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/*
* Copyright 2018 The OpenSSL Project Authors. All Rights Reserved.
*
* Licensed under the OpenSSL license (the "License"). You may not use
* this file except in compliance with the License. You can obtain a copy
* in the file LICENSE in the source distribution or at
* https://www.openssl.org/source/license.html
*/
#include <stdlib.h>
#include <openssl/evp.h>
#include "internal/cryptlib.h"
#include "internal/evp_int.h"
/* typedef EVP_MAC_IMPL */
struct evp_mac_impl_st {
EVP_CIPHER *cipher; /* Cache GCM cipher */
EVP_CIPHER_CTX *ctx; /* Cipher context */
ENGINE *engine; /* Engine implementating the algorithm */
};
static void gmac_free(EVP_MAC_IMPL *gctx)
{
if (gctx != NULL) {
EVP_CIPHER_CTX_free(gctx->ctx);
OPENSSL_free(gctx);
}
}
static EVP_MAC_IMPL *gmac_new(void)
{
EVP_MAC_IMPL *gctx;
if ((gctx = OPENSSL_zalloc(sizeof(*gctx))) == NULL
|| (gctx->ctx = EVP_CIPHER_CTX_new()) == NULL) {
gmac_free(gctx);
return NULL;
}
return gctx;
}
static int gmac_copy(EVP_MAC_IMPL *gdst, EVP_MAC_IMPL *gsrc)
{
gdst->cipher = gsrc->cipher;
gdst->engine = gsrc->engine;
return EVP_CIPHER_CTX_copy(gdst->ctx, gsrc->ctx);
}
static size_t gmac_size(EVP_MAC_IMPL *gctx)
{
return EVP_GCM_TLS_TAG_LEN;
}
static int gmac_init(EVP_MAC_IMPL *gctx)
{
return 1;
}
static int gmac_update(EVP_MAC_IMPL *gctx, const unsigned char *data,
size_t datalen)
{
EVP_CIPHER_CTX *ctx = gctx->ctx;
int outlen;
while (datalen > INT_MAX) {
if (!EVP_EncryptUpdate(ctx, NULL, &outlen, data, INT_MAX))
return 0;
data += INT_MAX;
datalen -= INT_MAX;
}
return EVP_EncryptUpdate(ctx, NULL, &outlen, data, datalen);
}
static int gmac_final(EVP_MAC_IMPL *gctx, unsigned char *out)
{
int hlen;
if (!EVP_EncryptFinal_ex(gctx->ctx, out, &hlen)
|| !EVP_CIPHER_CTX_ctrl(gctx->ctx, EVP_CTRL_AEAD_GET_TAG,
gmac_size(gctx), out))
return 0;
return 1;
}
static int gmac_ctrl(EVP_MAC_IMPL *gctx, int cmd, va_list args)
{
const unsigned char *p;
size_t len;
EVP_CIPHER_CTX *ctx = gctx->ctx;
const EVP_CIPHER *cipher;
ENGINE *engine;
switch (cmd) {
case EVP_MAC_CTRL_SET_CIPHER:
cipher = va_arg(args, const EVP_CIPHER *);
if (cipher == NULL)
return 0;
if (EVP_CIPHER_mode(cipher) != EVP_CIPH_GCM_MODE) {
EVPerr(EVP_F_GMAC_CTRL, EVP_R_CIPHER_NOT_GCM_MODE);
return 0;
}
return EVP_EncryptInit_ex(ctx, cipher, NULL, NULL, NULL);
case EVP_MAC_CTRL_SET_KEY:
p = va_arg(args, const unsigned char *);
len = va_arg(args, size_t);
if (len != (size_t)EVP_CIPHER_CTX_key_length(ctx)) {
EVPerr(EVP_F_GMAC_CTRL, EVP_R_INVALID_KEY_LENGTH);
return 0;
}
return EVP_EncryptInit_ex(ctx, NULL, NULL, p, NULL);
case EVP_MAC_CTRL_SET_IV:
p = va_arg(args, const unsigned char *);
len = va_arg(args, size_t);
return EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_IVLEN, len, NULL)
&& EVP_EncryptInit_ex(ctx, NULL, NULL, NULL, p);
case EVP_MAC_CTRL_SET_ENGINE:
engine = va_arg(args, ENGINE *);
return EVP_EncryptInit_ex(ctx, NULL, engine, NULL, NULL);
default:
return -2;
}
}
static int gmac_ctrl_int(EVP_MAC_IMPL *gctx, int cmd, ...)
{
int rv;
va_list args;
va_start(args, cmd);
rv = gmac_ctrl(gctx, cmd, args);
va_end(args);
return rv;
}
static int gmac_ctrl_str_cb(void *gctx, int cmd, void *buf, size_t buflen)
{
return gmac_ctrl_int(gctx, cmd, buf, buflen);
}
static int gmac_ctrl_str(EVP_MAC_IMPL *gctx, const char *type,
const char *value)
{
if (!value)
return 0;
if (strcmp(type, "cipher") == 0) {
const EVP_CIPHER *c = EVP_get_cipherbyname(value);
if (c == NULL)
return 0;
return gmac_ctrl_int(gctx, EVP_MAC_CTRL_SET_CIPHER, c);
}
if (strcmp(type, "key") == 0)
return EVP_str2ctrl(gmac_ctrl_str_cb, gctx, EVP_MAC_CTRL_SET_KEY,
value);
if (strcmp(type, "hexkey") == 0)
return EVP_hex2ctrl(gmac_ctrl_str_cb, gctx, EVP_MAC_CTRL_SET_KEY,
value);
if (strcmp(type, "iv") == 0)
return EVP_str2ctrl(gmac_ctrl_str_cb, gctx, EVP_MAC_CTRL_SET_IV,
value);
if (strcmp(type, "hexiv") == 0)
return EVP_hex2ctrl(gmac_ctrl_str_cb, gctx, EVP_MAC_CTRL_SET_IV,
value);
return -2;
}
const EVP_MAC gmac_meth = {
EVP_MAC_GMAC,
gmac_new,
gmac_copy,
gmac_free,
gmac_size,
gmac_init,
gmac_update,
gmac_final,
gmac_ctrl,
gmac_ctrl_str
};
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