Merge branch 'ike-sig-contraints'

Signature scheme constraints against IKEv2 authentication may now be
configured independently of constraints against trustchains.

NEWS

@@ -7,6 +7,10 @@ strongswan-5.4.0
   on different selectors via VICI/swanctl.  Unless disabled in strongswan.conf
   the charon daemon will follow redirect requests received from servers.
 
+- The ike: prefix enables the explicit configuration of signature scheme
+  constraints against IKEv2 authentication in rightauth, which allows the use
+  of different signature schemes for trustchain verification and authentication.
+
 - For the vici plugin a Vici:Session Perl CPAN module has been added to allow
   Perl applications to control and/or monitor the IKE daemon using the VICI
   interface, similar to the existing Python egg or Ruby gem.

man/ipsec.conf.5.in

@@ -587,18 +587,23 @@ or a key strength definition (for example
 or
 .BR rsa-2048-ecdsa-256-sha256-sha384-sha512 ).
 Unless disabled in
-.BR strongswan.conf (5)
-such key types and hash algorithms are also applied as constraints against IKEv2
+.BR strongswan.conf (5),
+or explicit IKEv2 signature constraints are configured (see below), such key
+types and hash algorithms are also applied as constraints against IKEv2
 signature authentication schemes used by the remote side.
 
 If both peers support RFC 7427 ("Signature Authentication in IKEv2") specific
 hash algorithms to be used during IKEv2 authentication may be configured.
-The syntax is the same as above. For example, with
-.B pubkey-sha384-sha256
+The syntax is the same as above, but with ike: prefix. For example, with
+.B ike:pubkey-sha384-sha256
 a public key signature scheme with either SHA-384 or SHA-256 would get used for
 authentication, in that order and depending on the hash algorithms supported by
 the peer.  If no specific hash algorithms are configured, the default is to
 prefer an algorithm that matches or exceeds the strength of the signature key.
+If no constraints with ike: prefix are configured any signature scheme
+constraint (without ike: prefix) will also apply to IKEv2 authentication, unless
+this is disabled in
+.BR strongswan.conf (5).
 
 For
 .BR eap ,

src/libcharon/plugins/stroke/stroke_config.c

@@ -506,14 +506,15 @@ static auth_cfg_t *build_auth_cfg(private_stroke_config_t *this,
 	}
 
 	/* authentication metod (class, actually) */
-	if (strpfx(auth, "pubkey") ||
+	if (strpfx(auth, "ike:") ||
+		strpfx(auth, "pubkey") ||
 		strpfx(auth, "rsa") ||
 		strpfx(auth, "ecdsa") ||
 		strpfx(auth, "bliss"))
 	{
 		cfg->add(cfg, AUTH_RULE_AUTH_CLASS, AUTH_CLASS_PUBKEY);
 		build_crl_policy(cfg, local, msg->add_conn.crl_policy);
-		cfg->add_pubkey_constraints(cfg, auth);
+		cfg->add_pubkey_constraints(cfg, auth, TRUE);
 	}
 	else if (streq(auth, "psk") || streq(auth, "secret"))
 	{
@@ -546,7 +547,7 @@ static auth_cfg_t *build_auth_cfg(private_stroke_config_t *this,
 		if (pos)
 		{
 			*pos = 0;
-			cfg->add_pubkey_constraints(cfg, pos + 1);
+			cfg->add_pubkey_constraints(cfg, pos + 1, FALSE);
 		}
 		type = eap_vendor_type_from_string(auth);
 		if (type)

src/libcharon/plugins/vici/vici_config.c

@@ -955,13 +955,14 @@ CALLBACK(parse_auth, bool,
 	{
 		return FALSE;
 	}
-	if (strpfx(buf, "pubkey") ||
+	if (strpfx(buf, "ike:") ||
+		strpfx(buf, "pubkey") ||
 		strpfx(buf, "rsa") ||
 		strpfx(buf, "ecdsa") ||
 		strpfx(buf, "bliss"))
 	{
 		cfg->add(cfg, AUTH_RULE_AUTH_CLASS, AUTH_CLASS_PUBKEY);
-		cfg->add_pubkey_constraints(cfg, buf);
+		cfg->add_pubkey_constraints(cfg, buf, TRUE);
 		return TRUE;
 	}
 	if (strcaseeq(buf, "psk"))
@@ -981,8 +982,16 @@ CALLBACK(parse_auth, bool,
 	}
 	if (strcasepfx(buf, "eap"))
 	{
+		char *pos;
+
 		cfg->add(cfg, AUTH_RULE_AUTH_CLASS, AUTH_CLASS_EAP);
 
+		pos = strchr(buf, ':');
+		if (pos)
+		{
+			*pos = 0;
+			cfg->add_pubkey_constraints(cfg, pos + 1, FALSE);
+		}
 		type = eap_vendor_type_from_string(buf);
 		if (type)
 		{

src/libcharon/sa/ikev2/authenticators/pubkey_authenticator.c

@@ -55,11 +55,6 @@ struct private_pubkey_authenticator_t {
 	 * Reserved bytes of ID payload
 	 */
 	char reserved[3];
-
-	/**
-	 * Whether to store signature schemes on remote auth configs.
-	 */
-	bool store_signature_scheme;
 };
 
 /**
@@ -130,7 +125,7 @@ static array_t *select_signature_schemes(keymat_v2_t *keymat,
 	enumerator = auth->create_enumerator(auth);
 	while (enumerator->enumerate(enumerator, &rule, &config))
 	{
-		if (rule != AUTH_RULE_SIGNATURE_SCHEME)
+		if (rule != AUTH_RULE_IKE_SIGNATURE_SCHEME)
 		{
 			continue;
 		}
@@ -425,10 +420,7 @@ METHOD(authenticator_t, process, status_t,
 			status = SUCCESS;
 			auth->merge(auth, current_auth, FALSE);
 			auth->add(auth, AUTH_RULE_AUTH_CLASS, AUTH_CLASS_PUBKEY);
-			if (this->store_signature_scheme)
-			{
-				auth->add(auth, AUTH_RULE_SIGNATURE_SCHEME, (uintptr_t)scheme);
-			}
+			auth->add(auth, AUTH_RULE_IKE_SIGNATURE_SCHEME, (uintptr_t)scheme);
 			break;
 		}
 		else
@@ -501,8 +493,6 @@ pubkey_authenticator_t *pubkey_authenticator_create_verifier(ike_sa_t *ike_sa,
 		.ike_sa = ike_sa,
 		.ike_sa_init = received_init,
 		.nonce = sent_nonce,
-		.store_signature_scheme = lib->settings->get_bool(lib->settings,
-					"%s.signature_authentication_constraints", TRUE, lib->ns),
 	);
 	memcpy(this->reserved, reserved, sizeof(this->reserved));
 

src/libcharon/sa/ikev2/tasks/ike_init.c

@@ -171,7 +171,7 @@ static void send_supported_hash_algorithms(private_ike_init_t *this,
 			enumerator = auth->create_enumerator(auth);
 			while (enumerator->enumerate(enumerator, &rule, &config))
 			{
-				if (rule == AUTH_RULE_SIGNATURE_SCHEME)
+				if (rule == AUTH_RULE_IKE_SIGNATURE_SCHEME)
 				{
 					hash = hasher_from_signature_scheme(config);
 					if (hasher_algorithm_for_ikev2(hash))

src/libstrongswan/credentials/auth_cfg.c

@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2008-2015 Tobias Brunner
+ * Copyright (C) 2008-2016 Tobias Brunner
  * Copyright (C) 2007-2009 Martin Willi
  * Hochschule fuer Technik Rapperswil
  *
@@ -51,6 +51,7 @@ ENUM(auth_rule_names, AUTH_RULE_IDENTITY, AUTH_HELPER_AC_CERT,
 	"RULE_ECDSA_STRENGTH",
 	"RULE_BLISS_STRENGTH",
 	"RULE_SIGNATURE_SCHEME",
+	"RULE_IKE_SIGNATURE_SCHEME",
 	"RULE_CERT_POLICY",
 	"HELPER_IM_CERT",
 	"HELPER_SUBJECT_CERT",
@@ -91,6 +92,7 @@ static inline bool is_multi_value_rule(auth_rule_t type)
 		case AUTH_RULE_IM_CERT:
 		case AUTH_RULE_CERT_POLICY:
 		case AUTH_RULE_SIGNATURE_SCHEME:
+		case AUTH_RULE_IKE_SIGNATURE_SCHEME:
 		case AUTH_HELPER_IM_CERT:
 		case AUTH_HELPER_IM_HASH_URL:
 		case AUTH_HELPER_REVOCATION_CERT:
@@ -211,6 +213,7 @@ static void init_entry(entry_t *this, auth_rule_t type, va_list args)
 		case AUTH_RULE_ECDSA_STRENGTH:
 		case AUTH_RULE_BLISS_STRENGTH:
 		case AUTH_RULE_SIGNATURE_SCHEME:
+		case AUTH_RULE_IKE_SIGNATURE_SCHEME:
 			/* integer type */
 			this->value = (void*)(uintptr_t)va_arg(args, u_int);
 			break;
@@ -260,6 +263,7 @@ static bool entry_equals(entry_t *e1, entry_t *e2)
 		case AUTH_RULE_ECDSA_STRENGTH:
 		case AUTH_RULE_BLISS_STRENGTH:
 		case AUTH_RULE_SIGNATURE_SCHEME:
+		case AUTH_RULE_IKE_SIGNATURE_SCHEME:
 		{
 			return e1->value == e2->value;
 		}
@@ -351,6 +355,7 @@ static void destroy_entry_value(entry_t *entry)
 		case AUTH_RULE_ECDSA_STRENGTH:
 		case AUTH_RULE_BLISS_STRENGTH:
 		case AUTH_RULE_SIGNATURE_SCHEME:
+		case AUTH_RULE_IKE_SIGNATURE_SCHEME:
 		case AUTH_RULE_MAX:
 			break;
 	}
@@ -383,6 +388,7 @@ static void replace(private_auth_cfg_t *this, entry_enumerator_t *enumerator,
 			case AUTH_RULE_ECDSA_STRENGTH:
 			case AUTH_RULE_BLISS_STRENGTH:
 			case AUTH_RULE_SIGNATURE_SCHEME:
+			case AUTH_RULE_IKE_SIGNATURE_SCHEME:
 				/* integer type */
 				entry->value = (void*)(uintptr_t)va_arg(args, u_int);
 				break;
@@ -459,6 +465,7 @@ METHOD(auth_cfg_t, get, void*,
 		case AUTH_RULE_BLISS_STRENGTH:
 			return (void*)0;
 		case AUTH_RULE_SIGNATURE_SCHEME:
+		case AUTH_RULE_IKE_SIGNATURE_SCHEME:
 			return (void*)HASH_UNKNOWN;
 		case AUTH_RULE_CRL_VALIDATION:
 		case AUTH_RULE_OCSP_VALIDATION:
@@ -511,13 +518,16 @@ static void add(private_auth_cfg_t *this, auth_rule_t type, ...)
 }
 
 METHOD(auth_cfg_t, add_pubkey_constraints, void,
-	private_auth_cfg_t *this, char* constraints)
+	private_auth_cfg_t *this, char* constraints, bool ike)
 {
 	enumerator_t *enumerator;
-	bool rsa = FALSE, ecdsa = FALSE, bliss = FALSE,
-		 rsa_len = FALSE, ecdsa_len = FALSE, bliss_strength = FALSE;
+	bool is_ike = FALSE, ike_added = FALSE;
+	key_type_t expected_type = -1;
+	auth_rule_t expected_strength = AUTH_RULE_MAX;
 	int strength;
 	char *token;
+	auth_rule_t type;
+	void *value;
 
 	enumerator = enumerator_create_token(constraints, "-", "");
 	while (enumerator->enumerate(enumerator, &token))
@@ -547,46 +557,47 @@ METHOD(auth_cfg_t, add_pubkey_constraints, void,
 			{ "sha512",		SIGN_BLISS_WITH_SHA2_512,		KEY_BLISS,	},
 		};
 
-		if (rsa_len || ecdsa_len || bliss_strength)
+		if (expected_strength != AUTH_RULE_MAX)
 		{	/* expecting a key strength token */
 			strength = atoi(token);
 			if (strength)
 			{
-				if (rsa_len)
-				{
-					add(this, AUTH_RULE_RSA_STRENGTH, (uintptr_t)strength);
-				}
-				else if (ecdsa_len)
-				{
-					add(this, AUTH_RULE_ECDSA_STRENGTH, (uintptr_t)strength);
-				}
-				else if (bliss_strength)
-				{
-					add(this, AUTH_RULE_BLISS_STRENGTH, (uintptr_t)strength);
-				}
+				add(this, expected_strength, (uintptr_t)strength);
 			}
-			rsa_len = ecdsa_len = bliss_strength = FALSE;
+			expected_strength = AUTH_RULE_MAX;
 			if (strength)
 			{
 				continue;
 			}
 		}
-		if (streq(token, "rsa"))
+		if (streq(token, "rsa") || streq(token, "ike:rsa"))
 		{
-			rsa = rsa_len = TRUE;
+			expected_type = KEY_RSA;
+			expected_strength = AUTH_RULE_RSA_STRENGTH;
+			is_ike = strpfx(token, "ike:");
 			continue;
 		}
-		if (streq(token, "ecdsa"))
+		if (streq(token, "ecdsa") || streq(token, "ike:ecdsa"))
 		{
-			ecdsa = ecdsa_len = TRUE;
+			expected_type = KEY_ECDSA;
+			expected_strength = AUTH_RULE_ECDSA_STRENGTH;
+			is_ike = strpfx(token, "ike:");
 			continue;
 		}
-		if (streq(token, "bliss"))
+		if (streq(token, "bliss") || streq(token, "ike:bliss"))
 		{
-			bliss = bliss_strength = TRUE;
+			expected_type = KEY_BLISS;
+			expected_strength = AUTH_RULE_BLISS_STRENGTH;
+			is_ike = strpfx(token, "ike:");
 			continue;
 		}
-		if (streq(token, "pubkey"))
+		if (streq(token, "pubkey") || streq(token, "ike:pubkey"))
+		{
+			expected_type = KEY_ANY;
+			is_ike = strpfx(token, "ike:");
+			continue;
+		}
+		if (is_ike && !ike)
 		{
 			continue;
 		}
@@ -595,18 +606,19 @@ METHOD(auth_cfg_t, add_pubkey_constraints, void,
 		{
 			if (streq(schemes[i].name, token))
 			{
-				/* for each matching string, allow the scheme, if:
-				 * - it is an RSA scheme, and we enforced RSA
-				 * - it is an ECDSA scheme, and we enforced ECDSA
-				 * - it is not a key type specific scheme
-				 */
-				if ((rsa && schemes[i].key == KEY_RSA) ||
-					(ecdsa && schemes[i].key == KEY_ECDSA) ||
-					(bliss && schemes[i].key == KEY_BLISS) ||
-					(!rsa && !ecdsa && !bliss))
+				if (expected_type == KEY_ANY || expected_type == schemes[i].key)
 				{
-					add(this, AUTH_RULE_SIGNATURE_SCHEME,
-					   (uintptr_t)schemes[i].scheme);
+					if (is_ike)
+					{
+						add(this, AUTH_RULE_IKE_SIGNATURE_SCHEME,
+							(uintptr_t)schemes[i].scheme);
+						ike_added = TRUE;
+					}
+					else
+					{
+						add(this, AUTH_RULE_SIGNATURE_SCHEME,
+						   (uintptr_t)schemes[i].scheme);
+					}
 				}
 				found = TRUE;
 			}
@@ -617,6 +629,69 @@ METHOD(auth_cfg_t, add_pubkey_constraints, void,
 		}
 	}
 	enumerator->destroy(enumerator);
+
+	/* if no explicit IKE signature contraints were added we add them for all
+	 * configured signature contraints */
+	if (ike && !ike_added &&
+		lib->settings->get_bool(lib->settings,
+							"%s.signature_authentication_constraints", TRUE,
+							lib->ns))
+	{
+		enumerator = create_enumerator(this);
+		while (enumerator->enumerate(enumerator, &type, &value))
+		{
+			if (type == AUTH_RULE_SIGNATURE_SCHEME)
+			{
+				add(this, AUTH_RULE_IKE_SIGNATURE_SCHEME,
+					(uintptr_t)value);
+			}
+		}
+		enumerator->destroy(enumerator);
+	}
+}
+
+/**
+ * Check if signature schemes of a specific type are compliant
+ */
+static bool complies_scheme(private_auth_cfg_t *this, auth_cfg_t *constraints,
+							auth_rule_t type, bool log_error)
+{
+	enumerator_t *e1, *e2;
+	auth_rule_t t1, t2;
+	signature_scheme_t scheme;
+	void *value;
+	bool success = TRUE;
+
+	e2 = create_enumerator(this);
+	while (e2->enumerate(e2, &t2, &scheme))
+	{
+		if (t2 == type)
+		{
+			success = FALSE;
+			e1 = constraints->create_enumerator(constraints);
+			while (e1->enumerate(e1, &t1, &value))
+			{
+				if (t1 == type && (uintptr_t)value == scheme)
+				{
+					success = TRUE;
+					break;
+				}
+			}
+			e1->destroy(e1);
+			if (!success)
+			{
+				if (log_error)
+				{
+					DBG1(DBG_CFG, "%s signature scheme %N not acceptable",
+						 AUTH_RULE_SIGNATURE_SCHEME == type ? "X.509" : "IKE",
+						 signature_scheme_names, (int)scheme);
+				}
+				break;
+			}
+		}
+	}
+	e2->destroy(e2);
+	return success;
 }
 
 METHOD(auth_cfg_t, complies, bool,
@@ -627,7 +702,7 @@ METHOD(auth_cfg_t, complies, bool,
 	bool ca_match = FALSE, cert_match = FALSE;
 	identification_t *require_group = NULL;
 	certificate_t *require_ca = NULL, *require_cert = NULL;
-	signature_scheme_t scheme = SIGN_UNKNOWN;
+	signature_scheme_t ike_scheme = SIGN_UNKNOWN, scheme = SIGN_UNKNOWN;
 	u_int strength = 0;
 	auth_rule_t t1, t2;
 	char *key_type;
@@ -823,6 +898,11 @@ METHOD(auth_cfg_t, complies, bool,
 				strength = (uintptr_t)value;
 				break;
 			}
+			case AUTH_RULE_IKE_SIGNATURE_SCHEME:
+			{
+				ike_scheme = (uintptr_t)value;
+				break;
+			}
 			case AUTH_RULE_SIGNATURE_SCHEME:
 			{
 				scheme = (uintptr_t)value;
@@ -875,35 +955,13 @@ METHOD(auth_cfg_t, complies, bool,
 	 * signature schemes. */
 	if (success && scheme != SIGN_UNKNOWN)
 	{
-		e2 = create_enumerator(this);
-		while (e2->enumerate(e2, &t2, &scheme))
-		{
-			if (t2 == AUTH_RULE_SIGNATURE_SCHEME)
-			{
-				success = FALSE;
-				e1 = constraints->create_enumerator(constraints);
-				while (e1->enumerate(e1, &t1, &value))
-				{
-					if (t1 == AUTH_RULE_SIGNATURE_SCHEME &&
-						(uintptr_t)value == scheme)
-					{
-						success = TRUE;
-						break;
-					}
-				}
-				e1->destroy(e1);
-				if (!success)
-				{
-					if (log_error)
-					{
-						DBG1(DBG_CFG, "signature scheme %N not acceptable",
-							 signature_scheme_names, (int)scheme);
-					}
-					break;
-				}
-			}
-		}
-		e2->destroy(e2);
+		success = complies_scheme(this, constraints,
+								  AUTH_RULE_SIGNATURE_SCHEME, log_error);
+	}
+	if (success && ike_scheme != SIGN_UNKNOWN)
+	{
+		success = complies_scheme(this, constraints,
+								  AUTH_RULE_IKE_SIGNATURE_SCHEME, log_error);
 	}
 
 	/* Check if we have a matching constraint (or none at all) for used
@@ -1027,6 +1085,7 @@ static void merge(private_auth_cfg_t *this, private_auth_cfg_t *other, bool copy
 				case AUTH_RULE_ECDSA_STRENGTH:
 				case AUTH_RULE_BLISS_STRENGTH:
 				case AUTH_RULE_SIGNATURE_SCHEME:
+				case AUTH_RULE_IKE_SIGNATURE_SCHEME:
 				{
 					add(this, type, (uintptr_t)value);
 					break;
@@ -1197,6 +1256,7 @@ METHOD(auth_cfg_t, clone_, auth_cfg_t*,
 			case AUTH_RULE_ECDSA_STRENGTH:
 			case AUTH_RULE_BLISS_STRENGTH:
 			case AUTH_RULE_SIGNATURE_SCHEME:
+			case AUTH_RULE_IKE_SIGNATURE_SCHEME:
 				clone->add(clone, type, (uintptr_t)value);
 				break;
 			case AUTH_RULE_MAX:

src/libstrongswan/credentials/auth_cfg.h

@@ -106,6 +106,8 @@ enum auth_rule_t {
 	AUTH_RULE_BLISS_STRENGTH,
 	/** required signature scheme, signature_scheme_t */
 	AUTH_RULE_SIGNATURE_SCHEME,
+	/** required signature scheme for IKE authentication, signature_scheme_t */
+	AUTH_RULE_IKE_SIGNATURE_SCHEME,
 	/** certificatePolicy constraint, numerical OID as char* */
 	AUTH_RULE_CERT_POLICY,
 
@@ -185,8 +187,10 @@ struct auth_cfg_t {
 	 * Add public key and signature scheme constraints to the set.
 	 *
 	 * @param constraints	constraints string (e.g. "rsa-sha384")
+	 * @param ike			whether to add/parse constraints for IKE signatures
 	 */
-	void (*add_pubkey_constraints)(auth_cfg_t *this, char *constraints);
+	void (*add_pubkey_constraints)(auth_cfg_t *this, char *constraints,
+								   bool ike);
 
 	/**
 	 * Get a rule value.

src/libstrongswan/tests/Makefile.am

@@ -44,6 +44,7 @@ tests_SOURCES = tests.h tests.c \
   suites/test_certpolicy.c \
   suites/test_certnames.c \
   suites/test_host.c \
+  suites/test_auth_cfg.c \
   suites/test_hasher.c \
   suites/test_crypter.c \
   suites/test_crypto_factory.c \

src/libstrongswan/tests/suites/test_auth_cfg.c

@@ -0,0 +1,122 @@
+/*
+ * Copyright (C) 2016 Tobias Brunner
+ * Hochschule fuer Technik Rapperswil
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * for more details.
+ */
+
+#include "test_suite.h"
+
+#include <credentials/auth_cfg.h>
+
+struct {
+	char *constraints;
+	signature_scheme_t sig[5];
+	signature_scheme_t ike[5];
+} sig_constraints_tests[] = {
+	{ "rsa-sha256", { SIGN_RSA_EMSA_PKCS1_SHA256, 0 }, {0}},
+	{ "rsa-sha256-sha512", { SIGN_RSA_EMSA_PKCS1_SHA256, SIGN_RSA_EMSA_PKCS1_SHA512, 0 }, {0}},
+	{ "ecdsa-sha256", { SIGN_ECDSA_WITH_SHA256_DER, SIGN_ECDSA_256, 0 }, {0}},
+	{ "rsa-sha256-ecdsa-sha256", { SIGN_RSA_EMSA_PKCS1_SHA256, SIGN_ECDSA_WITH_SHA256_DER, SIGN_ECDSA_256, 0 }, {0}},
+	{ "pubkey-sha256", { SIGN_RSA_EMSA_PKCS1_SHA256, SIGN_ECDSA_WITH_SHA256_DER, SIGN_ECDSA_256, SIGN_BLISS_WITH_SHA2_256, 0 }, {0}},
+	{ "ike:rsa-sha256", {0}, { SIGN_RSA_EMSA_PKCS1_SHA256, 0 }},
+	{ "ike:rsa-sha256-rsa-sha256", { SIGN_RSA_EMSA_PKCS1_SHA256, 0 }, { SIGN_RSA_EMSA_PKCS1_SHA256, 0 }},
+	{ "rsa-sha256-ike:rsa-sha256", { SIGN_RSA_EMSA_PKCS1_SHA256, 0 }, { SIGN_RSA_EMSA_PKCS1_SHA256, 0 }},
+	{ "ike:pubkey-sha256", {0}, { SIGN_RSA_EMSA_PKCS1_SHA256, SIGN_ECDSA_WITH_SHA256_DER, SIGN_ECDSA_256, SIGN_BLISS_WITH_SHA2_256, 0 }},
+	{ "rsa-ecdsa-sha256", { SIGN_ECDSA_WITH_SHA256_DER, SIGN_ECDSA_256, 0 }, {0}},
+	{ "rsa-4096-ecdsa-sha256", { SIGN_ECDSA_WITH_SHA256_DER, SIGN_ECDSA_256, 0 }, {0}},
+	{ "rsa-4096-ecdsa-256-sha256", { SIGN_ECDSA_WITH_SHA256_DER, SIGN_ECDSA_256, 0 }, {0}},
+	{ "rsa-ecdsa256-sha256", { SIGN_RSA_EMSA_PKCS1_SHA256, 0 }, {0}},
+	{ "rsa4096-sha256", {0}, {0}},
+	{ "sha256", {0}, {0}},
+	{ "ike:sha256", {0}, {0}},
+};
+
+static void check_sig_constraints(auth_cfg_t *cfg, auth_rule_t type,
+								  signature_scheme_t expected[])
+{
+	enumerator_t *enumerator;
+	auth_rule_t t;
+	void *value;
+	int i = 0;
+
+	enumerator = cfg->create_enumerator(cfg);
+	while (enumerator->enumerate(enumerator, &t, &value))
+	{
+		if (t == type)
+		{
+			ck_assert(expected[i]);
+			ck_assert_int_eq(expected[i], (signature_scheme_t)value);
+			i++;
+		}
+	}
+	enumerator->destroy(enumerator);
+	ck_assert(!expected[i]);
+}
+
+START_TEST(test_sig_contraints)
+{
+	auth_cfg_t *cfg;
+	signature_scheme_t none[] = {0};
+
+	cfg = auth_cfg_create();
+	cfg->add_pubkey_constraints(cfg, sig_constraints_tests[_i].constraints, FALSE);
+	check_sig_constraints(cfg, AUTH_RULE_SIGNATURE_SCHEME, sig_constraints_tests[_i].sig);
+	check_sig_constraints(cfg, AUTH_RULE_IKE_SIGNATURE_SCHEME, none);
+	cfg->destroy(cfg);
+
+	lib->settings->set_bool(lib->settings, "%s.signature_authentication_constraints",
+							FALSE, lib->ns);
+
+	cfg = auth_cfg_create();
+	cfg->add_pubkey_constraints(cfg, sig_constraints_tests[_i].constraints, TRUE);
+	check_sig_constraints(cfg, AUTH_RULE_SIGNATURE_SCHEME, sig_constraints_tests[_i].sig);
+	check_sig_constraints(cfg, AUTH_RULE_IKE_SIGNATURE_SCHEME, sig_constraints_tests[_i].ike);
+	cfg->destroy(cfg);
+}
+END_TEST
+
+START_TEST(test_ike_contraints_fallback)
+{
+	auth_cfg_t *cfg;
+
+	lib->settings->set_bool(lib->settings, "%s.signature_authentication_constraints",
+							TRUE, lib->ns);
+
+	cfg = auth_cfg_create();
+	cfg->add_pubkey_constraints(cfg, sig_constraints_tests[_i].constraints, TRUE);
+	check_sig_constraints(cfg, AUTH_RULE_SIGNATURE_SCHEME, sig_constraints_tests[_i].sig);
+	if (sig_constraints_tests[_i].ike[0])
+	{
+		check_sig_constraints(cfg, AUTH_RULE_IKE_SIGNATURE_SCHEME, sig_constraints_tests[_i].ike);
+	}
+	else
+	{
+		check_sig_constraints(cfg, AUTH_RULE_IKE_SIGNATURE_SCHEME, sig_constraints_tests[_i].sig);
+	}
+	cfg->destroy(cfg);
+}
+END_TEST
+
+Suite *auth_cfg_suite_create()
+{
+	Suite *s;
+	TCase *tc;
+
+	s = suite_create("auth_cfg");
+
+	tc = tcase_create("add_pubkey_constraints");
+	tcase_add_loop_test(tc, test_sig_contraints, 0, countof(sig_constraints_tests));
+	tcase_add_loop_test(tc, test_ike_contraints_fallback, 0, countof(sig_constraints_tests));
+	suite_add_tcase(s, tc);
+
+	return s;
+}

src/libstrongswan/tests/tests.h

@@ -37,6 +37,7 @@ TEST_SUITE_DEPEND(certpolicy_suite_create, CERT_ENCODE, CERT_X509)
 TEST_SUITE_DEPEND(certnames_suite_create, CERT_ENCODE, CERT_X509)
 TEST_SUITE(host_suite_create)
 TEST_SUITE(printf_suite_create)
+TEST_SUITE(auth_cfg_suite_create)
 TEST_SUITE(hasher_suite_create)
 TEST_SUITE(crypter_suite_create)
 TEST_SUITE(crypto_factory_suite_create)

src/swanctl/swanctl.opt

@@ -309,6 +309,19 @@ connections.<conn>.local<suffix>.auth = pubkey
 	An EAP module implementing the appropriate method is selected to perform
 	the EAP conversation.
 
+	If both peers support RFC 7427 ("Signature Authentication in IKEv2")
+	specific hash algorithms to be used during IKEv2 authentication may be
+	configured. To do so use _ike:_ followed by a trust chain signature scheme
+	constraint (see description of the **remote** section's **auth** keyword).
+	For example, with _ike:pubkey-sha384-sha256_ a public key signature scheme
+	with either SHA-384 or SHA-256 would get used for authentication, in that
+	order and depending on the hash algorithms supported by the peer. If no
+	specific hash algorithms are configured, the default is to prefer an
+	algorithm that matches or exceeds the strength of the signature key.
+	If no constraints with _ike:_ prefix are configured any signature scheme
+	constraint (without _ike:_ prefix) will also apply to IKEv2 authentication,
+	unless this is disabled in **strongswan.conf**(5).
+
 connections.<conn>.local<suffix>.id =
 	IKE identity to use for authentication round.
 
@@ -415,9 +428,25 @@ connections.<conn>.remote<suffix>.auth = pubkey
 	Authentication to expect from remote (_pubkey_, _psk_, _xauth[-backend]_ or
 	_eap[-method]_).
 
-	Authentication to expect from remote. See the **local** sections **auth**
+	Authentication to expect from remote. See the **local** section's **auth**
 	keyword description about the details of supported mechanisms.
 
+	To require a trustchain public key strength for the remote side, specify the
+	key type followed by the minimum strength in bits (for example _ecdsa-384_
+	or _rsa-2048-ecdsa-256_). To limit the acceptable set of hashing algorithms
+	for trustchain validation, append hash algorithms to _pubkey_ or a key
+	strength definition (for example _pubkey-sha1-sha256_ or
+	_rsa-2048-ecdsa-256-sha256-sha384-sha512_).
+	Unless disabled in **strongswan.conf**(5), or explicit IKEv2 signature
+	constraints are configured (refer to the description of the **local**
+	section's **auth** keyword for details), such key types and hash algorithms
+	are also applied as constraints against IKEv2 signature authentication
+	schemes used by the remote side.
+
+	To specify trust chain constraints for EAP-(T)TLS, append a colon to the
+	EAP method, followed by the key type/size and hash algorithm as discussed
+	above (e.g. _eap-tls:ecdsa-384-sha384_).
+
 connections.<conn>.children.<child> {}
 	CHILD_SA configuration sub-section.