Add parameters for controlling locations of server-side SSL files

This allows changing the location of the files that were previously
hard-coded to server.crt, server.key, root.crt, root.crl.

server.crt and server.key continue to be the default settings and are
thus required to be present by default if SSL is enabled.  But the
settings for the server-side CA and CRL are now empty by default, and
if they are set, the files are required to be present.  This replaces
the previous behavior of ignoring the functionality if the files were
not found.

Author: petere

doc/src/sgml/config.sgml

@@ -668,6 +668,70 @@ SET ENABLE_SEQSCAN TO OFF;
       </listitem>
      </varlistentry>
 
+     <varlistentry id="guc-ssl-ca-file" xreflabel="ssl_ca_file">
+      <term><varname>ssl_ca_file</varname> (<type>string</type>)</term>
+      <indexterm>
+       <primary><varname>ssl_ca_file</> configuration parameter</primary>
+      </indexterm>
+      <listitem>
+       <para>
+        Specifies the name of the file containing the SSL server certificate
+        authority (CA).  The default is empty, meaning no CA file is loaded,
+        and client certificate verification is not performed.  (In previous
+        releases of PostgreSQL, the name of this file was hard-coded
+        as <filename>root.crt</filename>.)  Relative paths are relative to the
+        data directory.  This parameter can only be set at server start.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="guc-ssl-cert-file" xreflabel="ssl_cert_file">
+      <term><varname>ssl_cert_file</varname> (<type>string</type>)</term>
+      <indexterm>
+       <primary><varname>ssl_cert_file</> configuration parameter</primary>
+      </indexterm>
+      <listitem>
+       <para>
+        Specifies the name of the file containing the SSL server certificate.
+        The default is <filename>server.crt</filename>.  Relative paths are
+        relative to the data directory.  This parameter can only be set at
+        server start.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="guc-ssl-crl-file" xreflabel="ssl_crl_file">
+      <term><varname>ssl_crl_file</varname> (<type>string</type>)</term>
+      <indexterm>
+       <primary><varname>ssl_crl_file</> configuration parameter</primary>
+      </indexterm>
+      <listitem>
+       <para>
+        Specifies the name of the file containing the SSL server certificate
+        revocation list (CRL).  The default is empty, meaning no CRL file is
+        loaded.  (In previous releases of PostgreSQL, the name of this file was
+        hard-coded as <filename>root.crl</filename>.)  Relative paths are
+        relative to the data directory.  This parameter can only be set at
+        server start.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="guc-ssl-key-file" xreflabel="ssl_key_file">
+      <term><varname>ssl_key_file</varname> (<type>string</type>)</term>
+      <indexterm>
+       <primary><varname>ssl_key_file</> configuration parameter</primary>
+      </indexterm>
+      <listitem>
+       <para>
+        Specifies the name of the file containing the SSL server private key.
+        The default is <filename>server.key</filename>.  Relative paths are
+        relative to the data directory.  This parameter can only be set at
+        server start.
+       </para>
+      </listitem>
+     </varlistentry>
+
      <varlistentry id="guc-ssl-renegotiation-limit" xreflabel="ssl_renegotiation_limit">
       <term><varname>ssl_renegotiation_limit</varname> (<type>integer</type>)</term>
       <indexterm>

doc/src/sgml/runtime.sgml

@@ -1831,10 +1831,8 @@ pg_dumpall -p 5432 | psql -d postgres -p 5433
    SSL certificates and make sure that clients check the server's certificate.
    To do that, the server
    must be configured to accept only <literal>hostssl</> connections (<xref
-   linkend="auth-pg-hba-conf">) and have SSL
-   <filename>server.key</filename> (key) and
-   <filename>server.crt</filename> (certificate) files (<xref
-   linkend="ssl-tcp">). The TCP client must connect using
+   linkend="auth-pg-hba-conf">) and have SSL key and certificate files
+   (<xref linkend="ssl-tcp">). The TCP client must connect using
    <literal>sslmode=verify-ca</> or
    <literal>verify-full</> and have the appropriate root certificate
    file installed (<xref linkend="libpq-connect">).
@@ -2053,10 +2051,12 @@ pg_dumpall -p 5432 | psql -d postgres -p 5433
   </note>
 
   <para>
-   To start in <acronym>SSL</> mode, the files <filename>server.crt</>
-   and <filename>server.key</> must exist in the server's data directory.
-   These files should contain the server certificate and private key,
-   respectively.
+   To start in <acronym>SSL</> mode, files containing the server certificate
+   and private key must exist.  By default, these files are expected to be
+   named <filename>server.crt</> and <filename>server.key</>, respectively, in
+   the server's data directory, but other names and locations can be specified
+   using the configuration parameters <xref linkend="guc-ssl-cert-file">
+   and <xref linkend="guc-ssl-key-file">.
    On Unix systems, the permissions on <filename>server.key</filename> must
    disallow any access to world or group; achieve this by the command
    <command>chmod 0600 server.key</command>.
@@ -2083,15 +2083,17 @@ pg_dumpall -p 5432 | psql -d postgres -p 5433
    To require the client to supply a trusted certificate, place
    certificates of the certificate authorities (<acronym>CA</acronym>s)
    you trust in the file <filename>root.crt</filename> in the data
-   directory, and set the <literal>clientcert</literal> parameter
+   directory, set the parameter <xref linkend="guc-ssl-ca-file"> in
+   <filename>postgresql.conf</filename> to <literal>root.crt</literal>,
+   and set the <literal>clientcert</literal> parameter
    to 1 on the appropriate <literal>hostssl</> line(s) in
    <filename>pg_hba.conf</>.
    A certificate will then be requested from the client during
    SSL connection startup.  (See <xref linkend="libpq-ssl"> for a
    description of how to set up certificates on the client.)  The server will
    verify that the client's certificate is signed by one of the trusted
    certificate authorities.  Certificate Revocation List (CRL) entries
-   are also checked if the file <filename>root.crl</filename> exists.
+   are also checked if the parameter <xref linkend="guc-ssl-crl-file"> is set.
    <!-- If this URL changes replace it with a URL to www.archive.org. -->
    (See <ulink
    url="http://h71000.www7.hp.com/DOC/83final/BA554_90007/ch04s02.html"></>
@@ -2103,7 +2105,7 @@ pg_dumpall -p 5432 | psql -d postgres -p 5433
    available for all authentication methods, but only for rows specified as
    <literal>hostssl</>.  When <literal>clientcert</literal> is not specified
    or is set to 0, the server will still verify presented client
-   certificates against <filename>root.crt</filename> if that file exists
+   certificates against its CA list, if one is configured,
    &mdash; but it will not insist that a client certificate be presented.
   </para>
 
@@ -2127,7 +2129,8 @@ pg_dumpall -p 5432 | psql -d postgres -p 5433
 
    <para>
     <xref linkend="ssl-file-usage"> summarizes the files that are
-    relevant to the SSL setup on the server.
+    relevant to the SSL setup on the server.  (The shown file names are default
+    or typical names.  The locally configured names could be different.)
    </para>
 
   <table id="ssl-file-usage">
@@ -2144,27 +2147,27 @@ pg_dumpall -p 5432 | psql -d postgres -p 5433
     <tbody>
 
      <row>
-      <entry><filename>$PGDATA/server.crt</></entry>
+      <entry><xref linkend="guc-ssl-cert-file"> (<filename>$PGDATA/server.crt</>)</entry>
       <entry>server certificate</entry>
       <entry>sent to client to indicate server's identity</entry>
      </row>
 
      <row>
-      <entry><filename>$PGDATA/server.key</></entry>
+      <entry><xref linkend="guc-ssl-key-file"> (<filename>$PGDATA/server.key</>)</entry>
       <entry>server private key</entry>
       <entry>proves server certificate was sent by the owner; does not indicate
       certificate owner is trustworthy</entry>
      </row>
 
      <row>
-      <entry><filename>$PGDATA/root.crt</></entry>
+      <entry><xref linkend="guc-ssl-ca-file"> (<filename>$PGDATA/root.crt</>)</entry>
       <entry>trusted certificate authorities</entry>
       <entry>checks that client certificate is
       signed by a trusted certificate authority</entry>
      </row>
 
      <row>
-      <entry><filename>$PGDATA/root.crl</></entry>
+      <entry><xref linkend="guc-ssl-crl-file"> (<filename>$PGDATA/root.crl</>)</entry>
       <entry>certificates revoked by certificate authorities</entry>
       <entry>client certificate must not be on this list</entry>
      </row>
@@ -2176,6 +2179,7 @@ pg_dumpall -p 5432 | psql -d postgres -p 5433
    <para>
     The files <filename>server.key</>, <filename>server.crt</>,
     <filename>root.crt</filename>, and <filename>root.crl</filename>
+    (or their configured alternative names)
     are only examined during server start; so you must restart
     the server for changes in them to take effect.
    </para>

src/backend/libpq/be-secure.c

@@ -77,10 +77,10 @@
 
 #ifdef USE_SSL
 
-#define ROOT_CERT_FILE			"root.crt"
-#define ROOT_CRL_FILE			"root.crl"
-#define SERVER_CERT_FILE		"server.crt"
-#define SERVER_PRIVATE_KEY_FILE "server.key"
+char *ssl_cert_file;
+char *ssl_key_file;
+char *ssl_ca_file;
+char *ssl_crl_file;
 
 static DH  *load_dh_file(int keylength);
 static DH  *load_dh_buffer(const char *, size_t);
@@ -746,17 +746,17 @@ initialize_SSL(void)
 		 * Load and verify server's certificate and private key
 		 */
 		if (SSL_CTX_use_certificate_chain_file(SSL_context,
-											   SERVER_CERT_FILE) != 1)
+											   ssl_cert_file) != 1)
 			ereport(FATAL,
 					(errcode(ERRCODE_CONFIG_FILE_ERROR),
 				  errmsg("could not load server certificate file \"%s\": %s",
-						 SERVER_CERT_FILE, SSLerrmessage())));
+						 ssl_cert_file, SSLerrmessage())));
 
-		if (stat(SERVER_PRIVATE_KEY_FILE, &buf) != 0)
+		if (stat(ssl_key_file, &buf) != 0)
 			ereport(FATAL,
 					(errcode_for_file_access(),
 					 errmsg("could not access private key file \"%s\": %m",
-							SERVER_PRIVATE_KEY_FILE)));
+							ssl_key_file)));
 
 		/*
 		 * Require no public access to key file.
@@ -771,16 +771,16 @@ initialize_SSL(void)
 			ereport(FATAL,
 					(errcode(ERRCODE_CONFIG_FILE_ERROR),
 				  errmsg("private key file \"%s\" has group or world access",
-						 SERVER_PRIVATE_KEY_FILE),
+						 ssl_key_file),
 				   errdetail("Permissions should be u=rw (0600) or less.")));
 #endif
 
 		if (SSL_CTX_use_PrivateKey_file(SSL_context,
-										SERVER_PRIVATE_KEY_FILE,
+										ssl_key_file,
 										SSL_FILETYPE_PEM) != 1)
 			ereport(FATAL,
 					(errmsg("could not load private key file \"%s\": %s",
-							SERVER_PRIVATE_KEY_FILE, SSLerrmessage())));
+							ssl_key_file, SSLerrmessage())));
 
 		if (SSL_CTX_check_private_key(SSL_context) != 1)
 			ereport(FATAL,
@@ -797,48 +797,30 @@ initialize_SSL(void)
 		elog(FATAL, "could not set the cipher list (no valid ciphers available)");
 
 	/*
-	 * Attempt to load CA store, so we can verify client certificates if
-	 * needed.
+	 * Load CA store, so we can verify client certificates if needed.
 	 */
-	ssl_loaded_verify_locations = false;
-
-	if (access(ROOT_CERT_FILE, R_OK) != 0)
+	if (ssl_ca_file[0])
 	{
-		/*
-		 * If root certificate file simply not found, don't log an error here,
-		 * because it's quite likely the user isn't planning on using client
-		 * certificates. If we can't access it for other reasons, it is an
-		 * error.
-		 */
-		if (errno != ENOENT)
+		if (SSL_CTX_load_verify_locations(SSL_context, ssl_ca_file, NULL) != 1 ||
+			(root_cert_list = SSL_load_client_CA_file(ssl_ca_file)) == NULL)
 			ereport(FATAL,
-				 (errmsg("could not access root certificate file \"%s\": %m",
-						 ROOT_CERT_FILE)));
+					(errmsg("could not load root certificate file \"%s\": %s",
+							ssl_ca_file, SSLerrmessage())));
 	}
-	else if (SSL_CTX_load_verify_locations(SSL_context, ROOT_CERT_FILE, NULL) != 1 ||
-		  (root_cert_list = SSL_load_client_CA_file(ROOT_CERT_FILE)) == NULL)
-	{
-		/*
-		 * File was there, but we could not load it. This means the file is
-		 * somehow broken, and we cannot do verification at all - so fail.
-		 */
-		ereport(FATAL,
-				(errmsg("could not load root certificate file \"%s\": %s",
-						ROOT_CERT_FILE, SSLerrmessage())));
-	}
-	else
+
+	/*----------
+	 * Load the Certificate Revocation List (CRL).
+	 * http://searchsecurity.techtarget.com/sDefinition/0,,sid14_gci803160,00.html
+	 *----------
+	 */
+	if (ssl_crl_file[0])
 	{
-		/*----------
-		 * Load the Certificate Revocation List (CRL) if file exists.
-		 * http://searchsecurity.techtarget.com/sDefinition/0,,sid14_gci803160,00.html
-		 *----------
-		 */
 		X509_STORE *cvstore = SSL_CTX_get_cert_store(SSL_context);
 
 		if (cvstore)
 		{
 			/* Set the flags to check against the complete CRL chain */
-			if (X509_STORE_load_locations(cvstore, ROOT_CRL_FILE, NULL) == 1)
+			if (X509_STORE_load_locations(cvstore, ssl_crl_file, NULL) == 1)
 			{
 				/* OpenSSL 0.96 does not support X509_V_FLAG_CRL_CHECK */
 #ifdef X509_V_FLAG_CRL_CHECK
@@ -847,32 +829,31 @@ initialize_SSL(void)
 #else
 				ereport(LOG,
 				(errmsg("SSL certificate revocation list file \"%s\" ignored",
-						ROOT_CRL_FILE),
+						ssl_crl_file),
 				 errdetail("SSL library does not support certificate revocation lists.")));
 #endif
 			}
 			else
-			{
-				/* Not fatal - we do not require CRL */
-				ereport(LOG,
-						(errmsg("SSL certificate revocation list file \"%s\" not found, skipping: %s",
-								ROOT_CRL_FILE, SSLerrmessage()),
-						 errdetail("Certificates will not be checked against revocation list.")));
-			}
+				ereport(FATAL,
+						(errmsg("could not load SSL certificate revocation list file \"%s\": %s",
+								ssl_crl_file, SSLerrmessage())));
+		}
+	}
 
-			/*
-			 * Always ask for SSL client cert, but don't fail if it's not
-			 * presented.  We might fail such connections later, depending on
-			 * what we find in pg_hba.conf.
-			 */
-			SSL_CTX_set_verify(SSL_context,
-							   (SSL_VERIFY_PEER |
-								SSL_VERIFY_CLIENT_ONCE),
-							   verify_cb);
+	if (ssl_ca_file[0])
+	{
+		/*
+		 * Always ask for SSL client cert, but don't fail if it's not
+		 * presented.  We might fail such connections later, depending on
+		 * what we find in pg_hba.conf.
+		 */
+		SSL_CTX_set_verify(SSL_context,
+						   (SSL_VERIFY_PEER |
+							SSL_VERIFY_CLIENT_ONCE),
+						   verify_cb);
 
-			/* Set flag to remember CA store is successfully loaded */
-			ssl_loaded_verify_locations = true;
-		}
+		/* Set flag to remember CA store is successfully loaded */
+		ssl_loaded_verify_locations = true;
 
 		/*
 		 * Tell OpenSSL to send the list of root certs we trust to clients in

src/backend/libpq/hba.c

@@ -1417,7 +1417,7 @@ parse_hba_auth_opt(char *name, char *val, HbaLine *hbaline, int line_num)
 				ereport(LOG,
 						(errcode(ERRCODE_CONFIG_FILE_ERROR),
 						 errmsg("client certificates can only be checked if a root certificate store is available"),
-						 errhint("Make sure the root.crt file is present and readable."),
+						 errhint("Make sure the configuration parameter \"ssl_ca_file\" is set."),
 				   errcontext("line %d of configuration file \"%s\"",
 							  line_num, HbaFileName)));
 				return false;