Add configuration parameter ssl_renegotiation_limit to control

mhagander · mhagander · commit 413d34be4e1f · 2010-02-25T13:26:16.000Z
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
@@ -1,4 +1,4 @@
-<!-- $PostgreSQL: pgsql/doc/src/sgml/config.sgml,v 1.252 2010/02/17 04:19:37 tgl Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/config.sgml,v 1.253 2010/02/25 13:26:15 mha Exp $ -->
 
 <chapter Id="runtime-config">
   <title>Server Configuration</title>
@@ -606,6 +606,32 @@ 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
@@ -11,7 +11,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/libpq/be-secure.c,v 1.97 2010/02/18 11:13:45 heikki Exp $
+ *	  $PostgreSQL: pgsql/src/backend/libpq/be-secure.c,v 1.98 2010/02/25 13:26:15 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;
 
@@ -320,7 +321,7 @@ 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
@@ -10,7 +10,7 @@
  * Written by Peter Eisentraut <peter_e@gmx.net>.
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.541 2010/02/17 04:19:40 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.542 2010/02/25 13:26:15 mha Exp $
  *
  *--------------------------------------------------------------------
  */
@@ -117,6 +117,7 @@ extern char *temp_tablespaces;
 extern bool synchronize_seqscans;
 extern bool fullPageWrites;
 extern int	vacuum_defer_cleanup_age;
+extern int	ssl_renegotiation_limit;
 
 int	trace_recovery_messages = LOG;
 
@@ -1968,6 +1969,16 @@ 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
@@ -80,6 +80,7 @@
 #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
 

Original file line number	Diff line number	Diff line change
`@@ -11,7 +11,7 @@`
`11`	`11`	`*`
`12`	`12`	`*`
`13`	`13`	`* IDENTIFICATION`
`14`		`- * $PostgreSQL: pgsql/src/backend/libpq/be-secure.c,v 1.97 2010/02/18 11:13:45 heikki Exp $`
	`14`	`+ * $PostgreSQL: pgsql/src/backend/libpq/be-secure.c,v 1.98 2010/02/25 13:26:15 mha Exp $`
`15`	`15`	`*`
`16`	`16`	`* Since the server static private key ($DataDir/server.key)`
`17`	`17`	`* will normally be stored unencrypted so that the database`
`@@ -93,13 +93,14 @@ static void close_SSL(Port *);`
`93`	`93`	`static const char *SSLerrmessage(void);`
`94`	`94`	`#endif`
`95`	`95`
`96`		`-#ifdef USE_SSL`
`97`	`96`	`/*`
`98`	`97`	`* How much data can be sent across a secure connection`
`99`	`98`	`* (total in both directions) before we require renegotiation.`
	`99`	`+ * Set to 0 to disable renegotiation completely.`
`100`	`100`	`*/`
`101`		`-#define RENEGOTIATION_LIMIT (512 * 1024 * 1024)`
	`101`	`+int ssl_renegotiation_limit;`
`102`	`102`
	`103`	`+#ifdef USE_SSL`
`103`	`104`	`static SSL_CTX *SSL_context = NULL;`
`104`	`105`	`static bool ssl_loaded_verify_locations = false;`
`105`	`106`
`@@ -320,7 +321,7 @@ secure_write(Port port, void ptr, size_t len)`
`320`	`321`	`{`
`321`	`322`	`int err;`
`322`	`323`
`323`		`- if (port->count > RENEGOTIATION_LIMIT)`
	`324`	`+ if (ssl_renegotiation_limit && port->count > ssl_renegotiation_limit * 1024L)`
`324`	`325`	`{`
`325`	`326`	`SSL_set_session_id_context(port->ssl, (void *) &SSL_context,`
`326`	`327`	`sizeof(SSL_context));`