2 * Copyright 2018-2020 The OpenSSL Project Authors. All Rights Reserved.
4 * Licensed under the Apache License 2.0 (the "License"). You may not use
5 * this file except in compliance with the License. You can obtain a copy
6 * in the file LICENSE in the source distribution or at
7 * https://www.openssl.org/source/license.html
13 #include <openssl/evp.h>
14 #include <openssl/kdf.h>
15 #include <openssl/core_names.h>
16 #include "internal/cryptlib.h"
17 #include "internal/numbers.h"
18 #include "crypto/evp.h"
19 #include "prov/provider_ctx.h"
20 #include "prov/providercommon.h"
21 #include "prov/providercommonerr.h"
22 #include "prov/implementations.h"
23 #include "prov/provider_util.h"
25 /* See RFC 4253, Section 7.2 */
26 static OSSL_FUNC_kdf_newctx_fn kdf_sshkdf_new;
27 static OSSL_FUNC_kdf_freectx_fn kdf_sshkdf_free;
28 static OSSL_FUNC_kdf_reset_fn kdf_sshkdf_reset;
29 static OSSL_FUNC_kdf_derive_fn kdf_sshkdf_derive;
30 static OSSL_FUNC_kdf_settable_ctx_params_fn kdf_sshkdf_settable_ctx_params;
31 static OSSL_FUNC_kdf_set_ctx_params_fn kdf_sshkdf_set_ctx_params;
32 static OSSL_FUNC_kdf_gettable_ctx_params_fn kdf_sshkdf_gettable_ctx_params;
33 static OSSL_FUNC_kdf_get_ctx_params_fn kdf_sshkdf_get_ctx_params;
35 static int SSHKDF(const EVP_MD *evp_md,
36 const unsigned char *key, size_t key_len,
37 const unsigned char *xcghash, size_t xcghash_len,
38 const unsigned char *session_id, size_t session_id_len,
39 char type, unsigned char *okey, size_t okey_len);
44 unsigned char *key; /* K */
46 unsigned char *xcghash; /* H */
49 unsigned char *session_id;
50 size_t session_id_len;
53 static void *kdf_sshkdf_new(void *provctx)
57 if (!ossl_prov_is_running())
60 if ((ctx = OPENSSL_zalloc(sizeof(*ctx))) == NULL)
61 ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE);
62 ctx->provctx = provctx;
66 static void kdf_sshkdf_free(void *vctx)
68 KDF_SSHKDF *ctx = (KDF_SSHKDF *)vctx;
71 kdf_sshkdf_reset(ctx);
76 static void kdf_sshkdf_reset(void *vctx)
78 KDF_SSHKDF *ctx = (KDF_SSHKDF *)vctx;
79 void *provctx = ctx->provctx;
81 ossl_prov_digest_reset(&ctx->digest);
82 OPENSSL_clear_free(ctx->key, ctx->key_len);
83 OPENSSL_clear_free(ctx->xcghash, ctx->xcghash_len);
84 OPENSSL_clear_free(ctx->session_id, ctx->session_id_len);
85 memset(ctx, 0, sizeof(*ctx));
86 ctx->provctx = provctx;
89 static int sshkdf_set_membuf(unsigned char **dst, size_t *dst_len,
92 OPENSSL_clear_free(*dst, *dst_len);
94 return OSSL_PARAM_get_octet_string(p, (void **)dst, 0, dst_len);
97 static int kdf_sshkdf_derive(void *vctx, unsigned char *key,
100 KDF_SSHKDF *ctx = (KDF_SSHKDF *)vctx;
103 if (!ossl_prov_is_running())
106 md = ossl_prov_digest_md(&ctx->digest);
108 ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_MESSAGE_DIGEST);
111 if (ctx->key == NULL) {
112 ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_KEY);
115 if (ctx->xcghash == NULL) {
116 ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_XCGHASH);
119 if (ctx->session_id == NULL) {
120 ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_SESSION_ID);
123 if (ctx->type == 0) {
124 ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_TYPE);
127 return SSHKDF(md, ctx->key, ctx->key_len,
128 ctx->xcghash, ctx->xcghash_len,
129 ctx->session_id, ctx->session_id_len,
130 ctx->type, key, keylen);
133 static int kdf_sshkdf_set_ctx_params(void *vctx, const OSSL_PARAM params[])
136 KDF_SSHKDF *ctx = vctx;
137 OSSL_LIB_CTX *provctx = PROV_LIBCTX_OF(ctx->provctx);
140 if (!ossl_prov_digest_load_from_params(&ctx->digest, params, provctx))
143 if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_KEY)) != NULL)
144 if (!sshkdf_set_membuf(&ctx->key, &ctx->key_len, p))
147 if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SSHKDF_XCGHASH))
149 if (!sshkdf_set_membuf(&ctx->xcghash, &ctx->xcghash_len, p))
152 if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SSHKDF_SESSION_ID))
154 if (!sshkdf_set_membuf(&ctx->session_id, &ctx->session_id_len, p))
157 if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SSHKDF_TYPE))
159 if (p->data == NULL || p->data_size == 0)
161 t = *(unsigned char *)p->data;
162 if (t < 65 || t > 70) {
163 ERR_raise(ERR_LIB_PROV, PROV_R_VALUE_ERROR);
171 static const OSSL_PARAM *kdf_sshkdf_settable_ctx_params(ossl_unused void *p_ctx)
173 static const OSSL_PARAM known_settable_ctx_params[] = {
174 OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_PROPERTIES, NULL, 0),
175 OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_DIGEST, NULL, 0),
176 OSSL_PARAM_octet_string(OSSL_KDF_PARAM_KEY, NULL, 0),
177 OSSL_PARAM_octet_string(OSSL_KDF_PARAM_SSHKDF_XCGHASH, NULL, 0),
178 OSSL_PARAM_octet_string(OSSL_KDF_PARAM_SSHKDF_SESSION_ID, NULL, 0),
179 OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_SSHKDF_TYPE, NULL, 0),
182 return known_settable_ctx_params;
185 static int kdf_sshkdf_get_ctx_params(void *vctx, OSSL_PARAM params[])
189 if ((p = OSSL_PARAM_locate(params, OSSL_KDF_PARAM_SIZE)) != NULL)
190 return OSSL_PARAM_set_size_t(p, SIZE_MAX);
194 static const OSSL_PARAM *kdf_sshkdf_gettable_ctx_params(ossl_unused void *p_ctx)
196 static const OSSL_PARAM known_gettable_ctx_params[] = {
197 OSSL_PARAM_size_t(OSSL_KDF_PARAM_SIZE, NULL),
200 return known_gettable_ctx_params;
203 const OSSL_DISPATCH ossl_kdf_sshkdf_functions[] = {
204 { OSSL_FUNC_KDF_NEWCTX, (void(*)(void))kdf_sshkdf_new },
205 { OSSL_FUNC_KDF_FREECTX, (void(*)(void))kdf_sshkdf_free },
206 { OSSL_FUNC_KDF_RESET, (void(*)(void))kdf_sshkdf_reset },
207 { OSSL_FUNC_KDF_DERIVE, (void(*)(void))kdf_sshkdf_derive },
208 { OSSL_FUNC_KDF_SETTABLE_CTX_PARAMS,
209 (void(*)(void))kdf_sshkdf_settable_ctx_params },
210 { OSSL_FUNC_KDF_SET_CTX_PARAMS, (void(*)(void))kdf_sshkdf_set_ctx_params },
211 { OSSL_FUNC_KDF_GETTABLE_CTX_PARAMS,
212 (void(*)(void))kdf_sshkdf_gettable_ctx_params },
213 { OSSL_FUNC_KDF_GET_CTX_PARAMS, (void(*)(void))kdf_sshkdf_get_ctx_params },
217 static int SSHKDF(const EVP_MD *evp_md,
218 const unsigned char *key, size_t key_len,
219 const unsigned char *xcghash, size_t xcghash_len,
220 const unsigned char *session_id, size_t session_id_len,
221 char type, unsigned char *okey, size_t okey_len)
223 EVP_MD_CTX *md = NULL;
224 unsigned char digest[EVP_MAX_MD_SIZE];
225 unsigned int dsize = 0;
229 md = EVP_MD_CTX_new();
233 if (!EVP_DigestInit_ex(md, evp_md, NULL))
236 if (!EVP_DigestUpdate(md, key, key_len))
239 if (!EVP_DigestUpdate(md, xcghash, xcghash_len))
242 if (!EVP_DigestUpdate(md, &type, 1))
245 if (!EVP_DigestUpdate(md, session_id, session_id_len))
248 if (!EVP_DigestFinal_ex(md, digest, &dsize))
251 if (okey_len < dsize) {
252 memcpy(okey, digest, okey_len);
257 memcpy(okey, digest, dsize);
259 for (cursize = dsize; cursize < okey_len; cursize += dsize) {
261 if (!EVP_DigestInit_ex(md, evp_md, NULL))
264 if (!EVP_DigestUpdate(md, key, key_len))
267 if (!EVP_DigestUpdate(md, xcghash, xcghash_len))
270 if (!EVP_DigestUpdate(md, okey, cursize))
273 if (!EVP_DigestFinal_ex(md, digest, &dsize))
276 if (okey_len < cursize + dsize) {
277 memcpy(okey + cursize, digest, okey_len - cursize);
282 memcpy(okey + cursize, digest, dsize);
289 OPENSSL_cleanse(digest, EVP_MAX_MD_SIZE);