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crypto/builtin: Split and simplify AES_encrypt_cbc 

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 <richard.henderson@linaro.org>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
This commit is contained in:
Richard Henderson 2020-08-28 10:05:20 -07:00 committed by Daniel P. Berrangé
parent a2d76b6b2e
commit ef186f4bc2
1 changed files with 42 additions and 55 deletions
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97
crypto/cipher-builtin.c.inc
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@ -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,