Add support for ECDH KARI.

Add support for ECDH in enveloped data. The CMS ctrls for the EC ASN1
method decode/encode the appropriate parameters from the CMS ASN1 data
and send appropriate data to the EC public key method.

crypto/ec/ec.h

@@ -1204,6 +1204,7 @@ void ERR_load_EC_strings(void);
 #define EC_R_INVALID_COMPRESSED_POINT			 110
 #define EC_R_INVALID_COMPRESSION_BIT			 109
 #define EC_R_INVALID_CURVE				 141
+#define EC_R_INVALID_DIGEST				 151
 #define EC_R_INVALID_DIGEST_TYPE			 138
 #define EC_R_INVALID_ENCODING				 102
 #define EC_R_INVALID_FIELD				 103

crypto/ec/ec_ameth.c

@@ -63,8 +63,12 @@
 #ifndef OPENSSL_NO_CMS
 #include <openssl/cms.h>
 #endif
+#include <openssl/asn1t.h>
 #include "asn1_locl.h"
 
+static int ecdh_cms_decrypt(CMS_RecipientInfo *ri);
+static int ecdh_cms_encrypt(CMS_RecipientInfo *ri);
+
 static int eckey_param2type(int *pptype, void **ppval, EC_KEY *ec_key)
 	{
 	const EC_GROUP  *group;
@@ -612,6 +616,17 @@ static int ec_pkey_ctrl(EVP_PKEY *pkey, int op, long arg1, void *arg2)
 			X509_ALGOR_set0(alg2, OBJ_nid2obj(snid), V_ASN1_UNDEF, 0);
 			}
 		return 1;
+
+		case ASN1_PKEY_CTRL_CMS_ENVELOPE:
+		if (arg1 == 1)
+			return ecdh_cms_decrypt(arg2);
+		else if (arg1 == 0)
+			return ecdh_cms_encrypt(arg2);
+		return -2;
+
+		case ASN1_PKEY_CTRL_CMS_RI_TYPE:
+		*(int *)arg2 = CMS_RECIPINFO_AGREE;
+		return 1;
 #endif
 
 		case ASN1_PKEY_CTRL_DEFAULT_MD_NID:
@@ -658,3 +673,365 @@ const EVP_PKEY_ASN1_METHOD eckey_asn1_meth =
 	old_ec_priv_decode,
 	old_ec_priv_encode
 	};
+
+#ifndef OPENSSL_NO_CMS
+
+static int ecdh_cms_set_peerkey(EVP_PKEY_CTX *pctx,
+				X509_ALGOR *alg, ASN1_BIT_STRING *pubkey)
+	{
+	ASN1_OBJECT *aoid;
+	int atype;
+	void *aval;
+	int rv = 0;
+	EVP_PKEY *pkpeer = NULL;
+	EC_KEY *ecpeer = NULL;
+	const unsigned char *p;
+	int plen;
+	X509_ALGOR_get0(&aoid, &atype, &aval, alg);
+	if (OBJ_obj2nid(aoid) != NID_X9_62_id_ecPublicKey)
+		goto err;
+	/* If absent parameters get group from main key */
+	if (atype == V_ASN1_UNDEF || atype == V_ASN1_NULL)
+		{
+		const EC_GROUP *grp;
+		EVP_PKEY *pk;
+		pk = EVP_PKEY_CTX_get0_pkey(pctx);
+		if (!pk)
+			goto err;
+		grp = EC_KEY_get0_group(pk->pkey.ec);
+		ecpeer = EC_KEY_new();
+		if (!ecpeer)
+			goto err;
+		if (!EC_KEY_set_group(ecpeer, grp))
+			goto err;
+		}
+	else
+		{
+		ecpeer = eckey_type2param(atype, aval);
+		if (!ecpeer)
+			goto err;
+		}
+	/* We have parameters now set public key */
+	plen = ASN1_STRING_length(pubkey);
+	p = ASN1_STRING_data(pubkey);
+	if (!p || !plen)
+		goto err;
+	if (!o2i_ECPublicKey(&ecpeer, &p, plen))
+		goto err;
+	pkpeer = EVP_PKEY_new();
+	if (!pkpeer)
+		goto err;
+	EVP_PKEY_set1_EC_KEY(pkpeer, ecpeer);
+	if (EVP_PKEY_derive_set_peer(pctx, pkpeer) > 0)
+		rv = 1;
+	err:
+	if (ecpeer)
+		EC_KEY_free(ecpeer);
+	if (pkpeer)
+		EVP_PKEY_free(pkpeer);
+	return rv;
+	}
+/* Set KDF parameters based on KDF NID */
+static int ecdh_cms_set_kdf_param(EVP_PKEY_CTX *pctx, int eckdf_nid)
+	{
+	int kdf_nid, kdfmd_nid, cofactor;
+	const EVP_MD *kdf_md;
+	if (eckdf_nid == NID_undef)
+		return 0;
+
+	/* Lookup KDF type, cofactor mode and digest */
+	if (!OBJ_find_sigid_algs(eckdf_nid, &kdfmd_nid, &kdf_nid))
+		return 0;
+
+	if (kdf_nid == NID_dh_std_kdf)
+		cofactor = 0;
+	else if (kdf_nid == NID_dh_cofactor_kdf)
+		cofactor = 1;
+	else return 0;
+
+	if (EVP_PKEY_CTX_set_ecdh_cofactor_mode(pctx, cofactor) <= 0)
+		return 0;
+
+	if (EVP_PKEY_CTX_set_ecdh_kdf_type(pctx, EVP_PKEY_ECDH_KDF_X9_62) <= 0)
+		return 0;
+
+	kdf_md = EVP_get_digestbynid(kdfmd_nid);
+	if (!kdf_md)
+		return 0;
+
+	if (EVP_PKEY_CTX_set_ecdh_kdf_md(pctx, kdf_md) <= 0)
+		return 0;
+	return 1;
+	}
+
+/* Utilities to encode the ECC_CMS_SharedInfo structure used during key
+ * derivation.
+ */
+
+typedef struct {
+	X509_ALGOR *keyInfo;
+	ASN1_OCTET_STRING *entityUInfo;
+	ASN1_OCTET_STRING *suppPubInfo;
+} ECC_CMS_SharedInfo;
+
+ASN1_SEQUENCE(ECC_CMS_SharedInfo) = {
+  ASN1_SIMPLE(ECC_CMS_SharedInfo, keyInfo, X509_ALGOR),
+  ASN1_EXP_OPT(ECC_CMS_SharedInfo, entityUInfo, ASN1_OCTET_STRING, 0),
+  ASN1_EXP_OPT(ECC_CMS_SharedInfo, suppPubInfo, ASN1_OCTET_STRING, 2),
+} ASN1_SEQUENCE_END(ECC_CMS_SharedInfo)
+
+static int ecdh_cms_set_ukm(EVP_PKEY_CTX *pctx, 
+					X509_ALGOR *kekalg, 
+					ASN1_OCTET_STRING *ukm,
+					int keylen)
+	{
+	union {
+		ECC_CMS_SharedInfo *pecsi;
+		ASN1_VALUE *a;
+	} intsi = {NULL};
+
+	unsigned char *der = NULL;
+	int plen;
+	ASN1_OCTET_STRING oklen;
+	unsigned char kl[4];
+	ECC_CMS_SharedInfo ecsi;
+
+	keylen <<= 3;
+	kl[0] = (keylen >> 24) & 0xff;
+	kl[1] = (keylen >> 16) & 0xff;
+	kl[2] = (keylen >> 8) & 0xff;
+	kl[3] = keylen & 0xff;
+	oklen.length = 4;
+	oklen.data = kl;
+	oklen.type = V_ASN1_OCTET_STRING;
+	oklen.flags = 0;
+	ecsi.keyInfo = kekalg;
+	ecsi.entityUInfo = ukm;
+	ecsi.suppPubInfo = &oklen;
+	intsi.pecsi = &ecsi;
+	plen = ASN1_item_i2d(intsi.a, &der, ASN1_ITEM_rptr(ECC_CMS_SharedInfo));
+	if (!der || !plen)
+		goto err;
+	if (EVP_PKEY_CTX_set0_ecdh_kdf_ukm(pctx, der, plen) <= 0)
+		goto err;
+	return 1;
+	err:
+	if (der)
+		OPENSSL_free(der);
+	return 0;
+	}
+
+static int ecdh_cms_set_shared_info(EVP_PKEY_CTX *pctx, CMS_RecipientInfo *ri)
+	{
+	int rv = 0;
+
+	X509_ALGOR *alg, *kekalg = NULL;
+	ASN1_OCTET_STRING *ukm;
+	const unsigned char *p;
+	int plen, keylen;
+	const EVP_CIPHER *kekcipher;
+	EVP_CIPHER_CTX *kekctx;
+
+	if (!CMS_RecipientInfo_kari_get0_alg(ri, &alg, &ukm))
+		return 0;
+
+	if (!ecdh_cms_set_kdf_param(pctx, OBJ_obj2nid(alg->algorithm)))
+		{
+		ECerr(EC_F_ECDH_CMS_SET_SHARED_INFO, EC_R_KDF_PARAMETER_ERROR);
+		return 0;
+		}
+
+	if (alg->parameter->type != V_ASN1_SEQUENCE)
+		return 0;
+
+	p = alg->parameter->value.sequence->data;
+	plen = alg->parameter->value.sequence->length;
+	kekalg = d2i_X509_ALGOR(NULL, &p, plen);
+	if (!kekalg)
+		goto err;
+	kekctx = CMS_RecipientInfo_kari_get0_ctx(ri);
+	if (!kekctx)
+		goto err;
+	kekcipher = EVP_get_cipherbyobj(kekalg->algorithm);
+	if (!kekcipher || EVP_CIPHER_mode(kekcipher) != EVP_CIPH_WRAP_MODE)
+		goto err;
+	if (!EVP_EncryptInit_ex(kekctx, kekcipher, NULL, NULL, NULL))
+		goto err;
+
+	keylen = EVP_CIPHER_CTX_key_length(kekctx);
+	if (EVP_PKEY_CTX_set_ecdh_kdf_outlen(pctx, keylen) <= 0)
+		goto err;
+
+	if (!ecdh_cms_set_ukm(pctx, kekalg, ukm, keylen))
+		goto err;
+
+	rv = 1;
+	err:
+	if (kekalg)
+		X509_ALGOR_free(kekalg);
+	return rv;
+	}
+
+static int ecdh_cms_decrypt(CMS_RecipientInfo *ri)
+	{
+	EVP_PKEY_CTX *pctx;
+	pctx = CMS_RecipientInfo_get0_pkey_ctx(ri);
+	if (!pctx)
+		return 0;
+	/* See if we need to set peer key */
+	if (!EVP_PKEY_CTX_get0_peerkey(pctx))
+		{
+		X509_ALGOR *alg;
+		ASN1_BIT_STRING *pubkey;
+		if (!CMS_RecipientInfo_kari_get0_orig_id(ri, &alg, &pubkey,
+							NULL, NULL, NULL))
+			return 0;
+		if (!alg || !pubkey)
+			return 0;
+		if (!ecdh_cms_set_peerkey(pctx, alg, pubkey))
+			{
+			ECerr(EC_F_ECDH_CMS_DECRYPT, EC_R_PEER_KEY_ERROR);
+			return 0;
+			}
+		}
+	/* Set ECDH derivation parameters and initialise unwrap context */
+	if (!ecdh_cms_set_shared_info(pctx, ri))
+		{
+		ECerr(EC_F_ECDH_CMS_DECRYPT, EC_R_SHARED_INFO_ERROR);
+		return 0;
+		}
+	return 1;
+	}
+
+static int ecdh_cms_encrypt(CMS_RecipientInfo *ri)
+	{
+	EVP_PKEY_CTX *pctx;
+	EVP_PKEY *pkey;
+	EVP_CIPHER_CTX *ctx;
+	int keylen;
+	X509_ALGOR *talg, *wrap_alg = NULL;
+	ASN1_OBJECT *aoid;
+	ASN1_BIT_STRING *pubkey;
+	ASN1_STRING *wrap_str;
+	ASN1_OCTET_STRING *ukm;
+	unsigned char *penc = NULL;
+	int penclen;
+	int rv = 0;
+	int ecdh_nid, kdf_type, kdf_nid, wrap_nid;
+	const EVP_MD *kdf_md;
+	pctx = CMS_RecipientInfo_get0_pkey_ctx(ri);
+	if (!pctx)
+		return 0;
+	/* Get ephemeral key */
+	pkey = EVP_PKEY_CTX_get0_pkey(pctx);
+	if (!CMS_RecipientInfo_kari_get0_orig_id(ri, &talg, &pubkey,
+							NULL, NULL, NULL))
+		goto err;
+	X509_ALGOR_get0(&aoid, NULL, NULL, talg);
+	/* Is everything uninitialised? */
+	if (aoid == OBJ_nid2obj(NID_undef))
+		{
+
+		EC_KEY *eckey = pkey->pkey.ec;
+		/* Set the key */
+		unsigned char *p;
+
+		penclen = i2o_ECPublicKey(eckey, NULL);
+		if (penclen <= 0)
+			goto err;
+		penc = OPENSSL_malloc(penclen);
+		if (!penc)
+			goto err;
+		p = penc;
+		penclen = i2o_ECPublicKey(eckey, &p);
+		if (penclen <= 0)
+			goto err;
+		ASN1_STRING_set0(pubkey, penc, penclen);
+		pubkey->flags&= ~(ASN1_STRING_FLAG_BITS_LEFT|0x07);
+		pubkey->flags|=ASN1_STRING_FLAG_BITS_LEFT;
+
+		penc = NULL;
+		X509_ALGOR_set0(talg, OBJ_nid2obj(NID_X9_62_id_ecPublicKey),
+							V_ASN1_UNDEF, NULL);
+		}
+
+	/* See if custom paraneters set */
+	kdf_type = EVP_PKEY_CTX_get_ecdh_kdf_type(pctx);
+	if (kdf_type <= 0)
+		goto err;
+	if (!EVP_PKEY_CTX_get_ecdh_kdf_md(pctx, &kdf_md))
+		goto err;
+	ecdh_nid = EVP_PKEY_CTX_get_ecdh_cofactor_mode(pctx);
+	if (ecdh_nid < 0)
+		goto err;
+	else if (ecdh_nid == 0)
+		ecdh_nid = NID_dh_std_kdf;
+	else if (ecdh_nid == 1)
+		ecdh_nid = NID_dh_cofactor_kdf;
+
+	if (kdf_type == EVP_PKEY_ECDH_KDF_NONE)
+		{
+		kdf_type = EVP_PKEY_ECDH_KDF_X9_62;
+		if (EVP_PKEY_CTX_set_ecdh_kdf_type(pctx, kdf_type) <= 0)
+			goto err;
+		}
+	else
+		/* Uknown KDF */
+		goto err;
+	if (kdf_md == NULL)
+		{
+		/* Fixme later for better MD */
+		kdf_md = EVP_sha1();
+		if (EVP_PKEY_CTX_set_ecdh_kdf_md(pctx, kdf_md) <= 0)
+			goto err;
+		}
+
+	if (!CMS_RecipientInfo_kari_get0_alg(ri, &talg, &ukm))
+		goto err;
+
+	/* Lookup NID for KDF+cofactor+digest */
+
+	if (!OBJ_find_sigid_by_algs(&kdf_nid, EVP_MD_type(kdf_md), ecdh_nid))
+		goto err;
+	/* Get wrap NID */
+	ctx = CMS_RecipientInfo_kari_get0_ctx(ri);
+	wrap_nid = EVP_CIPHER_CTX_type(ctx);
+	keylen = EVP_CIPHER_CTX_key_length(ctx);
+
+	/* Package wrap algorithm in an AlgorithmIdentifier */
+
+	wrap_alg = X509_ALGOR_new();
+	if (!wrap_alg)
+		goto err;
+	X509_ALGOR_set0(wrap_alg, OBJ_nid2obj(wrap_nid), V_ASN1_UNDEF, NULL);
+
+	if (EVP_PKEY_CTX_set_ecdh_kdf_outlen(pctx, keylen) <= 0)
+		goto err;
+	if (!ecdh_cms_set_ukm(pctx, wrap_alg, ukm, keylen))
+		goto err;
+
+	/* Now need to wrap encoding of wrap AlgorithmIdentifier into
+	 * parameter of another AlgorithmIdentifier.
+	 */
+	penc = NULL;
+	penclen = i2d_X509_ALGOR(wrap_alg, &penc);
+	if (!penc || !penclen)
+		goto err;
+	wrap_str = ASN1_STRING_new();
+	if (!wrap_str)
+		goto err;
+	ASN1_STRING_set0(wrap_str, penc, penclen);
+	penc = NULL;
+	X509_ALGOR_set0(talg, OBJ_nid2obj(kdf_nid), V_ASN1_SEQUENCE, wrap_str);
+
+	rv = 1;
+
+	err:
+	if (penc)
+		OPENSSL_free(penc);
+	if (wrap_alg)
+		X509_ALGOR_free(wrap_alg);
+	return rv;
+	}
+
+#endif

crypto/ec/ec_err.c

@@ -1,6 +1,6 @@
 /* crypto/ec/ec_err.c */
 /* ====================================================================
- * Copyright (c) 1999-2011 The OpenSSL Project.  All rights reserved.
+ * Copyright (c) 1999-2013 The OpenSSL Project.  All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -76,6 +76,8 @@ static ERR_STRING_DATA EC_str_functs[]=
 {ERR_FUNC(EC_F_D2I_ECPKPARAMETERS),	"d2i_ECPKParameters"},
 {ERR_FUNC(EC_F_D2I_ECPRIVATEKEY),	"d2i_ECPrivateKey"},
 {ERR_FUNC(EC_F_DO_EC_KEY_PRINT),	"DO_EC_KEY_PRINT"},
+{ERR_FUNC(EC_F_ECDH_CMS_DECRYPT),	"ECDH_CMS_DECRYPT"},
+{ERR_FUNC(EC_F_ECDH_CMS_SET_SHARED_INFO),	"ECDH_CMS_SET_SHARED_INFO"},
 {ERR_FUNC(EC_F_ECKEY_PARAM2TYPE),	"ECKEY_PARAM2TYPE"},
 {ERR_FUNC(EC_F_ECKEY_PARAM_DECODE),	"ECKEY_PARAM_DECODE"},
 {ERR_FUNC(EC_F_ECKEY_PRIV_DECODE),	"ECKEY_PRIV_DECODE"},
@@ -229,6 +231,7 @@ static ERR_STRING_DATA EC_str_reasons[]=
 {ERR_REASON(EC_R_INVALID_COMPRESSED_POINT),"invalid compressed point"},
 {ERR_REASON(EC_R_INVALID_COMPRESSION_BIT),"invalid compression bit"},
 {ERR_REASON(EC_R_INVALID_CURVE)          ,"invalid curve"},
+{ERR_REASON(EC_R_INVALID_DIGEST)         ,"invalid digest"},
 {ERR_REASON(EC_R_INVALID_DIGEST_TYPE)    ,"invalid digest type"},
 {ERR_REASON(EC_R_INVALID_ENCODING)       ,"invalid encoding"},
 {ERR_REASON(EC_R_INVALID_FIELD)          ,"invalid field"},
@@ -237,6 +240,7 @@ static ERR_STRING_DATA EC_str_reasons[]=
 {ERR_REASON(EC_R_INVALID_PENTANOMIAL_BASIS),"invalid pentanomial basis"},
 {ERR_REASON(EC_R_INVALID_PRIVATE_KEY)    ,"invalid private key"},
 {ERR_REASON(EC_R_INVALID_TRINOMIAL_BASIS),"invalid trinomial basis"},
+{ERR_REASON(EC_R_KDF_PARAMETER_ERROR)    ,"kdf parameter error"},
 {ERR_REASON(EC_R_KEYS_NOT_SET)           ,"keys not set"},
 {ERR_REASON(EC_R_MISSING_PARAMETERS)     ,"missing parameters"},
 {ERR_REASON(EC_R_MISSING_PRIVATE_KEY)    ,"missing private key"},
@@ -247,9 +251,11 @@ static ERR_STRING_DATA EC_str_reasons[]=
 {ERR_REASON(EC_R_NO_FIELD_MOD)           ,"no field mod"},
 {ERR_REASON(EC_R_NO_PARAMETERS_SET)      ,"no parameters set"},
 {ERR_REASON(EC_R_PASSED_NULL_PARAMETER)  ,"passed null parameter"},
+{ERR_REASON(EC_R_PEER_KEY_ERROR)         ,"peer key error"},
 {ERR_REASON(EC_R_PKPARAMETERS2GROUP_FAILURE),"pkparameters2group failure"},
 {ERR_REASON(EC_R_POINT_AT_INFINITY)      ,"point at infinity"},
 {ERR_REASON(EC_R_POINT_IS_NOT_ON_CURVE)  ,"point is not on curve"},
+{ERR_REASON(EC_R_SHARED_INFO_ERROR)      ,"shared info error"},
 {ERR_REASON(EC_R_SLOT_FULL)              ,"slot full"},
 {ERR_REASON(EC_R_UNDEFINED_GENERATOR)    ,"undefined generator"},
 {ERR_REASON(EC_R_UNDEFINED_ORDER)        ,"undefined order"},

crypto/ec/ec_pmeth.c

@@ -319,7 +319,7 @@ static int pkey_ec_ctrl(EVP_PKEY_CTX *ctx, int type, int p1, void *p2)
 		case EVP_PKEY_CTRL_EC_ECDH_COFACTOR:
 		if (p1 == -2)
 			{
-			if (dctx->co_key)
+			if (dctx->cofactor_mode != -1)
 				return dctx->cofactor_mode;
 			else
 				{
@@ -459,6 +459,22 @@ static int pkey_ec_ctrl_str(EVP_PKEY_CTX *ctx,
 			return -2;
 		return EVP_PKEY_CTX_set_ec_param_enc(ctx, param_enc);
 		}
+	else if (!strcmp(type, "ecdh_kdf_md"))
+		{
+		const EVP_MD *md;
+		if (!(md = EVP_get_digestbyname(value)))
+			{
+			ECerr(EC_F_PKEY_EC_CTRL_STR, EC_R_INVALID_DIGEST);
+			return 0;
+			}
+		return EVP_PKEY_CTX_set_ecdh_kdf_md(ctx, md);
+		}
+	else if (!strcmp(type, "ecdh_cofactor_mode"))
+		{
+		int co_mode;
+		co_mode = atoi(value);
+		return EVP_PKEY_CTX_set_ecdh_cofactor_mode(ctx, co_mode);
+		}
 			
 	return -2;
 	}