Don't share SSL_CTX between libpq connections.

There were several issues with the old coding:

1. There was a race condition, if two threads opened a connection at the
   same time. We used a mutex around SSL_CTX_* calls, but that was not
   enough, e.g. if one thread SSL_CTX_load_verify_locations() with one
   path, and another thread set it with a different path, before the first
   thread got to establish the connection.

2. Opening two different connections, with different sslrootcert settings,
   seemed to fail outright with "SSL error: block type is not 01". Not sure
   why.

3. We created the SSL object, before calling SSL_CTX_load_verify_locations
   and SSL_CTX_use_certificate_chain_file on the SSL context. That was
   wrong, because the options set on the SSL context are propagated to the
   SSL object, when the SSL object is created. If they are set after the
   SSL object has already been created, they won't take effect until the
   next connection. (This is bug #14329)

At least some of these could've been fixed while still using a shared
context, but it would've been more complicated and error-prone. To keep
things simple, let's just use a separate SSL context for each connection,
and accept the overhead.

Backpatch to all supported versions.

Report, analysis and test case by Kacper Zuk.

Discussion: <20160920101051.1355.79453@wrigleys.postgresql.org>

src/test/ssl/Makefile

@@ -23,7 +23,8 @@ SSLFILES := $(CERTIFICATES:%=ssl/%.key) $(CERTIFICATES:%=ssl/%.crt) \
 	ssl/client.crl ssl/server.crl ssl/root.crl \
 	ssl/both-cas-1.crt ssl/both-cas-2.crt \
 	ssl/root+server_ca.crt ssl/root+server.crl \
-	ssl/root+client_ca.crt ssl/root+client.crl
+	ssl/root+client_ca.crt ssl/root+client.crl \
+	ssl/client+client_ca.crt
 
 # This target generates all the key and certificate files.
 sslfiles: $(SSLFILES)
@@ -99,6 +100,9 @@ ssl/root+server_ca.crt: ssl/root_ca.crt ssl/server_ca.crt
 ssl/root+client_ca.crt: ssl/root_ca.crt ssl/client_ca.crt
 	cat $^ > $@
 
+ssl/client+client_ca.crt: ssl/client.crt ssl/client_ca.crt
+	cat $^ > $@
+
 #### CRLs
 
 ssl/client.crl: ssl/client-revoked.crt

src/test/ssl/README

@@ -65,6 +65,10 @@ root+server_ca
 root+client_ca
 	Contains root_crt and client_ca.crt. For use as server's "ssl_ca_file".
 
+client+client_ca
+	Contains client.crt and client_ca.crt in that order. For use as client's
+	certificate chain.
+
 There are also CRLs for each of the CAs: root.crl, server.crl and client.crl.
 
 For convenience, all of these keypairs and certificates are included in the

src/test/ssl/ServerSetup.pm

@@ -75,6 +75,7 @@ sub configure_test_server_for_ssl
 	copy_files("ssl/server-*.key", $pgdata);
 	chmod(0600, glob "$pgdata/server-*.key") or die $!;
 	copy_files("ssl/root+client_ca.crt", $pgdata);
+	copy_files("ssl/root_ca.crt", $pgdata);
 	copy_files("ssl/root+client.crl",    $pgdata);
 
   # Only accept SSL connections from localhost. Our tests don't depend on this
@@ -101,13 +102,14 @@ sub switch_server_cert
 {
 	my $node     = $_[0];
 	my $certfile = $_[1];
+	my $cafile = $_[2] || "root+client_ca";
 	my $pgdata   = $node->data_dir;
 
-	diag "Restarting server with certfile \"$certfile\"...";
+	diag "Restarting server with certfile \"$certfile\" and cafile \"$cafile\"...";
 
 	open SSLCONF, ">$pgdata/sslconfig.conf";
 	print SSLCONF "ssl=on\n";
-	print SSLCONF "ssl_ca_file='root+client_ca.crt'\n";
+	print SSLCONF "ssl_ca_file='$cafile.crt'\n";
 	print SSLCONF "ssl_cert_file='$certfile.crt'\n";
 	print SSLCONF "ssl_key_file='$certfile.key'\n";
 	print SSLCONF "ssl_crl_file='root+client.crl'\n";

src/test/ssl/ssl/client+client_ca.crt

+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----
+-----BEGIN CERTIFICATE-----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=
+-----END CERTIFICATE-----

src/test/ssl/t/001_ssltests.pl

@@ -2,7 +2,7 @@ use strict;
 use warnings;
 use PostgresNode;
 use TestLib;
-use Test::More tests => 38;
+use Test::More tests => 40;
 use ServerSetup;
 use File::Copy;
 
@@ -239,3 +239,11 @@ test_connect_fails(
 test_connect_fails(
 "user=ssltestuser sslcert=ssl/client-revoked.crt sslkey=ssl/client-revoked.key"
 );
+
+# intermediate client_ca.crt is provided by client, and isn't in server's ssl_ca_file
+switch_server_cert($node, 'server-cn-only', 'root_ca');
+$common_connstr =
+"user=ssltestuser dbname=certdb sslkey=ssl/client.key sslrootcert=ssl/root+server_ca.crt hostaddr=$SERVERHOSTADDR";
+
+test_connect_ok("sslmode=require sslcert=ssl/client+client_ca.crt");
+test_connect_fails("sslmode=require sslcert=ssl/client.crt");