From b5015e834aa7d3f0a5d7585a8fae05cecbdbb848 Mon Sep 17 00:00:00 2001 From: Eneas U de Queiroz Date: Wed, 28 Nov 2018 11:26:27 -0200 Subject: [PATCH] eng_devcrypto: fix ctr mode Make CTR mode behave like a stream cipher. Signed-off-by: Eneas U de Queiroz Reviewed-by: Matthias St. Pierre Reviewed-by: Richard Levitte (Merged from https://github.com/openssl/openssl/pull/7585) --- crypto/engine/eng_devcrypto.c | 125 +++++++++++++++++++++++++++------- 1 file changed, 102 insertions(+), 23 deletions(-) diff --git a/crypto/engine/eng_devcrypto.c b/crypto/engine/eng_devcrypto.c index 90ce672680..8e2080390a 100644 --- a/crypto/engine/eng_devcrypto.c +++ b/crypto/engine/eng_devcrypto.c @@ -47,10 +47,12 @@ static int cfd; struct cipher_ctx { struct session_op sess; - - /* to pass from init to do_cipher */ - const unsigned char *iv; int op; /* COP_ENCRYPT or COP_DECRYPT */ + unsigned long mode; /* EVP_CIPH_*_MODE */ + + /* to handle ctr mode being a stream cipher */ + unsigned char partial[EVP_MAX_BLOCK_LENGTH]; + unsigned int blocksize, num; }; static const struct cipher_data_st { @@ -87,9 +89,9 @@ static const struct cipher_data_st { { NID_aes_256_xts, 16, 256 / 8 * 2, 16, EVP_CIPH_XTS_MODE, CRYPTO_AES_XTS }, #endif #if !defined(CHECK_BSD_STYLE_MACROS) || defined(CRYPTO_AES_ECB) - { NID_aes_128_ecb, 16, 128 / 8, 16, EVP_CIPH_ECB_MODE, CRYPTO_AES_ECB }, - { NID_aes_192_ecb, 16, 192 / 8, 16, EVP_CIPH_ECB_MODE, CRYPTO_AES_ECB }, - { NID_aes_256_ecb, 16, 256 / 8, 16, EVP_CIPH_ECB_MODE, CRYPTO_AES_ECB }, + { NID_aes_128_ecb, 16, 128 / 8, 0, EVP_CIPH_ECB_MODE, CRYPTO_AES_ECB }, + { NID_aes_192_ecb, 16, 192 / 8, 0, EVP_CIPH_ECB_MODE, CRYPTO_AES_ECB }, + { NID_aes_256_ecb, 16, 256 / 8, 0, EVP_CIPH_ECB_MODE, CRYPTO_AES_ECB }, #endif #if 0 /* Not yet supported */ { NID_aes_128_gcm, 16, 128 / 8, 16, EVP_CIPH_GCM_MODE, CRYPTO_AES_GCM }, @@ -146,6 +148,8 @@ static int cipher_init(EVP_CIPHER_CTX *ctx, const unsigned char *key, cipher_ctx->sess.keylen = cipher_d->keylen; cipher_ctx->sess.key = (void *)key; cipher_ctx->op = enc ? COP_ENCRYPT : COP_DECRYPT; + cipher_ctx->mode = cipher_d->flags & EVP_CIPH_MODE; + cipher_ctx->blocksize = cipher_d->blocksize; if (ioctl(cfd, CIOCGSESSION, &cipher_ctx->sess) < 0) { SYSerr(SYS_F_IOCTL, errno); return 0; @@ -160,8 +164,11 @@ static int cipher_do_cipher(EVP_CIPHER_CTX *ctx, unsigned char *out, struct cipher_ctx *cipher_ctx = (struct cipher_ctx *)EVP_CIPHER_CTX_get_cipher_data(ctx); struct crypt_op cryp; + unsigned char *iv = EVP_CIPHER_CTX_iv_noconst(ctx); #if !defined(COP_FLAG_WRITE_IV) unsigned char saved_iv[EVP_MAX_IV_LENGTH]; + const unsigned char *ivptr; + size_t nblocks, ivlen; #endif memset(&cryp, 0, sizeof(cryp)); @@ -169,19 +176,28 @@ static int cipher_do_cipher(EVP_CIPHER_CTX *ctx, unsigned char *out, cryp.len = inl; cryp.src = (void *)in; cryp.dst = (void *)out; - cryp.iv = (void *)EVP_CIPHER_CTX_iv_noconst(ctx); + cryp.iv = (void *)iv; cryp.op = cipher_ctx->op; #if !defined(COP_FLAG_WRITE_IV) cryp.flags = 0; - if (EVP_CIPHER_CTX_iv_length(ctx) > 0) { - assert(inl >= EVP_CIPHER_CTX_iv_length(ctx)); - if (!EVP_CIPHER_CTX_encrypting(ctx)) { - unsigned char *ivptr = in + inl - EVP_CIPHER_CTX_iv_length(ctx); - - memcpy(saved_iv, ivptr, EVP_CIPHER_CTX_iv_length(ctx)); + ivlen = EVP_CIPHER_CTX_iv_length(ctx); + if (ivlen > 0) + switch (cipher_ctx->mode) { + case EVP_CIPH_CBC_MODE: + assert(inl >= ivlen); + if (!EVP_CIPHER_CTX_encrypting(ctx)) { + ivptr = in + inl - ivlen; + memcpy(saved_iv, ivptr, ivlen); + } + break; + + case EVP_CIPH_CTR_MODE: + break; + + default: /* should not happen */ + return 0; } - } #else cryp.flags = COP_FLAG_WRITE_IV; #endif @@ -192,17 +208,74 @@ static int cipher_do_cipher(EVP_CIPHER_CTX *ctx, unsigned char *out, } #if !defined(COP_FLAG_WRITE_IV) - if (EVP_CIPHER_CTX_iv_length(ctx) > 0) { - unsigned char *ivptr = saved_iv; + if (ivlen > 0) + switch (cipher_ctx->mode) { + case EVP_CIPH_CBC_MODE: + assert(inl >= ivlen); + if (EVP_CIPHER_CTX_encrypting(ctx)) + ivptr = out + inl - ivlen; + else + ivptr = saved_iv; + + memcpy(iv, ivptr, ivlen); + break; + + case EVP_CIPH_CTR_MODE: + nblocks = (inl + cipher_ctx->blocksize - 1) + / cipher_ctx->blocksize; + do { + ivlen--; + nblocks += iv[ivlen]; + iv[ivlen] = (uint8_t) nblocks; + nblocks >>= 8; + } while (ivlen); + break; + + default: /* should not happen */ + return 0; + } +#endif - assert(inl >= EVP_CIPHER_CTX_iv_length(ctx)); - if (!EVP_CIPHER_CTX_encrypting(ctx)) - ivptr = out + inl - EVP_CIPHER_CTX_iv_length(ctx); + return 1; +} - memcpy(EVP_CIPHER_CTX_iv_noconst(ctx), ivptr, - EVP_CIPHER_CTX_iv_length(ctx)); +static int ctr_do_cipher(EVP_CIPHER_CTX *ctx, unsigned char *out, + const unsigned char *in, size_t inl) +{ + struct cipher_ctx *cipher_ctx = + (struct cipher_ctx *)EVP_CIPHER_CTX_get_cipher_data(ctx); + size_t nblocks, len; + + /* initial partial block */ + while (cipher_ctx->num && inl) { + (*out++) = *(in++) ^ cipher_ctx->partial[cipher_ctx->num]; + --inl; + cipher_ctx->num = (cipher_ctx->num + 1) % cipher_ctx->blocksize; + } + + /* full blocks */ + if (inl > (unsigned int) cipher_ctx->blocksize) { + nblocks = inl/cipher_ctx->blocksize; + len = nblocks * cipher_ctx->blocksize; + if (cipher_do_cipher(ctx, out, in, len) < 1) + return 0; + inl -= len; + out += len; + in += len; + } + + /* final partial block */ + if (inl) { + memset(cipher_ctx->partial, 0, cipher_ctx->blocksize); + if (cipher_do_cipher(ctx, cipher_ctx->partial, cipher_ctx->partial, + cipher_ctx->blocksize) < 1) + return 0; + while (inl--) { + out[cipher_ctx->num] = in[cipher_ctx->num] + ^ cipher_ctx->partial[cipher_ctx->num]; + cipher_ctx->num++; + } } -#endif return 1; } @@ -249,6 +322,7 @@ static void prepare_cipher_methods(void) { size_t i; struct session_op sess; + unsigned long cipher_mode; memset(&sess, 0, sizeof(sess)); sess.key = (void *)"01234567890123456789012345678901234567890123456789"; @@ -266,9 +340,12 @@ static void prepare_cipher_methods(void) || ioctl(cfd, CIOCFSESSION, &sess.ses) < 0) continue; + cipher_mode = cipher_data[i].flags & EVP_CIPH_MODE; + if ((known_cipher_methods[i] = EVP_CIPHER_meth_new(cipher_data[i].nid, - cipher_data[i].blocksize, + cipher_mode == EVP_CIPH_CTR_MODE ? 1 : + cipher_data[i].blocksize, cipher_data[i].keylen)) == NULL || !EVP_CIPHER_meth_set_iv_length(known_cipher_methods[i], cipher_data[i].ivlen) @@ -278,6 +355,8 @@ static void prepare_cipher_methods(void) | EVP_CIPH_FLAG_DEFAULT_ASN1) || !EVP_CIPHER_meth_set_init(known_cipher_methods[i], cipher_init) || !EVP_CIPHER_meth_set_do_cipher(known_cipher_methods[i], + cipher_mode == EVP_CIPH_CTR_MODE ? + ctr_do_cipher : cipher_do_cipher) || !EVP_CIPHER_meth_set_ctrl(known_cipher_methods[i], cipher_ctrl) || !EVP_CIPHER_meth_set_cleanup(known_cipher_methods[i], -- 2.25.1