merged EAP framework from branch into trunk

includes a lot of other modifications

src/libstrongswan/crypto/hashers/hasher.h

@@ -122,10 +122,24 @@ struct hasher_t {
 	 */
 	void (*reset) (hasher_t *this);
 	
+	/**
+	 * @brief Get the state of the hasher.
+	 *
+	 * A hasher stores internal state information. This state may be
+	 * manipulated to include a "seed" into the hashing operation. It used by
+	 * some exotic protocols (such as AKA).
+	 * The data pointed by chunk may be manipulated, but not replaced nor freed.
+	 * This is more a hack than a feature. The hasher's state may be byte
+	 * order dependant; use with care.
+	 *
+	 * @param this			calling object
+	 */
+	chunk_t (*get_state) (hasher_t *this);
+	
 	/**
 	 * @brief Destroys a hasher object.
 	 *
-	 * @param this 	calling object
+	 * @param this 			calling object
 	 */
 	void (*destroy) (hasher_t *this);
 };

src/libstrongswan/crypto/hashers/md5_hasher.c

@@ -363,6 +363,19 @@ static void reset(private_md5_hasher_t *this)
 	this->count[1] = 0;
 }
 
+/**
+ * Implementation of hasher_t.get_state
+ */
+static chunk_t get_state(private_md5_hasher_t *this)
+{
+	chunk_t chunk;
+	
+	chunk.ptr = (u_char*)&this->state[0];
+	chunk.len = sizeof(this->state);
+	
+	return chunk;
+}
+
 /**
  * Implementation of hasher_t.destroy.
  */
@@ -382,6 +395,7 @@ md5_hasher_t *md5_hasher_create(void)
 	this->public.hasher_interface.allocate_hash = (void (*) (hasher_t*, chunk_t, chunk_t*))allocate_hash;
 	this->public.hasher_interface.get_hash_size = (size_t (*) (hasher_t*))get_hash_size;
 	this->public.hasher_interface.reset = (void (*) (hasher_t*))reset;
+	this->public.hasher_interface.get_state = (chunk_t (*) (hasher_t*))get_state;
 	this->public.hasher_interface.destroy = (void (*) (hasher_t*))destroy;
 	
 	/* initialize */

src/libstrongswan/crypto/hashers/sha1_hasher.c

@@ -223,7 +223,7 @@ static size_t get_hash_size(private_sha1_hasher_t *this)
 {
 	return HASH_SIZE_SHA1;
 }
-	
+
 /**
  * Implementation of hasher_t.reset.
  */
@@ -237,6 +237,20 @@ static void reset(private_sha1_hasher_t *this)
     this->count[0] = 0;
     this->count[1] = 0;
 }
+
+/**
+ * Implementation of hasher_t.get_state
+ */
+static chunk_t get_state(private_sha1_hasher_t *this)
+{
+	chunk_t chunk;
+	
+	chunk.ptr = (u_char*)&this->state[0];
+	chunk.len = sizeof(this->state);
+	
+	return chunk;
+}
+
 /**
  * Implementation of hasher_t.destroy.
  */
@@ -256,6 +270,7 @@ sha1_hasher_t *sha1_hasher_create(void)
 	this->public.hasher_interface.allocate_hash = (void (*) (hasher_t*, chunk_t, chunk_t*))allocate_hash;
 	this->public.hasher_interface.get_hash_size = (size_t (*) (hasher_t*))get_hash_size;
 	this->public.hasher_interface.reset = (void (*) (hasher_t*))reset;
+	this->public.hasher_interface.get_state = (chunk_t (*) (hasher_t*))get_state;
 	this->public.hasher_interface.destroy = (void (*) (hasher_t*))destroy;
 	
 	/* initialize */

src/libstrongswan/crypto/hashers/sha2_hasher.c

@@ -586,6 +586,38 @@ static void reset512(private_sha512_hasher_t *ctx)
 	ctx->sha_bufCnt = 0;
 }
 
+/**
+ * Implementation of hasher_t.get_state for SHA256
+ */
+static chunk_t get_state256(private_sha256_hasher_t *ctx)
+{
+	chunk_t chunk;
+	chunk.ptr = (u_char*)&ctx->sha_H[0];
+	chunk.len = HASH_SIZE_SHA256;
+	return chunk;
+}
+
+/**
+ * Implementation of hasher_t.get_state for SHA384
+ */
+static chunk_t get_state384(private_sha512_hasher_t *ctx)
+{
+	chunk_t chunk;
+	chunk.ptr = (u_char*)&ctx->sha_H[0];
+	chunk.len = HASH_SIZE_SHA384;
+	return chunk;
+}
+/**
+ * Implementation of hasher_t.get_state for SHA512
+ */
+static chunk_t get_state512(private_sha512_hasher_t *ctx)
+{
+	chunk_t chunk;
+	chunk.ptr = (u_char*)&ctx->sha_H[0];
+	chunk.len = HASH_SIZE_SHA512;
+	return chunk;
+}
+
 /**
  * Implementation of hasher_t.destroy.
  */
@@ -606,6 +638,7 @@ sha2_hasher_t *sha2_hasher_create(hash_algorithm_t algorithm)
 		case HASH_SHA256:
 			this = (sha2_hasher_t*)malloc_thing(private_sha256_hasher_t);
 			this->hasher_interface.reset = (void(*)(hasher_t*))reset256;
+			this->hasher_interface.get_state = (chunk_t(*)(hasher_t*))get_state256;
 			this->hasher_interface.get_hash_size = (size_t(*)(hasher_t*))get_hash_size256;
 			this->hasher_interface.get_hash = (void(*)(hasher_t*,chunk_t,u_int8_t*))get_hash256;
 			this->hasher_interface.allocate_hash = (void(*)(hasher_t*,chunk_t,chunk_t*))allocate_hash256;
@@ -614,6 +647,7 @@ sha2_hasher_t *sha2_hasher_create(hash_algorithm_t algorithm)
 			/* uses SHA512 data structure */
 			this = (sha2_hasher_t*)malloc_thing(private_sha512_hasher_t);
 			this->hasher_interface.reset = (void(*)(hasher_t*))reset384;
+			this->hasher_interface.get_state = (chunk_t(*)(hasher_t*))get_state384;
 			this->hasher_interface.get_hash_size = (size_t(*)(hasher_t*))get_hash_size384;
 			this->hasher_interface.get_hash = (void(*)(hasher_t*,chunk_t,u_int8_t*))get_hash384;
 			this->hasher_interface.allocate_hash = (void(*)(hasher_t*,chunk_t,chunk_t*))allocate_hash384;
@@ -621,6 +655,7 @@ sha2_hasher_t *sha2_hasher_create(hash_algorithm_t algorithm)
 		case HASH_SHA512:
 			this = (sha2_hasher_t*)malloc_thing(private_sha512_hasher_t);
 			this->hasher_interface.reset = (void(*)(hasher_t*))reset512;
+			this->hasher_interface.get_state = (chunk_t(*)(hasher_t*))get_state512;
 			this->hasher_interface.get_hash_size = (size_t(*)(hasher_t*))get_hash_size512;
 			this->hasher_interface.get_hash = (void(*)(hasher_t*,chunk_t,u_int8_t*))get_hash512;
 			this->hasher_interface.allocate_hash = (void(*)(hasher_t*,chunk_t,chunk_t*))allocate_hash512;

src/libstrongswan/crypto/prfs/fips_prf.c

@@ -0,0 +1,258 @@
+/**
+ * @file fips_prf.c
+ * 
+ * @brief Implementation for fips_prf_t.
+ * 
+ */
+
+/*
+ * Copyright (C) 2006 Martin Willi
+ * 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 "fips_prf.h"
+
+#include <arpa/inet.h>
+
+#include <debug.h>
+
+typedef struct private_fips_prf_t private_fips_prf_t;
+
+/**
+ * Private data of a fips_prf_t object.
+ */
+struct private_fips_prf_t {
+	/**
+	 * Public fips_prf_t interface.
+	 */
+	fips_prf_t public;
+	
+	/**
+	 * key of prf function, "b" long
+	 */
+	u_int8_t *key;
+	
+	/**
+	 * size of "b" in bytes
+	 */
+	size_t b;
+	
+	/**
+	 * G function, either SHA1 or DES
+	 */
+	void (*g)(u_int8_t t[], chunk_t c, u_int8_t res[]);
+};
+
+/**
+ * t used in G(), equals to initial SHA1 value
+ */
+static u_int8_t t[] = {
+	0x67,0x45,0x23,0x01,0xEF,0xCD,0xAB,0x89,0x98,0xBA,
+	0xDC,0xFE,0x10,0x32,0x54,0x76,0xC3,0xD2,0xE1,0xF0,
+};
+
+/**
+ * sum = (a + b) mod 2 ^ (length * 8)
+ */
+static void add_mod(size_t length, u_int8_t a[], u_int8_t b[], u_int8_t sum[])
+{
+	int i;
+	
+	for(i = length - 1; i >= 0; i--)
+	{
+		u_int32_t tmp;
+		int c = 0;
+		
+		tmp = a[i] + b[i] + c;
+		sum[i] = 0xff & tmp;
+		c = tmp >> 8;
+	}
+}
+
+/**
+ * calculate "chunk mod 2^(length*8)" and save it into buffer
+ */
+static void chunk_mod(size_t length, chunk_t chunk, u_int8_t buffer[])
+{
+	if (chunk.len < length)
+	{
+		/* apply seed as least significant bits, others are zero */
+		memset(buffer, 0, length - chunk.len);
+		memcpy(buffer + length - chunk.len, chunk.ptr, chunk.len);
+	}
+	else
+	{
+		/* use least significant bytes from seed, as we use mod 2^b */
+		memcpy(buffer, chunk.ptr + chunk.len - length, length);
+	}
+}
+
+/**
+ * Implementation of prf_t.get_bytes.
+ *
+ * Test vector:
+ *
+ * key:
+ * 0xbd, 0x02, 0x9b, 0xbe, 0x7f, 0x51, 0x96, 0x0b,
+ * 0xcf, 0x9e, 0xdb, 0x2b, 0x61, 0xf0, 0x6f, 0x0f,
+ * 0xeb, 0x5a, 0x38, 0xb6
+ *
+ * seed:
+ * 0x00
+ *
+ * result:
+ * 0x20, 0x70, 0xb3, 0x22, 0x3d, 0xba, 0x37, 0x2f,
+ * 0xde, 0x1c, 0x0f, 0xfc, 0x7b, 0x2e, 0x3b, 0x49,
+ * 0x8b, 0x26, 0x06, 0x14, 0x3c, 0x6c, 0x18, 0xba,
+ * 0xcb, 0x0f, 0x6c, 0x55, 0xba, 0xbb, 0x13, 0x78,
+ * 0x8e, 0x20, 0xd7, 0x37, 0xa3, 0x27, 0x51, 0x16
+ */
+static void get_bytes(private_fips_prf_t *this, chunk_t seed, u_int8_t w[])
+{
+	int i;
+	u_int8_t xval[this->b];
+	u_int8_t xseed[this->b];
+	u_int8_t *xkey = this->key;
+	u_int8_t one[this->b];
+	chunk_t xval_chunk = chunk_from_buf(xval);
+	
+	memset(one, 0, this->b);
+	one[this->b - 1] = 0x01;
+	
+	/* 3.1 */
+	chunk_mod(this->b, seed, xseed);
+	
+	/* 3.2 */
+	for (i = 0; i < 2; i++) /* twice */
+	{
+		/* a. XVAL = (XKEY + XSEED j) mod 2^b */
+		add_mod(this->b, xkey, xseed, xval);
+		DBG3("XVAL %b", xval, this->b);
+		/* b. wi = G(t, XVAL ) */
+		this->g(t, xval_chunk, &w[i * this->b]);
+		DBG3("w[%d] %b", i, &w[i * this->b], this->b);
+		/* c. XKEY = (1 + XKEY + wi) mod 2b */
+		add_mod(this->b, xkey, one, xkey);
+		add_mod(this->b, xkey, &w[i * this->b], xkey);
+		DBG3("XKEY %b", xkey, this->b);
+	}
+	
+	/* 3.3 done already, mod q not used */
+}
+
+/**
+ * Implementation of prf_t.get_block_size.
+ */
+static size_t get_block_size(private_fips_prf_t *this)
+{
+	return 2 * this->b;
+}
+/**
+ * Implementation of prf_t.allocate_bytes.
+ */
+static void allocate_bytes(private_fips_prf_t *this, chunk_t seed, chunk_t *chunk)
+{
+	*chunk = chunk_alloc(get_block_size(this));
+	get_bytes(this, seed, chunk->ptr);
+}
+
+/**
+ * Implementation of prf_t.get_key_size.
+ */
+static size_t get_key_size(private_fips_prf_t *this)
+{
+	return this->b;
+}
+
+/**
+ * Implementation of prf_t.set_key.
+ */
+static void set_key(private_fips_prf_t *this, chunk_t key)
+{
+	/* save key as "key mod 2^b" */
+	chunk_mod(this->b, key, this->key);
+}
+
+/**
+ * Implementation of the G() function based on SHA1
+ */
+void g_sha1(u_int8_t t[], chunk_t c, u_int8_t res[])
+{
+	hasher_t *hasher;
+	u_int8_t buf[64];
+	chunk_t state_chunk;
+	u_int32_t *state, *iv, *hash;
+	
+	if (c.len < sizeof(buf))
+	{
+		/* pad c with zeros */
+		memset(buf, 0, sizeof(buf));
+		memcpy(buf, c.ptr, c.len);
+		c.ptr = buf;
+		c.len = sizeof(buf);
+	}
+	else
+	{
+		/* not more than 512 bits can be G()-ed */
+		c.len = sizeof(buf);
+	}
+	
+	/* our SHA1 hasher's state is 32-Bit integers in host order. We must
+	 * convert them */
+	hasher = hasher_create(HASH_SHA1);
+	state_chunk = hasher->get_state(hasher);
+	state = (u_int32_t*)state_chunk.ptr;
+	iv = (u_int32_t*)t;
+	hash = (u_int32_t*)res;
+	state[0] = htonl(iv[0]);
+	state[1] = htonl(iv[1]);
+	state[2] = htonl(iv[2]);
+	state[3] = htonl(iv[3]);
+	hasher->get_hash(hasher, c, NULL);
+	hash[0] = htonl(state[0]);
+	hash[1] = htonl(state[1]);
+	hash[2] = htonl(state[2]);
+	hash[3] = htonl(state[3]);
+	hash[4] = htonl(state[4]);
+	hasher->destroy(hasher);
+}
+
+/**
+ * Implementation of prf_t.destroy.
+ */
+static void destroy(private_fips_prf_t *this)
+{
+	free(this->key);
+	free(this);
+}
+
+/*
+ * Described in header.
+ */
+fips_prf_t *fips_prf_create(size_t b, void(*g)(u_int8_t[],chunk_t,u_int8_t[]))
+{
+	private_fips_prf_t *this = malloc_thing(private_fips_prf_t);
+	
+	this->public.prf_interface.get_bytes = (void (*) (prf_t *,chunk_t,u_int8_t*))get_bytes;
+	this->public.prf_interface.allocate_bytes = (void (*) (prf_t*,chunk_t,chunk_t*))allocate_bytes;
+	this->public.prf_interface.get_block_size = (size_t (*) (prf_t*))get_block_size;
+	this->public.prf_interface.get_key_size = (size_t (*) (prf_t*))get_key_size;
+	this->public.prf_interface.set_key = (void (*) (prf_t *,chunk_t))set_key;
+	this->public.prf_interface.destroy = (void (*) (prf_t *))destroy;
+	
+	this->g = g;
+	this->b = b;
+	this->key = malloc(b);
+	
+	return &(this->public);
+}

src/libstrongswan/crypto/prfs/fips_prf.h

@@ -0,0 +1,80 @@
+/**
+ * @file fips_prf.h
+ * 
+ * @brief Interface of fips_prf_t.
+ * 
+ */
+
+/*
+ * Copyright (C) 2006 Martin Willi
+ * 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.
+ */
+
+#ifndef FIPS_PRF_H_
+#define FIPS_PRF_H_
+
+typedef struct fips_prf_t fips_prf_t;
+
+#include <library.h>
+#include <crypto/prfs/prf.h>
+#include <crypto/hashers/hasher.h>
+
+/**
+ * @brief Implementation of prf_t using the FIPS 186-2-change1 standard.
+ *
+ * FIPS defines a "General Purpose Random Number Generator" (Revised
+ * Algorithm for Computing m values of x (Appendix 3.1 of FIPS 186-2)). This
+ * implementation is not intended for private key generation and therefore does
+ * not include the "mod q" operation (see FIPS 186-2-change1 p74).
+ * The FIPS PRF is stateful; the key changes every time when bytes are acquired.
+ *
+ * @b Constructors:
+ *  - fips_prf_create()
+ *  - prf_create() using one of the FIPS algorithms
+ * 
+ * @ingroup prfs
+ */
+struct fips_prf_t {
+	
+	/**
+	 * Generic prf_t interface for this fips_prf_t class.
+	 */
+	prf_t prf_interface;
+};
+
+/**
+ * @brief Creates a new fips_prf_t object.
+ * 
+ * FIPS 186-2 defines G() functions used in the PRF function. It can
+ * be implemented either based on SHA1 or DES.
+ *
+ * @param b		size of b (in bytes, not bits)
+ * @param g		G() function to use (e.g. g_sha1)
+ * @return
+ *				- fips_prf_t object
+ *				- NULL if b invalid not supported
+ * 
+ * @ingroup prfs
+ */
+fips_prf_t *fips_prf_create(size_t b, void(*g)(u_int8_t[],chunk_t,u_int8_t[]));
+
+/**
+ * @brief Implementation of the G() function based on SHA1.
+ *
+ * @param t		initialization vector for SHA1 hasher, 20 bytes long
+ * @param c		value to hash, not longer than 512 bit
+ * @param res	result of G(), requries 20 bytes
+ */
+void g_sha1(u_int8_t t[], chunk_t c, u_int8_t res[]);
+
+#endif /* FIPS_PRF_H_ */

src/libstrongswan/crypto/prfs/prf.c

@@ -26,10 +26,13 @@
 
 #include <crypto/hashers/hasher.h>
 #include <crypto/prfs/hmac_prf.h>
+#include <crypto/prfs/fips_prf.h>
 
-ENUM_BEGIN(pseudo_random_function_names, PRF_UNDEFINED, PRF_UNDEFINED,
-	"PRF_UNDEFINED");
-ENUM_NEXT(pseudo_random_function_names, PRF_HMAC_MD5, PRF_AES128_CBC, PRF_UNDEFINED,
+ENUM_BEGIN(pseudo_random_function_names, PRF_UNDEFINED, PRF_FIPS_DES,
+	"PRF_UNDEFINED",
+	"PRF_FIPS_SHA1_160",
+	"PRF_FIPS_DES");
+ENUM_NEXT(pseudo_random_function_names, PRF_HMAC_MD5, PRF_AES128_CBC, PRF_FIPS_DES,
 	"PRF_HMAC_MD5",
 	"PRF_HMAC_SHA1",
 	"PRF_HMAC_TIGER",
@@ -44,13 +47,12 @@ prf_t *prf_create(pseudo_random_function_t pseudo_random_function)
 	switch (pseudo_random_function)
 	{
 		case PRF_HMAC_SHA1:
-		{
 			return (prf_t*)hmac_prf_create(HASH_SHA1);
-		}
 		case PRF_HMAC_MD5:
-		{
 			return (prf_t*)hmac_prf_create(HASH_MD5);
-		}
+		case PRF_FIPS_SHA1_160:
+			return (prf_t*)fips_prf_create(20, g_sha1);
+		case PRF_FIPS_DES:
 		case PRF_HMAC_TIGER:
 		case PRF_AES128_CBC:
 		default:

src/libstrongswan/crypto/prfs/prf.h

@@ -31,11 +31,10 @@ typedef struct prf_t prf_t;
 
 /**
  * @brief Pseudo random function, as in IKEv2 RFC 3.3.2.
- * 
- * Currently only the following algorithms are implemented:
- * - PRF_HMAC_MD5
- * - PRF_HMAC_SHA1
- * 
+ *
+ * PRF algorithms not defined in IKEv2 are allocated in "private use"
+ * space.
+ *
  * @ingroup prfs
  */
 enum pseudo_random_function_t {
@@ -46,6 +45,10 @@ enum pseudo_random_function_t {
 	PRF_HMAC_SHA1 = 2,
 	PRF_HMAC_TIGER = 3,
 	PRF_AES128_CBC = 4,
+	/** Implemented via fips_prf_t, other output sizes would be possible */
+	PRF_FIPS_SHA1_160 = 1025,
+	/** Could be implemented via fips_prf_t, uses fixed output size of 160bit */
+	PRF_FIPS_DES = 1026,
 };
 
 /**
@@ -93,6 +96,9 @@ struct prf_t {
 	
 	/**
 	 * @brief Get the key size of this prf_t object.
+	 *
+	 * This is a suggestion only, all implemented PRFs accept variable key
+	 * length.
 	 * 
 	 * @param this			calling object
 	 * @return				key size in bytes

src/libstrongswan/crypto/signers/hmac_signer.c

@@ -27,11 +27,6 @@
 
 #include <crypto/prfs/hmac_prf.h>
 
-/**
- * This class represents a hmac signer with 12 byte (96 bit) output.
- */
-#define BLOCK_SIZE	12
-
 typedef struct private_hmac_signer_t private_hmac_signer_t;
 
 /**
@@ -43,10 +38,15 @@ struct private_hmac_signer_t {
 	 */
 	hmac_signer_t public;
 	
-	/*
+	/**
 	 * Assigned hmac function.
 	 */
 	prf_t *hmac_prf;
+	
+	/**
+	 * Block size (truncation of HMAC Hash)
+	 */
+	size_t block_size;
 };
 
 /**
@@ -56,10 +56,10 @@ static void get_signature (private_hmac_signer_t *this, chunk_t data, u_int8_t *
 {
 	u_int8_t full_mac[this->hmac_prf->get_block_size(this->hmac_prf)];
 	
-	this->hmac_prf->get_bytes(this->hmac_prf,data,full_mac);
+	this->hmac_prf->get_bytes(this->hmac_prf, data, full_mac);
 
-	/* copy mac aka signature :-) */
-	memcpy(buffer,full_mac,BLOCK_SIZE);
+	/* copy MAC depending on truncation */
+	memcpy(buffer, full_mac, this->block_size);
 }
 
 /**
@@ -72,11 +72,11 @@ static void allocate_signature (private_hmac_signer_t *this, chunk_t data, chunk
 	
 	this->hmac_prf->get_bytes(this->hmac_prf,data,full_mac);
 
-	signature.ptr = malloc(BLOCK_SIZE);
-	signature.len = BLOCK_SIZE;
+	signature.ptr = malloc(this->block_size);
+	signature.len = this->block_size;
 	
 	/* copy signature */
-	memcpy(signature.ptr,full_mac,BLOCK_SIZE);
+	memcpy(signature.ptr, full_mac, this->block_size);
 
 	*chunk = signature;
 }
@@ -84,19 +84,19 @@ static void allocate_signature (private_hmac_signer_t *this, chunk_t data, chunk
 /**
  * Implementation of signer_t.verify_signature.
  */
-static bool verify_signature (private_hmac_signer_t *this, chunk_t data, chunk_t signature)
+static bool verify_signature(private_hmac_signer_t *this, chunk_t data, chunk_t signature)
 {
 	u_int8_t full_mac[this->hmac_prf->get_block_size(this->hmac_prf)];
 	
-	this->hmac_prf->get_bytes(this->hmac_prf,data,full_mac);
+	this->hmac_prf->get_bytes(this->hmac_prf, data, full_mac);
 	
-	if (signature.len != BLOCK_SIZE)
+	if (signature.len != this->block_size)
 	{
 		return FALSE;
 	}
 	
 	/* compare mac aka signature :-) */
-	if (memcmp(signature.ptr,full_mac,BLOCK_SIZE) == 0)
+	if (memcmp(signature.ptr, full_mac, this->block_size) == 0)
 	{
 		return TRUE;
 	}
@@ -109,7 +109,7 @@ static bool verify_signature (private_hmac_signer_t *this, chunk_t data, chunk_t
 /**
  * Implementation of signer_t.get_key_size.
  */
-static size_t get_key_size (private_hmac_signer_t *this)
+static size_t get_key_size(private_hmac_signer_t *this)
 {
 	/* for HMAC signer, IKEv2 uses block size as key size */
 	return this->hmac_prf->get_block_size(this->hmac_prf);
@@ -118,17 +118,17 @@ static size_t get_key_size (private_hmac_signer_t *this)
 /**
  * Implementation of signer_t.get_block_size.
  */
-static size_t get_block_size (private_hmac_signer_t *this)
+static size_t get_block_size(private_hmac_signer_t *this)
 {
-	return BLOCK_SIZE;
+	return this->block_size;
 }
 
 /**
  * Implementation of signer_t.set_key.
  */
-static void set_key (private_hmac_signer_t *this, chunk_t key)
+static void set_key(private_hmac_signer_t *this, chunk_t key)
 {
-	this->hmac_prf->set_key(this->hmac_prf,key);
+	this->hmac_prf->set_key(this->hmac_prf, key);
 }
 
 /**
@@ -144,12 +144,12 @@ static status_t destroy(private_hmac_signer_t *this)
 /*
  * Described in header
  */
-hmac_signer_t *hmac_signer_create(hash_algorithm_t hash_algoritm)
+hmac_signer_t *hmac_signer_create(hash_algorithm_t hash_algoritm, size_t block_size)
 {
+	size_t hmac_block_size;
 	private_hmac_signer_t *this = malloc_thing(private_hmac_signer_t);
 
 	this->hmac_prf = (prf_t *) hmac_prf_create(hash_algoritm);
-	
 	if (this->hmac_prf == NULL)
 	{
 		/* algorithm not supported */
@@ -157,6 +157,10 @@ hmac_signer_t *hmac_signer_create(hash_algorithm_t hash_algoritm)
 		return NULL;
 	}
 	
+	/* prevent invalid truncation */
+	hmac_block_size = this->hmac_prf->get_block_size(this->hmac_prf);
+	this->block_size = min(block_size, hmac_block_size);
+	
 	/* interface functions */
 	this->public.signer_interface.get_signature = (void (*) (signer_t*, chunk_t, u_int8_t*))get_signature;
 	this->public.signer_interface.allocate_signature = (void (*) (signer_t*, chunk_t, chunk_t*))allocate_signature;

src/libstrongswan/crypto/signers/hmac_signer.h

@@ -30,9 +30,11 @@ typedef struct hmac_signer_t hmac_signer_t;
 #include <crypto/hashers/hasher.h>
 
 /**
- * @brief Implementation of signer_t interface using the
- * HMAC algorithm in combination with either MD5 or SHA1.
- * 
+ * @brief Implementation of signer_t interface using HMAC.
+ *
+ * HMAC uses a standard hash function implemented in a hasher_t to build
+ * a MAC.
+ *
  * @ingroup signers
  */
 struct hmac_signer_t {
@@ -45,15 +47,22 @@ struct hmac_signer_t {
 
 /**
  * @brief Creates a new hmac_signer_t.
- * 
+ *
+ * HMAC signatures are often truncated to shorten them to a more usable, but
+ * still secure enough length.
+ * Block size must be equal or smaller then the hash algorithms
+ * hash.
+ *
  * @param hash_algoritm		Hash algorithm to use with signer
+ * @param block_size		Size of resulting signature (truncated to block_size)
  * @return					
  * 							- hmac_signer_t
  * 							- NULL if hash algorithm not supported
  * 
  * @ingroup signers
  */
-hmac_signer_t *hmac_signer_create(hash_algorithm_t hash_algoritm);
+hmac_signer_t *hmac_signer_create(hash_algorithm_t hash_algoritm,
+								  size_t block_size);
 
 
 #endif /*HMAC_SIGNER_H_*/

src/libstrongswan/crypto/signers/signer.c

@@ -25,9 +25,10 @@
 
 #include <crypto/signers/hmac_signer.h>
 
-ENUM_BEGIN(integrity_algorithm_names, AUTH_UNDEFINED, AUTH_UNDEFINED,
-	"UNDEFINED");
-ENUM_NEXT(integrity_algorithm_names, AUTH_HMAC_MD5_96, AUTH_AES_XCBC_96, AUTH_UNDEFINED,
+ENUM_BEGIN(integrity_algorithm_names, AUTH_UNDEFINED, AUTH_HMAC_SHA1_128,
+	"UNDEFINED",
+	"AUTH_HMAC_SHA1_128");
+ENUM_NEXT(integrity_algorithm_names, AUTH_HMAC_MD5_96, AUTH_AES_XCBC_96, AUTH_HMAC_SHA1_128,
 	"HMAC_MD5_96",
 	"HMAC_SHA1_96",
 	"DES_MAC",
@@ -43,13 +44,11 @@ signer_t *signer_create(integrity_algorithm_t integrity_algorithm)
 	switch(integrity_algorithm)
 	{
 		case AUTH_HMAC_SHA1_96:
-		{
-			return ((signer_t *) hmac_signer_create(HASH_SHA1));
-		}
+			return (signer_t *)hmac_signer_create(HASH_SHA1, 12);
+		case AUTH_HMAC_SHA1_128:
+			return (signer_t *)hmac_signer_create(HASH_SHA1, 16);
 		case AUTH_HMAC_MD5_96:
-		{
-			return ((signer_t *) hmac_signer_create(HASH_MD5));
-		}
+			return (signer_t *)hmac_signer_create(HASH_MD5, 12);
 		default:
 			return NULL;
 	}

src/libstrongswan/crypto/signers/signer.h

@@ -31,11 +31,9 @@ typedef struct signer_t signer_t;
 
 /**
  * @brief Integrity algorithm, as in IKEv2 RFC 3.3.2.
- * 
- * Currently only the following algorithms are implemented and therefore supported:
- * - AUTH_HMAC_MD5_96
- * - AUTH_HMAC_SHA1_96
- * 
+ *
+ * Algorithms not specified in IKEv2 are allocated in private use space.
+ *
  * @ingroup signers
  */
 enum integrity_algorithm_t {
@@ -46,7 +44,9 @@ enum integrity_algorithm_t {
 	AUTH_HMAC_SHA1_96 = 2,
 	AUTH_DES_MAC = 3,
 	AUTH_KPDK_MD5 = 4,
-	AUTH_AES_XCBC_96 = 5
+	AUTH_AES_XCBC_96 = 5,
+	/** Implemented via hmac_signer_t */
+	AUTH_HMAC_SHA1_128 = 1025,
 };
 
 /**