From ef186f4bc24ea7159a57776e8add1e9478b9702e Mon Sep 17 00:00:00 2001 From: Richard Henderson Date: Fri, 28 Aug 2020 10:05:20 -0700 Subject: [PATCH] crypto/builtin: Split and simplify AES_encrypt_cbc MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Split into encrypt/decrypt functions, dropping the "enc" argument. Now that the function is private to this file, we know that "len" is a multiple of AES_BLOCK_SIZE. So drop the odd block size code. Name the functions do_aes_*crypt_cbc to match the *_ecb functions. Reorder and re-type the arguments to match as well. Signed-off-by: Richard Henderson Signed-off-by: Daniel P. Berrangé --- crypto/cipher-builtin.c.inc | 97 ++++++++++++++++--------------------- 1 file changed, 42 insertions(+), 55 deletions(-) diff --git a/crypto/cipher-builtin.c.inc b/crypto/cipher-builtin.c.inc index 61baad265a..b1fe3b08c3 100644 --- a/crypto/cipher-builtin.c.inc +++ b/crypto/cipher-builtin.c.inc @@ -104,61 +104,50 @@ static void do_aes_decrypt_ecb(const void *vctx, } } -static void AES_cbc_encrypt(const unsigned char *in, unsigned char *out, - const unsigned long length, const AES_KEY *key, - unsigned char *ivec, const int enc) +static void do_aes_encrypt_cbc(const AES_KEY *key, + size_t len, + uint8_t *out, + const uint8_t *in, + uint8_t *ivec) { - unsigned long n; - unsigned long len = length; - unsigned char tmp[AES_BLOCK_SIZE]; + uint8_t tmp[AES_BLOCK_SIZE]; + size_t n; - assert(in && out && key && ivec); - - if (enc) { - while (len >= AES_BLOCK_SIZE) { - for (n = 0; n < AES_BLOCK_SIZE; ++n) { - tmp[n] = in[n] ^ ivec[n]; - } - AES_encrypt(tmp, out, key); - memcpy(ivec, out, AES_BLOCK_SIZE); - len -= AES_BLOCK_SIZE; - in += AES_BLOCK_SIZE; - out += AES_BLOCK_SIZE; - } - if (len) { - for (n = 0; n < len; ++n) { - tmp[n] = in[n] ^ ivec[n]; - } - for (n = len; n < AES_BLOCK_SIZE; ++n) { - tmp[n] = ivec[n]; - } - AES_encrypt(tmp, tmp, key); - memcpy(out, tmp, AES_BLOCK_SIZE); - memcpy(ivec, tmp, AES_BLOCK_SIZE); - } - } else { - while (len >= AES_BLOCK_SIZE) { - memcpy(tmp, in, AES_BLOCK_SIZE); - AES_decrypt(in, out, key); - for (n = 0; n < AES_BLOCK_SIZE; ++n) { - out[n] ^= ivec[n]; - } - memcpy(ivec, tmp, AES_BLOCK_SIZE); - len -= AES_BLOCK_SIZE; - in += AES_BLOCK_SIZE; - out += AES_BLOCK_SIZE; - } - if (len) { - memcpy(tmp, in, AES_BLOCK_SIZE); - AES_decrypt(tmp, tmp, key); - for (n = 0; n < len; ++n) { - out[n] = tmp[n] ^ ivec[n]; - } - memcpy(ivec, tmp, AES_BLOCK_SIZE); + /* We have already verified that len % AES_BLOCK_SIZE == 0. */ + while (len) { + for (n = 0; n < AES_BLOCK_SIZE; ++n) { + tmp[n] = in[n] ^ ivec[n]; } + AES_encrypt(tmp, out, key); + memcpy(ivec, out, AES_BLOCK_SIZE); + len -= AES_BLOCK_SIZE; + in += AES_BLOCK_SIZE; + out += AES_BLOCK_SIZE; } } +static void do_aes_decrypt_cbc(const AES_KEY *key, + size_t len, + uint8_t *out, + const uint8_t *in, + uint8_t *ivec) +{ + uint8_t tmp[AES_BLOCK_SIZE]; + size_t n; + + /* We have already verified that len % AES_BLOCK_SIZE == 0. */ + while (len) { + memcpy(tmp, in, AES_BLOCK_SIZE); + AES_decrypt(in, out, key); + for (n = 0; n < AES_BLOCK_SIZE; ++n) { + out[n] ^= ivec[n]; + } + memcpy(ivec, tmp, AES_BLOCK_SIZE); + len -= AES_BLOCK_SIZE; + in += AES_BLOCK_SIZE; + out += AES_BLOCK_SIZE; + } +} static int qcrypto_cipher_encrypt_aes(QCryptoCipher *cipher, const void *in, @@ -174,9 +163,8 @@ static int qcrypto_cipher_encrypt_aes(QCryptoCipher *cipher, do_aes_encrypt_ecb(&ctxt->state.aes.key, len, out, in); break; case QCRYPTO_CIPHER_MODE_CBC: - AES_cbc_encrypt(in, out, len, - &ctxt->state.aes.key.enc, - ctxt->state.aes.iv, 1); + do_aes_encrypt_cbc(&ctxt->state.aes.key.enc, len, out, in, + ctxt->state.aes.iv); break; case QCRYPTO_CIPHER_MODE_XTS: xts_encrypt(&ctxt->state.aes.key, @@ -208,9 +196,8 @@ static int qcrypto_cipher_decrypt_aes(QCryptoCipher *cipher, do_aes_decrypt_ecb(&ctxt->state.aes.key, len, out, in); break; case QCRYPTO_CIPHER_MODE_CBC: - AES_cbc_encrypt(in, out, len, - &ctxt->state.aes.key.dec, - ctxt->state.aes.iv, 0); + do_aes_decrypt_cbc(&ctxt->state.aes.key.dec, len, out, in, + ctxt->state.aes.iv); break; case QCRYPTO_CIPHER_MODE_XTS: xts_decrypt(&ctxt->state.aes.key,