Add more columns to pg_stat_ssl

Add columns client_serial and issuer_dn to pg_stat_ssl.  These allow
uniquely identifying the client certificate.

Rename the existing column clientdn to client_dn, to make the naming
more consistent and easier to read.

Discussion: https://www.postgresql.org/message-id/flat/398754d8-6bb5-c5cf-e7b8-22e5f0983caf@2ndquadrant.com/

doc/src/sgml/monitoring.sgml

@@ -2201,15 +2201,31 @@ SELECT pid, wait_event_type, wait_event FROM pg_stat_activity WHERE wait_event i
       or NULL if SSL is not in use on this connection</entry>
     </row>
     <row>
-     <entry><structfield>clientdn</structfield></entry>
+     <entry><structfield>client_dn</structfield></entry>
      <entry><type>text</type></entry>
      <entry>Distinguished Name (DN) field from the client certificate
       used, or NULL if no client certificate was supplied or if SSL
       is not in use on this connection. This field is truncated if the
       DN field is longer than <symbol>NAMEDATALEN</symbol> (64 characters
-      in a standard build)
+      in a standard build).
      </entry>
     </row>
+    <row>
+     <entry><structfield>client_serial</structfield></entry>
+     <entry><type>numeric</type></entry>
+     <entry>Serial number of the client certificate, or NULL if no client
+     certificate was supplied or if SSL is not in use on this connection.  The
+     combination of certificate serial number and certificate issuer uniquely
+     identifies a certificate (unless the issuer erroneously reuses serial
+     numbers).</entry>
+    </row>
+    <row>
+     <entry><structfield>issuer_dn</structfield></entry>
+     <entry><type>text</type></entry>
+     <entry>DN of the issuer of the client certificate, or NULL if no client
+     certificate was supplied or if SSL is not in use on this connection.
+     This field is truncated like <structfield>client_dn</structfield>.</entry>
+    </row>
    </tbody>
    </tgroup>
   </table>

src/backend/catalog/system_views.sql

@@ -782,7 +782,9 @@ CREATE VIEW pg_stat_ssl AS
             S.sslcipher AS cipher,
             S.sslbits AS bits,
             S.sslcompression AS compression,
-            S.sslclientdn AS clientdn
+            S.ssl_client_dn AS client_dn,
+            S.ssl_client_serial AS client_serial,
+            S.ssl_issuer_dn AS issuer_dn
     FROM pg_stat_get_activity(NULL) AS S;
 
 CREATE VIEW pg_replication_slots AS

src/backend/libpq/be-secure-openssl.c

@@ -1109,7 +1109,7 @@ be_tls_get_cipher(Port *port)
 }
 
 void
-be_tls_get_peerdn_name(Port *port, char *ptr, size_t len)
+be_tls_get_peer_subject_name(Port *port, char *ptr, size_t len)
 {
 	if (port->peer)
 		strlcpy(ptr, X509_NAME_to_cstring(X509_get_subject_name(port->peer)), len);
@@ -1117,6 +1117,35 @@ be_tls_get_peerdn_name(Port *port, char *ptr, size_t len)
 		ptr[0] = '\0';
 }
 
+void
+be_tls_get_peer_issuer_name(Port *port, char *ptr, size_t len)
+{
+	if (port->peer)
+		strlcpy(ptr, X509_NAME_to_cstring(X509_get_issuer_name(port->peer)), len);
+	else
+		ptr[0] = '\0';
+}
+
+void
+be_tls_get_peer_serial(Port *port, char *ptr, size_t len)
+{
+	if (port->peer)
+	{
+		ASN1_INTEGER *serial;
+		BIGNUM	   *b;
+		char	   *decimal;
+
+		serial = X509_get_serialNumber(port->peer);
+		b = ASN1_INTEGER_to_BN(serial, NULL);
+		decimal = BN_bn2dec(b);
+		BN_free(b);
+		strlcpy(ptr, decimal, len);
+		OPENSSL_free(decimal);
+	}
+	else
+		ptr[0] = '\0';
+}
+
 #ifdef HAVE_X509_GET_SIGNATURE_NID
 char *
 be_tls_get_certificate_hash(Port *port, size_t *len)

src/backend/postmaster/pgstat.c

@@ -2906,7 +2906,9 @@ pgstat_bestart(void)
 		beentry->st_sslstatus->ssl_compression = be_tls_get_compression(MyProcPort);
 		strlcpy(beentry->st_sslstatus->ssl_version, be_tls_get_version(MyProcPort), NAMEDATALEN);
 		strlcpy(beentry->st_sslstatus->ssl_cipher, be_tls_get_cipher(MyProcPort), NAMEDATALEN);
-		be_tls_get_peerdn_name(MyProcPort, beentry->st_sslstatus->ssl_clientdn, NAMEDATALEN);
+		be_tls_get_peer_subject_name(MyProcPort, beentry->st_sslstatus->ssl_client_dn, NAMEDATALEN);
+		be_tls_get_peer_serial(MyProcPort, beentry->st_sslstatus->ssl_client_serial, NAMEDATALEN);
+		be_tls_get_peer_issuer_name(MyProcPort, beentry->st_sslstatus->ssl_issuer_dn, NAMEDATALEN);
 	}
 	else
 	{

src/backend/utils/adt/pgstatfuncs.c

@@ -541,7 +541,7 @@ pg_stat_get_progress_info(PG_FUNCTION_ARGS)
 Datum
 pg_stat_get_activity(PG_FUNCTION_ARGS)
 {
-#define PG_STAT_GET_ACTIVITY_COLS	24
+#define PG_STAT_GET_ACTIVITY_COLS	26
 	int			num_backends = pgstat_fetch_stat_numbackends();
 	int			curr_backend;
 	int			pid = PG_ARGISNULL(0) ? -1 : PG_GETARG_INT32(0);
@@ -652,15 +652,29 @@ pg_stat_get_activity(PG_FUNCTION_ARGS)
 			values[20] = CStringGetTextDatum(beentry->st_sslstatus->ssl_cipher);
 			values[21] = Int32GetDatum(beentry->st_sslstatus->ssl_bits);
 			values[22] = BoolGetDatum(beentry->st_sslstatus->ssl_compression);
-			if (beentry->st_sslstatus->ssl_clientdn[0])
-				values[23] = CStringGetTextDatum(beentry->st_sslstatus->ssl_clientdn);
+
+			if (beentry->st_sslstatus->ssl_client_dn[0])
+				values[23] = CStringGetTextDatum(beentry->st_sslstatus->ssl_client_dn);
 			else
 				nulls[23] = true;
+
+			if (beentry->st_sslstatus->ssl_client_serial[0])
+				values[24] = DirectFunctionCall3(numeric_in,
+												 CStringGetDatum(beentry->st_sslstatus->ssl_client_serial),
+												 ObjectIdGetDatum(InvalidOid),
+												 Int32GetDatum(-1));
+			else
+				nulls[24] = true;
+
+			if (beentry->st_sslstatus->ssl_issuer_dn[0])
+				values[25] = CStringGetTextDatum(beentry->st_sslstatus->ssl_issuer_dn);
+			else
+				nulls[25] = true;
 		}
 		else
 		{
 			values[18] = BoolGetDatum(false);	/* ssl */
-			nulls[19] = nulls[20] = nulls[21] = nulls[22] = nulls[23] = true;
+			nulls[19] = nulls[20] = nulls[21] = nulls[22] = nulls[23] = nulls[24] = nulls[25] = true;
 		}
 
 		/* Values only available to role member or pg_read_all_stats */

src/include/catalog/catversion.h

@@ -53,6 +53,6 @@
  */
 
 /*							yyyymmddN */
-#define CATALOG_VERSION_NO	201901041
+#define CATALOG_VERSION_NO	201902011
 
 #endif

src/include/catalog/pg_proc.dat

@@ -5058,9 +5058,9 @@
   proname => 'pg_stat_get_activity', prorows => '100', proisstrict => 'f',
   proretset => 't', provolatile => 's', proparallel => 'r',
   prorettype => 'record', proargtypes => 'int4',
-  proallargtypes => '{int4,oid,int4,oid,text,text,text,text,text,timestamptz,timestamptz,timestamptz,timestamptz,inet,text,int4,xid,xid,text,bool,text,text,int4,bool,text}',
-  proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}',
-  proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,sslcompression,sslclientdn}',
+  proallargtypes => '{int4,oid,int4,oid,text,text,text,text,text,timestamptz,timestamptz,timestamptz,timestamptz,inet,text,int4,xid,xid,text,bool,text,text,int4,bool,text,numeric,text}',
+  proargmodes => '{i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}',
+  proargnames => '{pid,datid,pid,usesysid,application_name,state,query,wait_event_type,wait_event,xact_start,query_start,backend_start,state_change,client_addr,client_hostname,client_port,backend_xid,backend_xmin,backend_type,ssl,sslversion,sslcipher,sslbits,sslcompression,ssl_client_dn,ssl_client_serial,ssl_issuer_dn}',
   prosrc => 'pg_stat_get_activity' },
 { oid => '3318',
   descr => 'statistics: information about progress of backends running maintenance command',

src/include/libpq/libpq-be.h

@@ -258,7 +258,9 @@ extern int	be_tls_get_cipher_bits(Port *port);
 extern bool be_tls_get_compression(Port *port);
 extern const char *be_tls_get_version(Port *port);
 extern const char *be_tls_get_cipher(Port *port);
-extern void be_tls_get_peerdn_name(Port *port, char *ptr, size_t len);
+extern void be_tls_get_peer_subject_name(Port *port, char *ptr, size_t len);
+extern void be_tls_get_peer_issuer_name(Port *port, char *ptr, size_t len);
+extern void be_tls_get_peer_serial(Port *port, char *ptr, size_t len);
 
 /*
  * Get the server certificate hash for SCRAM channel binding type

src/include/pgstat.h

@@ -950,15 +950,25 @@ typedef enum ProgressCommandType
  *
  * For each backend, we keep the SSL status in a separate struct, that
  * is only filled in if SSL is enabled.
+ *
+ * All char arrays must be null-terminated.
  */
 typedef struct PgBackendSSLStatus
 {
 	/* Information about SSL connection */
 	int			ssl_bits;
 	bool		ssl_compression;
-	char		ssl_version[NAMEDATALEN];	/* MUST be null-terminated */
-	char		ssl_cipher[NAMEDATALEN];	/* MUST be null-terminated */
-	char		ssl_clientdn[NAMEDATALEN];	/* MUST be null-terminated */
+	char		ssl_version[NAMEDATALEN];
+	char		ssl_cipher[NAMEDATALEN];
+	char		ssl_client_dn[NAMEDATALEN];
+
+	/*
+	 * serial number is max "20 octets" per RFC 5280, so this size should be
+	 * fine
+	 */
+	char		ssl_client_serial[NAMEDATALEN];
+
+	char		ssl_issuer_dn[NAMEDATALEN];
 } PgBackendSSLStatus;
 
 

src/test/regress/expected/rules.out

@@ -1731,7 +1731,7 @@ pg_stat_activity| SELECT s.datid,
     s.backend_xmin,
     s.query,
     s.backend_type
-   FROM ((pg_stat_get_activity(NULL::integer) s(datid, pid, usesysid, application_name, state, query, wait_event_type, wait_event, xact_start, query_start, backend_start, state_change, client_addr, client_hostname, client_port, backend_xid, backend_xmin, backend_type, ssl, sslversion, sslcipher, sslbits, sslcompression, sslclientdn)
+   FROM ((pg_stat_get_activity(NULL::integer) s(datid, pid, usesysid, application_name, state, query, wait_event_type, wait_event, xact_start, query_start, backend_start, state_change, client_addr, client_hostname, client_port, backend_xid, backend_xmin, backend_type, ssl, sslversion, sslcipher, sslbits, sslcompression, ssl_client_dn, ssl_client_serial, ssl_issuer_dn)
      LEFT JOIN pg_database d ON ((s.datid = d.oid)))
      LEFT JOIN pg_authid u ON ((s.usesysid = u.oid)));
 pg_stat_all_indexes| SELECT c.oid AS relid,
@@ -1863,7 +1863,7 @@ pg_stat_replication| SELECT s.pid,
     w.sync_priority,
     w.sync_state,
     w.reply_time
-   FROM ((pg_stat_get_activity(NULL::integer) s(datid, pid, usesysid, application_name, state, query, wait_event_type, wait_event, xact_start, query_start, backend_start, state_change, client_addr, client_hostname, client_port, backend_xid, backend_xmin, backend_type, ssl, sslversion, sslcipher, sslbits, sslcompression, sslclientdn)
+   FROM ((pg_stat_get_activity(NULL::integer) s(datid, pid, usesysid, application_name, state, query, wait_event_type, wait_event, xact_start, query_start, backend_start, state_change, client_addr, client_hostname, client_port, backend_xid, backend_xmin, backend_type, ssl, sslversion, sslcipher, sslbits, sslcompression, ssl_client_dn, ssl_client_serial, ssl_issuer_dn)
      JOIN pg_stat_get_wal_senders() w(pid, state, sent_lsn, write_lsn, flush_lsn, replay_lsn, write_lag, flush_lag, replay_lag, sync_priority, sync_state, reply_time) ON ((s.pid = w.pid)))
      LEFT JOIN pg_authid u ON ((s.usesysid = u.oid)));
 pg_stat_ssl| SELECT s.pid,
@@ -1872,8 +1872,10 @@ pg_stat_ssl| SELECT s.pid,
     s.sslcipher AS cipher,
     s.sslbits AS bits,
     s.sslcompression AS compression,
-    s.sslclientdn AS clientdn
-   FROM pg_stat_get_activity(NULL::integer) s(datid, pid, usesysid, application_name, state, query, wait_event_type, wait_event, xact_start, query_start, backend_start, state_change, client_addr, client_hostname, client_port, backend_xid, backend_xmin, backend_type, ssl, sslversion, sslcipher, sslbits, sslcompression, sslclientdn);
+    s.ssl_client_dn AS client_dn,
+    s.ssl_client_serial AS client_serial,
+    s.ssl_issuer_dn AS issuer_dn
+   FROM pg_stat_get_activity(NULL::integer) s(datid, pid, usesysid, application_name, state, query, wait_event_type, wait_event, xact_start, query_start, backend_start, state_change, client_addr, client_hostname, client_port, backend_xid, backend_xmin, backend_type, ssl, sslversion, sslcipher, sslbits, sslcompression, ssl_client_dn, ssl_client_serial, ssl_issuer_dn);
 pg_stat_subscription| SELECT su.oid AS subid,
     su.subname,
     st.pid,

src/test/ssl/t/001_ssltests.pl

@@ -315,8 +315,8 @@ command_like([
 	'-d', "$common_connstr sslrootcert=invalid",
 	'-c', "SELECT * FROM pg_stat_ssl WHERE pid = pg_backend_pid()"
 			 ],
-			 qr{^pid,ssl,version,cipher,bits,compression,clientdn\n
-				^\d+,t,TLSv[\d.]+,[\w-]+,\d+,f,_null_$}mx,
+			 qr{^pid,ssl,version,cipher,bits,compression,client_dn,client_serial,issuer_dn\n
+				^\d+,t,TLSv[\d.]+,[\w-]+,\d+,f,_null_,_null_,_null_$}mx,
 			 'pg_stat_ssl view without client certificate');
 
 ### Server-side tests.
@@ -347,8 +347,8 @@ command_like([
 	'-d', "$common_connstr user=ssltestuser sslcert=ssl/client.crt sslkey=ssl/client_tmp.key",
 	'-c', "SELECT * FROM pg_stat_ssl WHERE pid = pg_backend_pid()"
 			 ],
-			 qr{^pid,ssl,version,cipher,bits,compression,clientdn\n
-				^\d+,t,TLSv[\d.]+,[\w-]+,\d+,f,/CN=ssltestuser$}mx,
+			 qr{^pid,ssl,version,cipher,bits,compression,client_dn,client_serial,issuer_dn\n
+				^\d+,t,TLSv[\d.]+,[\w-]+,\d+,f,/CN=ssltestuser,1,\Q/CN=Test CA for PostgreSQL SSL regression test client certs\E$}mx,
 			 'pg_stat_ssl with client certificate');
 
 # client key with wrong permissions