/* * Copyright 2011-2021 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 */ #include #include #include #include #include #include #include #include #include #include "internal/thread_once.h" #include "prov/providercommon.h" #include "prov/provider_ctx.h" #include "prov/provider_util.h" #include "prov/implementations.h" #include "drbg_local.h" static OSSL_FUNC_rand_newctx_fn drbg_hash_new_wrapper; static OSSL_FUNC_rand_freectx_fn drbg_hash_free; static OSSL_FUNC_rand_instantiate_fn drbg_hash_instantiate_wrapper; static OSSL_FUNC_rand_uninstantiate_fn drbg_hash_uninstantiate_wrapper; static OSSL_FUNC_rand_generate_fn drbg_hash_generate_wrapper; static OSSL_FUNC_rand_reseed_fn drbg_hash_reseed_wrapper; static OSSL_FUNC_rand_settable_ctx_params_fn drbg_hash_settable_ctx_params; static OSSL_FUNC_rand_set_ctx_params_fn drbg_hash_set_ctx_params; static OSSL_FUNC_rand_gettable_ctx_params_fn drbg_hash_gettable_ctx_params; static OSSL_FUNC_rand_get_ctx_params_fn drbg_hash_get_ctx_params; static OSSL_FUNC_rand_verify_zeroization_fn drbg_hash_verify_zeroization; /* 888 bits from SP800-90Ar1 10.1 table 2 */ #define HASH_PRNG_MAX_SEEDLEN (888/8) /* 440 bits from SP800-90Ar1 10.1 table 2 */ #define HASH_PRNG_SMALL_SEEDLEN (440/8) /* Determine what seedlen to use based on the block length */ #define MAX_BLOCKLEN_USING_SMALL_SEEDLEN (256/8) #define INBYTE_IGNORE ((unsigned char)0xFF) typedef struct rand_drbg_hash_st { PROV_DIGEST digest; EVP_MD_CTX *ctx; size_t blocklen; unsigned char V[HASH_PRNG_MAX_SEEDLEN]; unsigned char C[HASH_PRNG_MAX_SEEDLEN]; /* Temporary value storage: should always exceed max digest length */ unsigned char vtmp[HASH_PRNG_MAX_SEEDLEN]; } PROV_DRBG_HASH; /* * SP800-90Ar1 10.3.1 Derivation function using a Hash Function (Hash_df). * The input string used is composed of: * inbyte - An optional leading byte (ignore if equal to INBYTE_IGNORE) * in - input string 1 (A Non NULL value). * in2 - optional input string (Can be NULL). * in3 - optional input string (Can be NULL). * These are concatenated as part of the DigestUpdate process. */ static int hash_df(PROV_DRBG *drbg, unsigned char *out, const unsigned char inbyte, const unsigned char *in, size_t inlen, const unsigned char *in2, size_t in2len, const unsigned char *in3, size_t in3len) { PROV_DRBG_HASH *hash = (PROV_DRBG_HASH *)drbg->data; EVP_MD_CTX *ctx = hash->ctx; unsigned char *vtmp = hash->vtmp; /* tmp = counter || num_bits_returned || [inbyte] */ unsigned char tmp[1 + 4 + 1]; int tmp_sz = 0; size_t outlen = drbg->seedlen; size_t num_bits_returned = outlen * 8; /* * No need to check outlen size here, as the standard only ever needs * seedlen bytes which is always less than the maximum permitted. */ /* (Step 3) counter = 1 (tmp[0] is the 8 bit counter) */ tmp[tmp_sz++] = 1; /* tmp[1..4] is the fixed 32 bit no_of_bits_to_return */ tmp[tmp_sz++] = (unsigned char)((num_bits_returned >> 24) & 0xff); tmp[tmp_sz++] = (unsigned char)((num_bits_returned >> 16) & 0xff); tmp[tmp_sz++] = (unsigned char)((num_bits_returned >> 8) & 0xff); tmp[tmp_sz++] = (unsigned char)(num_bits_returned & 0xff); /* Tack the additional input byte onto the end of tmp if it exists */ if (inbyte != INBYTE_IGNORE) tmp[tmp_sz++] = inbyte; /* (Step 4) */ for (;;) { /* * (Step 4.1) out = out || Hash(tmp || in || [in2] || [in3]) * (where tmp = counter || num_bits_returned || [inbyte]) */ if (!(EVP_DigestInit_ex(ctx, ossl_prov_digest_md(&hash->digest), NULL) && EVP_DigestUpdate(ctx, tmp, tmp_sz) && EVP_DigestUpdate(ctx, in, inlen) && (in2 == NULL || EVP_DigestUpdate(ctx, in2, in2len)) && (in3 == NULL || EVP_DigestUpdate(ctx, in3, in3len)))) return 0; if (outlen < hash->blocklen) { if (!EVP_DigestFinal(ctx, vtmp, NULL)) return 0; memcpy(out, vtmp, outlen); OPENSSL_cleanse(vtmp, hash->blocklen); break; } else if(!EVP_DigestFinal(ctx, out, NULL)) { return 0; } outlen -= hash->blocklen; if (outlen == 0) break; /* (Step 4.2) counter++ */ tmp[0]++; out += hash->blocklen; } return 1; } /* Helper function that just passes 2 input parameters to hash_df() */ static int hash_df1(PROV_DRBG *drbg, unsigned char *out, const unsigned char in_byte, const unsigned char *in1, size_t in1len) { return hash_df(drbg, out, in_byte, in1, in1len, NULL, 0, NULL, 0); } /* * Add 2 byte buffers together. The first elements in each buffer are the top * most bytes. The result is stored in the dst buffer. * The final carry is ignored i.e: dst = (dst + in) mod (2^seedlen_bits). * where dst size is drbg->seedlen, and inlen <= drbg->seedlen. */ static int add_bytes(PROV_DRBG *drbg, unsigned char *dst, unsigned char *in, size_t inlen) { size_t i; int result; const unsigned char *add; unsigned char carry = 0, *d; assert(drbg->seedlen >= 1 && inlen >= 1 && inlen <= drbg->seedlen); d = &dst[drbg->seedlen - 1]; add = &in[inlen - 1]; for (i = inlen; i > 0; i--, d--, add--) { result = *d + *add + carry; carry = (unsigned char)(result >> 8); *d = (unsigned char)(result & 0xff); } if (carry != 0) { /* Add the carry to the top of the dst if inlen is not the same size */ for (i = drbg->seedlen - inlen; i > 0; --i, d--) { *d += 1; /* Carry can only be 1 */ if (*d != 0) /* exit if carry doesnt propagate to the next byte */ break; } } return 1; } /* V = (V + Hash(inbyte || V || [additional_input]) mod (2^seedlen) */ static int add_hash_to_v(PROV_DRBG *drbg, unsigned char inbyte, const unsigned char *adin, size_t adinlen) { PROV_DRBG_HASH *hash = (PROV_DRBG_HASH *)drbg->data; EVP_MD_CTX *ctx = hash->ctx; return EVP_DigestInit_ex(ctx, ossl_prov_digest_md(&hash->digest), NULL) && EVP_DigestUpdate(ctx, &inbyte, 1) && EVP_DigestUpdate(ctx, hash->V, drbg->seedlen) && (adin == NULL || EVP_DigestUpdate(ctx, adin, adinlen)) && EVP_DigestFinal(ctx, hash->vtmp, NULL) && add_bytes(drbg, hash->V, hash->vtmp, hash->blocklen); } /* * The Hashgen() as listed in SP800-90Ar1 10.1.1.4 Hash_DRBG_Generate_Process. * * drbg contains the current value of V. * outlen is the requested number of bytes. * out is a buffer to return the generated bits. * * The algorithm to generate the bits is: * data = V * w = NULL * for (i = 1 to m) { * W = W || Hash(data) * data = (data + 1) mod (2^seedlen) * } * out = Leftmost(W, outlen) * * Returns zero if an error occurs otherwise it returns 1. */ static int hash_gen(PROV_DRBG *drbg, unsigned char *out, size_t outlen) { PROV_DRBG_HASH *hash = (PROV_DRBG_HASH *)drbg->data; unsigned char one = 1; if (outlen == 0) return 1; memcpy(hash->vtmp, hash->V, drbg->seedlen); for(;;) { if (!EVP_DigestInit_ex(hash->ctx, ossl_prov_digest_md(&hash->digest), NULL) || !EVP_DigestUpdate(hash->ctx, hash->vtmp, drbg->seedlen)) return 0; if (outlen < hash->blocklen) { if (!EVP_DigestFinal(hash->ctx, hash->vtmp, NULL)) return 0; memcpy(out, hash->vtmp, outlen); return 1; } else { if (!EVP_DigestFinal(hash->ctx, out, NULL)) return 0; outlen -= hash->blocklen; if (outlen == 0) break; out += hash->blocklen; } add_bytes(drbg, hash->vtmp, &one, 1); } return 1; } /* * SP800-90Ar1 10.1.1.2 Hash_DRBG_Instantiate_Process: * * ent is entropy input obtained from a randomness source of length ent_len. * nonce is a string of bytes of length nonce_len. * pstr is a personalization string received from an application. May be NULL. * * Returns zero if an error occurs otherwise it returns 1. */ static int drbg_hash_instantiate(PROV_DRBG *drbg, const unsigned char *ent, size_t ent_len, const unsigned char *nonce, size_t nonce_len, const unsigned char *pstr, size_t pstr_len) { PROV_DRBG_HASH *hash = (PROV_DRBG_HASH *)drbg->data; EVP_MD_CTX_free(hash->ctx); hash->ctx = EVP_MD_CTX_new(); /* (Step 1-3) V = Hash_df(entropy||nonce||pers, seedlen) */ return hash->ctx != NULL && hash_df(drbg, hash->V, INBYTE_IGNORE, ent, ent_len, nonce, nonce_len, pstr, pstr_len) /* (Step 4) C = Hash_df(0x00||V, seedlen) */ && hash_df1(drbg, hash->C, 0x00, hash->V, drbg->seedlen); } static int drbg_hash_instantiate_wrapper(void *vdrbg, unsigned int strength, int prediction_resistance, const unsigned char *pstr, size_t pstr_len, const OSSL_PARAM params[]) { PROV_DRBG *drbg = (PROV_DRBG *)vdrbg; if (!ossl_prov_is_running() || !drbg_hash_set_ctx_params(drbg, params)) return 0; return ossl_prov_drbg_instantiate(drbg, strength, prediction_resistance, pstr, pstr_len); } /* * SP800-90Ar1 10.1.1.3 Hash_DRBG_Reseed_Process: * * ent is entropy input bytes obtained from a randomness source. * addin is additional input received from an application. May be NULL. * * Returns zero if an error occurs otherwise it returns 1. */ static int drbg_hash_reseed(PROV_DRBG *drbg, const unsigned char *ent, size_t ent_len, const unsigned char *adin, size_t adin_len) { PROV_DRBG_HASH *hash = (PROV_DRBG_HASH *)drbg->data; /* (Step 1-2) V = Hash_df(0x01 || V || entropy_input || additional_input) */ /* V about to be updated so use C as output instead */ if (!hash_df(drbg, hash->C, 0x01, hash->V, drbg->seedlen, ent, ent_len, adin, adin_len)) return 0; memcpy(hash->V, hash->C, drbg->seedlen); /* (Step 4) C = Hash_df(0x00||V, seedlen) */ return hash_df1(drbg, hash->C, 0x00, hash->V, drbg->seedlen); } static int drbg_hash_reseed_wrapper(void *vdrbg, int prediction_resistance, const unsigned char *ent, size_t ent_len, const unsigned char *adin, size_t adin_len) { PROV_DRBG *drbg = (PROV_DRBG *)vdrbg; return ossl_prov_drbg_reseed(drbg, prediction_resistance, ent, ent_len, adin, adin_len); } /* * SP800-90Ar1 10.1.1.4 Hash_DRBG_Generate_Process: * * Generates pseudo random bytes using the drbg. * out is a buffer to fill with outlen bytes of pseudo random data. * addin is additional input received from an application. May be NULL. * * Returns zero if an error occurs otherwise it returns 1. */ static int drbg_hash_generate(PROV_DRBG *drbg, unsigned char *out, size_t outlen, const unsigned char *adin, size_t adin_len) { PROV_DRBG_HASH *hash = (PROV_DRBG_HASH *)drbg->data; unsigned char counter[4]; int reseed_counter = drbg->generate_counter; counter[0] = (unsigned char)((reseed_counter >> 24) & 0xff); counter[1] = (unsigned char)((reseed_counter >> 16) & 0xff); counter[2] = (unsigned char)((reseed_counter >> 8) & 0xff); counter[3] = (unsigned char)(reseed_counter & 0xff); return hash->ctx != NULL && (adin == NULL /* (Step 2) if adin != NULL then V = V + Hash(0x02||V||adin) */ || adin_len == 0 || add_hash_to_v(drbg, 0x02, adin, adin_len)) /* (Step 3) Hashgen(outlen, V) */ && hash_gen(drbg, out, outlen) /* (Step 4/5) H = V = (V + Hash(0x03||V) mod (2^seedlen_bits) */ && add_hash_to_v(drbg, 0x03, NULL, 0) /* (Step 5) V = (V + H + C + reseed_counter) mod (2^seedlen_bits) */ /* V = (V + C) mod (2^seedlen_bits) */ && add_bytes(drbg, hash->V, hash->C, drbg->seedlen) /* V = (V + reseed_counter) mod (2^seedlen_bits) */ && add_bytes(drbg, hash->V, counter, 4); } static int drbg_hash_generate_wrapper (void *vdrbg, unsigned char *out, size_t outlen, unsigned int strength, int prediction_resistance, const unsigned char *adin, size_t adin_len) { PROV_DRBG *drbg = (PROV_DRBG *)vdrbg; return ossl_prov_drbg_generate(drbg, out, outlen, strength, prediction_resistance, adin, adin_len); } static int drbg_hash_uninstantiate(PROV_DRBG *drbg) { PROV_DRBG_HASH *hash = (PROV_DRBG_HASH *)drbg->data; OPENSSL_cleanse(hash->V, sizeof(hash->V)); OPENSSL_cleanse(hash->C, sizeof(hash->C)); OPENSSL_cleanse(hash->vtmp, sizeof(hash->vtmp)); return ossl_prov_drbg_uninstantiate(drbg); } static int drbg_hash_uninstantiate_wrapper(void *vdrbg) { return drbg_hash_uninstantiate((PROV_DRBG *)vdrbg); } static int drbg_hash_verify_zeroization(void *vdrbg) { PROV_DRBG *drbg = (PROV_DRBG *)vdrbg; PROV_DRBG_HASH *hash = (PROV_DRBG_HASH *)drbg->data; PROV_DRBG_VERYIFY_ZEROIZATION(hash->V); PROV_DRBG_VERYIFY_ZEROIZATION(hash->C); PROV_DRBG_VERYIFY_ZEROIZATION(hash->vtmp); return 1; } static int drbg_hash_new(PROV_DRBG *ctx) { PROV_DRBG_HASH *hash; hash = OPENSSL_secure_zalloc(sizeof(*hash)); if (hash == NULL) { ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE); return 0; } ctx->data = hash; ctx->seedlen = HASH_PRNG_MAX_SEEDLEN; ctx->max_entropylen = DRBG_MAX_LENGTH; ctx->max_noncelen = DRBG_MAX_LENGTH; ctx->max_perslen = DRBG_MAX_LENGTH; ctx->max_adinlen = DRBG_MAX_LENGTH; /* Maximum number of bits per request = 2^19 = 2^16 bytes */ ctx->max_request = 1 << 16; return 1; } static void *drbg_hash_new_wrapper(void *provctx, void *parent, const OSSL_DISPATCH *parent_dispatch) { return ossl_rand_drbg_new(provctx, parent, parent_dispatch, &drbg_hash_new, &drbg_hash_instantiate, &drbg_hash_uninstantiate, &drbg_hash_reseed, &drbg_hash_generate); } static void drbg_hash_free(void *vdrbg) { PROV_DRBG *drbg = (PROV_DRBG *)vdrbg; PROV_DRBG_HASH *hash; if (drbg != NULL && (hash = (PROV_DRBG_HASH *)drbg->data) != NULL) { EVP_MD_CTX_free(hash->ctx); ossl_prov_digest_reset(&hash->digest); OPENSSL_secure_clear_free(hash, sizeof(*hash)); } ossl_rand_drbg_free(drbg); } static int drbg_hash_get_ctx_params(void *vdrbg, OSSL_PARAM params[]) { PROV_DRBG *drbg = (PROV_DRBG *)vdrbg; PROV_DRBG_HASH *hash = (PROV_DRBG_HASH *)drbg->data; const EVP_MD *md; OSSL_PARAM *p; p = OSSL_PARAM_locate(params, OSSL_DRBG_PARAM_DIGEST); if (p != NULL) { md = ossl_prov_digest_md(&hash->digest); if (md == NULL || !OSSL_PARAM_set_utf8_string(p, EVP_MD_get0_name(md))) return 0; } return ossl_drbg_get_ctx_params(drbg, params); } static const OSSL_PARAM *drbg_hash_gettable_ctx_params(ossl_unused void *vctx, ossl_unused void *p_ctx) { static const OSSL_PARAM known_gettable_ctx_params[] = { OSSL_PARAM_utf8_string(OSSL_DRBG_PARAM_DIGEST, NULL, 0), OSSL_PARAM_DRBG_GETTABLE_CTX_COMMON, OSSL_PARAM_END }; return known_gettable_ctx_params; } static int drbg_hash_set_ctx_params(void *vctx, const OSSL_PARAM params[]) { PROV_DRBG *ctx = (PROV_DRBG *)vctx; PROV_DRBG_HASH *hash = (PROV_DRBG_HASH *)ctx->data; OSSL_LIB_CTX *libctx = PROV_LIBCTX_OF(ctx->provctx); const EVP_MD *md; if (!ossl_prov_digest_load_from_params(&hash->digest, params, libctx)) return 0; md = ossl_prov_digest_md(&hash->digest); if (md != NULL) { if ((EVP_MD_get_flags(md) & EVP_MD_FLAG_XOF) != 0) { ERR_raise(ERR_LIB_PROV, PROV_R_XOF_DIGESTS_NOT_ALLOWED); return 0; } /* These are taken from SP 800-90 10.1 Table 2 */ hash->blocklen = EVP_MD_get_size(md); /* See SP800-57 Part1 Rev4 5.6.1 Table 3 */ ctx->strength = 64 * (hash->blocklen >> 3); if (ctx->strength > 256) ctx->strength = 256; if (hash->blocklen > MAX_BLOCKLEN_USING_SMALL_SEEDLEN) ctx->seedlen = HASH_PRNG_MAX_SEEDLEN; else ctx->seedlen = HASH_PRNG_SMALL_SEEDLEN; ctx->min_entropylen = ctx->strength / 8; ctx->min_noncelen = ctx->min_entropylen / 2; } return ossl_drbg_set_ctx_params(ctx, params); } static const OSSL_PARAM *drbg_hash_settable_ctx_params(ossl_unused void *vctx, ossl_unused void *p_ctx) { static const OSSL_PARAM known_settable_ctx_params[] = { OSSL_PARAM_utf8_string(OSSL_DRBG_PARAM_PROPERTIES, NULL, 0), OSSL_PARAM_utf8_string(OSSL_DRBG_PARAM_DIGEST, NULL, 0), OSSL_PARAM_DRBG_SETTABLE_CTX_COMMON, OSSL_PARAM_END }; return known_settable_ctx_params; } const OSSL_DISPATCH ossl_drbg_hash_functions[] = { { OSSL_FUNC_RAND_NEWCTX, (void(*)(void))drbg_hash_new_wrapper }, { OSSL_FUNC_RAND_FREECTX, (void(*)(void))drbg_hash_free }, { OSSL_FUNC_RAND_INSTANTIATE, (void(*)(void))drbg_hash_instantiate_wrapper }, { OSSL_FUNC_RAND_UNINSTANTIATE, (void(*)(void))drbg_hash_uninstantiate_wrapper }, { OSSL_FUNC_RAND_GENERATE, (void(*)(void))drbg_hash_generate_wrapper }, { OSSL_FUNC_RAND_RESEED, (void(*)(void))drbg_hash_reseed_wrapper }, { OSSL_FUNC_RAND_ENABLE_LOCKING, (void(*)(void))ossl_drbg_enable_locking }, { OSSL_FUNC_RAND_LOCK, (void(*)(void))ossl_drbg_lock }, { OSSL_FUNC_RAND_UNLOCK, (void(*)(void))ossl_drbg_unlock }, { OSSL_FUNC_RAND_SETTABLE_CTX_PARAMS, (void(*)(void))drbg_hash_settable_ctx_params }, { OSSL_FUNC_RAND_SET_CTX_PARAMS, (void(*)(void))drbg_hash_set_ctx_params }, { OSSL_FUNC_RAND_GETTABLE_CTX_PARAMS, (void(*)(void))drbg_hash_gettable_ctx_params }, { OSSL_FUNC_RAND_GET_CTX_PARAMS, (void(*)(void))drbg_hash_get_ctx_params }, { OSSL_FUNC_RAND_VERIFY_ZEROIZATION, (void(*)(void))drbg_hash_verify_zeroization }, { OSSL_FUNC_RAND_GET_SEED, (void(*)(void))ossl_drbg_get_seed }, { OSSL_FUNC_RAND_CLEAR_SEED, (void(*)(void))ossl_drbg_clear_seed }, { 0, NULL } };