r10066: This is the second in my patches to work on Samba4's kerberos support,

with an aim to make the code simpiler and more correct.

Gone is the old (since the very early Samba 3.0 krb5 days) 'iterate over
all keytypes)' code in gensec_krb5, we now follow the approach used in
gensec_gssapi, and use a keytab.

I have also done a lot of work in the GSSAPI code, to try and reduce
the diff between us and upstream heimdal.  It was becoming hard to
track patches in this code, and I also want this patch (the DCE_STYLE
support) to be in a 'manageable' state for when lha considers it for
merging.  (metze assures me it still has memory leak problems, but
I've started to address some of that).

This patch also includes a simple update of other code to current
heimdal, as well as changes we need for better PAC verification.

On the PAC side of things we now match windows member servers by
checking the name and authtime on an incoming PAC.  Not generating these
right was the cause of the PAC pain, and so now both the main code and
torture test validate this behaviour.

One thing doesn't work with this patch:
 - the sealing of RPC pipes with kerberos, Samba -> Samba seems
broken.  I'm pretty sure this is related to AES, and the need to break
apart the gss_wrap interface.

Andrew Bartlett
(This used to be commit a3aba57c00a9c5318f4706db55d03f64e8bea60c)

2 files changed, 153 insertions, 95 deletions

diff --git a/source4/auth/gensec/gensec_gssapi.c b/source4/auth/gensec/gensec_gssapi.c
index 6316b52bad..c3f7c52085 100644
--- a/source4/auth/gensec/gensec_gssapi.c
+++ b/source4/auth/gensec/gensec_gssapi.c
@@ -118,7 +118,7 @@ static NTSTATUS gensec_gssapi_start(struct gensec_security *gensec_security)
 	/* TODO: Fill in channel bindings */
 	gensec_gssapi_state->input_chan_bindings = GSS_C_NO_CHANNEL_BINDINGS;
 	
-	gensec_gssapi_state->want_flags = 0;
+	gensec_gssapi_state->want_flags = GSS_C_MUTUAL_FLAG;
 	gensec_gssapi_state->got_flags = 0;
 
 	gensec_gssapi_state->session_key = data_blob(NULL, 0);
@@ -388,12 +388,15 @@ static NTSTATUS gensec_gssapi_update(struct gensec_security *gensec_security,
 		
 	}
 
-	*out = data_blob_talloc(out_mem_ctx, output_token.value, output_token.length);
-	gss_release_buffer(&min_stat2, &output_token);
-
 	if (maj_stat == GSS_S_COMPLETE) {
+		*out = data_blob_talloc(out_mem_ctx, output_token.value, output_token.length);
+		gss_release_buffer(&min_stat2, &output_token);
+
 		return NT_STATUS_OK;
 	} else if (maj_stat == GSS_S_CONTINUE_NEEDED) {
+		*out = data_blob_talloc(out_mem_ctx, output_token.value, output_token.length);
+		gss_release_buffer(&min_stat2, &output_token);
+
 		return NT_STATUS_MORE_PROCESSING_REQUIRED;
 	} else {
 		if (maj_stat == GSS_S_FAILURE
@@ -427,12 +430,12 @@ static NTSTATUS gensec_gssapi_wrap(struct gensec_security *gensec_security,
 			    &conf_state,
 			    &output_token);
 	if (GSS_ERROR(maj_stat)) {
-		DEBUG(1, ("GSS Wrap failed: %s\n", 
+		DEBUG(1, ("gensec_gssapi_wrap: GSS Wrap failed: %s\n", 
 			  gssapi_error_string(mem_ctx, maj_stat, min_stat)));
 		return NT_STATUS_ACCESS_DENIED;
 	}
-	*out = data_blob_talloc(mem_ctx, output_token.value, output_token.length);
 
+	*out = data_blob_talloc(mem_ctx, output_token.value, output_token.length);
 	gss_release_buffer(&min_stat, &output_token);
 
 	if (gensec_have_feature(gensec_security, GENSEC_FEATURE_SEAL)
@@ -462,12 +465,12 @@ static NTSTATUS gensec_gssapi_unwrap(struct gensec_security *gensec_security,
 			      &conf_state,
 			      &qop_state);
 	if (GSS_ERROR(maj_stat)) {
-		DEBUG(1, ("GSS UnWrap failed: %s\n", 
+		DEBUG(1, ("gensec_gssapi_unwrap: GSS UnWrap failed: %s\n", 
 			  gssapi_error_string(mem_ctx, maj_stat, min_stat)));
 		return NT_STATUS_ACCESS_DENIED;
 	}
-	*out = data_blob_talloc(mem_ctx, output_token.value, output_token.length);
 
+	*out = data_blob_talloc(mem_ctx, output_token.value, output_token.length);
 	gss_release_buffer(&min_stat, &output_token);
 	
 	if (gensec_have_feature(gensec_security, GENSEC_FEATURE_SEAL)
@@ -506,7 +509,7 @@ static NTSTATUS gensec_gssapi_seal_packet(struct gensec_security *gensec_securit
 			    &conf_state,
 			    &output_token);
 	if (GSS_ERROR(maj_stat)) {
-		DEBUG(1, ("GSS Wrap failed: %s\n", 
+		DEBUG(1, ("gensec_gssapi_seal_packet: GSS Wrap failed: %s\n", 
 			  gssapi_error_string(mem_ctx, maj_stat, min_stat)));
 		return NT_STATUS_ACCESS_DENIED;
 	}
@@ -546,7 +549,7 @@ static NTSTATUS gensec_gssapi_unseal_packet(struct gensec_security *gensec_secur
 	gss_qop_t qop_state;
 	DATA_BLOB in;
 
-	dump_data_pw("gensec_gssapi_seal_packet: sig\n", sig->data, sig->length);
+	dump_data_pw("gensec_gssapi_unseal_packet: sig\n", sig->data, sig->length);
 
 	in = data_blob_talloc(mem_ctx, NULL, sig->length + length);
 
@@ -563,7 +566,7 @@ static NTSTATUS gensec_gssapi_unseal_packet(struct gensec_security *gensec_secur
 			      &conf_state,
 			      &qop_state);
 	if (GSS_ERROR(maj_stat)) {
-		DEBUG(1, ("GSS UnWrap failed: %s\n", 
+		DEBUG(1, ("gensec_gssapi_unseal_packet: GSS UnWrap failed: %s\n", 
 			  gssapi_error_string(mem_ctx, maj_stat, min_stat)));
 		return NT_STATUS_ACCESS_DENIED;
 	}
@@ -688,7 +691,7 @@ static BOOL gensec_gssapi_have_feature(struct gensec_security *gensec_security,
 		}
 	}
 	if (feature & GENSEC_FEATURE_DCE_STYLE) {
-		return True;
+		return gensec_gssapi_state->got_flags & GSS_C_DCE_STYLE;
 	}
 	if (feature & GENSEC_FEATURE_ASYNC_REPLIES) {
 		return True;
@@ -744,15 +747,21 @@ static NTSTATUS gensec_gssapi_session_info(struct gensec_security *gensec_securi
 	struct auth_serversupplied_info *server_info = NULL;
 	struct auth_session_info *session_info = NULL;
 	struct PAC_LOGON_INFO *logon_info;
-	char *p;
-	char *principal;
-	const char *account_name;
-	const char *realm;
 	OM_uint32 maj_stat, min_stat;
 	gss_buffer_desc name_token;
 	gss_buffer_desc pac;
 	krb5_keyblock *keyblock;
+	time_t authtime;
+	krb5_principal principal;
+	char *principal_string;
 	
+	if ((gensec_gssapi_state->gss_oid->length != gss_mech_krb5->length)
+	    || (memcmp(gensec_gssapi_state->gss_oid->elements, gss_mech_krb5->elements, 
+		       gensec_gssapi_state->gss_oid->length) != 0)) {
+		DEBUG(1, ("NO session info available for this mech\n"));
+		return NT_STATUS_INVALID_PARAMETER;
+	}
+		
 	mem_ctx = talloc_named(gensec_gssapi_state, 0, "gensec_gssapi_session_info context"); 
 	NT_STATUS_HAVE_NO_MEMORY(mem_ctx);
 
@@ -764,49 +773,56 @@ static NTSTATUS gensec_gssapi_session_info(struct gensec_security *gensec_securi
 		return NT_STATUS_FOOBAR;
 	}
 
-	principal = talloc_strndup(mem_ctx, name_token.value, name_token.length);
+	principal_string = talloc_strndup(mem_ctx, name_token.value, name_token.length);
 
 	gss_release_buffer(&min_stat, &name_token);
 
-	if (!principal) {
+	if (!principal_string) {
 		talloc_free(mem_ctx);
 		return NT_STATUS_NO_MEMORY;
 	}
 
-	p = strchr(principal, '@');
-	if (p) {
-		*p = '\0';
-		p++;
-		realm = p;
-	} else {
-		realm = lp_realm();
-	}
-	account_name = principal;
-	
 	maj_stat = gss_krb5_copy_service_keyblock(&min_stat, 
 						  gensec_gssapi_state->gssapi_context, 
 						  &keyblock);
 
-	maj_stat = gsskrb5_extract_authz_data_from_sec_context(&min_stat, 
-							       gensec_gssapi_state->gssapi_context, 
-							       KRB5_AUTHDATA_IF_RELEVANT,
-							       &pac);
+	if (maj_stat == 0) {
+		maj_stat = gsskrb5_extract_authtime_from_sec_context(&min_stat,
+								     gensec_gssapi_state->gssapi_context, 
+								     &authtime);
+	}
+
+	if (maj_stat == 0) {
+		maj_stat = gsskrb5_extract_authz_data_from_sec_context(&min_stat, 
+								       gensec_gssapi_state->gssapi_context, 
+								       KRB5_AUTHDATA_IF_RELEVANT,
+								       &pac);
+	}
 	
 	if (maj_stat == 0) {
+		krb5_error_code ret;
 		DATA_BLOB pac_blob = data_blob_talloc(mem_ctx, pac.value, pac.length);
 		pac_blob = unwrap_pac(mem_ctx, &pac_blob);
 		gss_release_buffer(&min_stat, &pac);
+
+		ret = krb5_parse_name(gensec_gssapi_state->smb_krb5_context->krb5_context,
+				      principal_string, &principal);
+		if (ret) {
+			talloc_free(mem_ctx);
+			return NT_STATUS_INVALID_PARAMETER;
+		}
 		
 		/* decode and verify the pac */
 		nt_status = kerberos_pac_logon_info(mem_ctx, &logon_info, pac_blob,
 						    gensec_gssapi_state->smb_krb5_context->krb5_context,
-						    NULL, keyblock);
+						    NULL, keyblock, principal, authtime);
+		krb5_free_principal(gensec_gssapi_state->smb_krb5_context->krb5_context, principal);
 
 		if (NT_STATUS_IS_OK(nt_status)) {
 			union netr_Validation validation;
 			validation.sam3 = &logon_info->info3;
 			nt_status = make_server_info_netlogon_validation(gensec_gssapi_state, 
-									 account_name,
+									 NULL,
 									 3, &validation,
 									 &server_info); 
 			if (!NT_STATUS_IS_OK(nt_status)) {
@@ -819,6 +835,9 @@ static NTSTATUS gensec_gssapi_session_info(struct gensec_security *gensec_securi
 	}
 	
 	if (maj_stat) {
+		krb5_error_code ret;
+		DATA_BLOB user_sess_key = data_blob(NULL, 0);
+		DATA_BLOB lm_sess_key = data_blob(NULL, 0);
 		/* IF we have the PAC - otherwise we need to get this
 		 * data from elsewere - local ldb, or (TODO) lookup of some
 		 * kind... 
@@ -827,12 +846,32 @@ static NTSTATUS gensec_gssapi_session_info(struct gensec_security *gensec_securi
 		 * no PAC present
 		 */
 
-		DATA_BLOB user_sess_key = data_blob(NULL, 0);
-		DATA_BLOB lm_sess_key = data_blob(NULL, 0);
-		/* TODO: should we pass the krb5 session key in here? */
+		char *account_name;
+		const char *realm;
+		ret = krb5_parse_name(gensec_gssapi_state->smb_krb5_context->krb5_context,
+				      principal_string, &principal);
+		if (ret) {
+			talloc_free(mem_ctx);
+			return NT_STATUS_INVALID_PARAMETER;
+		}
+		
+		realm = krb5_principal_get_realm(gensec_gssapi_state->smb_krb5_context->krb5_context, 
+						 principal);
+		ret = krb5_unparse_name_norealm(gensec_gssapi_state->smb_krb5_context->krb5_context, 
+						principal, &account_name);
+		if (ret) {
+			krb5_free_principal(gensec_gssapi_state->smb_krb5_context->krb5_context, principal);
+			talloc_free(mem_ctx);
+			return NT_STATUS_NO_MEMORY;
+		}
+
+		DEBUG(1, ("Unable to use PAC, resorting to local user lookup!\n"));
 		nt_status = sam_get_server_info(mem_ctx, account_name, realm,
 						user_sess_key, lm_sess_key,
 						&server_info);
+		free(account_name);
+		krb5_free_principal(gensec_gssapi_state->smb_krb5_context->krb5_context, principal);
+
 		if (!NT_STATUS_IS_OK(nt_status)) {
 			talloc_free(mem_ctx);
 			return nt_status;
@@ -841,6 +880,7 @@ static NTSTATUS gensec_gssapi_session_info(struct gensec_security *gensec_securi
 
 	/* references the server_info into the session_info */
 	nt_status = auth_generate_session_info(gensec_gssapi_state, server_info, &session_info);
+	talloc_free(mem_ctx);
 	talloc_free(server_info);
 	NT_STATUS_NOT_OK_RETURN(nt_status);
 
diff --git a/source4/auth/gensec/gensec_krb5.c b/source4/auth/gensec/gensec_krb5.c
index 09722af10b..d4147496fd 100644
--- a/source4/auth/gensec/gensec_krb5.c
+++ b/source4/auth/gensec/gensec_krb5.c
@@ -45,19 +45,25 @@ struct gensec_krb5_state {
 	enum GENSEC_KRB5_STATE state_position;
 	struct smb_krb5_context *smb_krb5_context;
 	krb5_auth_context auth_context;
-	krb5_data ticket;
+	krb5_data enc_ticket;
 	krb5_keyblock *keyblock;
-	char *peer_principal;
+	krb5_ticket *ticket;
 };
 
 static int gensec_krb5_destory(void *ptr) 
 {
 	struct gensec_krb5_state *gensec_krb5_state = ptr;
 
-	if (gensec_krb5_state->ticket.length) { 
+	if (gensec_krb5_state->enc_ticket.length) { 
 		kerberos_free_data_contents(gensec_krb5_state->smb_krb5_context->krb5_context, 
-					    &gensec_krb5_state->ticket); 
+					    &gensec_krb5_state->enc_ticket); 
 	}
+
+	if (gensec_krb5_state->ticket) {
+		krb5_free_ticket(gensec_krb5_state->smb_krb5_context->krb5_context, 
+				 gensec_krb5_state->ticket);
+	}
+
 	/* ccache freed in a child destructor */
 
 	krb5_free_keyblock(gensec_krb5_state->smb_krb5_context->krb5_context, 
@@ -83,8 +89,9 @@ static NTSTATUS gensec_krb5_start(struct gensec_security *gensec_security)
 	gensec_security->private_data = gensec_krb5_state;
 
 	gensec_krb5_state->auth_context = NULL;
-	ZERO_STRUCT(gensec_krb5_state->ticket);
-	ZERO_STRUCT(gensec_krb5_state->keyblock);
+	gensec_krb5_state->ticket = NULL;
+	ZERO_STRUCT(gensec_krb5_state->enc_ticket);
+	gensec_krb5_state->keyblock = NULL;
 	gensec_krb5_state->session_key = data_blob(NULL, 0);
 	gensec_krb5_state->pac = data_blob(NULL, 0);
 
@@ -114,6 +121,14 @@ static NTSTATUS gensec_krb5_server_start(struct gensec_security *gensec_security
 		return NT_STATUS_INTERNAL_ERROR;
 	}
 
+	ret = krb5_auth_con_init(gensec_krb5_state->smb_krb5_context->krb5_context, &gensec_krb5_state->auth_context);
+	if (ret) {
+		DEBUG(1,("gensec_krb5_start: krb5_auth_con_init failed (%s)\n", 
+			 smb_get_krb5_error_message(gensec_krb5_state->smb_krb5_context->krb5_context, 
+						    ret, gensec_krb5_state)));
+		return NT_STATUS_INTERNAL_ERROR;
+	}
+
 	gensec_krb5_state = gensec_security->private_data;
 	gensec_krb5_state->state_position = GENSEC_KRB5_SERVER_START;
 
@@ -173,7 +188,7 @@ static NTSTATUS gensec_krb5_client_start(struct gensec_security *gensec_security
 				  gensec_get_target_service(gensec_security),
 				  hostname,
 				  &in_data, ccache_container->ccache, 
-				  &gensec_krb5_state->ticket);
+				  &gensec_krb5_state->enc_ticket);
 		
 	}
 	switch (ret) {
@@ -249,31 +264,23 @@ static NTSTATUS gensec_krb5_update(struct gensec_security *gensec_security,
 {
 	struct gensec_krb5_state *gensec_krb5_state = gensec_security->private_data;
 	krb5_error_code ret = 0;
-	DATA_BLOB pac;
 	NTSTATUS nt_status;
 
 	switch (gensec_krb5_state->state_position) {
 	case GENSEC_KRB5_CLIENT_START:
 	{
-		if (ret) {
-			DEBUG(1,("ads_krb5_mk_req (request ticket) failed (%s)\n",
-				 smb_get_krb5_error_message(gensec_krb5_state->smb_krb5_context->krb5_context, ret, out_mem_ctx)));
-			nt_status = NT_STATUS_LOGON_FAILURE;
-		} else {
-			DATA_BLOB unwrapped_out;
-
+		DATA_BLOB unwrapped_out;
+		
 #ifndef GENSEC_SEND_UNWRAPPED_KRB5 /* This should be a switch for the torture code to set */
-			unwrapped_out = data_blob_talloc(out_mem_ctx, gensec_krb5_state->ticket.data, gensec_krb5_state->ticket.length);
-			
-			/* wrap that up in a nice GSS-API wrapping */
-			*out = gensec_gssapi_gen_krb5_wrap(out_mem_ctx, &unwrapped_out, TOK_ID_KRB_AP_REQ);
+		unwrapped_out = data_blob_talloc(out_mem_ctx, gensec_krb5_state->enc_ticket.data, gensec_krb5_state->enc_ticket.length);
+		
+		/* wrap that up in a nice GSS-API wrapping */
+		*out = gensec_gssapi_gen_krb5_wrap(out_mem_ctx, &unwrapped_out, TOK_ID_KRB_AP_REQ);
 #else
-			*out = data_blob_talloc(out_mem_ctx, gensec_krb5_state->ticket.data, gensec_krb5_state->ticket.length);
+		*out = data_blob_talloc(out_mem_ctx, gensec_krb5_state->ticket.data, gensec_krb5_state->ticket.length);
 #endif
-			gensec_krb5_state->state_position = GENSEC_KRB5_CLIENT_MUTUAL_AUTH;
-			nt_status = NT_STATUS_MORE_PROCESSING_REQUIRED;
-		}
-		
+		gensec_krb5_state->state_position = GENSEC_KRB5_CLIENT_MUTUAL_AUTH;
+		nt_status = NT_STATUS_MORE_PROCESSING_REQUIRED;
 		return nt_status;
 	}
 		
@@ -314,7 +321,6 @@ static NTSTATUS gensec_krb5_update(struct gensec_security *gensec_security,
 
 	case GENSEC_KRB5_SERVER_START:
 	{
-		char *principal;
 		DATA_BLOB unwrapped_in;
 		DATA_BLOB unwrapped_out = data_blob(NULL, 0);
 		uint8_t tok_id[2];
@@ -328,20 +334,20 @@ static NTSTATUS gensec_krb5_update(struct gensec_security *gensec_security,
 		if (!gensec_gssapi_parse_krb5_wrap(out_mem_ctx, &in, &unwrapped_in, tok_id)) {
 			nt_status = ads_verify_ticket(out_mem_ctx, 
 						      gensec_krb5_state->smb_krb5_context,
-						      gensec_krb5_state->auth_context, 
+						      &gensec_krb5_state->auth_context, 
 						      lp_realm(), 
 						      gensec_get_target_service(gensec_security), &in, 
-						      &principal, &pac, &unwrapped_out,
+						      &gensec_krb5_state->ticket, &unwrapped_out,
 						      &gensec_krb5_state->keyblock);
 		} else {
 			/* TODO: check the tok_id */
 			nt_status = ads_verify_ticket(out_mem_ctx, 
 						      gensec_krb5_state->smb_krb5_context,
-						      gensec_krb5_state->auth_context, 
+						      &gensec_krb5_state->auth_context, 
 						      lp_realm(), 
 						      gensec_get_target_service(gensec_security), 
 						      &unwrapped_in, 
-						      &principal, &pac, &unwrapped_out,
+						      &gensec_krb5_state->ticket, &unwrapped_out,
 						      &gensec_krb5_state->keyblock);
 		}
 
@@ -349,10 +355,6 @@ static NTSTATUS gensec_krb5_update(struct gensec_security *gensec_security,
 			return nt_status;
 		}
 
-		if (pac.data) {
-			gensec_krb5_state->pac = data_blob_talloc_reference(gensec_krb5_state, &pac);
-		}
-
 		if (NT_STATUS_IS_OK(nt_status)) {
 			gensec_krb5_state->state_position = GENSEC_KRB5_DONE;
 			/* wrap that up in a nice GSS-API wrapping */
@@ -361,7 +363,6 @@ static NTSTATUS gensec_krb5_update(struct gensec_security *gensec_security,
 #else
 			*out = unwrapped_out;
 #endif
-			gensec_krb5_state->peer_principal = talloc_steal(gensec_krb5_state, principal);
 		}
 		return nt_status;
 	}
@@ -418,28 +419,29 @@ static NTSTATUS gensec_krb5_session_info(struct gensec_security *gensec_security
 	struct auth_serversupplied_info *server_info = NULL;
 	struct auth_session_info *session_info = NULL;
 	struct PAC_LOGON_INFO *logon_info;
-	char *p;
-	char *principal;
-	const char *account_name;
-	const char *realm;
-
-	principal = talloc_strdup(gensec_krb5_state, gensec_krb5_state->peer_principal);
-	NT_STATUS_HAVE_NO_MEMORY(principal);
-
-	p = strchr(principal, '@');
-	if (p) {
-		*p = '\0';
-		p++;
-		realm = p;
-	} else {
-		realm = lp_realm();
+
+	krb5_const_principal client_principal;
+	
+	DATA_BLOB pac_wrapped;
+	DATA_BLOB pac;
+
+	TALLOC_CTX *mem_ctx = talloc_new(gensec_security);
+	if (!mem_ctx) {
+		return NT_STATUS_NO_MEMORY;
 	}
-	account_name = principal;
+
+	pac_wrapped = get_auth_data_from_tkt(mem_ctx, gensec_krb5_state->ticket);
+
+	pac = unwrap_pac(mem_ctx, &pac_wrapped);
+
+	client_principal = get_principal_from_tkt(gensec_krb5_state->ticket);
 
 	/* decode and verify the pac */
-	nt_status = kerberos_pac_logon_info(gensec_krb5_state, &logon_info, gensec_krb5_state->pac,
+	nt_status = kerberos_pac_logon_info(gensec_krb5_state, &logon_info, pac,
 					    gensec_krb5_state->smb_krb5_context->krb5_context,
-					    NULL, gensec_krb5_state->keyblock);
+					    NULL, gensec_krb5_state->keyblock,
+					    client_principal,
+					    gensec_krb5_state->ticket->ticket.authtime);
 
 	/* IF we have the PAC - otherwise we need to get this
 	 * data from elsewere - local ldb, or (TODO) lookup of some
@@ -453,25 +455,41 @@ static NTSTATUS gensec_krb5_session_info(struct gensec_security *gensec_security
 		union netr_Validation validation;
 		validation.sam3 = &logon_info->info3;
 		nt_status = make_server_info_netlogon_validation(gensec_krb5_state, 
-								 account_name,
+								 NULL,
 								 3, &validation,
 								 &server_info); 
-		talloc_free(principal);
+		talloc_free(mem_ctx);
 		NT_STATUS_NOT_OK_RETURN(nt_status);
 	} else {
+		krb5_error_code ret;
 		DATA_BLOB user_sess_key = data_blob(NULL, 0);
 		DATA_BLOB lm_sess_key = data_blob(NULL, 0);
+
+		char *account_name;
+		const char *realm = krb5_principal_get_realm(gensec_krb5_state->smb_krb5_context->krb5_context, 
+							     get_principal_from_tkt(gensec_krb5_state->ticket));
+		ret = krb5_unparse_name_norealm(gensec_krb5_state->smb_krb5_context->krb5_context, 
+						get_principal_from_tkt(gensec_krb5_state->ticket), &account_name);
+		if (ret) {
+			return NT_STATUS_NO_MEMORY;
+		}
+
 		/* TODO: should we pass the krb5 session key in here? */
-		nt_status = sam_get_server_info(gensec_krb5_state, account_name, realm,
+		nt_status = sam_get_server_info(mem_ctx, account_name, realm,
 						user_sess_key, lm_sess_key,
 						&server_info);
-		talloc_free(principal);
-		NT_STATUS_NOT_OK_RETURN(nt_status);
+		free(account_name);
+		
+		if (!NT_STATUS_IS_OK(nt_status)) {
+			talloc_free(mem_ctx);
+			return nt_status;
+		}
 	}
 
 	/* references the server_info into the session_info */
 	nt_status = auth_generate_session_info(gensec_krb5_state, server_info, &session_info);
-	talloc_free(server_info);
+	talloc_free(mem_ctx);
+
 	NT_STATUS_NOT_OK_RETURN(nt_status);
 
 	nt_status = gensec_krb5_session_key(gensec_security, &session_info->session_key);