SSL improvements:

	o read global SSL configuration file
	o add GUC "ssl_ciphers" to control allowed ciphers
	o add libpq environment variable PGSSLKEY to control SSL hardware keys

Victor B. Wagner

Author: bmomjian

doc/src/sgml/config.sgml

@@ -1,4 +1,4 @@
-<!-- $PostgreSQL: pgsql/doc/src/sgml/config.sgml,v 1.110 2007/02/08 15:46:03 momjian Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/config.sgml,v 1.111 2007/02/16 02:59:40 momjian Exp $ -->
 
 <chapter Id="runtime-config">
   <title>Server Configuration</title>
@@ -569,6 +569,20 @@ SET ENABLE_SEQSCAN TO OFF;
       </listitem>
      </varlistentry>
 
+     <varlistentry id="guc-ssl-ciphers" xreflabel="ssl-ciphers">
+      <term><varname>ssl_ciphers> (<type>string</type>)</term>
+      <indexterm>
+       <primary><varname>ssl_ciphers</> configuration parameter</primary>
+      </indexterm>
+      <listitem>
+       <para>
+        Specifies a list of <acronym>SSL</> ciphers which can be used to
+        establish secure connections. See the <application>openssl</>
+        manual page for a list of supported ciphers.
+       </para>
+      </listitem>
+     </varlistentry>
+
      <varlistentry id="guc-password-encryption" xreflabel="password_encryption">
       <term><varname>password_encryption</varname> (<type>boolean</type>)</term>
       <indexterm>

doc/src/sgml/libpq.sgml

@@ -1,4 +1,4 @@
-<!-- $PostgreSQL: pgsql/doc/src/sgml/libpq.sgml,v 1.228 2007/02/06 03:03:11 tgl Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/libpq.sgml,v 1.229 2007/02/16 02:59:40 momjian Exp $ -->
 
  <chapter id="libpq">
   <title><application>libpq</application> - C Library</title>
@@ -4174,6 +4174,18 @@ setting, and is only available if
 </listitem>
 <listitem>
 <para>
+<indexterm>
+<primary><envar>PGSSLKEY</envar></primary>
+</indexterm>
+<envar>PGSSLKEY</envar>
+specifies the hardware token which stores the secret key for the client
+certificate, instead of a file. The value of this variable should consist
+of a colon-separated engine name (engines are <productname>OpenSSL</>
+loadable modules) and an engine-specific key identifier.
+</para>
+</listitem>
+<listitem>
+<para>
 <indexterm>
  <primary><envar>PGKRBSRVNAME</envar></primary>
 </indexterm>
@@ -4438,19 +4450,44 @@ ldap://ldap.mycompany.com/dc=mycompany,dc=com?uniqueMember?one?(cn=mydatabase)
    for increased security. See <xref linkend="ssl-tcp"> for details
    about the server-side <acronym>SSL</> functionality.
   </para>
-
+  <para>
+  <application>libpq</application> reads the system-wide
+  <productname>OpenSSL</productname> configuration file. By default, this
+  file is named <filename>openssl.cnf</filename> and is located in the
+  directory reported by <application>openssl</>:
+  <programlisting>
+  openssl version -d
+  </programlisting>
+  The default can be overriden by setting environment variable
+  <envar>OPENSSL_CONF</envar> to the name of the desired configuration
+  file.
+  </para>
   <para>
    If the server demands a client certificate, 
    <application>libpq</application>
    will send the certificate stored in file
    <filename>~/.postgresql/postgresql.crt</> within the user's home directory.
    A matching private key file <filename>~/.postgresql/postgresql.key</>
-   must also be present, and must not be world-readable.
+   must also be present, and must not be world-readable, unless the secret
+   key is stored in a hardware token, as specified by
+   <envar>PGSSLKEY</envar>.
    (On Microsoft Windows these files are named
    <filename>%APPDATA%\postgresql\postgresql.crt</filename> and
    <filename>%APPDATA%\postgresql\postgresql.key</filename>.)
   </para>
 
+  <para>
+   If the environment variable <envar>PGSSLKEY</envar> is set, its value
+   should consist of a colon-separated engine name and key identifier. In
+   this case, <application>libpq</application> will load the specified
+   engine, i.e. the <productname>OpenSSL</> module which supports special
+   hardware and reference the key with the specified identifier.
+   Identifiers are engine-specific. Typically, cryptography hardware tokens
+   do not reveal secret keys to the application. Instead, applications
+   delegate all cryptography operations which require the secret key to
+   the hardware token.
+  </para>	
+	
   <para>
    If the file <filename>~/.postgresql/root.crt</> is present in the user's
    home directory,

doc/src/sgml/runtime.sgml

@@ -1,4 +1,4 @@
-<!-- $PostgreSQL: pgsql/doc/src/sgml/runtime.sgml,v 1.376 2007/02/01 00:28:18 momjian Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/runtime.sgml,v 1.377 2007/02/16 02:59:40 momjian Exp $ -->
 
 <chapter Id="runtime">
  <title>Operating System Environment</title>
@@ -1515,6 +1515,25 @@ $ <userinput>kill -INT `head -1 /usr/local/pgsql/data/postmaster.pid`</userinput
    require use of <acronym>SSL</> for some or all connections.
   </para>
 
+  <para>
+   <productname>OpenSSL</productname> supports a wide range of ciphers
+   and authentication algorithms, whose strength varies significantly.
+   You can restrict the list of ciphers which can be used to connect to
+   your server using the <xref linkend="guc-ssl-ciphers"> parameter.
+  </para>
+
+  <para>
+   <productname>PostgreSQL</productname> reads a system-wide
+   <productname>OpenSSL</productname> configuration file. By default this
+   file is named <filename>openssl.cnf</filename> and is located in the
+   directory reported by <application>openssl</>:
+   <programlisting>
+   openssl version -d
+   </programlisting>
+   This default can be overriden by setting environment variable
+   <envar>OPENSSL_CONF</envar> to the name of desired configuration file.
+  </para>
+
   <para>
    For details on how to create your server private key and certificate,
    refer to the <productname>OpenSSL</> documentation. A
@@ -1528,8 +1547,8 @@ $ <userinput>kill -INT `head -1 /usr/local/pgsql/data/postmaster.pid`</userinput
 <programlisting>
 openssl req -new -text -out server.req
 </programlisting>
-   Fill out the information that <command>openssl</> asks for. Make sure
-   that you enter the local host name as <quote>Common Name</>; the challenge
+   Fill out the information that <application>openssl</> asks for. Make sure
+   you enter the local host name as <quote>Common Name</>; the challenge
    password can be left blank. The program will generate a key that is
    passphrase protected; it will not accept a passphrase that is less
    than four characters long. To remove the passphrase (as you must if

src/backend/libpq/be-secure.c

@@ -11,7 +11,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/libpq/be-secure.c,v 1.77 2007/02/07 00:52:35 petere Exp $
+ *	  $PostgreSQL: pgsql/src/backend/libpq/be-secure.c,v 1.78 2007/02/16 02:59:40 momjian Exp $
  *
  *	  Since the server static private key ($DataDir/server.key)
  *	  will normally be stored unencrypted so that the database
@@ -92,6 +92,10 @@
 #ifdef USE_SSL
 #include <openssl/ssl.h>
 #include <openssl/dh.h>
+#if SSLEAY_VERSION_NUMBER >= 0x0907000L
+#include <openssl/conf.h>
+#endif
+
 #endif
 
 #include "libpq/libpq.h"
@@ -125,6 +129,10 @@ static const char *SSLerrmessage(void);
 #define RENEGOTIATION_LIMIT (512 * 1024 * 1024)
 
 static SSL_CTX *SSL_context = NULL;
+
+/* GUC variable controlling SSL cipher list*/
+extern char *SSLCipherSuites;
+
 #endif
 
 /* ------------------------------------------------------------ */
@@ -719,6 +727,9 @@ initialize_SSL(void)
 
 	if (!SSL_context)
 	{
+#if SSLEAY_VERSION_NUMBER >= 0x0907000L
+		OPENSSL_config(NULL);
+#endif
 		SSL_library_init();
 		SSL_load_error_strings();
 		SSL_context = SSL_CTX_new(SSLv23_method());
@@ -780,7 +791,7 @@ initialize_SSL(void)
 	SSL_CTX_set_options(SSL_context, SSL_OP_SINGLE_DH_USE | SSL_OP_NO_SSLv2);
 
 	/* setup the allowed cipher list */
-	if (SSL_CTX_set_cipher_list(SSL_context, "ALL:!ADH:!LOW:!EXP:!MD5:@STRENGTH") != 1)
+	if (SSL_CTX_set_cipher_list(SSL_context, SSLCipherSuites) != 1)
 		elog(FATAL, "could not set the cipher list (no valid ciphers available)");
 
 	/*

src/backend/postmaster/postmaster.c

@@ -37,7 +37,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/postmaster/postmaster.c,v 1.523 2007/02/16 02:10:07 alvherre Exp $
+ *	  $PostgreSQL: pgsql/src/backend/postmaster/postmaster.c,v 1.524 2007/02/16 02:59:41 momjian Exp $
  *
  * NOTES
  *
@@ -187,6 +187,7 @@ static int	SendStop = false;
 
 /* still more option variables */
 bool		EnableSSL = false;
+char	   *SSLCipherSuites;
 bool		SilentMode = false; /* silent mode (-S) */
 
 int			PreAuthDelay = 0;

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 1.374 2007/02/14 03:08:44 neilc Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.375 2007/02/16 02:59:41 momjian Exp $
  *
  *--------------------------------------------------------------------
  */
@@ -2314,6 +2314,16 @@ static struct config_string ConfigureNamesString[] =
 		NULL, assign_temp_tablespaces, NULL
 	},
 
+	{
+		{"ssl_ciphers", PGC_POSTMASTER, CONN_AUTH_SECURITY,
+			gettext_noop("Sets the list of allowed SSL ciphers."),
+			NULL,
+			GUC_SUPERUSER_ONLY
+		},
+		&SSLCipherSuites,
+		"ALL:!ADH:!LOW:!EXP:!MD5:@STRENGTH", NULL, NULL
+	},
+			
 	/* End-of-list marker */
 	{
 		{NULL, 0, 0, NULL, NULL}, NULL, NULL, NULL, NULL

src/backend/utils/misc/postgresql.conf.sample

@@ -74,6 +74,7 @@
 
 #authentication_timeout = 1min		# 1s-600s
 #ssl = off				# (change requires restart)
+#ssl_ciphers = 'ALL:!ADH:!LOW:!EXP:!MD5:@STRENGTH' # List of ciphers to use
 #password_encryption = on
 #db_user_namespace = off
 

src/include/postmaster/postmaster.h

@@ -6,7 +6,7 @@
  * Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/postmaster/postmaster.h,v 1.15 2007/01/05 22:19:57 momjian Exp $
+ * $PostgreSQL: pgsql/src/include/postmaster/postmaster.h,v 1.16 2007/02/16 02:59:41 momjian Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -15,6 +15,7 @@
 
 /* GUC options */
 extern bool EnableSSL;
+extern char *SSLCipherSuites;
 extern bool SilentMode;
 extern int	ReservedBackends;
 extern int	PostPortNumber;