Rename ident authentication over local connections to peer

This removes an overloading of two authentication options where
one is very secure (peer) and one is often insecure (ident). Peer
is also the name used in libpq from 9.1 to specify the same type
of authentication.

Also make initdb select peer for local connections when ident is
chosen, and ident for TCP connections when peer is chosen.

ident keyword in pg_hba.conf is still accepted and maps to peer
authentication.

5 files changed, 93 insertions, 69 deletions

diff --git a/src/backend/libpq/auth.c b/src/backend/libpq/auth.c
index af43c2a7cbc..5f56020cc76 100644
--- a/src/backend/libpq/auth.c
+++ b/src/backend/libpq/auth.c
@@ -60,7 +60,10 @@ static int	recv_and_check_password_packet(Port *port);
 /* Standard TCP port number for Ident service.	Assigned by IANA */
 #define IDENT_PORT 113
 
-static int	authident(hbaPort *port);
+static int	ident_inet(hbaPort *port);
+#ifdef HAVE_UNIX_SOCKETS
+static int	auth_peer(hbaPort *port);
+#endif
 
 
 /*----------------------------------------------------------------
@@ -269,6 +272,9 @@ auth_failed(Port *port, int status)
 		case uaIdent:
 			errstr = gettext_noop("Ident authentication failed for user \"%s\"");
 			break;
+		case uaPeer:
+			errstr = gettext_noop("Peer authentication failed for user \"%s\"");
+			break;
 		case uaPassword:
 		case uaMD5:
 			errstr = gettext_noop("password authentication failed for user \"%s\"");
@@ -506,11 +512,12 @@ ClientAuthentication(Port *port)
 #endif
 			break;
 
-		case uaIdent:
+		case uaPeer:
+#ifdef HAVE_UNIX_SOCKETS
 
 			/*
-			 * If we are doing ident on unix-domain sockets, use SCM_CREDS
-			 * only if it is defined and SO_PEERCRED isn't.
+			 * If we are doing peer on unix-domain sockets, use SCM_CREDS only
+			 * if it is defined and SO_PEERCRED isn't.
 			 */
 #if !defined(HAVE_GETPEEREID) && !defined(SO_PEERCRED) && \
 	(defined(HAVE_STRUCT_CMSGCRED) || defined(HAVE_STRUCT_FCRED) || \
@@ -535,7 +542,14 @@ ClientAuthentication(Port *port)
 				sendAuthRequest(port, AUTH_REQ_SCM_CREDS);
 			}
 #endif
-			status = authident(port);
+			status = auth_peer(port);
+#else /* HAVE_UNIX_SOCKETS */
+			Assert(false);
+#endif
+			break;
+
+		case uaIdent:
+			status = ident_inet(port);
 			break;
 
 		case uaMD5:
@@ -1599,11 +1613,12 @@ interpret_ident_response(const char *ident_response,
  *
  *	But iff we're unable to get the information from ident, return false.
  */
-static bool
-ident_inet(const SockAddr remote_addr,
-		   const SockAddr local_addr,
-		   char *ident_user)
+static int
+ident_inet(hbaPort *port)
 {
+	const SockAddr remote_addr = port->raddr;
+	const SockAddr local_addr = port->laddr;
+	char		ident_user[IDENT_USERNAME_MAX + 1];
 	pgsocket	sock_fd,		/* File descriptor for socket on which we talk
 								 * to Ident */
 				rc;				/* Return code from a locally called function */
@@ -1646,7 +1661,7 @@ ident_inet(const SockAddr remote_addr,
 	{
 		if (ident_serv)
 			pg_freeaddrinfo_all(hints.ai_family, ident_serv);
-		return false;			/* we don't expect this to happen */
+		return STATUS_ERROR;	/* we don't expect this to happen */
 	}
 
 	hints.ai_flags = AI_NUMERICHOST;
@@ -1662,7 +1677,7 @@ ident_inet(const SockAddr remote_addr,
 	{
 		if (la)
 			pg_freeaddrinfo_all(hints.ai_family, la);
-		return false;			/* we don't expect this to happen */
+		return STATUS_ERROR;	/* we don't expect this to happen */
 	}
 
 	sock_fd = socket(ident_serv->ai_family, ident_serv->ai_socktype,
@@ -1751,7 +1766,11 @@ ident_inet_done:
 		closesocket(sock_fd);
 	pg_freeaddrinfo_all(remote_addr.addr.ss_family, ident_serv);
 	pg_freeaddrinfo_all(local_addr.addr.ss_family, la);
-	return ident_return;
+
+	if (ident_return)
+		/* Success! Check the usermap */
+		return check_usermap(port->hba->usermap, port->user_name, ident_user, false);
+	return STATUS_ERROR;
 }
 
 /*
@@ -1763,9 +1782,12 @@ ident_inet_done:
  */
 #ifdef HAVE_UNIX_SOCKETS
 
-static bool
-ident_unix(int sock, char *ident_user)
+static int
+auth_peer(hbaPort *port)
 {
+	int			sock = port->sock;
+	char		ident_user[IDENT_USERNAME_MAX + 1];
+
 #if defined(HAVE_GETPEEREID)
 	/* OpenBSD style:  */
 	uid_t		uid;
@@ -1779,7 +1801,7 @@ ident_unix(int sock, char *ident_user)
 		ereport(LOG,
 				(errcode_for_socket_access(),
 				 errmsg("could not get peer credentials: %m")));
-		return false;
+		return STATUS_ERROR;
 	}
 
 	pass = getpwuid(uid);
@@ -1789,12 +1811,11 @@ ident_unix(int sock, char *ident_user)
 		ereport(LOG,
 				(errmsg("local user with ID %d does not exist",
 						(int) uid)));
-		return false;
+		return STATUS_ERROR;
 	}
 
 	strlcpy(ident_user, pass->pw_name, IDENT_USERNAME_MAX + 1);
 
-	return true;
 #elif defined(SO_PEERCRED)
 	/* Linux style: use getsockopt(SO_PEERCRED) */
 	struct ucred peercred;
@@ -1809,7 +1830,7 @@ ident_unix(int sock, char *ident_user)
 		ereport(LOG,
 				(errcode_for_socket_access(),
 				 errmsg("could not get peer credentials: %m")));
-		return false;
+		return STATUS_ERROR;
 	}
 
 	pass = getpwuid(peercred.uid);
@@ -1819,12 +1840,11 @@ ident_unix(int sock, char *ident_user)
 		ereport(LOG,
 				(errmsg("local user with ID %d does not exist",
 						(int) peercred.uid)));
-		return false;
+		return STATUS_ERROR;
 	}
 
 	strlcpy(ident_user, pass->pw_name, IDENT_USERNAME_MAX + 1);
 
-	return true;
 #elif defined(HAVE_GETPEERUCRED)
 	/* Solaris > 10 */
 	uid_t		uid;
@@ -1837,7 +1857,7 @@ ident_unix(int sock, char *ident_user)
 		ereport(LOG,
 				(errcode_for_socket_access(),
 				 errmsg("could not get peer credentials: %m")));
-		return false;
+		return STATUS_ERROR;
 	}
 
 	if ((uid = ucred_geteuid(ucred)) == -1)
@@ -1845,7 +1865,7 @@ ident_unix(int sock, char *ident_user)
 		ereport(LOG,
 				(errcode_for_socket_access(),
 		   errmsg("could not get effective UID from peer credentials: %m")));
-		return false;
+		return STATUS_ERROR;
 	}
 
 	ucred_free(ucred);
@@ -1856,12 +1876,11 @@ ident_unix(int sock, char *ident_user)
 		ereport(LOG,
 				(errmsg("local user with ID %d does not exist",
 						(int) uid)));
-		return false;
+		return STATUS_ERROR;
 	}
 
 	strlcpy(ident_user, pass->pw_name, IDENT_USERNAME_MAX + 1);
 
-	return true;
 #elif defined(HAVE_STRUCT_CMSGCRED) || defined(HAVE_STRUCT_FCRED) || (defined(HAVE_STRUCT_SOCKCRED) && defined(LOCAL_CREDS))
 	struct msghdr msg;
 
@@ -1913,7 +1932,7 @@ ident_unix(int sock, char *ident_user)
 		ereport(LOG,
 				(errcode_for_socket_access(),
 				 errmsg("could not get peer credentials: %m")));
-		return false;
+		return STATUS_ERROR;
 	}
 
 	cred = (Cred *) CMSG_DATA(cmsg);
@@ -1925,59 +1944,22 @@ ident_unix(int sock, char *ident_user)
 		ereport(LOG,
 				(errmsg("local user with ID %d does not exist",
 						(int) cred->cruid)));
-		return false;
+		return STATUS_ERROR;
 	}
 
 	strlcpy(ident_user, pw->pw_name, IDENT_USERNAME_MAX + 1);
 
-	return true;
 #else
 	ereport(LOG,
 			(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 			 errmsg("Ident authentication is not supported on local connections on this platform")));
 
-	return false;
-#endif
-}
-#endif   /* HAVE_UNIX_SOCKETS */
-
-
-/*
- *	Determine the username of the initiator of the connection described
- *	by "port".	Then look in the usermap file under the usermap
- *	port->hba->usermap and see if that user is equivalent to Postgres user
- *	port->user.
- *
- *	Return STATUS_OK if yes, STATUS_ERROR if no match (or couldn't get info).
- */
-static int
-authident(hbaPort *port)
-{
-	char		ident_user[IDENT_USERNAME_MAX + 1];
-
-	switch (port->raddr.addr.ss_family)
-	{
-		case AF_INET:
-#ifdef	HAVE_IPV6
-		case AF_INET6:
+	return STATUS_ERROR;
 #endif
-			if (!ident_inet(port->raddr, port->laddr, ident_user))
-				return STATUS_ERROR;
-			break;
-
-#ifdef HAVE_UNIX_SOCKETS
-		case AF_UNIX:
-			if (!ident_unix(port->sock, ident_user))
-				return STATUS_ERROR;
-			break;
-#endif
-
-		default:
-			return STATUS_ERROR;
-	}
 
 	return check_usermap(port->hba->usermap, port->user_name, ident_user, false);
 }
+#endif   /* HAVE_UNIX_SOCKETS */
 
 
 /*----------------------------------------------------------------
diff --git a/src/backend/libpq/hba.c b/src/backend/libpq/hba.c
index 1b3a71431c9..2def6cea894 100644
--- a/src/backend/libpq/hba.c
+++ b/src/backend/libpq/hba.c
@@ -1060,6 +1060,8 @@ parse_hba_line(List *line, int line_num, HbaLine *parsedline)
 		parsedline->auth_method = uaTrust;
 	else if (strcmp(token, "ident") == 0)
 		parsedline->auth_method = uaIdent;
+	else if (strcmp(token, "peer") == 0)
+		parsedline->auth_method = uaPeer;
 	else if (strcmp(token, "password") == 0)
 		parsedline->auth_method = uaPassword;
 	else if (strcmp(token, "krb5") == 0)
@@ -1137,6 +1139,14 @@ parse_hba_line(List *line, int line_num, HbaLine *parsedline)
 		return false;
 	}
 
+	/*
+	 * XXX: When using ident on local connections, change it to peer, for
+	 * backwards compatibility.
+	 */
+	if (parsedline->conntype == ctLocal &&
+		parsedline->auth_method == uaIdent)
+		parsedline->auth_method = uaPeer;
+
 	/* Invalid authentication combinations */
 	if (parsedline->conntype == ctLocal &&
 		parsedline->auth_method == uaKrb5)
@@ -1160,6 +1170,17 @@ parse_hba_line(List *line, int line_num, HbaLine *parsedline)
 		return false;
 	}
 
+	if (parsedline->conntype != ctLocal &&
+		parsedline->auth_method == uaPeer)
+	{
+		ereport(LOG,
+				(errcode(ERRCODE_CONFIG_FILE_ERROR),
+			errmsg("peer authentication is only supported on local sockets"),
+				 errcontext("line %d of configuration file \"%s\"",
+							line_num, HbaFileName)));
+		return false;
+	}
+
 	/*
 	 * SSPI authentication can never be enabled on ctLocal connections,
 	 * because it's only supported on Windows, where ctLocal isn't supported.
@@ -1203,11 +1224,12 @@ parse_hba_line(List *line, int line_num, HbaLine *parsedline)
 			if (strcmp(token, "map") == 0)
 			{
 				if (parsedline->auth_method != uaIdent &&
+					parsedline->auth_method != uaPeer &&
 					parsedline->auth_method != uaKrb5 &&
 					parsedline->auth_method != uaGSS &&
 					parsedline->auth_method != uaSSPI &&
 					parsedline->auth_method != uaCert)
-					INVALID_AUTH_OPTION("map", gettext_noop("ident, krb5, gssapi, sspi and cert"));
+					INVALID_AUTH_OPTION("map", gettext_noop("ident, peer, krb5, gssapi, sspi and cert"));
 				parsedline->usermap = pstrdup(c);
 			}
 			else if (strcmp(token, "clientcert") == 0)
diff --git a/src/backend/libpq/pg_hba.conf.sample b/src/backend/libpq/pg_hba.conf.sample
index 87f84991bca..0a90b68c100 100644
--- a/src/backend/libpq/pg_hba.conf.sample
+++ b/src/backend/libpq/pg_hba.conf.sample
@@ -41,7 +41,7 @@
 # directly connected to.
 #
 # METHOD can be "trust", "reject", "md5", "password", "gss", "sspi",
-# "krb5", "ident", "pam", "ldap", "radius" or "cert".  Note that
+# "krb5", "ident", "peer", "pam", "ldap", "radius" or "cert".  Note that
 # "password" sends passwords in clear text; "md5" is preferred since
 # it sends encrypted passwords.
 #
@@ -75,7 +75,7 @@
 # TYPE  DATABASE        USER            ADDRESS                 METHOD
 
 @remove-line-for-nolocal@# "local" is for Unix domain socket connections only
-@remove-line-for-nolocal@local   all             all                                     @authmethod@
+@remove-line-for-nolocal@local   all             all                                     @authmethodlocal@
 # IPv4 local connections:
 host    all             all             127.0.0.1/32            @authmethod@
 # IPv6 local connections:
diff --git a/src/bin/initdb/initdb.c b/src/bin/initdb/initdb.c
index 7a4b698b99f..d509b1311d1 100644
--- a/src/bin/initdb/initdb.c
+++ b/src/bin/initdb/initdb.c
@@ -82,6 +82,7 @@ static char *username = "";
 static bool pwprompt = false;
 static char *pwfilename = NULL;
 static char *authmethod = "";
+static char *authmethodlocal = "";
 static bool debug = false;
 static bool noclean = false;
 static bool show_setting = false;
@@ -1076,6 +1077,9 @@ setup_config(void)
 	conflines = replace_token(conflines,
 							  "@authmethod@",
 							  authmethod);
+	conflines = replace_token(conflines,
+							  "@authmethodlocal@",
+							  authmethodlocal);
 
 	conflines = replace_token(conflines,
 							  "@authcomment@",
@@ -2637,6 +2641,7 @@ main(int argc, char *argv[])
 	}
 
 	if (strcmp(authmethod, "md5") &&
+		strcmp(authmethod, "peer") &&
 		strcmp(authmethod, "ident") &&
 		strcmp(authmethod, "trust") &&
 #ifdef USE_PAM
@@ -2666,6 +2671,20 @@ main(int argc, char *argv[])
 		exit(1);
 	}
 
+	/*
+	 * When ident is specified, use peer for local connections. Mirrored, when
+	 * peer is specified, use ident for TCP connections.
+	 */
+	if (strcmp(authmethod, "ident") == 0)
+		authmethodlocal = "peer";
+	else if (strcmp(authmethod, "peer") == 0)
+	{
+		authmethodlocal = "peer";
+		authmethod = "ident";
+	}
+	else
+		authmethodlocal = authmethod;
+
 	if (strlen(pg_data) == 0)
 	{
 		pgdenv = getenv("PGDATA");
diff --git a/src/include/libpq/hba.h b/src/include/libpq/hba.h
index aa60d8d4f17..b92dc0d3a47 100644
--- a/src/include/libpq/hba.h
+++ b/src/include/libpq/hba.h
@@ -29,7 +29,8 @@ typedef enum UserAuth
 	uaPAM,
 	uaLDAP,
 	uaCert,
-	uaRADIUS
+	uaRADIUS,
+	uaPeer
 } UserAuth;
 
 typedef enum IPCompareMethod