diff -up openssh-6.6p1/auth2.c.expose-auth openssh-6.6p1/auth2.c

--- openssh-6.6p1/auth2.c.expose-auth	2016-06-27 12:19:39.134443822 +0200

+++ openssh-6.6p1/auth2.c	2016-06-27 12:19:39.178443747 +0200

@@ -309,6 +309,7 @@ userauth_finish(Authctxt *authctxt, int

     const char *submethod)

 {

 	char *methods;

+	char *prev_auth_details;

 	int partial = 0;

 	if (!authctxt->valid && authenticated)

@@ -339,6 +340,18 @@ userauth_finish(Authctxt *authctxt, int

 	if (authctxt->postponed)

 		return;

+	if (authenticated || partial) {

+		prev_auth_details = authctxt->auth_details;

+		xasprintf(&authctxt->auth_details, "%s%s%s%s%s",

+		    prev_auth_details ? prev_auth_details : "",

+		    prev_auth_details ? ", " : "", method,

+		    authctxt->last_details ? ": " : "",

+		    authctxt->last_details ? authctxt->last_details : "");

+		free(authctxt->last_details);

+		authctxt->last_details = NULL;

+		free(prev_auth_details);

+	}

+

 #ifdef USE_PAM

 	if (options.use_pam && authenticated) {

 		if (!PRIVSEP(do_pam_account())) {

diff -up openssh-6.6p1/auth2-gss.c.expose-auth openssh-6.6p1/auth2-gss.c

--- openssh-6.6p1/auth2-gss.c.expose-auth	2016-06-27 12:19:39.102443877 +0200

+++ openssh-6.6p1/auth2-gss.c	2016-06-27 12:19:39.179443745 +0200

@@ -272,6 +272,9 @@ input_gssapi_exchange_complete(int type,

 	authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user,

 	    authctxt->pw));

+	if (authenticated)

+		authctxt->last_details = ssh_gssapi_get_displayname();

+

 	authctxt->postponed = 0;

 	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);

 	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, NULL);

@@ -317,6 +320,9 @@ input_gssapi_mic(int type, u_int32_t ple

 	else

 		logit("GSSAPI MIC check failed");

+	if (authenticated)

+		authctxt->last_details = ssh_gssapi_get_displayname();

+

 	buffer_free(&b);

 	if (micuser != authctxt->user)

 		free(micuser);

diff -up openssh-6.6p1/auth2-hostbased.c.expose-auth openssh-6.6p1/auth2-hostbased.c

--- openssh-6.6p1/auth2-hostbased.c.expose-auth	2016-06-27 12:19:39.051443964 +0200

+++ openssh-6.6p1/auth2-hostbased.c	2016-06-27 12:19:39.179443745 +0200

@@ -58,7 +58,7 @@ userauth_hostbased(Authctxt *authctxt)

 {

 	Buffer b;

 	Key *key = NULL;

-	char *pkalg, *cuser, *chost, *service;

+	char *pkalg, *cuser, *chost, *service, *pubkey;

 	u_char *pkblob, *sig;

 	u_int alen, blen, slen;

 	int pktype;

@@ -131,15 +131,21 @@ userauth_hostbased(Authctxt *authctxt)

 	buffer_dump(&b);

 #endif

-	pubkey_auth_info(authctxt, key,

-	    "client user \"%.100s\", client host \"%.100s\"", cuser, chost);

+	pubkey = key_format_oneline(key);

+	auth_info(authctxt,

+	    "%s, client user \"%.100s\", client host \"%.100s\"",

+	    pubkey, cuser, chost);

 	/* test for allowed key and correct signature */

 	authenticated = 0;

 	if (PRIVSEP(hostbased_key_allowed(authctxt->pw, cuser, chost, key)) &&

 	    PRIVSEP(key_verify(key, sig, slen, buffer_ptr(&b),

-			buffer_len(&b))) == 1)

+			buffer_len(&b))) == 1) {

 		authenticated = 1;

+		authctxt->last_details = pubkey;

+	} else {

+		free(pubkey);

+	}

 	buffer_free(&b);

 done:

diff -up openssh-6.6p1/auth2-pubkey.c.expose-auth openssh-6.6p1/auth2-pubkey.c

--- openssh-6.6p1/auth2-pubkey.c.expose-auth	2016-06-27 12:19:39.068443935 +0200

+++ openssh-6.6p1/auth2-pubkey.c	2016-06-27 12:19:39.179443745 +0200

@@ -75,7 +75,7 @@ userauth_pubkey(Authctxt *authctxt)

 {

 	Buffer b;

 	Key *key = NULL;

-	char *pkalg, *userstyle;

+	char *pkalg, *userstyle, *pubkey;

 	u_char *pkblob, *sig;

 	u_int alen, blen, slen;

 	int have_sig, pktype;

@@ -155,14 +155,19 @@ userauth_pubkey(Authctxt *authctxt)

 #ifdef DEBUG_PK

 		buffer_dump(&b);

 #endif

-		pubkey_auth_info(authctxt, key, NULL);

+		pubkey = key_format_oneline(key);

+		auth_info(authctxt, "%s", pubkey);

 		/* test for correct signature */

 		authenticated = 0;

 		if (PRIVSEP(user_key_allowed(authctxt->pw, key)) &&

 		    PRIVSEP(key_verify(key, sig, slen, buffer_ptr(&b),

-		    buffer_len(&b))) == 1)

+		    buffer_len(&b))) == 1) {

+			authctxt->last_details = pubkey;

 			authenticated = 1;

+		} else {

+			free(pubkey);

+ 		}

 		buffer_free(&b);

 		free(sig);

 	} else {

@@ -200,7 +205,7 @@ done:

 void

 pubkey_auth_info(Authctxt *authctxt, const Key *key, const char *fmt, ...)

 {

-	char *fp, *extra;

+	char *extra, *pubkey;

 	va_list ap;

 	int i;

@@ -210,24 +215,13 @@ pubkey_auth_info(Authctxt *authctxt, con

 		i = vasprintf(&extra, fmt, ap);

 		va_end(ap);

 		if (i < 0 || extra == NULL)

-			fatal("%s: vasprintf failed", __func__);	

+			fatal("%s: vasprintf failed", __func__);

 	}

-	if (key_is_cert(key)) {

-		fp = key_fingerprint(key->cert->signature_key,

-		    SSH_FP_MD5, SSH_FP_HEX);

-		auth_info(authctxt, "%s ID %s (serial %llu) CA %s %s%s%s", 

-		    key_type(key), key->cert->key_id,

-		    (unsigned long long)key->cert->serial,

-		    key_type(key->cert->signature_key), fp,

-		    extra == NULL ? "" : ", ", extra == NULL ? "" : extra);

-		free(fp);

-	} else {

-		fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX);

-		auth_info(authctxt, "%s %s%s%s", key_type(key), fp,

-		    extra == NULL ? "" : ", ", extra == NULL ? "" : extra);

-		free(fp);

-	}

+	pubkey = key_format_oneline(key);

+	auth_info(authctxt, "%s%s%s", pubkey, extra == NULL ? "" : ", ",

+	    extra == NULL ? "" : extra);

+	free(pubkey);

 	free(extra);

 }

diff -up openssh-6.6p1/auth.h.expose-auth openssh-6.6p1/auth.h

--- openssh-6.6p1/auth.h.expose-auth	2016-06-27 12:19:39.144443805 +0200

+++ openssh-6.6p1/auth.h	2016-06-27 12:19:39.179443745 +0200

@@ -78,6 +78,9 @@ struct Authctxt {

 #endif

 	Buffer		*loginmsg;

 	void		*methoddata;

+

+	char		*last_details;

+	char		*auth_details;

 };

 /*

  * Every authentication method has to handle authentication requests for

diff -up openssh-6.6p1/auth-pam.c.expose-auth openssh-6.6p1/auth-pam.c

--- openssh-6.6p1/auth-pam.c.expose-auth	2016-06-27 12:19:39.049443967 +0200

+++ openssh-6.6p1/auth-pam.c	2016-06-27 12:19:39.179443745 +0200

@@ -688,6 +688,11 @@ sshpam_init_ctx(Authctxt *authctxt)

 		return (NULL);

 	}

+	/* Notify PAM about any already successful auth methods */

+	if (options.expose_auth_methods >= EXPOSE_AUTHMETH_PAMONLY &&

+			authctxt->auth_details)

+		do_pam_putenv("SSH_USER_AUTH", authctxt->auth_details);

+

 	ctxt = xcalloc(1, sizeof *ctxt);

 	/* Start the authentication thread */

diff -up openssh-6.6p1/gss-serv.c.expose-auth openssh-6.6p1/gss-serv.c

--- openssh-6.6p1/gss-serv.c.expose-auth	2016-06-27 12:19:39.160443778 +0200

+++ openssh-6.6p1/gss-serv.c	2016-06-27 12:19:39.180443743 +0200

@@ -471,6 +471,16 @@ ssh_gssapi_userok(char *user, struct pas

 	return (0);

 }

+/* Privileged */

+char*

+ssh_gssapi_get_displayname(void)

+{

+	if (gssapi_client.displayname.length != 0 &&

+	    gssapi_client.displayname.value != NULL)

+		return strdup((char *)gssapi_client.displayname.value);

+	return NULL;

+}

+

 /* These bits are only used for rekeying. The unpriviledged child is running 

  * as the user, the monitor is root.

  *

diff -up openssh-6.6p1/key.c.expose-auth openssh-6.6p1/key.c

--- openssh-6.6p1/key.c.expose-auth	2016-06-27 12:19:39.105443872 +0200

+++ openssh-6.6p1/key.c	2016-06-27 12:19:39.180443743 +0200

@@ -57,6 +57,7 @@

 #include "misc.h"

 #include "ssh2.h"

 #include "digest.h"

+#include "xmalloc.h"

 static int to_blob(const Key *, u_char **, u_int *, int);

 static Key *key_from_blob2(const u_char *, u_int, int);

@@ -628,6 +629,30 @@ key_fingerprint(const Key *k, enum fp_ty

 	return retval;

 }

+char *

+key_format_oneline(const Key *key)

+{

+	char *fp, *result;

+

+	if (key_is_cert(key)) {

+		fp = key_fingerprint(key->cert->signature_key, SSH_FP_MD5,

+		    SSH_FP_HEX);

+		xasprintf(&result, "%s ID %s (serial %llu) CA %s %s",

+		    key_type(key), key->cert->key_id,

+		    (unsigned long long)key->cert->serial,

+		    key_type(key->cert->signature_key),

+		    fp == NULL ? "(null)" : fp);

+		free(fp);

+	} else {

+		fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX);

+		xasprintf(&result, "%s %s", key_type(key),

+		    fp == NULL ? "(null)" : fp);

+		free(fp);

+	}

+

+	return result;

+}

+

 enum fp_type

 key_fingerprint_selection(void)

 {

diff -up openssh-6.6p1/key.h.expose-auth openssh-6.6p1/key.h

--- openssh-6.6p1/key.h.expose-auth	2016-06-27 12:19:43.322436657 +0200

+++ openssh-6.6p1/key.h	2016-06-27 12:20:25.898363835 +0200

@@ -108,6 +108,7 @@ u_char		*key_fingerprint_raw(const Key *

 enum fp_type	 key_fingerprint_selection(void);

 char		*key_selected_fingerprint(Key *, enum fp_rep);

 char		*key_fingerprint_prefix(void);

+char		*key_format_oneline(const Key *k);

 const char	*key_type(const Key *);

 const char	*key_cert_type(const Key *);

 int		 key_write(const Key *, FILE *);

diff -up openssh-6.6p1/monitor.c.expose-auth openssh-6.6p1/monitor.c

--- openssh-6.6p1/monitor.c.expose-auth	2016-06-27 12:19:39.165443769 +0200

+++ openssh-6.6p1/monitor.c	2016-06-27 12:19:39.180443743 +0200

@@ -357,6 +357,7 @@ monitor_child_preauth(Authctxt *_authctx

 {

 	struct mon_table *ent;

 	int authenticated = 0, partial = 0;

+	char *prev_auth_details;

 	debug3("preauth child monitor started");

@@ -394,6 +395,18 @@ monitor_child_preauth(Authctxt *_authctx

 		auth_submethod = NULL;

 		authenticated = (monitor_read(pmonitor, mon_dispatch, &ent) == 1);

+		if (authenticated) {

+			prev_auth_details = authctxt->auth_details;

+			xasprintf(&authctxt->auth_details, "%s%s%s%s%s",

+			    prev_auth_details ? prev_auth_details : "",

+			    prev_auth_details ? ", " : "", auth_method,

+			    authctxt->last_details ? ": " : "",

+			    authctxt->last_details ? authctxt->last_details : "");

+			free(authctxt->last_details);

+			authctxt->last_details = NULL;

+			free(prev_auth_details);

+		}

+

 		/* Special handling for multiple required authentications */

 		if (options.num_auth_methods != 0) {

 			if (!compat20)

@@ -1432,6 +1445,9 @@ mm_answer_keyverify(int sock, Buffer *m)

 	debug3("%s: key %p signature %s",

 	    __func__, key, (verified == 1) ? "verified" : "unverified");

+	if (verified == 1)

+		authctxt->last_details = key_format_oneline(key);

+

 	key_free(key);

 	free(blob);

 	free(signature);

@@ -2224,6 +2240,9 @@ mm_answer_gss_userok(int sock, Buffer *m

 	auth_method = "gssapi-with-mic";

+	if (authenticated)

+		authctxt->last_details = ssh_gssapi_get_displayname();

+

 	/* Monitor loop will terminate if authenticated */

 	return (authenticated);

 }

diff -up openssh-6.6p1/servconf.c.expose-auth openssh-6.6p1/servconf.c

--- openssh-6.6p1/servconf.c.expose-auth	2016-06-27 12:19:39.177443748 +0200

+++ openssh-6.6p1/servconf.c	2016-06-27 12:19:39.181443742 +0200

@@ -161,6 +161,7 @@ initialize_server_options(ServerOptions

 	options->version_addendum = NULL;

 	options->use_kuserok = -1;

 	options->enable_k5users = -1;

+	options->expose_auth_methods = -1;

 }

 void

@@ -322,6 +323,8 @@ fill_default_server_options(ServerOption

 		options->use_kuserok = 1;

 	if (options->enable_k5users == -1)

 		options->enable_k5users = 0;

+	if (options->expose_auth_methods == -1)

+		options->expose_auth_methods = EXPOSE_AUTHMETH_NEVER;

 	/* Turn privilege separation on by default */

 	if (use_privsep == -1)

@@ -380,6 +383,7 @@ typedef enum {

 	sKexAlgorithms, sIPQoS, sVersionAddendum,

 	sAuthorizedKeysCommand, sAuthorizedKeysCommandUser,

 	sAuthenticationMethods, sHostKeyAgent,

+	sExposeAuthenticationMethods,

 	sDeprecated, sUnsupported

 } ServerOpCodes;

@@ -523,6 +527,7 @@ static struct {

 	{ "authorizedkeyscommanduser", sAuthorizedKeysCommandUser, SSHCFG_ALL },

 	{ "versionaddendum", sVersionAddendum, SSHCFG_GLOBAL },

 	{ "authenticationmethods", sAuthenticationMethods, SSHCFG_ALL },

+	{ "exposeauthenticationmethods", sExposeAuthenticationMethods, SSHCFG_ALL },

 	{ NULL, sBadOption, 0 }

 };

@@ -869,6 +874,12 @@ static const struct multistate multistat

 	{ "local",			FORWARD_LOCAL },

 	{ NULL, -1 }

 };

+static const struct multistate multistate_exposeauthmeth[] = {

+	{ "never",			EXPOSE_AUTHMETH_NEVER },

+	{ "pam-only",			EXPOSE_AUTHMETH_PAMONLY },

+	{ "pam-and-env",		EXPOSE_AUTHMETH_PAMENV },

+	{ NULL, -1}

+};

 int

 process_server_config_line(ServerOptions *options, char *line,

@@ -1727,6 +1738,11 @@ process_server_config_line(ServerOptions

 		}

 		return 0;

+	case sExposeAuthenticationMethods:

+		intptr = &options->expose_auth_methods;

+		multistate_ptr = multistate_exposeauthmeth;

+		goto parse_multistate;

+

 	case sDeprecated:

 		logit("%s line %d: Deprecated option %s",

 		    filename, linenum, arg);

@@ -1883,6 +1899,7 @@ copy_set_server_options(ServerOptions *d

 	M_CP_INTOPT(enable_k5users);

 	M_CP_INTOPT(rekey_limit);

 	M_CP_INTOPT(rekey_interval);

+	M_CP_INTOPT(expose_auth_methods);

 	/* M_CP_STROPT and M_CP_STRARRAYOPT should not appear before here */

 #define M_CP_STROPT(n) do {\

@@ -1971,6 +1988,8 @@ fmt_intarg(ServerOpCodes code, int val)

 		return fmt_multistate_int(val, multistate_privsep);

 	case sAllowTcpForwarding:

 		return fmt_multistate_int(val, multistate_tcpfwd);

+	case sExposeAuthenticationMethods:

+		return fmt_multistate_int(val, multistate_exposeauthmeth);

 	case sProtocol:

 		switch (val) {

 		case SSH_PROTO_1:

@@ -2182,6 +2201,7 @@ dump_config(ServerOptions *o)

 	dump_cfg_strarray(sAcceptEnv, o->num_accept_env, o->accept_env);

 	dump_cfg_strarray_oneline(sAuthenticationMethods,

 	    o->num_auth_methods, o->auth_methods);

+	dump_cfg_fmtint(sExposeAuthenticationMethods, o->expose_auth_methods);

 	/* other arguments */

 	for (i = 0; i < o->num_subsystems; i++)

diff -up openssh-6.6p1/servconf.h.expose-auth openssh-6.6p1/servconf.h

--- openssh-6.6p1/servconf.h.expose-auth	2016-06-27 12:19:39.162443774 +0200

+++ openssh-6.6p1/servconf.h	2016-06-27 12:19:39.181443742 +0200

@@ -48,6 +48,11 @@

 #define FORWARD_LOCAL		(1<<1)

 #define FORWARD_ALLOW		(FORWARD_REMOTE|FORWARD_LOCAL)

+/* Expose AuthenticationMethods */

+#define EXPOSE_AUTHMETH_NEVER   0

+#define EXPOSE_AUTHMETH_PAMONLY 1

+#define EXPOSE_AUTHMETH_PAMENV  2

+

 #define DEFAULT_AUTH_FAIL_MAX	6	/* Default for MaxAuthTries */

 #define DEFAULT_SESSIONS_MAX	10	/* Default for MaxSessions */

@@ -190,6 +195,8 @@ typedef struct {

 	u_int	num_auth_methods;

 	char   *auth_methods[MAX_AUTH_METHODS];

+

+	int	expose_auth_methods; /* EXPOSE_AUTHMETH_* above */

 }       ServerOptions;

 /* Information about the incoming connection as used by Match */

diff -up openssh-6.6p1/session.c.expose-auth openssh-6.6p1/session.c

--- openssh-6.6p1/session.c.expose-auth	2016-06-27 12:19:39.171443759 +0200

+++ openssh-6.6p1/session.c	2016-06-27 12:19:39.181443742 +0200

@@ -1196,6 +1196,12 @@ copy_environment(char **source, char ***

 		}

 		*var_val++ = '\0';

+		if (options.expose_auth_methods < EXPOSE_AUTHMETH_PAMENV &&

+				strcmp(var_name, "SSH_USER_AUTH") == 0) {

+			free(var_name);

+			continue;

+		}

+

 		debug3("Copy environment: %s=%s", var_name, var_val);

 		child_set_env(env, envsize, var_name, var_val);

@@ -1375,6 +1381,11 @@ do_setup_env(Session *s, const char *she

 	}

 #endif /* USE_PAM */

+	if (options.expose_auth_methods >= EXPOSE_AUTHMETH_PAMENV &&

+			s->authctxt->auth_details)

+		child_set_env(&env, &envsize, "SSH_USER_AUTH",

+		     s->authctxt->auth_details);

+

 	if (auth_sock_name != NULL)

 		child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME,

 		    auth_sock_name);

@@ -2805,6 +2816,9 @@ do_cleanup(Authctxt *authctxt)

 	if (authctxt == NULL)

 		return;

+	free(authctxt->auth_details);

+	authctxt->auth_details = NULL;

+

 #ifdef USE_PAM

 	if (options.use_pam) {

 		sshpam_cleanup();

diff -up openssh-6.6p1/ssh.1.expose-auth openssh-6.6p1/ssh.1

--- openssh-6.6p1/ssh.1.expose-auth	2016-06-27 12:19:39.163443772 +0200

+++ openssh-6.6p1/ssh.1	2016-06-27 12:19:39.181443742 +0200

@@ -1289,6 +1289,10 @@ server IP address, and server port numbe

 This variable contains the original command line if a forced command

 is executed.

 It can be used to extract the original arguments.

+.It Ev SSH_USER_AUTH

+This variable contains, for SSH2 only, a comma-separated list of authentication

+methods that were successfuly used to authenticate. When possible, these

+methods are extended with detailed information on the credential used.

 .It Ev SSH_TTY

 This is set to the name of the tty (path to the device) associated

 with the current shell or command.

diff -up openssh-6.6p1/sshd_config.5.expose-auth openssh-6.6p1/sshd_config.5

--- openssh-6.6p1/sshd_config.5.expose-auth	2016-06-27 12:19:39.177443748 +0200

+++ openssh-6.6p1/sshd_config.5	2016-06-27 12:19:39.182443740 +0200

@@ -466,6 +466,21 @@ is allowed to log in.

 See PATTERNS in

 .Xr ssh_config 5

 for more information on patterns.

+.It Cm ExposeAuthenticationMethods

+When using SSH2, this option controls the exposure of the list of

+successful authentication methods to PAM during the authentication

+and to the shell environment via the

+.Cm SSH_USER_AUTH

+variable. See the description of this variable for more details.

+Valid options are:

+.Dq never

+(Do not expose successful authentication methods),

+.Dq pam-only

+(Only expose them to PAM during authentication, not afterwards),

+.Dq pam-and-env

+(Expose them to PAM and keep them in the shell environment).

+The default is

+.Dq never .

 .It Cm ForceCommand

 Forces the execution of the command specified by

 .Cm ForceCommand ,

diff -up openssh-6.6p1/ssh-gss.h.expose-auth openssh-6.6p1/ssh-gss.h

--- openssh-6.6p1/ssh-gss.h.expose-auth	2016-06-27 12:19:39.163443772 +0200

+++ openssh-6.6p1/ssh-gss.h	2016-06-27 12:19:39.182443740 +0200

@@ -160,6 +160,7 @@ int ssh_gssapi_server_check_mech(Gssctxt

     const char *);

 OM_uint32 ssh_gssapi_server_ctx(Gssctxt **, gss_OID);

 int ssh_gssapi_userok(char *name, struct passwd *);

+char* ssh_gssapi_get_displayname(void);

 OM_uint32 ssh_gssapi_checkmic(Gssctxt *, gss_buffer_t, gss_buffer_t);

 void ssh_gssapi_do_child(char ***, u_int *);

 void ssh_gssapi_cleanup_creds(void);