Add configuration parameter ssl_renegotiation_limit to control

how often we do SSL session key renegotiation. Can be set to
0 to disable renegotiation completely, which is required if
a broken SSL library is used (broken patches to CVE-2009-3555
a known cause) or when using a client library that can't do
renegotiation.

diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index 0864465f32aa40dda5b45445b19229482fa9727b..f4c219373c9210c39a137a6e0020a85e6a34fb64 100644 (file)
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -1,4 +1,4 @@
-<!-- $PostgreSQL: pgsql/doc/src/sgml/config.sgml,v 1.220.2.1 2009/08/24 20:08:40 tgl Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/config.sgml,v 1.220.2.2 2010/02/25 13:26:26 mha Exp $ -->
 
 <chapter Id="runtime-config">
   <title>Server Configuration</title>
@@ -580,6 +580,32 @@ SET ENABLE_SEQSCAN TO OFF;
       </listitem>
      </varlistentry>
 
+     <varlistentry id="guc-ssl-renegotiation-limit" xreflabel="ssl_renegotiation_limit">
+      <term><varname>ssl_renegotiation_limit</varname> (<type>int</type>)</term>
+      <indexterm>
+       <primary><varname>ssl_renegotiation_limit</> configuration parameter</primary>
+      </indexterm>
+      <listitem>
+       <para>
+        Specifies how much data can flow over an <acronym>SSL</> encrypted connection
+        before renegotiation of the session will take place. Renegotiation of the
+        session decreases the chance of doing cryptanalysis when large amounts of data
+        are sent, but it also carries a large performance penalty. The sum of
+        sent and received traffic is used to check the limit. If the parameter is
+        set to 0, renegotiation is disabled. The default is <literal>512MB</>.
+       </para>
+       <note>
+        <para>
+         SSL libraries from before November 2009 are insecure when using SSL
+         renegotiation, due to a vulnerability in the SSL protocol. As a stop-gap fix
+         for this vulnerability, some vendors also shipped SSL libraries incapable
+         of doing renegotiation. If any of these libraries are in use on the client
+         or server, SSL renegotiation should be disabled.
+        </para>
+       </note>
+      </listitem>
+     </varlistentry>
+
      <varlistentry id="guc-ssl-ciphers" xreflabel="ssl_ciphers">
       <term><varname>ssl_ciphers</varname> (<type>string</type>)</term>
       <indexterm>

diff --git a/src/backend/libpq/be-secure.c b/src/backend/libpq/be-secure.c
index 1b59c19b3351dedc7971629ae502eef7fef9fc0a..6f38b2c7292e52383a8b16b3b2d3179d55d4177e 100644 (file)
--- a/src/backend/libpq/be-secure.c
+++ b/src/backend/libpq/be-secure.c
@@ -11,7 +11,7 @@
  *
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/libpq/be-secure.c,v 1.92.2.2 2009/12/30 03:45:53 tgl Exp $
+ *       $PostgreSQL: pgsql/src/backend/libpq/be-secure.c,v 1.92.2.3 2010/02/25 13:26:26 mha Exp $
  *
  *       Since the server static private key ($DataDir/server.key)
  *       will normally be stored unencrypted so that the database
@@ -93,13 +93,14 @@ static void close_SSL(Port *);
 static const char *SSLerrmessage(void);
 #endif
 
-#ifdef USE_SSL
 /*
  *     How much data can be sent across a secure connection
  *     (total in both directions) before we require renegotiation.
+ *     Set to 0 to disable renegotiation completely.
  */
-#define RENEGOTIATION_LIMIT (512 * 1024 * 1024)
+int ssl_renegotiation_limit;
 
+#ifdef USE_SSL
 static SSL_CTX *SSL_context = NULL;
 static bool ssl_loaded_verify_locations = false;
 
@@ -314,7 +315,7 @@ secure_write(Port *port, void *ptr, size_t len)
        {
                int                     err;
 
-               if (port->count > RENEGOTIATION_LIMIT)
+               if (ssl_renegotiation_limit && port->count > ssl_renegotiation_limit * 1024L)
                {
                        SSL_set_session_id_context(port->ssl, (void *) &SSL_context,
                                                                           sizeof(SSL_context));

diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index fe81112ca00a21ee9d6a128d68d154c025173dbf..d841dd7f346eb94235c1b2c4662f18ffa950e427 100644 (file)
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -10,7 +10,7 @@
  * Written by Peter Eisentraut <peter_e@gmx.net>.
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.505.2.4 2010/01/24 21:49:31 tgl Exp $
+ *       $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.505.2.5 2010/02/25 13:26:26 mha Exp $
  *
  *--------------------------------------------------------------------
  */
@@ -114,6 +114,7 @@ extern char *default_tablespace;
 extern char *temp_tablespaces;
 extern bool synchronize_seqscans;
 extern bool fullPageWrites;
+extern int     ssl_renegotiation_limit;
 
 #ifdef TRACE_SORT
 extern bool trace_sort;
@@ -1889,6 +1890,16 @@ static struct config_int ConfigureNamesInt[] =
                0, 0, INT_MAX, assign_tcp_keepalives_interval, show_tcp_keepalives_interval
        },
 
+       {
+               {"ssl_renegotiation_limit", PGC_USERSET, CONN_AUTH_SECURITY,
+                       gettext_noop("Set the amount of traffic to send and receive before renegotiating the encryption keys."),
+                       NULL,
+                       GUC_UNIT_KB,
+               },
+               &ssl_renegotiation_limit,
+               512 * 1024, 0, MAX_KILOBYTES, NULL, NULL
+       },
+
        {
                {"tcp_keepalives_count", PGC_USERSET, CLIENT_CONN_OTHER,
                        gettext_noop("Maximum number of TCP keepalive retransmits."),

diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample
index 645f355b07e9b9cb8d2088a834bcd975a75c7e8f..fabfc75f55d25d9f5adde115ac01a87a5a9e5a34 100644 (file)
--- a/src/backend/utils/misc/postgresql.conf.sample
+++ b/src/backend/utils/misc/postgresql.conf.sample
@@ -78,6 +78,7 @@
 #ssl = off                             # (change requires restart)
 #ssl_ciphers = 'ALL:!ADH:!LOW:!EXP:!MD5:@STRENGTH'     # allowed SSL ciphers
                                        # (change requires restart)
+#ssl_renegotiation_limit = 512MB       # amount of data between renegotiations
 #password_encryption = on
 #db_user_namespace = off