Provide the Diffie Hellman parameters from a central location, so that we do not have to replicate them in every plugin that implements the DH interface.

The main reason for this change is that Android's libcrypto does not
include the get_rfcX_prime_Y functions by default.  Therefore we would
have had to replicate the primes a third time.

1 files changed, 12 insertions, 62 deletions

diff --git a/src/libstrongswan/plugins/openssl/openssl_diffie_hellman.c b/src/libstrongswan/plugins/openssl/openssl_diffie_hellman.c
index 80a1ee878..92ba348c2 100644
--- a/src/libstrongswan/plugins/openssl/openssl_diffie_hellman.c
+++ b/src/libstrongswan/plugins/openssl/openssl_diffie_hellman.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2008 Tobias Brunner
+ * Copyright (C) 2008-2010 Tobias Brunner
  * Copyright (C) 2008 Martin Willi
  * Hochschule fuer Technik Rapperswil
  *
@@ -20,47 +20,6 @@
 
 #include <debug.h>
 
-typedef struct modulus_entry_t modulus_entry_t;
-
-/**
- * Entry of the modulus list.
- */
-struct modulus_entry_t {
-	/**
-	 * Group number as it is defined in file transform_substructure.h.
-	 */
-	diffie_hellman_group_t group;
-
-	/**
-	 * Pointer to the function to get the modulus.
-	 */
-	BIGNUM *(*get_prime)(BIGNUM *bn);
-
-	/*
-	 * Optimum length of exponent in bits.
-	 */
-	long opt_exponent_len;
-
-	/*
-	 * Generator value.
-	 */
-	u_int16_t generator;
-};
-
-/**
- * All supported modulus values - optimum exponent size according to RFC 3526.
- */
-static modulus_entry_t modulus_entries[] = {
-	{MODP_768_BIT,  get_rfc2409_prime_768,  256, 2},
-	{MODP_1024_BIT, get_rfc2409_prime_1024, 256, 2},
-	{MODP_1536_BIT, get_rfc3526_prime_1536, 256, 2},
-	{MODP_2048_BIT, get_rfc3526_prime_2048, 384, 2},
-	{MODP_3072_BIT, get_rfc3526_prime_3072, 384, 2},
-	{MODP_4096_BIT, get_rfc3526_prime_4096, 512, 2},
-	{MODP_6144_BIT, get_rfc3526_prime_6144, 512, 2},
-	{MODP_8192_BIT, get_rfc3526_prime_8192, 512, 2},
-};
-
 typedef struct private_openssl_diffie_hellman_t private_openssl_diffie_hellman_t;
 
 /**
@@ -125,7 +84,6 @@ static status_t get_shared_secret(private_openssl_diffie_hellman_t *this,
 	memset(secret->ptr, 0, secret->len);
 	memcpy(secret->ptr + secret->len - this->shared_secret.len,
 		   this->shared_secret.ptr, this->shared_secret.len);
-
 	return SUCCESS;
 }
 
@@ -165,27 +123,19 @@ static diffie_hellman_group_t get_dh_group(private_openssl_diffie_hellman_t *thi
  */
 static status_t set_modulus(private_openssl_diffie_hellman_t *this)
 {
-	int i;
-	bool ansi_x9_42;
-
-	ansi_x9_42 = lib->settings->get_bool(lib->settings,
-										 "libstrongswan.dh_exponent_ansi_x9_42", TRUE);
-
-	for (i = 0; i < (sizeof(modulus_entries) / sizeof(modulus_entry_t)); i++)
+	diffie_hellman_params_t *params = diffie_hellman_get_params(this->group);
+	if (!params)
 	{
-		if (modulus_entries[i].group == this->group)
-		{
-			this->dh->p = modulus_entries[i].get_prime(NULL);
-			this->dh->g = BN_new();
-			BN_set_word(this->dh->g, modulus_entries[i].generator);
-			if (!ansi_x9_42)
-			{
-				this->dh->length = modulus_entries[i].opt_exponent_len;
-			}
-			return SUCCESS;
-		}
+		return NOT_FOUND;
 	}
-	return NOT_FOUND;
+	this->dh->p = BN_bin2bn(params->prime, params->prime_len, NULL);
+	this->dh->g = BN_new();
+	BN_set_word(this->dh->g, params->generator);
+	if (params->exp_len != params->prime_len)
+	{
+		this->dh->length = params->exp_len * 8;
+	}
+	return SUCCESS;
 }
 
 /**