diff options
Diffstat (limited to 'providers/implementations/exchange')
-rw-r--r-- | providers/implementations/exchange/build.info | 2 | ||||
-rw-r--r-- | providers/implementations/exchange/ecdh_exch.c | 533 |
2 files changed, 535 insertions, 0 deletions
diff --git a/providers/implementations/exchange/build.info b/providers/implementations/exchange/build.info index 51d32fc090..82b688def3 100644 --- a/providers/implementations/exchange/build.info +++ b/providers/implementations/exchange/build.info @@ -3,6 +3,7 @@ $DH_GOAL=../../libimplementations.a $ECX_GOAL=../../libimplementations.a +$ECDH_GOAL=../../libimplementations.a IF[{- !$disabled{dh} -}] SOURCE[$DH_GOAL]=dh_exch.c @@ -21,4 +22,5 @@ ENDIF IF[{- !$disabled{ec} -}] SOURCE[$ECX_GOAL]=ecx_exch.c DEFINE[$ECX_GOAL]=$ECDEF + SOURCE[$ECDH_GOAL]=ecdh_exch.c ENDIF diff --git a/providers/implementations/exchange/ecdh_exch.c b/providers/implementations/exchange/ecdh_exch.c new file mode 100644 index 0000000000..bf353fa175 --- /dev/null +++ b/providers/implementations/exchange/ecdh_exch.c @@ -0,0 +1,533 @@ +/* + * Copyright 2020 The OpenSSL Project Authors. All Rights Reserved. + * + * Licensed under the Apache License 2.0 (the "License"). You may not use + * this file except in compliance with the License. You can obtain a copy + * in the file LICENSE in the source distribution or at + * https://www.openssl.org/source/license.html + */ + +/* + * ECDH low level APIs are deprecated for public use, but still ok for + * internal use. + */ +#include "internal/deprecated.h" + +#include <string.h> +#include <openssl/crypto.h> +#include <openssl/evp.h> +#include <openssl/core_numbers.h> +#include <openssl/core_names.h> +#include <openssl/ec.h> +#include <openssl/params.h> +#include <openssl/err.h> +#include "prov/provider_ctx.h" +#include "prov/implementations.h" +#include "crypto/ec.h" /* ecdh_KDF_X9_63() */ + +static OSSL_OP_keyexch_newctx_fn ecdh_newctx; +static OSSL_OP_keyexch_init_fn ecdh_init; +static OSSL_OP_keyexch_set_peer_fn ecdh_set_peer; +static OSSL_OP_keyexch_derive_fn ecdh_derive; +static OSSL_OP_keyexch_freectx_fn ecdh_freectx; +static OSSL_OP_keyexch_dupctx_fn ecdh_dupctx; +static OSSL_OP_keyexch_set_ctx_params_fn ecdh_set_ctx_params; +static OSSL_OP_keyexch_settable_ctx_params_fn ecdh_settable_ctx_params; +static OSSL_OP_keyexch_get_ctx_params_fn ecdh_get_ctx_params; +static OSSL_OP_keyexch_gettable_ctx_params_fn ecdh_gettable_ctx_params; + +enum kdf_type { + PROV_ECDH_KDF_NONE = 0, + PROV_ECDH_KDF_X9_63 +}; + +/* + * What's passed as an actual key is defined by the KEYMGMT interface. + * We happen to know that our KEYMGMT simply passes EC_KEY structures, so + * we use that here too. + */ + +typedef struct { + OPENSSL_CTX *libctx; + + EC_KEY *k; + EC_KEY *peerk; + + /* + * ECDH cofactor mode: + * + * . 0 disabled + * . 1 enabled + * . -1 use cofactor mode set for k + */ + int cofactor_mode; + + /************ + * ECDH KDF * + ************/ + /* KDF (if any) to use for ECDH */ + enum kdf_type kdf_type; + /* Message digest to use for key derivation */ + EVP_MD *kdf_md; + /* User key material */ + unsigned char *kdf_ukm; + size_t kdf_ukmlen; + /* KDF output length */ + size_t kdf_outlen; +} PROV_ECDH_CTX; + +static +void *ecdh_newctx(void *provctx) +{ + PROV_ECDH_CTX *pectx = OPENSSL_zalloc(sizeof(*pectx)); + + if (pectx == NULL) + return NULL; + + pectx->libctx = PROV_LIBRARY_CONTEXT_OF(provctx); + pectx->cofactor_mode = -1; + pectx->kdf_type = PROV_ECDH_KDF_NONE; + + return (void *)pectx; +} + +static +int ecdh_init(void *vpecdhctx, void *vecdh) +{ + PROV_ECDH_CTX *pecdhctx = (PROV_ECDH_CTX *)vpecdhctx; + + if (pecdhctx == NULL || vecdh == NULL || !EC_KEY_up_ref(vecdh)) + return 0; + EC_KEY_free(pecdhctx->k); + pecdhctx->k = vecdh; + pecdhctx->cofactor_mode = -1; + pecdhctx->kdf_type = PROV_ECDH_KDF_NONE; + return 1; +} + +static +int ecdh_set_peer(void *vpecdhctx, void *vecdh) +{ + PROV_ECDH_CTX *pecdhctx = (PROV_ECDH_CTX *)vpecdhctx; + + if (pecdhctx == NULL || vecdh == NULL || !EC_KEY_up_ref(vecdh)) + return 0; + EC_KEY_free(pecdhctx->peerk); + pecdhctx->peerk = vecdh; + return 1; +} + +static +void ecdh_freectx(void *vpecdhctx) +{ + PROV_ECDH_CTX *pecdhctx = (PROV_ECDH_CTX *)vpecdhctx; + + EC_KEY_free(pecdhctx->k); + EC_KEY_free(pecdhctx->peerk); + + EVP_MD_free(pecdhctx->kdf_md); + OPENSSL_clear_free(pecdhctx->kdf_ukm, pecdhctx->kdf_ukmlen); + + OPENSSL_free(pecdhctx); +} + +static +void *ecdh_dupctx(void *vpecdhctx) +{ + PROV_ECDH_CTX *srcctx = (PROV_ECDH_CTX *)vpecdhctx; + PROV_ECDH_CTX *dstctx; + + dstctx = OPENSSL_zalloc(sizeof(*srcctx)); + if (dstctx == NULL) + return NULL; + + *dstctx = *srcctx; + + /* clear all pointers */ + + dstctx->k= NULL; + dstctx->peerk = NULL; + dstctx->kdf_md = NULL; + dstctx->kdf_ukm = NULL; + + /* up-ref all ref-counted objects referenced in dstctx */ + + if (srcctx->k != NULL && !EC_KEY_up_ref(srcctx->k)) + goto err; + else + dstctx->k = srcctx->k; + + if (srcctx->peerk != NULL && !EC_KEY_up_ref(srcctx->peerk)) + goto err; + else + dstctx->peerk = srcctx->peerk; + + if (srcctx->kdf_md != NULL && !EVP_MD_up_ref(srcctx->kdf_md)) + goto err; + else + dstctx->kdf_md = srcctx->kdf_md; + + /* Duplicate UKM data if present */ + if (srcctx->kdf_ukm != NULL && srcctx->kdf_ukmlen > 0) { + dstctx->kdf_ukm = OPENSSL_memdup(srcctx->kdf_ukm, + srcctx->kdf_ukmlen); + if (dstctx->kdf_ukm == NULL) + goto err; + } + + return dstctx; + + err: + ecdh_freectx(dstctx); + return NULL; +} + +static +int ecdh_set_ctx_params(void *vpecdhctx, const OSSL_PARAM params[]) +{ + char name[80] = { '\0' }; /* should be big enough */ + char *str = NULL; + PROV_ECDH_CTX *pectx = (PROV_ECDH_CTX *)vpecdhctx; + const OSSL_PARAM *p; + + if (pectx == NULL || params == NULL) + return 0; + + p = OSSL_PARAM_locate_const(params, OSSL_EXCHANGE_PARAM_EC_ECDH_COFACTOR_MODE); + if (p != NULL) { + int mode; + + if (!OSSL_PARAM_get_int(p, &mode)) + return 0; + + if (mode < -1 || mode > 1) + return 0; + + pectx->cofactor_mode = mode; + } + + p = OSSL_PARAM_locate_const(params, OSSL_EXCHANGE_PARAM_KDF_TYPE); + if (p != NULL) { + str = name; + if (!OSSL_PARAM_get_utf8_string(p, &str, sizeof(name))) + return 0; + + if (name[0] == '\0') + pectx->kdf_type = PROV_ECDH_KDF_NONE; + else if (strcmp(name, OSSL_KDF_NAME_X963KDF) == 0) + pectx->kdf_type = PROV_ECDH_KDF_X9_63; + else + return 0; + } + + p = OSSL_PARAM_locate_const(params, OSSL_EXCHANGE_PARAM_KDF_DIGEST); + if (p != NULL) { + char mdprops[80] = { '\0' }; /* should be big enough */ + + str = name; + if (!OSSL_PARAM_get_utf8_string(p, &str, sizeof(name))) + return 0; + + str = mdprops; + p = OSSL_PARAM_locate_const(params, + OSSL_EXCHANGE_PARAM_KDF_DIGEST_PROPS); + + if (p != NULL) { + if (!OSSL_PARAM_get_utf8_string(p, &str, sizeof(mdprops))) + return 0; + } + + EVP_MD_free(pectx->kdf_md); + pectx->kdf_md = EVP_MD_fetch(pectx->libctx, name, mdprops); + + if (pectx->kdf_md == NULL) + return 0; + } + + p = OSSL_PARAM_locate_const(params, OSSL_EXCHANGE_PARAM_KDF_OUTLEN); + if (p != NULL) { + size_t outlen; + + if (!OSSL_PARAM_get_size_t(p, &outlen)) + return 0; + pectx->kdf_outlen = outlen; + } + + p = OSSL_PARAM_locate_const(params, OSSL_EXCHANGE_PARAM_KDF_UKM); + if (p != NULL) { + void *tmp_ukm = NULL; + size_t tmp_ukmlen; + + if (!OSSL_PARAM_get_octet_string(p, &tmp_ukm, 0, &tmp_ukmlen)) + return 0; + OPENSSL_free(pectx->kdf_ukm); + pectx->kdf_ukm = tmp_ukm; + pectx->kdf_ukmlen = tmp_ukmlen; + } + + return 1; +} + +static const OSSL_PARAM known_settable_ctx_params[] = { + OSSL_PARAM_int(OSSL_EXCHANGE_PARAM_EC_ECDH_COFACTOR_MODE, NULL), + OSSL_PARAM_utf8_string(OSSL_EXCHANGE_PARAM_KDF_TYPE, NULL, 0), + OSSL_PARAM_utf8_string(OSSL_EXCHANGE_PARAM_KDF_DIGEST, NULL, 0), + OSSL_PARAM_utf8_string(OSSL_EXCHANGE_PARAM_KDF_DIGEST_PROPS, NULL, 0), + OSSL_PARAM_size_t(OSSL_EXCHANGE_PARAM_KDF_OUTLEN, NULL), + OSSL_PARAM_octet_string(OSSL_EXCHANGE_PARAM_KDF_UKM, NULL, 0), + OSSL_PARAM_END +}; + +static +const OSSL_PARAM *ecdh_settable_ctx_params(void) +{ + return known_settable_ctx_params; +} + +static +int ecdh_get_ctx_params(void *vpecdhctx, OSSL_PARAM params[]) +{ + PROV_ECDH_CTX *pectx = (PROV_ECDH_CTX *)vpecdhctx; + OSSL_PARAM *p; + + if (pectx == NULL || params == NULL) + return 0; + + p = OSSL_PARAM_locate(params, OSSL_EXCHANGE_PARAM_EC_ECDH_COFACTOR_MODE); + if (p != NULL) { + int mode = pectx->cofactor_mode; + + if (mode == -1) { + /* check what is the default for pecdhctx->k */ + mode = EC_KEY_get_flags(pectx->k) & EC_FLAG_COFACTOR_ECDH ? 1 : 0; + } + + if (!OSSL_PARAM_set_int(p, mode)) + return 0; + } + + p = OSSL_PARAM_locate(params, OSSL_EXCHANGE_PARAM_KDF_TYPE); + if (p != NULL) { + const char *kdf_type = NULL; + + switch (pectx->kdf_type) { + case PROV_ECDH_KDF_NONE: + kdf_type = ""; + break; + case PROV_ECDH_KDF_X9_63: + kdf_type = OSSL_KDF_NAME_X963KDF; + break; + default: + return 0; + } + + if (!OSSL_PARAM_set_utf8_string(p, kdf_type)) + return 0; + } + + p = OSSL_PARAM_locate(params, OSSL_EXCHANGE_PARAM_KDF_DIGEST); + if (p != NULL + && !OSSL_PARAM_set_utf8_string(p, pectx->kdf_md == NULL + ? "" + : EVP_MD_name(pectx->kdf_md))){ + return 0; + } + + p = OSSL_PARAM_locate(params, OSSL_EXCHANGE_PARAM_KDF_OUTLEN); + if (p != NULL && !OSSL_PARAM_set_size_t(p, pectx->kdf_outlen)) + return 0; + + p = OSSL_PARAM_locate(params, OSSL_EXCHANGE_PARAM_KDF_UKM); + if (p != NULL && !OSSL_PARAM_set_octet_ptr(p, pectx->kdf_ukm, 0)) + return 0; + + p = OSSL_PARAM_locate(params, OSSL_EXCHANGE_PARAM_KDF_UKM_LEN); + if (p != NULL && !OSSL_PARAM_set_size_t(p, pectx->kdf_ukmlen)) + return 0; + + return 1; +} + +static const OSSL_PARAM known_gettable_ctx_params[] = { + OSSL_PARAM_int(OSSL_EXCHANGE_PARAM_EC_ECDH_COFACTOR_MODE, NULL), + OSSL_PARAM_utf8_string(OSSL_EXCHANGE_PARAM_KDF_TYPE, NULL, 0), + OSSL_PARAM_utf8_string(OSSL_EXCHANGE_PARAM_KDF_DIGEST, NULL, 0), + OSSL_PARAM_size_t(OSSL_EXCHANGE_PARAM_KDF_OUTLEN, NULL), + OSSL_PARAM_DEFN(OSSL_EXCHANGE_PARAM_KDF_UKM, OSSL_PARAM_OCTET_PTR, + NULL, 0), + OSSL_PARAM_size_t(OSSL_EXCHANGE_PARAM_KDF_UKM_LEN, NULL), + OSSL_PARAM_END +}; + +static +const OSSL_PARAM *ecdh_gettable_ctx_params(void) +{ + return known_gettable_ctx_params; +} + +static ossl_inline +size_t ecdh_size(const EC_KEY *k) +{ + size_t degree = 0; + const EC_GROUP *group; + + if (k == NULL + || (group = EC_KEY_get0_group(k)) == NULL) + return 0; + + degree = EC_GROUP_get_degree(group); + + return (degree + 7) / 8; +} + +static ossl_inline +int ecdh_plain_derive(void *vpecdhctx, unsigned char *secret, + size_t *psecretlen, size_t outlen) +{ + PROV_ECDH_CTX *pecdhctx = (PROV_ECDH_CTX *)vpecdhctx; + int retlen, ret = 0; + size_t ecdhsize, size; + const EC_POINT *ppubkey = NULL; + EC_KEY *privk = NULL; + const EC_GROUP *group; + const BIGNUM *cofactor; + int key_cofactor_mode; + + if (pecdhctx->k == NULL || pecdhctx->peerk == NULL) { + ERR_raise(ERR_LIB_PROV, EC_R_KEYS_NOT_SET); + return 0; + } + + ecdhsize = ecdh_size(pecdhctx->k); + if (secret == NULL) { + *psecretlen = ecdhsize; + return 1; + } + + if ((group = EC_KEY_get0_group(pecdhctx->k)) == NULL + || (cofactor = EC_GROUP_get0_cofactor(group)) == NULL ) + return 0; + + /* + * NB: unlike PKCS#3 DH, if outlen is less than maximum size this is not + * an error, the result is truncated. + */ + size = outlen < ecdhsize ? outlen : ecdhsize; + + /* + * The ctx->cofactor_mode flag has precedence over the + * cofactor_mode flag set on ctx->k. + * + * - if ctx->cofactor_mode == -1, use ctx->k directly + * - if ctx->cofactor_mode == key_cofactor_mode, use ctx->k directly + * - if ctx->cofactor_mode != key_cofactor_mode: + * - if ctx->k->cofactor == 1, the cofactor_mode flag is irrelevant, use + * ctx->k directly + * - if ctx->k->cofactor != 1, use a duplicate of ctx->k with the flag + * set to ctx->cofactor_mode + */ + key_cofactor_mode = + (EC_KEY_get_flags(pecdhctx->k) & EC_FLAG_COFACTOR_ECDH) ? 1 : 0; + if (pecdhctx->cofactor_mode != -1 + && pecdhctx->cofactor_mode != key_cofactor_mode + && !BN_is_one(cofactor)) { + if ((privk = EC_KEY_dup(pecdhctx->k)) == NULL) + return 0; + + if (pecdhctx->cofactor_mode == 1) + EC_KEY_set_flags(privk, EC_FLAG_COFACTOR_ECDH); + else + EC_KEY_clear_flags(privk, EC_FLAG_COFACTOR_ECDH); + } else { + privk = pecdhctx->k; + } + + ppubkey = EC_KEY_get0_public_key(pecdhctx->peerk); + + retlen = ECDH_compute_key(secret, size, ppubkey, privk, NULL); + + if (retlen <= 0) + goto end; + + *psecretlen = retlen; + ret = 1; + + end: + if (privk != pecdhctx->k) + EC_KEY_free(privk); + return ret; +} + +static ossl_inline +int ecdh_X9_63_kdf_derive(void *vpecdhctx, unsigned char *secret, + size_t *psecretlen, size_t outlen) +{ + PROV_ECDH_CTX *pecdhctx = (PROV_ECDH_CTX *)vpecdhctx; + unsigned char *stmp = NULL; + size_t stmplen; + int ret = 0; + + if (secret == NULL) { + *psecretlen = pecdhctx->kdf_outlen; + return 1; + } + + if (pecdhctx->kdf_outlen > outlen) + return 0; + if (!ecdh_plain_derive(vpecdhctx, NULL, &stmplen, 0)) + return 0; + if ((stmp = OPENSSL_secure_malloc(stmplen)) == NULL) { + ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE); + return 0; + } + if (!ecdh_plain_derive(vpecdhctx, stmp, &stmplen, stmplen)) + goto err; + + /* Do KDF stuff */ + if (!ecdh_KDF_X9_63(secret, pecdhctx->kdf_outlen, + stmp, stmplen, + pecdhctx->kdf_ukm, + pecdhctx->kdf_ukmlen, + pecdhctx->kdf_md)) + goto err; + *psecretlen = pecdhctx->kdf_outlen; + ret = 1; + + err: + OPENSSL_secure_clear_free(stmp, stmplen); + return ret; +} + +static +int ecdh_derive(void *vpecdhctx, unsigned char *secret, + size_t *psecretlen, size_t outlen) +{ + PROV_ECDH_CTX *pecdhctx = (PROV_ECDH_CTX *)vpecdhctx; + + switch (pecdhctx->kdf_type) { + case PROV_ECDH_KDF_NONE: + return ecdh_plain_derive(vpecdhctx, secret, psecretlen, outlen); + case PROV_ECDH_KDF_X9_63: + return ecdh_X9_63_kdf_derive(vpecdhctx, secret, psecretlen, outlen); + } + + return 0; +} + + + +const OSSL_DISPATCH ecdh_keyexch_functions[] = { + { OSSL_FUNC_KEYEXCH_NEWCTX, (void (*)(void))ecdh_newctx }, + { OSSL_FUNC_KEYEXCH_INIT, (void (*)(void))ecdh_init }, + { OSSL_FUNC_KEYEXCH_DERIVE, (void (*)(void))ecdh_derive }, + { OSSL_FUNC_KEYEXCH_SET_PEER, (void (*)(void))ecdh_set_peer }, + { OSSL_FUNC_KEYEXCH_FREECTX, (void (*)(void))ecdh_freectx }, + { OSSL_FUNC_KEYEXCH_DUPCTX, (void (*)(void))ecdh_dupctx }, + { OSSL_FUNC_KEYEXCH_SET_CTX_PARAMS, (void (*)(void))ecdh_set_ctx_params }, + { OSSL_FUNC_KEYEXCH_SETTABLE_CTX_PARAMS, + (void (*)(void))ecdh_settable_ctx_params }, + { OSSL_FUNC_KEYEXCH_GET_CTX_PARAMS, (void (*)(void))ecdh_get_ctx_params }, + { OSSL_FUNC_KEYEXCH_GETTABLE_CTX_PARAMS, + (void (*)(void))ecdh_gettable_ctx_params }, + { 0, NULL } +}; |