--- /dev/null
+/*
+ * Copyright 2019 The OpenSSL Project Authors. All Rights Reserved.
+ * Copyright 2019 Red Hat, Inc.
+ *
+ * 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
+ */
+
+/*
+ * This implements https://csrc.nist.gov/publications/detail/sp/800-108/final
+ * section 5.1 ("counter mode") in HMAC only. That document does not name the
+ * KDFs it defines; the name is derived from
+ * https://csrc.nist.gov/Projects/Cryptographic-Algorithm-Validation-Program/Key-Derivation
+ *
+ * Note that sections 5.2 ("feedback mode") and 5.3 ("double-pipeline mode")
+ * are not implemented, though it would be possible to do so in the future.
+ * CMAC mode is also not implemented; some plumbing would be required.
+ *
+ * These versions all assume the counter is used. It would be relatively
+ * straightforward to expose a configuration handle should the need arise.
+ *
+ * Variable names attempt to match those of SP800-108.
+ */
+
+#include <stdarg.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <openssl/core_names.h>
+#include <openssl/evp.h>
+#include <openssl/hmac.h>
+#include <openssl/kdf.h>
+#include <openssl/params.h>
+
+#include "internal/cryptlib.h"
+#include "crypto/evp.h"
+#include "internal/numbers.h"
+#include "internal/provider_algs.h"
+#include "internal/provider_ctx.h"
+#include "internal/provider_util.h"
+#include "internal/providercommonerr.h"
+
+#include "e_os.h"
+
+#define MIN(a, b) ((a) < (b)) ? (a) : (b)
+
+/* Our context structure. */
+typedef struct {
+ void *provctx;
+ EVP_MAC_CTX *ctx_init;
+
+ /* Names are lowercased versions of those found in SP800-108. */
+ unsigned char *ki;
+ size_t ki_len;
+ unsigned char *label;
+ size_t label_len;
+ unsigned char *context;
+ size_t context_len;
+} KBKDF;
+
+/* Definitions needed for typechecking. */
+static OSSL_OP_kdf_newctx_fn kbkdf_new;
+static OSSL_OP_kdf_freectx_fn kbkdf_free;
+static OSSL_OP_kdf_reset_fn kbkdf_reset;
+static OSSL_OP_kdf_derive_fn kbkdf_derive;
+static OSSL_OP_kdf_settable_ctx_params_fn kbkdf_settable_ctx_params;
+static OSSL_OP_kdf_set_ctx_params_fn kbkdf_set_ctx_params;
+
+/* Not all platforms have htobe32(). */
+static uint32_t be32(uint32_t host)
+{
+ uint32_t big = 0;
+ const union {
+ long one;
+ char little;
+ } is_endian = { 1 };
+
+ if (!is_endian.little)
+ return host;
+
+ big |= (host & 0xff000000) >> 24;
+ big |= (host & 0x00ff0000) >> 8;
+ big |= (host & 0x0000ff00) << 8;
+ big |= (host & 0x000000ff) << 24;
+ return big;
+}
+
+static void *kbkdf_new(void *provctx)
+{
+ KBKDF *ctx;
+
+ ctx = OPENSSL_zalloc(sizeof(*ctx));
+ if (ctx == NULL) {
+ ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE);
+ return NULL;
+ }
+
+ ctx->provctx = provctx;
+ return ctx;
+}
+
+static void kbkdf_free(void *vctx)
+{
+ KBKDF *ctx = (KBKDF *)vctx;
+
+ kbkdf_reset(ctx);
+ OPENSSL_free(ctx);
+}
+
+static void kbkdf_reset(void *vctx)
+{
+ KBKDF *ctx = (KBKDF *)vctx;
+
+ EVP_MAC_CTX_free(ctx->ctx_init);
+ OPENSSL_clear_free(ctx->context, ctx->context_len);
+ OPENSSL_clear_free(ctx->label, ctx->label_len);
+ OPENSSL_clear_free(ctx->ki, ctx->ki_len);
+ memset(ctx, 0, sizeof(*ctx));
+}
+
+/* SP800-108 section 5.1. */
+static int kbkdf_derive_counter(EVP_MAC_CTX *ctx_init,
+ unsigned char *label, size_t label_len,
+ unsigned char *context, size_t context_len,
+ unsigned char *k_i, size_t h, uint32_t l,
+ unsigned char *ko, size_t ko_len)
+{
+ int ret = 0;
+ EVP_MAC_CTX *ctx = NULL;
+ size_t written = 0, to_write;
+ const unsigned char zero = 0;
+ uint32_t counter, i;
+
+ for (counter = 1; written < ko_len; counter++) {
+ i = be32(counter);
+
+ ctx = EVP_MAC_CTX_dup(ctx_init);
+ if (ctx == NULL)
+ goto done;
+
+ if (!EVP_MAC_update(ctx, (unsigned char *)&i, 4)
+ || !EVP_MAC_update(ctx, label, label_len)
+ || !EVP_MAC_update(ctx, &zero, 1)
+ || !EVP_MAC_update(ctx, context, context_len)
+ || !EVP_MAC_update(ctx, (unsigned char *)&l, 4)
+ || !EVP_MAC_final(ctx, k_i, NULL, h))
+ goto done;
+
+ to_write = ko_len - written;
+ memcpy(ko + written, k_i, MIN(to_write, h));
+ written += h;
+
+ EVP_MAC_CTX_free(ctx);
+ ctx = NULL;
+ }
+
+ ret = 1;
+done:
+ EVP_MAC_CTX_free(ctx);
+ return ret;
+}
+
+static int kbkdf_derive(void *vctx, unsigned char *key, size_t keylen)
+{
+ KBKDF *ctx = (KBKDF *)vctx;
+ int ret = 0;
+ unsigned char *k_i = NULL;
+ uint32_t l = be32(keylen * 8);
+ size_t h = 0;
+
+ /* Label and Context are permitted to be empty. Check everything else. */
+ if (ctx->ctx_init == NULL) {
+ if (ctx->ki_len == 0 || ctx->ki == NULL) {
+ ERR_raise(ERR_LIB_PROV, PROV_R_NO_KEY_SET);
+ return 0;
+ }
+ /* Could either be missing MAC or missing message digest -
+ * arbitrarily, I pick this one. */
+ ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_MAC);
+ return 0;
+ }
+
+ h = EVP_MAC_size(ctx->ctx_init);
+ if (h == 0)
+ goto done;
+
+ k_i = OPENSSL_zalloc(h);
+ if (k_i == NULL)
+ goto done;
+
+ ret = kbkdf_derive_counter(
+ ctx->ctx_init, ctx->label, ctx->label_len, ctx->context,
+ ctx->context_len, k_i, h, l, key, keylen);
+done:
+ if (ret != 1)
+ OPENSSL_cleanse(key, keylen);
+ OPENSSL_clear_free(k_i, h);
+ return ret;
+}
+
+static int kbkdf_set_buffer(unsigned char **out, size_t *out_len,
+ const OSSL_PARAM *p)
+{
+ if (p->data == NULL || p->data_size == 0)
+ return 1;
+
+ OPENSSL_clear_free(*out, *out_len);
+ *out = NULL;
+ return OSSL_PARAM_get_octet_string(p, (void **)out, 0, out_len);
+}
+
+static int kbkdf_set_ctx_params(void *vctx, const OSSL_PARAM params[])
+{
+ KBKDF *ctx = (KBKDF *)vctx;
+ OPENSSL_CTX *libctx = PROV_LIBRARY_CONTEXT_OF(ctx->provctx);
+ const OSSL_PARAM *p;
+ OSSL_PARAM mparams[2];
+
+ if (!ossl_prov_macctx_load_from_params(&ctx->ctx_init, params, NULL,
+ NULL, NULL, libctx))
+ return 0;
+ else if (ctx->ctx_init != NULL
+ && !EVP_MAC_is_a(EVP_MAC_CTX_mac(ctx->ctx_init),
+ OSSL_MAC_NAME_HMAC)) {
+ ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_MAC);
+ return 0;
+ }
+
+ p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_KEY);
+ if (p != NULL && !kbkdf_set_buffer(&ctx->ki, &ctx->ki_len, p))
+ return 0;
+
+ p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SALT);
+ if (p != NULL && !kbkdf_set_buffer(&ctx->label, &ctx->label_len, p))
+ return 0;
+
+ p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_INFO);
+ if (p != NULL && !kbkdf_set_buffer(&ctx->context, &ctx->context_len, p))
+ return 0;
+
+ /* Set up digest context, if we can. */
+ if (ctx->ctx_init != NULL && ctx->ki_len != 0) {
+ mparams[0] = OSSL_PARAM_construct_octet_string(OSSL_MAC_PARAM_KEY,
+ ctx->ki, ctx->ki_len);
+ mparams[1] = OSSL_PARAM_construct_end();
+
+ if (!EVP_MAC_CTX_set_params(ctx->ctx_init, mparams)
+ || !EVP_MAC_init(ctx->ctx_init))
+ return 0;
+ }
+
+ return 1;
+}
+
+static const OSSL_PARAM *kbkdf_settable_ctx_params(void)
+{
+ static const OSSL_PARAM known_settable_ctx_params[] = {
+ OSSL_PARAM_octet_string(OSSL_KDF_PARAM_INFO, NULL, 0),
+ OSSL_PARAM_octet_string(OSSL_KDF_PARAM_SALT, NULL, 0),
+ OSSL_PARAM_octet_string(OSSL_KDF_PARAM_KEY, NULL, 0),
+ OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_DIGEST, NULL, 0),
+ OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_MAC, NULL, 0),
+
+ OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_PROPERTIES, NULL, 0),
+ OSSL_PARAM_END,
+ };
+ return known_settable_ctx_params;
+}
+
+static int kbkdf_get_ctx_params(void *vctx, OSSL_PARAM params[])
+{
+ OSSL_PARAM *p;
+
+ p = OSSL_PARAM_locate(params, OSSL_KDF_PARAM_SIZE);
+ if (p == NULL)
+ return -2;
+
+ /* KBKDF can produce results as large as you like. */
+ return OSSL_PARAM_set_size_t(p, SIZE_MAX);
+}
+
+static const OSSL_PARAM *kbkdf_gettable_ctx_params(void)
+{
+ static const OSSL_PARAM known_gettable_ctx_params[] =
+ { OSSL_PARAM_size_t(OSSL_KDF_PARAM_SIZE, NULL), OSSL_PARAM_END };
+ return known_gettable_ctx_params;
+}
+
+const OSSL_DISPATCH kdf_kbkdf_functions[] = {
+ { OSSL_FUNC_KDF_NEWCTX, (void(*)(void))kbkdf_new },
+ { OSSL_FUNC_KDF_FREECTX, (void(*)(void))kbkdf_free },
+ { OSSL_FUNC_KDF_RESET, (void(*)(void))kbkdf_reset },
+ { OSSL_FUNC_KDF_DERIVE, (void(*)(void))kbkdf_derive },
+ { OSSL_FUNC_KDF_SETTABLE_CTX_PARAMS,
+ (void(*)(void))kbkdf_settable_ctx_params },
+ { OSSL_FUNC_KDF_SET_CTX_PARAMS, (void(*)(void))kbkdf_set_ctx_params },
+ { OSSL_FUNC_KDF_GETTABLE_CTX_PARAMS,
+ (void(*)(void))kbkdf_gettable_ctx_params },
+ { OSSL_FUNC_KDF_GET_CTX_PARAMS, (void(*)(void))kbkdf_get_ctx_params },
+ { 0, NULL },
+};
projects / oweals / openssl.git / blobdiff