From f6a5fec6b971e2a8c69d92ab20ed13693be82ddb Mon Sep 17 00:00:00 2001
From: Lennart Poettering <lennart@poettering.net>
Date: Fri, 21 Aug 2015 16:04:59 +0200
Subject: [PATCH] resolved: when passing RRs across the bus, make sure not to
 use name compression

We explicitly need to turn off name compression when marshalling or
demarshalling RRs for bus transfer, since they otherwise refer to packet
offsets that reference packets that are not transmitted themselves.
---
 src/resolve-host/resolve-host.c   |  2 ++
 src/resolve/resolved-bus.c        |  2 ++
 src/resolve/resolved-dns-packet.c | 22 ++++++++++++++++++----
 src/resolve/resolved-dns-packet.h |  1 +
 4 files changed, 23 insertions(+), 4 deletions(-)

diff --git a/src/resolve-host/resolve-host.c b/src/resolve-host/resolve-host.c
index 3f45a9f..feec192 100644
--- a/src/resolve-host/resolve-host.c
+++ b/src/resolve-host/resolve-host.c
@@ -392,6 +392,8 @@ static int resolve_record(sd_bus *bus, const char *name) {
                 if (r < 0)
                         return log_oom();
 
+                p->refuse_compression = true;
+
                 r = dns_packet_append_blob(p, d, l, NULL);
                 if (r < 0)
                         return log_oom();
diff --git a/src/resolve/resolved-bus.c b/src/resolve/resolved-bus.c
index de5e8e9..1f23834 100644
--- a/src/resolve/resolved-bus.c
+++ b/src/resolve/resolved-bus.c
@@ -542,6 +542,8 @@ static void bus_method_resolve_record_complete(DnsQuery *q) {
                         if (r < 0)
                                 goto finish;
 
+                        p->refuse_compression = true;
+
                         r = dns_packet_append_rr(p, answer->items[i].rr, &start);
                         if (r < 0)
                                 goto finish;
diff --git a/src/resolve/resolved-dns-packet.c b/src/resolve/resolved-dns-packet.c
index ad337c2..bebd1ee 100644
--- a/src/resolve/resolved-dns-packet.c
+++ b/src/resolve/resolved-dns-packet.c
@@ -388,14 +388,21 @@ int dns_packet_append_label(DnsPacket *p, const char *d, size_t l, size_t *start
         return 0;
 }
 
-int dns_packet_append_name(DnsPacket *p, const char *name,
-                           bool allow_compression, size_t *start) {
+int dns_packet_append_name(
+                DnsPacket *p,
+                const char *name,
+                bool allow_compression,
+                size_t *start) {
+
         size_t saved_size;
         int r;
 
         assert(p);
         assert(name);
 
+        if (p->refuse_compression)
+                allow_compression = false;
+
         saved_size = p->size;
 
         while (*name) {
@@ -1053,8 +1060,12 @@ fail:
         return r;
 }
 
-int dns_packet_read_name(DnsPacket *p, char **_ret,
-                         bool allow_compression, size_t *start) {
+int dns_packet_read_name(
+                DnsPacket *p,
+                char **_ret,
+                bool allow_compression,
+                size_t *start) {
+
         size_t saved_rindex, after_rindex = 0, jump_barrier;
         _cleanup_free_ char *ret = NULL;
         size_t n = 0, allocated = 0;
@@ -1064,6 +1075,9 @@ int dns_packet_read_name(DnsPacket *p, char **_ret,
         assert(p);
         assert(_ret);
 
+        if (p->refuse_compression)
+                allow_compression = false;
+
         saved_rindex = p->rindex;
         jump_barrier = p->rindex;
 
diff --git a/src/resolve/resolved-dns-packet.h b/src/resolve/resolved-dns-packet.h
index 58559c8..e81f8a8 100644
--- a/src/resolve/resolved-dns-packet.h
+++ b/src/resolve/resolved-dns-packet.h
@@ -86,6 +86,7 @@ struct DnsPacket {
         uint32_t ttl;
 
         bool extracted;
+        bool refuse_compression;
 };
 
 static inline uint8_t* DNS_PACKET_DATA(DnsPacket *p) {
-- 
2.7.4