providers/implementations/kdfs/sshkdf.c

   1 /*
   2  * Copyright 2018-2019 The OpenSSL Project Authors. All Rights Reserved.
   3  *
   4  * Licensed under the OpenSSL license (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
   8  */
   9
  10 #include <stdlib.h>
  11 #include <stdarg.h>
  12 #include <string.h>
  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 "internal/provider_ctx.h"
  20 #include "internal/providercommonerr.h"
  21 #include "prov/implementations.h"
  22 # include "internal/provider_util.h"
  23
  24 /* See RFC 4253, Section 7.2 */
  25 static OSSL_OP_kdf_newctx_fn kdf_sshkdf_new;
  26 static OSSL_OP_kdf_freectx_fn kdf_sshkdf_free;
  27 static OSSL_OP_kdf_reset_fn kdf_sshkdf_reset;
  28 static OSSL_OP_kdf_derive_fn kdf_sshkdf_derive;
  29 static OSSL_OP_kdf_settable_ctx_params_fn kdf_sshkdf_settable_ctx_params;
  30 static OSSL_OP_kdf_set_ctx_params_fn kdf_sshkdf_set_ctx_params;
  31 static OSSL_OP_kdf_gettable_ctx_params_fn kdf_sshkdf_gettable_ctx_params;
  32 static OSSL_OP_kdf_get_ctx_params_fn kdf_sshkdf_get_ctx_params;
  33
  34 static int SSHKDF(const EVP_MD *evp_md,
  35                   const unsigned char *key, size_t key_len,
  36                   const unsigned char *xcghash, size_t xcghash_len,
  37                   const unsigned char *session_id, size_t session_id_len,
  38                   char type, unsigned char *okey, size_t okey_len);
  39
  40 typedef struct {
  41     void *provctx;
  42     PROV_DIGEST digest;
  43     unsigned char *key; /* K */
  44     size_t key_len;
  45     unsigned char *xcghash; /* H */
  46     size_t xcghash_len;
  47     char type; /* X */
  48     unsigned char *session_id;
  49     size_t session_id_len;
  50 } KDF_SSHKDF;
  51
  52 static void *kdf_sshkdf_new(void *provctx)
  53 {
  54     KDF_SSHKDF *ctx;
  55
  56     if ((ctx = OPENSSL_zalloc(sizeof(*ctx))) == NULL)
  57         ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE);
  58     ctx->provctx = provctx;
  59     return ctx;
  60 }
  61
  62 static void kdf_sshkdf_free(void *vctx)
  63 {
  64     KDF_SSHKDF *ctx = (KDF_SSHKDF *)vctx;
  65
  66     kdf_sshkdf_reset(ctx);
  67     OPENSSL_free(ctx);
  68 }
  69
  70 static void kdf_sshkdf_reset(void *vctx)
  71 {
  72     KDF_SSHKDF *ctx = (KDF_SSHKDF *)vctx;
  73
  74     ossl_prov_digest_reset(&ctx->digest);
  75     OPENSSL_clear_free(ctx->key, ctx->key_len);
  76     OPENSSL_clear_free(ctx->xcghash, ctx->xcghash_len);
  77     OPENSSL_clear_free(ctx->session_id, ctx->session_id_len);
  78     memset(ctx, 0, sizeof(*ctx));
  79 }
  80
  81 static int sshkdf_set_membuf(unsigned char **dst, size_t *dst_len,
  82                              const OSSL_PARAM *p)
  83 {
  84     OPENSSL_clear_free(*dst, *dst_len);
  85     *dst = NULL;
  86     return OSSL_PARAM_get_octet_string(p, (void **)dst, 0, dst_len);
  87 }
  88
  89 static int kdf_sshkdf_derive(void *vctx, unsigned char *key,
  90                              size_t keylen)
  91 {
  92     KDF_SSHKDF *ctx = (KDF_SSHKDF *)vctx;
  93     const EVP_MD *md = ossl_prov_digest_md(&ctx->digest);
  94
  95     if (md == NULL) {
  96         ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_MESSAGE_DIGEST);
  97         return 0;
  98     }
  99     if (ctx->key == NULL) {
 100         ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_KEY);
 101         return 0;
 102     }
 103     if (ctx->xcghash == NULL) {
 104         ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_XCGHASH);
 105         return 0;
 106     }
 107     if (ctx->session_id == NULL) {
 108         ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_SESSION_ID);
 109         return 0;
 110     }
 111     if (ctx->type == 0) {
 112         ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_TYPE);
 113         return 0;
 114     }
 115     return SSHKDF(md, ctx->key, ctx->key_len,
 116                   ctx->xcghash, ctx->xcghash_len,
 117                   ctx->session_id, ctx->session_id_len,
 118                   ctx->type, key, keylen);
 119 }
 120
 121 static int kdf_sshkdf_set_ctx_params(void *vctx, const OSSL_PARAM params[])
 122 {
 123     const OSSL_PARAM *p;
 124     KDF_SSHKDF *ctx = vctx;
 125     OPENSSL_CTX *provctx = PROV_LIBRARY_CONTEXT_OF(ctx->provctx);
 126     int t;
 127
 128     if (!ossl_prov_digest_load_from_params(&ctx->digest, params, provctx))
 129         return 0;
 130
 131     if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_KEY)) != NULL)
 132         if (!sshkdf_set_membuf(&ctx->key, &ctx->key_len, p))
 133             return 0;
 134
 135     if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SSHKDF_XCGHASH))
 136         != NULL)
 137         if (!sshkdf_set_membuf(&ctx->xcghash, &ctx->xcghash_len, p))
 138             return 0;
 139
 140     if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SSHKDF_SESSION_ID))
 141         != NULL)
 142         if (!sshkdf_set_membuf(&ctx->session_id, &ctx->session_id_len, p))
 143             return 0;
 144
 145     if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SSHKDF_TYPE))
 146         != NULL) {
 147         if (p->data == NULL || p->data_size == 0)
 148             return 0;
 149         t = *(unsigned char *)p->data;
 150         if (t < 65 || t > 70) {
 151             ERR_raise(ERR_LIB_PROV, PROV_R_VALUE_ERROR);
 152             return 0;
 153         }
 154         ctx->type = (char)t;
 155     }
 156     return 1;
 157 }
 158
 159 static const OSSL_PARAM *kdf_sshkdf_settable_ctx_params(void)
 160 {
 161     static const OSSL_PARAM known_settable_ctx_params[] = {
 162         OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_PROPERTIES, NULL, 0),
 163         OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_DIGEST, NULL, 0),
 164         OSSL_PARAM_octet_string(OSSL_KDF_PARAM_KEY, NULL, 0),
 165         OSSL_PARAM_octet_string(OSSL_KDF_PARAM_SSHKDF_XCGHASH, NULL, 0),
 166         OSSL_PARAM_octet_string(OSSL_KDF_PARAM_SSHKDF_SESSION_ID, NULL, 0),
 167         OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_SSHKDF_TYPE, NULL, 0),
 168         OSSL_PARAM_END
 169     };
 170     return known_settable_ctx_params;
 171 }
 172
 173 static int kdf_sshkdf_get_ctx_params(void *vctx, OSSL_PARAM params[])
 174 {
 175     OSSL_PARAM *p;
 176
 177     if ((p = OSSL_PARAM_locate(params, OSSL_KDF_PARAM_SIZE)) != NULL)
 178         return OSSL_PARAM_set_size_t(p, SIZE_MAX);
 179     return -2;
 180 }
 181
 182 static const OSSL_PARAM *kdf_sshkdf_gettable_ctx_params(void)
 183 {
 184     static const OSSL_PARAM known_gettable_ctx_params[] = {
 185         OSSL_PARAM_size_t(OSSL_KDF_PARAM_SIZE, NULL),
 186         OSSL_PARAM_END
 187     };
 188     return known_gettable_ctx_params;
 189 }
 190
 191 const OSSL_DISPATCH kdf_sshkdf_functions[] = {
 192     { OSSL_FUNC_KDF_NEWCTX, (void(*)(void))kdf_sshkdf_new },
 193     { OSSL_FUNC_KDF_FREECTX, (void(*)(void))kdf_sshkdf_free },
 194     { OSSL_FUNC_KDF_RESET, (void(*)(void))kdf_sshkdf_reset },
 195     { OSSL_FUNC_KDF_DERIVE, (void(*)(void))kdf_sshkdf_derive },
 196     { OSSL_FUNC_KDF_SETTABLE_CTX_PARAMS,
 197       (void(*)(void))kdf_sshkdf_settable_ctx_params },
 198     { OSSL_FUNC_KDF_SET_CTX_PARAMS, (void(*)(void))kdf_sshkdf_set_ctx_params },
 199     { OSSL_FUNC_KDF_GETTABLE_CTX_PARAMS,
 200       (void(*)(void))kdf_sshkdf_gettable_ctx_params },
 201     { OSSL_FUNC_KDF_GET_CTX_PARAMS, (void(*)(void))kdf_sshkdf_get_ctx_params },
 202     { 0, NULL }
 203 };
 204
 205 static int SSHKDF(const EVP_MD *evp_md,
 206                   const unsigned char *key, size_t key_len,
 207                   const unsigned char *xcghash, size_t xcghash_len,
 208                   const unsigned char *session_id, size_t session_id_len,
 209                   char type, unsigned char *okey, size_t okey_len)
 210 {
 211     EVP_MD_CTX *md = NULL;
 212     unsigned char digest[EVP_MAX_MD_SIZE];
 213     unsigned int dsize = 0;
 214     size_t cursize = 0;
 215     int ret = 0;
 216
 217     md = EVP_MD_CTX_new();
 218     if (md == NULL)
 219         return 0;
 220
 221     if (!EVP_DigestInit_ex(md, evp_md, NULL))
 222         goto out;
 223
 224     if (!EVP_DigestUpdate(md, key, key_len))
 225         goto out;
 226
 227     if (!EVP_DigestUpdate(md, xcghash, xcghash_len))
 228         goto out;
 229
 230     if (!EVP_DigestUpdate(md, &type, 1))
 231         goto out;
 232
 233     if (!EVP_DigestUpdate(md, session_id, session_id_len))
 234         goto out;
 235
 236     if (!EVP_DigestFinal_ex(md, digest, &dsize))
 237         goto out;
 238
 239     if (okey_len < dsize) {
 240         memcpy(okey, digest, okey_len);
 241         ret = 1;
 242         goto out;
 243     }
 244
 245     memcpy(okey, digest, dsize);
 246
 247     for (cursize = dsize; cursize < okey_len; cursize += dsize) {
 248
 249         if (!EVP_DigestInit_ex(md, evp_md, NULL))
 250             goto out;
 251
 252         if (!EVP_DigestUpdate(md, key, key_len))
 253             goto out;
 254
 255         if (!EVP_DigestUpdate(md, xcghash, xcghash_len))
 256             goto out;
 257
 258         if (!EVP_DigestUpdate(md, okey, cursize))
 259             goto out;
 260
 261         if (!EVP_DigestFinal_ex(md, digest, &dsize))
 262             goto out;
 263
 264         if (okey_len < cursize + dsize) {
 265             memcpy(okey + cursize, digest, okey_len - cursize);
 266             ret = 1;
 267             goto out;
 268         }
 269
 270         memcpy(okey + cursize, digest, dsize);
 271     }
 272
 273     ret = 1;
 274
 275 out:
 276     EVP_MD_CTX_free(md);
 277     OPENSSL_cleanse(digest, EVP_MAX_MD_SIZE);
 278     return ret;
 279 }
 280