#
# This patch contains a couple of PAM enhancements:
#   1) Each SSHv2 userauth method has its own PAM service name so that PAM can
#      be used to control what userauth methods are allowed.
#   2) The PAMServiceName and PAMServicePrefix options.
# 
# We have contributed back this feature to the OpenSSH upstream community. 
# For more information, see https://bugzilla.mindrot.org/show_bug.cgi?id=2246
# In the future, if these enhancements are accepted by the upsteam in a 
# later release, we will remove this patch when we upgrade to that release.
#
--- orig/auth-pam.c	Fri Jun 20 15:39:05 2014
+++ new/auth-pam.c	Fri Jun 20 16:47:09 2014
@@ -617,6 +617,72 @@
 	sshpam_handle = NULL;
 }
 
+#ifdef PAM_ENHANCEMENT
+char *
+derive_pam_service_name(Authctxt *authctxt)
+{
+	char *svcname = xmalloc(BUFSIZ);
+
+	/*
+	 * If PamServiceName is set we use that for everything, including
+	 * SSHv1
+	 */
+	if (options.pam_service_name != NULL) {
+		(void) strlcpy(svcname, options.pam_service_name, BUFSIZ);
+		return (svcname);
+	}
+
+	if (compat20) {
+		char *method_name = authctxt->authmethod_name;
+
+		if (!method_name)
+			fatal("Userauth method unknown while starting PAM");
+
+		/*
+		 * For SSHv2 we use "sshd-<userauth name>
+		 * The "sshd" prefix can be changed via the PAMServicePrefix
+		 * sshd_config option.
+		 */
+		if (strcmp(method_name, "none") == 0) {
+			snprintf(svcname, BUFSIZ, "%s-none",
+			    options.pam_service_prefix);
+		}
+		if (strcmp(method_name, "password") == 0) {
+			snprintf(svcname, BUFSIZ, "%s-password",
+			    options.pam_service_prefix);
+		}
+		if (strcmp(method_name, "keyboard-interactive") == 0) {
+			/* "keyboard-interactive" is too long, shorten it */
+			snprintf(svcname, BUFSIZ, "%s-kbdint",
+			    options.pam_service_prefix);
+		}
+		if (strcmp(method_name, "publickey") == 0) {
+			/* "publickey" is too long, shorten it */
+			snprintf(svcname, BUFSIZ, "%s-pubkey",
+			    options.pam_service_prefix);
+		}
+		if (strcmp(method_name, "hostbased") == 0) {
+			snprintf(svcname, BUFSIZ, "%s-hostbased",
+			    options.pam_service_prefix);
+		}
+		if (strncmp(method_name, "gssapi-", 7) == 0) {
+		        /*
+			 * Although OpenSSH only supports "gssapi-with-mic"
+			 * for now. We will still map any userauth method
+                         * prefixed with "gssapi-" to the gssapi PAM service.
+			 */ 
+			snprintf(svcname, BUFSIZ, "%s-gssapi",
+			    options.pam_service_prefix);
+		}
+		return svcname;
+	} else {
+		/* SSHv1 doesn't get to be so cool */
+	        snprintf(svcname, BUFSIZ, "sshd-v1");
+	}
+	return svcname;
+}
+#endif /* PAM_ENHANCEMENT */
+
 static int
 sshpam_init(Authctxt *authctxt)
 {
@@ -624,18 +690,61 @@
 	const char *pam_rhost, *pam_user, *user = authctxt->user;
 	const char **ptr_pam_user = &pam_user;
 
+#ifdef PAM_ENHANCEMENT
+	const char *pam_service;
+        const char **ptr_pam_service = &pam_service;
+	char *svc = NULL;
+
+	svc = derive_pam_service_name(authctxt);
+        debug3("PAM service is %s", svc);
+#endif
+
 	if (sshpam_handle != NULL) {
+#ifdef PAM_ENHANCEMENT
+	        /* get the pam service name */
+		sshpam_err = pam_get_item(sshpam_handle,
+		    PAM_SERVICE, (sshpam_const void **)ptr_pam_service);
+                if (sshpam_err != PAM_SUCCESS) 
+		    fatal("Failed to get the PAM service name");
+		debug3("Previous pam_service is %s", pam_service ?
+                    pam_service : "NULL");
+
+		/* get the pam user name */
+		sshpam_err = pam_get_item(sshpam_handle,
+		    PAM_USER, (sshpam_const void **)ptr_pam_user);
+
+		/*
+		 * only need to re-start if either user or service is 
+                 * different.
+                 */
+		if (sshpam_err == PAM_SUCCESS && strcmp(user, pam_user) == 0
+		    && strncmp(svc, pam_service, strlen(svc)) == 0) {
+		        free(svc);
+			return (0);
+                }
+
+#else /* Original */
 		/* We already have a PAM context; check if the user matches */
 		sshpam_err = pam_get_item(sshpam_handle,
 		    PAM_USER, (sshpam_const void **)ptr_pam_user);
 		if (sshpam_err == PAM_SUCCESS && strcmp(user, pam_user) == 0)
 			return (0);
+#endif /* PAM_ENHANCEMENT */
 		pam_end(sshpam_handle, sshpam_err);
 		sshpam_handle = NULL;
 	}
 	debug("PAM: initializing for \"%s\"", user);
+
+#ifdef PAM_ENHANCEMENT
+        debug3("Starting PAM service %s for user %s method %s", svc, user,
+            authctxt->authmethod_name);
 	sshpam_err =
+	    pam_start(svc, user, &store_conv, &sshpam_handle);
+	free(svc);
+#else /* Original */
+	sshpam_err =
 	    pam_start(SSHD_PAM_SERVICE, user, &store_conv, &sshpam_handle);
+#endif
 	sshpam_authctxt = authctxt;
 
 	if (sshpam_err != PAM_SUCCESS) {
--- orig/auth.h	Fri Jun 20 15:39:05 2014
+++ new/auth.h	Fri Jun 20 15:39:05 2014
@@ -76,6 +76,9 @@
 #endif
 	Buffer		*loginmsg;
 	void		*methoddata;
+#ifdef PAM_ENHANCEMENT
+        char            *authmethod_name;
+#endif 
 };
 /*
  * Every authentication method has to handle authentication requests for
--- orig/auth2.c	Fri Jun 20 15:39:05 2014
+++ new/auth2.c	Fri Jun 20 15:39:05 2014
@@ -249,10 +249,13 @@
 			PRIVSEP(audit_event(SSH_INVALID_USER));
 #endif
 		}
+
+#ifndef PAM_ENHANCEMENT
 #ifdef USE_PAM
 		if (options.use_pam)
 			PRIVSEP(start_pam(authctxt));
 #endif
+#endif
 		setproctitle("%s%s", authctxt->valid ? user : "unknown",
 		    use_privsep ? " [net]" : "");
 		authctxt->service = xstrdup(service);
@@ -286,6 +289,14 @@
 	/* try to authenticate user */
 	m = authmethod_lookup(authctxt, method);
 	if (m != NULL && authctxt->failures < options.max_authtries) {
+
+#ifdef PAM_ENHANCEMENT
+                authctxt->authmethod_name = xstrdup(method);
+                if (use_privsep)
+                       mm_inform_authmethod(method);
+		if (options.use_pam)
+		       PRIVSEP(start_pam(authctxt));
+#endif
 		debug2("input_userauth_request: try method %s", method);
 		authenticated =	m->userauth(authctxt);
 	}
@@ -303,6 +314,10 @@
 	char *methods;
 	int partial = 0;
 
+#ifdef  PAM_ENHANCEMENT
+        debug3("%s: entering", __func__);
+#endif
+
 	if (!authctxt->valid && authenticated)
 		fatal("INTERNAL ERROR: authenticated invalid user %s",
 		    authctxt->user);
@@ -623,5 +638,3 @@
 		fatal("%s: method not in AuthenticationMethods", __func__);
 	return 0;
 }
-
-
--- orig/monitor_wrap.c	Fri Jun 20 15:39:05 2014
+++ new/monitor_wrap.c	Fri Jun 20 15:39:05 2014
@@ -338,6 +338,24 @@
 	buffer_free(&m);
 }
 
+#ifdef PAM_ENHANCEMENT
+/* Inform the privileged process about the authentication method */
+void
+mm_inform_authmethod(char *authmethod)
+{
+	Buffer m;
+
+	debug3("%s entering", __func__);
+
+	buffer_init(&m);
+	buffer_put_cstring(&m, authmethod);
+
+	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_AUTHMETHOD, &m);
+
+	buffer_free(&m);
+}
+#endif
+
 /* Do the password authentication */
 int
 mm_auth_password(Authctxt *authctxt, char *password)
--- orig/monitor.c	Fri Jun 20 15:39:05 2014
+++ new/monitor.c	Fri Jun 20 15:39:05 2014
@@ -146,6 +146,9 @@
 int mm_answer_pwnamallow(int, Buffer *);
 int mm_answer_auth2_read_banner(int, Buffer *);
 int mm_answer_authserv(int, Buffer *);
+#ifdef PAM_ENHANCEMENT
+int mm_answer_authmethod(int, Buffer *);
+#endif
 int mm_answer_authpassword(int, Buffer *);
 int mm_answer_bsdauthquery(int, Buffer *);
 int mm_answer_bsdauthrespond(int, Buffer *);
@@ -225,10 +228,17 @@
     {MONITOR_REQ_SIGN, MON_ONCE, mm_answer_sign},
     {MONITOR_REQ_PWNAM, MON_ONCE, mm_answer_pwnamallow},
     {MONITOR_REQ_AUTHSERV, MON_ONCE, mm_answer_authserv},
+#ifdef PAM_ENHANCEMENT
+    {MONITOR_REQ_AUTHMETHOD, MON_ISAUTH, mm_answer_authmethod},
+#endif
     {MONITOR_REQ_AUTH2_READ_BANNER, MON_ONCE, mm_answer_auth2_read_banner},
     {MONITOR_REQ_AUTHPASSWORD, MON_AUTH, mm_answer_authpassword},
 #ifdef USE_PAM
+#ifdef PAM_ENHANCEMENT
+    {MONITOR_REQ_PAM_START, MON_ISAUTH, mm_answer_pam_start},
+#else
     {MONITOR_REQ_PAM_START, MON_ONCE, mm_answer_pam_start},
+#endif
     {MONITOR_REQ_PAM_ACCOUNT, 0, mm_answer_pam_account},
     {MONITOR_REQ_PAM_INIT_CTX, MON_ISAUTH, mm_answer_pam_init_ctx},
     {MONITOR_REQ_PAM_QUERY, MON_ISAUTH, mm_answer_pam_query},
@@ -828,6 +838,10 @@
 		/* Allow service/style information on the auth context */
 		monitor_permit(mon_dispatch, MONITOR_REQ_AUTHSERV, 1);
 		monitor_permit(mon_dispatch, MONITOR_REQ_AUTH2_READ_BANNER, 1);
+#ifdef PAM_ENHANCEMENT
+                /* Allow authmethod information on the auth context */
+		monitor_permit(mon_dispatch, MONITOR_REQ_AUTHMETHOD, 1);
+#endif
 	}
 #ifdef USE_PAM
 	if (options.use_pam)
@@ -868,7 +882,25 @@
 	return (0);
 }
 
+#ifdef PAM_ENHANCEMENT
 int
+mm_answer_authmethod(int sock, Buffer *m)
+{
+	monitor_permit_authentications(1);
+
+	authctxt->authmethod_name = buffer_get_string(m, NULL);
+	debug3("%s: authmethod_name=%s", __func__, authctxt->authmethod_name);
+
+	if (strlen(authctxt->authmethod_name) == 0) {
+		free(authctxt->authmethod_name);
+		authctxt->authmethod_name = NULL;
+	}
+
+	return (0);
+}
+#endif
+
+int
 mm_answer_authpassword(int sock, Buffer *m)
 {
 	static int call_count;
--- orig/monitor.h	Fri Jun 20 15:39:05 2014
+++ new/monitor.h	Fri Jun 20 15:39:05 2014
@@ -70,6 +70,9 @@
 	MONITOR_REQ_PAM_FREE_CTX = 110, MONITOR_ANS_PAM_FREE_CTX = 111,
 	MONITOR_REQ_AUDIT_EVENT = 112, MONITOR_REQ_AUDIT_COMMAND = 113,
 
+#ifdef PAM_ENHANCEMENT
+        MONITOR_REQ_AUTHMETHOD = 114,
+#endif        
 };
 
 struct mm_master;
--- orig/servconf.c	Fri Jun 20 15:39:05 2014
+++ new/servconf.c	Fri Jun 20 15:39:05 2014
@@ -154,6 +154,10 @@
 	options->ip_qos_interactive = -1;
 	options->ip_qos_bulk = -1;
 	options->version_addendum = NULL;
+#ifdef PAM_ENHANCEMENT
+	options->pam_service_name = NULL;
+	options->pam_service_prefix = NULL;
+#endif
 }
 
 void
@@ -303,6 +307,12 @@
 		options->ip_qos_bulk = IPTOS_THROUGHPUT;
 	if (options->version_addendum == NULL)
 		options->version_addendum = xstrdup("");
+
+#ifdef PAM_ENHANCEMENT
+        if (options->pam_service_prefix == NULL)
+                options->pam_service_prefix = _SSH_PAM_SERVICE_PREFIX;
+#endif
+
 	/* Turn privilege separation on by default */
 	if (use_privsep == -1)
 		use_privsep = PRIVSEP_NOSANDBOX;
@@ -351,6 +361,9 @@
 	sKexAlgorithms, sIPQoS, sVersionAddendum,
 	sAuthorizedKeysCommand, sAuthorizedKeysCommandUser,
 	sAuthenticationMethods, sHostKeyAgent,
+#ifdef PAM_ENHANCEMENT
+	sPAMServicePrefix, sPAMServiceName,
+#endif
 	sDeprecated, sUnsupported
 } ServerOpCodes;
 
@@ -482,6 +495,10 @@
 	{ "authorizedkeyscommanduser", sAuthorizedKeysCommandUser, SSHCFG_ALL },
 	{ "versionaddendum", sVersionAddendum, SSHCFG_GLOBAL },
 	{ "authenticationmethods", sAuthenticationMethods, SSHCFG_ALL },
+#ifdef PAM_ENHANCEMENT
+        { "pamserviceprefix", sPAMServicePrefix, SSHCFG_GLOBAL },
+        { "pamservicename", sPAMServiceName, SSHCFG_GLOBAL },
+#endif
 	{ NULL, sBadOption, 0 }
 };
 
@@ -1632,6 +1649,30 @@
 		}
 		return 0;
 
+	case sPAMServicePrefix:
+		arg = strdelim(&cp);
+		if (!arg || *arg == '\0')
+			fatal("%s line %d: Missing argument.",
+			    filename, linenum);
+		if (options->pam_service_name != NULL)
+			fatal("%s line %d: PAMServiceName and PAMServicePrefix"
+			    " are mutually exclusive.", filename, linenum);
+		if (options->pam_service_prefix == NULL)
+			options->pam_service_prefix = xstrdup(arg);
+		break;
+
+	case sPAMServiceName:
+		arg = strdelim(&cp);
+		if (!arg || *arg == '\0')
+			fatal("%s line %d: Missing argument.",
+			    filename, linenum);
+		if (options->pam_service_prefix != NULL)
+			fatal("%s line %d: PAMServiceName and PAMServicePrefix"
+			    " are mutually exclusive.", filename, linenum);
+		if (options->pam_service_name == NULL)
+			options->pam_service_name = xstrdup(arg);
+		break;
+
 	case sDeprecated:
 		logit("%s line %d: Deprecated option %s",
 		    filename, linenum, arg);
--- orig/servconf.h	Fri Jun 20 15:39:05 2014
+++ new/servconf.h	Fri Jun 20 15:39:05 2014
@@ -54,6 +54,10 @@
 /* Magic name for internal sftp-server */
 #define INTERNAL_SFTP_NAME	"internal-sftp"
 
+#ifdef PAM_ENHANCEMENT
+#define _SSH_PAM_SERVICE_PREFIX "sshd"
+#endif
+
 typedef struct {
 	u_int	num_ports;
 	u_int	ports_from_cmdline;
@@ -185,6 +189,12 @@
 
 	u_int	num_auth_methods;
 	char   *auth_methods[MAX_AUTH_METHODS];
+
+#ifdef PAM_ENHANCEMENT
+	char   *pam_service_prefix;
+	char   *pam_service_name;
+#endif
+        
 }       ServerOptions;
 
 /* Information about the incoming connection as used by Match */
--- orig/sshd_config.5	Fri Jun 20 15:39:05 2014
+++ new/sshd_config.5	Fri Jun 20 15:39:05 2014
@@ -868,6 +868,21 @@
 are refused if the number of unauthenticated connections reaches
 .Dq full
 (60).
+.It Cm PAMServiceName
+Specifies the PAM service name for the PAM session. The PAMServiceName and 
+PAMServicePrefix options are mutually exclusive and if both set, sshd does not
+start. If this option is set the service name is the same for all user 
+authentication methods. The option has no default value. See PAMServicePrefix 
+for more information.
+.It Cm PAMServicePrefix
+Specifies the PAM service name prefix for service names used for individual 
+user authentication methods. The default is sshd. The PAMServiceName and 
+PAMServicePrefix options are mutually exclusive and if both set, sshd does not 
+start.
+.Pp
+For example, if this option is set to admincli, the service name for the 
+keyboard-interactive authentication method is admincli-kbdint instead of the 
+default sshd-kbdint.
 .It Cm PasswordAuthentication
 Specifies whether password authentication is allowed.
 The default is
--- orig/sshd.8	Fri Jun 20 15:39:05 2014
+++ new/sshd.8	Fri Jun 20 15:39:05 2014
@@ -951,6 +951,33 @@
 started last).
 The content of this file is not sensitive; it can be world-readable.
 .El
+
+.Sh SECURITY
+sshd uses pam(3PAM) for password and keyboard-interactive methods as well as 
+for account management, session management, and the password management for all
+authentication methods.
+.Pp
+Each SSHv2 userauth type has its own PAM service name:
+
+.Bd -literal -offset 3n
+
+-----------------------------------------------
+| SSHv2 Userauth       | PAM Service Name     |
+-----------------------------------------------
+| none                 | sshd-none            |
+-----------------------------------------------
+| password             | sshd-password        |
+-----------------------------------------------
+| keyboard-interactive | sshd-kbdint          |
+-----------------------------------------------
+| pubkey               | sshd-pubkey          |
+-----------------------------------------------
+| hostbased            | sshd-hostbased       |
+-----------------------------------------------
+| gssapi-with-mic      | sshd-gssapi          |
+-----------------------------------------------
+.Ed
+
 .Sh SEE ALSO
 .Xr scp 1 ,
 .Xr sftp 1 ,