From dbdcc04f27db70ac71748eb595ce23c9733afbe7 Mon Sep 17 00:00:00 2001 From: Kurt Roeckx Date: Sat, 10 Mar 2018 12:23:21 +0100 Subject: [PATCH] DRBG: Use the EVP layer to do AES encryption Reviewed-by: Rich Salz GH: #5580 --- crypto/rand/drbg_ctr.c | 193 +++++++++++++++++++++++++++-------------- crypto/rand/rand_lcl.h | 7 +- 2 files changed, 133 insertions(+), 67 deletions(-) diff --git a/crypto/rand/drbg_ctr.c b/crypto/rand/drbg_ctr.c index ac4af331d7..fe15164451 100644 --- a/crypto/rand/drbg_ctr.c +++ b/crypto/rand/drbg_ctr.c @@ -65,53 +65,63 @@ static void ctr_XOR(RAND_DRBG_CTR *ctr, const unsigned char *in, size_t inlen) /* * Process a complete block using BCC algorithm of SP 800-90A 10.3.3 */ -static void ctr_BCC_block(RAND_DRBG_CTR *ctr, unsigned char *out, - const unsigned char *in) +__owur static int ctr_BCC_block(RAND_DRBG_CTR *ctr, unsigned char *out, + const unsigned char *in) { - int i; + int i, outlen = AES_BLOCK_SIZE; for (i = 0; i < 16; i++) out[i] ^= in[i]; - AES_encrypt(out, out, &ctr->df_ks); + + if (!EVP_CipherUpdate(ctr->ctx_df, out, &outlen, out, AES_BLOCK_SIZE) + || outlen != AES_BLOCK_SIZE) + return 0; + return 1; } /* * Handle several BCC operations for as much data as we need for K and X */ -static void ctr_BCC_blocks(RAND_DRBG_CTR *ctr, const unsigned char *in) +__owur static int ctr_BCC_blocks(RAND_DRBG_CTR *ctr, const unsigned char *in) { - ctr_BCC_block(ctr, ctr->KX, in); - ctr_BCC_block(ctr, ctr->KX + 16, in); - if (ctr->keylen != 16) - ctr_BCC_block(ctr, ctr->KX + 32, in); + if (!ctr_BCC_block(ctr, ctr->KX, in) + || !ctr_BCC_block(ctr, ctr->KX + 16, in)) + return 0; + if (ctr->keylen != 16 && !ctr_BCC_block(ctr, ctr->KX + 32, in)) + return 0; + return 1; } /* * Initialise BCC blocks: these have the value 0,1,2 in leftmost positions: * see 10.3.1 stage 7. */ -static void ctr_BCC_init(RAND_DRBG_CTR *ctr) +__owur static int ctr_BCC_init(RAND_DRBG_CTR *ctr) { memset(ctr->KX, 0, 48); memset(ctr->bltmp, 0, 16); - ctr_BCC_block(ctr, ctr->KX, ctr->bltmp); + if (!ctr_BCC_block(ctr, ctr->KX, ctr->bltmp)) + return 0; ctr->bltmp[3] = 1; - ctr_BCC_block(ctr, ctr->KX + 16, ctr->bltmp); + if (!ctr_BCC_block(ctr, ctr->KX + 16, ctr->bltmp)) + return 0; if (ctr->keylen != 16) { ctr->bltmp[3] = 2; - ctr_BCC_block(ctr, ctr->KX + 32, ctr->bltmp); + if (!ctr_BCC_block(ctr, ctr->KX + 32, ctr->bltmp)) + return 0; } + return 1; } /* * Process several blocks into BCC algorithm, some possibly partial */ -static void ctr_BCC_update(RAND_DRBG_CTR *ctr, - const unsigned char *in, size_t inlen) +__owur static int ctr_BCC_update(RAND_DRBG_CTR *ctr, + const unsigned char *in, size_t inlen) { if (in == NULL || inlen == 0) - return; + return 1; /* If we have partial block handle it first */ if (ctr->bltmp_pos) { @@ -120,7 +130,8 @@ static void ctr_BCC_update(RAND_DRBG_CTR *ctr, /* If we now have a complete block process it */ if (inlen >= left) { memcpy(ctr->bltmp + ctr->bltmp_pos, in, left); - ctr_BCC_blocks(ctr, ctr->bltmp); + if (!ctr_BCC_blocks(ctr, ctr->bltmp)) + return 0; ctr->bltmp_pos = 0; inlen -= left; in += left; @@ -129,7 +140,8 @@ static void ctr_BCC_update(RAND_DRBG_CTR *ctr, /* Process zero or more complete blocks */ for (; inlen >= 16; in += 16, inlen -= 16) { - ctr_BCC_blocks(ctr, in); + if (!ctr_BCC_blocks(ctr, in)) + return 0; } /* Copy any remaining partial block to the temporary buffer */ @@ -137,26 +149,31 @@ static void ctr_BCC_update(RAND_DRBG_CTR *ctr, memcpy(ctr->bltmp + ctr->bltmp_pos, in, inlen); ctr->bltmp_pos += inlen; } + return 1; } -static void ctr_BCC_final(RAND_DRBG_CTR *ctr) +__owur static int ctr_BCC_final(RAND_DRBG_CTR *ctr) { if (ctr->bltmp_pos) { memset(ctr->bltmp + ctr->bltmp_pos, 0, 16 - ctr->bltmp_pos); - ctr_BCC_blocks(ctr, ctr->bltmp); + if (!ctr_BCC_blocks(ctr, ctr->bltmp)) + return 0; } + return 1; } -static void ctr_df(RAND_DRBG_CTR *ctr, - const unsigned char *in1, size_t in1len, - const unsigned char *in2, size_t in2len, - const unsigned char *in3, size_t in3len) +__owur static int ctr_df(RAND_DRBG_CTR *ctr, + const unsigned char *in1, size_t in1len, + const unsigned char *in2, size_t in2len, + const unsigned char *in3, size_t in3len) { static unsigned char c80 = 0x80; size_t inlen; unsigned char *p = ctr->bltmp; + int outlen = AES_BLOCK_SIZE; - ctr_BCC_init(ctr); + if (!ctr_BCC_init(ctr)) + return 0; if (in1 == NULL) in1len = 0; if (in2 == NULL) @@ -176,18 +193,30 @@ static void ctr_df(RAND_DRBG_CTR *ctr, *p++ = 0; *p = (unsigned char)((ctr->keylen + 16) & 0xff); ctr->bltmp_pos = 8; - ctr_BCC_update(ctr, in1, in1len); - ctr_BCC_update(ctr, in2, in2len); - ctr_BCC_update(ctr, in3, in3len); - ctr_BCC_update(ctr, &c80, 1); - ctr_BCC_final(ctr); + if (!ctr_BCC_update(ctr, in1, in1len) + || !ctr_BCC_update(ctr, in2, in2len) + || !ctr_BCC_update(ctr, in3, in3len) + || !ctr_BCC_update(ctr, &c80, 1) + || !ctr_BCC_final(ctr)) + return 0; /* Set up key K */ - AES_set_encrypt_key(ctr->KX, ctr->keylen * 8, &ctr->df_kxks); + if (!EVP_CipherInit_ex(ctr->ctx, ctr->cipher, NULL, ctr->KX, NULL, 1)) + return 0; /* X follows key K */ - AES_encrypt(ctr->KX + ctr->keylen, ctr->KX, &ctr->df_kxks); - AES_encrypt(ctr->KX, ctr->KX + 16, &ctr->df_kxks); + if (!EVP_CipherUpdate(ctr->ctx, ctr->KX, &outlen, ctr->KX + ctr->keylen, + AES_BLOCK_SIZE) + || outlen != AES_BLOCK_SIZE) + return 0; + if (!EVP_CipherUpdate(ctr->ctx, ctr->KX + 16, &outlen, ctr->KX, + AES_BLOCK_SIZE) + || outlen != AES_BLOCK_SIZE) + return 0; if (ctr->keylen != 16) - AES_encrypt(ctr->KX + 16, ctr->KX + 32, &ctr->df_kxks); + if (!EVP_CipherUpdate(ctr->ctx, ctr->KX + 32, &outlen, ctr->KX + 16, + AES_BLOCK_SIZE) + || outlen != AES_BLOCK_SIZE) + return 0; + return 1; } /* @@ -196,24 +225,32 @@ static void ctr_df(RAND_DRBG_CTR *ctr, * zeroes if necessary and have up to two parameters XORed together, * so we handle both cases in this function instead. */ -static void ctr_update(RAND_DRBG *drbg, - const unsigned char *in1, size_t in1len, - const unsigned char *in2, size_t in2len, - const unsigned char *nonce, size_t noncelen) +__owur static int ctr_update(RAND_DRBG *drbg, + const unsigned char *in1, size_t in1len, + const unsigned char *in2, size_t in2len, + const unsigned char *nonce, size_t noncelen) { RAND_DRBG_CTR *ctr = &drbg->data.ctr; + int outlen = AES_BLOCK_SIZE; - /* ks is already setup for correct key */ + /* correct key is already set up. */ inc_128(ctr); - AES_encrypt(ctr->V, ctr->K, &ctr->ks); + if (!EVP_CipherUpdate(ctr->ctx, ctr->K, &outlen, ctr->V, AES_BLOCK_SIZE) + || outlen != AES_BLOCK_SIZE) + return 0; /* If keylen longer than 128 bits need extra encrypt */ if (ctr->keylen != 16) { inc_128(ctr); - AES_encrypt(ctr->V, ctr->K + 16, &ctr->ks); + if (!EVP_CipherUpdate(ctr->ctx, ctr->K+16, &outlen, ctr->V, + AES_BLOCK_SIZE) + || outlen != AES_BLOCK_SIZE) + return 0; } inc_128(ctr); - AES_encrypt(ctr->V, ctr->V, &ctr->ks); + if (!EVP_CipherUpdate(ctr->ctx, ctr->V, &outlen, ctr->V, AES_BLOCK_SIZE) + || outlen != AES_BLOCK_SIZE) + return 0; /* If 192 bit key part of V is on end of K */ if (ctr->keylen == 24) { @@ -224,7 +261,8 @@ static void ctr_update(RAND_DRBG *drbg, if ((drbg->flags & RAND_DRBG_FLAG_CTR_NO_DF) == 0) { /* If no input reuse existing derived value */ if (in1 != NULL || nonce != NULL || in2 != NULL) - ctr_df(ctr, in1, in1len, nonce, noncelen, in2, in2len); + if (!ctr_df(ctr, in1, in1len, nonce, noncelen, in2, in2len)) + return 0; /* If this a reuse input in1len != 0 */ if (in1len) ctr_XOR(ctr, ctr->KX, drbg->seedlen); @@ -233,13 +271,15 @@ static void ctr_update(RAND_DRBG *drbg, ctr_XOR(ctr, in2, in2len); } - AES_set_encrypt_key(ctr->K, drbg->strength, &ctr->ks); + if (!EVP_CipherInit_ex(ctr->ctx, ctr->cipher, NULL, ctr->K, NULL, 1)) + return 0; + return 1; } -static int drbg_ctr_instantiate(RAND_DRBG *drbg, - const unsigned char *entropy, size_t entropylen, - const unsigned char *nonce, size_t noncelen, - const unsigned char *pers, size_t perslen) +__owur static int drbg_ctr_instantiate(RAND_DRBG *drbg, + const unsigned char *entropy, size_t entropylen, + const unsigned char *nonce, size_t noncelen, + const unsigned char *pers, size_t perslen) { RAND_DRBG_CTR *ctr = &drbg->data.ctr; @@ -248,29 +288,33 @@ static int drbg_ctr_instantiate(RAND_DRBG *drbg, memset(ctr->K, 0, sizeof(ctr->K)); memset(ctr->V, 0, sizeof(ctr->V)); - AES_set_encrypt_key(ctr->K, drbg->strength, &ctr->ks); - ctr_update(drbg, entropy, entropylen, pers, perslen, nonce, noncelen); + if (!EVP_CipherInit_ex(ctr->ctx, ctr->cipher, NULL, ctr->K, NULL, 1)) + return 0; + if (!ctr_update(drbg, entropy, entropylen, pers, perslen, nonce, noncelen)) + return 0; return 1; } -static int drbg_ctr_reseed(RAND_DRBG *drbg, - const unsigned char *entropy, size_t entropylen, - const unsigned char *adin, size_t adinlen) +__owur static int drbg_ctr_reseed(RAND_DRBG *drbg, + const unsigned char *entropy, size_t entropylen, + const unsigned char *adin, size_t adinlen) { if (entropy == NULL) return 0; - ctr_update(drbg, entropy, entropylen, adin, adinlen, NULL, 0); + if (!ctr_update(drbg, entropy, entropylen, adin, adinlen, NULL, 0)) + return 0; return 1; } -static int drbg_ctr_generate(RAND_DRBG *drbg, - unsigned char *out, size_t outlen, - const unsigned char *adin, size_t adinlen) +__owur static int drbg_ctr_generate(RAND_DRBG *drbg, + unsigned char *out, size_t outlen, + const unsigned char *adin, size_t adinlen) { RAND_DRBG_CTR *ctr = &drbg->data.ctr; if (adin != NULL && adinlen != 0) { - ctr_update(drbg, adin, adinlen, NULL, 0, NULL, 0); + if (!ctr_update(drbg, adin, adinlen, NULL, 0, NULL, 0)) + return 0; /* This means we reuse derived value */ if ((drbg->flags & RAND_DRBG_FLAG_CTR_NO_DF) == 0) { adin = NULL; @@ -281,26 +325,36 @@ static int drbg_ctr_generate(RAND_DRBG *drbg, } for ( ; ; ) { + int outl = AES_BLOCK_SIZE; + inc_128(ctr); if (outlen < 16) { /* Use K as temp space as it will be updated */ - AES_encrypt(ctr->V, ctr->K, &ctr->ks); + if (!EVP_CipherUpdate(ctr->ctx, ctr->K, &outl, ctr->V, + AES_BLOCK_SIZE) + || outl != AES_BLOCK_SIZE) + return 0; memcpy(out, ctr->K, outlen); break; } - AES_encrypt(ctr->V, out, &ctr->ks); + if (!EVP_CipherUpdate(ctr->ctx, out, &outl, ctr->V, AES_BLOCK_SIZE) + || outl != AES_BLOCK_SIZE) + return 0; out += 16; outlen -= 16; if (outlen == 0) break; } - ctr_update(drbg, adin, adinlen, NULL, 0, NULL, 0); + if (!ctr_update(drbg, adin, adinlen, NULL, 0, NULL, 0)) + return 0; return 1; } static int drbg_ctr_uninstantiate(RAND_DRBG *drbg) { + EVP_CIPHER_CTX_free(drbg->data.ctr.ctx); + EVP_CIPHER_CTX_free(drbg->data.ctr.ctx_df); OPENSSL_cleanse(&drbg->data.ctr, sizeof(drbg->data.ctr)); return 1; } @@ -323,31 +377,44 @@ int drbg_ctr_init(RAND_DRBG *drbg) return 0; case NID_aes_128_ctr: keylen = 16; + ctr->cipher = EVP_aes_128_ecb(); break; case NID_aes_192_ctr: keylen = 24; + ctr->cipher = EVP_aes_192_ecb(); break; case NID_aes_256_ctr: keylen = 32; + ctr->cipher = EVP_aes_256_ecb(); break; } drbg->meth = &drbg_ctr_meth; ctr->keylen = keylen; + if (ctr->ctx == NULL) + ctr->ctx = EVP_CIPHER_CTX_new(); + if (ctr->ctx == NULL) + return 0; drbg->strength = keylen * 8; drbg->seedlen = keylen + 16; if ((drbg->flags & RAND_DRBG_FLAG_CTR_NO_DF) == 0) { /* df initialisation */ - static unsigned char df_key[32] = { + static const unsigned char df_key[32] = { 0x00,0x01,0x02,0x03,0x04,0x05,0x06,0x07, 0x08,0x09,0x0a,0x0b,0x0c,0x0d,0x0e,0x0f, 0x10,0x11,0x12,0x13,0x14,0x15,0x16,0x17, 0x18,0x19,0x1a,0x1b,0x1c,0x1d,0x1e,0x1f }; + + if (ctr->ctx_df == NULL) + ctr->ctx_df = EVP_CIPHER_CTX_new(); + if (ctr->ctx_df == NULL) + return 0; /* Set key schedule for df_key */ - AES_set_encrypt_key(df_key, drbg->strength, &ctr->df_ks); + if (!EVP_CipherInit_ex(ctr->ctx_df, ctr->cipher, NULL, df_key, NULL, 1)) + return 0; drbg->min_entropylen = ctr->keylen; drbg->max_entropylen = DRBG_MINMAX_FACTOR * drbg->min_entropylen; diff --git a/crypto/rand/rand_lcl.h b/crypto/rand/rand_lcl.h index 32526fbb54..60c42f7ad5 100644 --- a/crypto/rand/rand_lcl.h +++ b/crypto/rand/rand_lcl.h @@ -94,13 +94,12 @@ typedef struct rand_drbg_method_st { * The state of a DRBG AES-CTR. */ typedef struct rand_drbg_ctr_st { - AES_KEY ks; + EVP_CIPHER_CTX *ctx; + EVP_CIPHER_CTX *ctx_df; + const EVP_CIPHER *cipher; size_t keylen; unsigned char K[32]; unsigned char V[16]; - /* Temp variables used by derivation function */ - AES_KEY df_ks; - AES_KEY df_kxks; /* Temporary block storage used by ctr_df */ unsigned char bltmp[16]; size_t bltmp_pos; -- 2.34.1