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 4d7119fed260816827bce1648fb5b32f457f1772..e14dbfdbd791d21650561f0798beed6d5bd977e5 100644 (file)
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -1,4 +1,4 @@
-
+
 
 
   Server Configuration
@@ -606,6 +606,32 @@ SET ENABLE_SEQSCAN TO OFF;
       
      
 
+     
+      ssl_renegotiation_limit (int)
+      
+       ssl_renegotiation_limit configuration parameter
+      
+      
+       
+        Specifies how much data can flow over an 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 512MB.
+       
+       
+        
+         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.
+        
+       
+      
+     
+
      
       ssl_ciphers (string)
       

diff --git a/src/backend/libpq/be-secure.c b/src/backend/libpq/be-secure.c
index 9499899950174fb9a02507ec4a1845684d97091b..6dac77bff7890221220826f1748879992ce3f8f1 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 1.97 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
index bde3be91cf3548e7995d3aab8329abda2cd77bf0..d5330788452d40609d543818484d70a950be443f 100644 (file)
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -10,7 +10,7 @@
  * Written by Peter Eisentraut .
  *
  * 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
index 1d2b9f0f673b8a43ae49bf416fedeb33a4661ff5..b550132d11adc0adc01a2edf84d9dce5ec8f3322 100644 (file)
--- 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