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tls: fold AES CBC en/decryption into single functions

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Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko
2017-02-04 16:23:49 +01:00
parent 5b05d9db29
commit c31b54fd81
3 changed files with 64 additions and 34 deletions
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30
networking/tls.c
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@@ -722,17 +722,12 @@ static void xwrite_encrypted(tls_state_t *tls, unsigned size, unsigned type)
} while ((size & (AES_BLOCKSIZE - 1)) != 0);
/* Encrypt content+MAC+padding in place */
{
psCipherContext_t ctx;
psAesInit(&ctx, buf - AES_BLOCKSIZE, /* IV */
tls->client_write_key, tls->key_size /* selects 128/256 */
);
psAesEncrypt(&ctx,
buf, /* plaintext */
buf, /* ciphertext */
size
);
}
aes_cbc_encrypt(
tls->client_write_key, tls->key_size, /* selects 128/256 */
buf - AES_BLOCKSIZE, /* IV */
buf, size, /* plaintext */
buf /* ciphertext */
);
/* Write out */
dbg("writing 5 + %u IV + %u encrypted bytes, padding_length:0x%02x\n",
@@ -875,7 +870,6 @@ static int tls_xread_record(tls_state_t *tls)
/* Needs to be decrypted? */
if (tls->min_encrypted_len_on_read > tls->MAC_size) {
psCipherContext_t ctx;
uint8_t *p = tls->inbuf + RECHDR_LEN;
int padding_len;
@@ -886,14 +880,12 @@ static int tls_xread_record(tls_state_t *tls)
sz, tls->min_encrypted_len_on_read);
}
/* Decrypt content+MAC+padding, moving it over IV in the process */
psAesInit(&ctx, p, /* IV */
tls->server_write_key, tls->key_size /* selects 128/256 */
);
sz -= AES_BLOCKSIZE; /* we will overwrite IV now */
psAesDecrypt(&ctx,
p + AES_BLOCKSIZE, /* ciphertext */
p, /* plaintext */
sz
aes_cbc_decrypt(
tls->server_write_key, tls->key_size, /* selects 128/256 */
p, /* IV */
p + AES_BLOCKSIZE, sz, /* ciphertext */
p /* plaintext */
);
padding_len = p[sz - 1];
dbg("encrypted size:%u type:0x%02x padding_length:0x%02x\n", sz, p[0], padding_len);