +948,13 @@ static void dispatch_packet(AvahiServer *s, AvahiDnsPacket *p, const AvahiAddres
+             legacy_unicast = 1;
+         }
+ 
++        if (!is_mdns_mcast_address(dst_address) &&
++            !avahi_interface_address_on_link(i, src_address)) {
++
++            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);
++            return;
++        }
++
+         if (legacy_unicast)
+             reflect_legacy_unicast_query_packet(s, p, i, src_address, port);
+