Merge branch 'rn/resolver-leaking-ports' into dev

* rn/resolver-leaking-ports:
  Resolver: make inet_dns decode ugly truncated reply
  Resolver: stop inet_res leaking ports

OTP-8652 inet_res leaking ports

The kernel DNS resolver was leaking one or two ports if the DNS reply could
not be parsed or if the resolver(s) caused noconnection type errors. Bug
now fixed. A DNS specification borderline truncated reply triggering the
port leakage bug has also been fixed.

1 files changed, 27 insertions, 17 deletions

diff --git a/lib/kernel/src/inet_dns.erl b/lib/kernel/src/inet_dns.erl
index 669a361c9d..1289e176c7 100644
--- a/lib/kernel/src/inet_dns.erl
+++ b/lib/kernel/src/inet_dns.erl
@@ -1,19 +1,19 @@
 %%
 %% %CopyrightBegin%
-%% 
-%% Copyright Ericsson AB 1997-2009. All Rights Reserved.
-%% 
+%%
+%% Copyright Ericsson AB 1997-2010. All Rights Reserved.
+%%
 %% The contents of this file are subject to the Erlang Public License,
 %% Version 1.1, (the "License"); you may not use this file except in
 %% compliance with the License. You should have received a copy of the
 %% Erlang Public License along with this software. If not, it can be
 %% retrieved online at http://www.erlang.org/.
-%% 
+%%
 %% Software distributed under the License is distributed on an "AS IS"
 %% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
 %% the License for the specific language governing rights and limitations
 %% under the License.
-%% 
+%%
 %% %CopyrightEnd%
 %%
 -module(inet_dns).
@@ -129,27 +129,33 @@ do_decode(<<Id:16,
 	   RA:1,PR:1,_:2,Rcode:4,
 	   QdCount:16,AnCount:16,NsCount:16,ArCount:16,
 	   QdBuf/binary>>=Buffer) ->
-    {AnBuf,QdList} = decode_query_section(QdBuf,QdCount,Buffer),
-    {NsBuf,AnList} = decode_rr_section(AnBuf,AnCount,Buffer),
-    {ArBuf,NsList} = decode_rr_section(NsBuf,NsCount,Buffer),
-    {Rest,ArList} = decode_rr_section(ArBuf,ArCount,Buffer),
+    {AnBuf,QdList,QdTC} = decode_query_section(QdBuf,QdCount,Buffer),
+    {NsBuf,AnList,AnTC} = decode_rr_section(AnBuf,AnCount,Buffer),
+    {ArBuf,NsList,NsTC} = decode_rr_section(NsBuf,NsCount,Buffer),
+    {Rest,ArList,ArTC} = decode_rr_section(ArBuf,ArCount,Buffer),
 	case Rest of
 	    <<>> ->
+		HdrTC = decode_boolean(TC),
 		DnsHdr =
 		    #dns_header{id=Id,
 				qr=decode_boolean(QR),
 				opcode=decode_opcode(Opcode),
 				aa=decode_boolean(AA),
-				tc=decode_boolean(TC),
+				tc=HdrTC,
 				rd=decode_boolean(RD),
 				ra=decode_boolean(RA),
 				pr=decode_boolean(PR),
 				rcode=Rcode},
-		#dns_rec{header=DnsHdr,
-			 qdlist=QdList,
-			 anlist=AnList,
-			 nslist=NsList,
-			 arlist=ArList};
+		case QdTC or AnTC or NsTC or ArTC of
+		    true when not HdrTC ->
+			throw(?DECODE_ERROR);
+		    _ ->
+			#dns_rec{header=DnsHdr,
+				 qdlist=QdList,
+				 anlist=AnList,
+				 nslist=NsList,
+				 arlist=ArList}
+		end;
 	    _ ->
 		%% Garbage data after DNS message
 		throw(?DECODE_ERROR)
@@ -161,8 +167,10 @@ do_decode(_) ->
 decode_query_section(Bin, N, Buffer) ->
     decode_query_section(Bin, N, Buffer, []).
 
+decode_query_section(<<>>=Rest, N, _Buffer, Qs) ->
+    {Rest,reverse(Qs),N =/= 0};
 decode_query_section(Rest, 0, _Buffer, Qs) ->
-    {Rest,reverse(Qs)};
+    {Rest,reverse(Qs),false};
 decode_query_section(Bin, N, Buffer, Qs) ->
     case decode_name(Bin, Buffer) of
 	{<<Type:16,Class:16,Rest/binary>>,Name} ->
@@ -179,8 +187,10 @@ decode_query_section(Bin, N, Buffer, Qs) ->
 decode_rr_section(Bin, N, Buffer) ->
     decode_rr_section(Bin, N, Buffer, []).
 
+decode_rr_section(<<>>=Rest, N, _Buffer, RRs) ->
+    {Rest,reverse(RRs),N =/= 0};
 decode_rr_section(Rest, 0, _Buffer, RRs) ->
-    {Rest,reverse(RRs)};
+    {Rest,reverse(RRs),false};
 decode_rr_section(Bin, N, Buffer, RRs) ->
     case decode_name(Bin, Buffer) of
 	{<<T:16/unsigned,C:16/unsigned,TTL:4/binary,