/* Copyright (c) 2014, Google Inc.
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
* SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
* OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
* CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
#include <openssl/aead.h>
#include <assert.h>
#include <string.h>
#include <openssl/cipher.h>
#include <openssl/err.h>
#include <openssl/mem.h>
#include "internal.h"
#include "../../internal.h"
size_t EVP_AEAD_key_length(const EVP_AEAD *aead) { return aead->key_len; }
size_t EVP_AEAD_nonce_length(const EVP_AEAD *aead) { return aead->nonce_len; }
size_t EVP_AEAD_max_overhead(const EVP_AEAD *aead) { return aead->overhead; }
size_t EVP_AEAD_max_tag_len(const EVP_AEAD *aead) { return aead->max_tag_len; }
void EVP_AEAD_CTX_zero(EVP_AEAD_CTX *ctx) {
OPENSSL_memset(ctx, 0, sizeof(EVP_AEAD_CTX));
}
EVP_AEAD_CTX *EVP_AEAD_CTX_new(const EVP_AEAD *aead, const uint8_t *key,
size_t key_len, size_t tag_len) {
EVP_AEAD_CTX *ctx = OPENSSL_malloc(sizeof(EVP_AEAD_CTX));
EVP_AEAD_CTX_zero(ctx);
if (EVP_AEAD_CTX_init(ctx, aead, key, key_len, tag_len, NULL)) {
return ctx;
}
EVP_AEAD_CTX_free(ctx);
return NULL;
}
void EVP_AEAD_CTX_free(EVP_AEAD_CTX *ctx) {
EVP_AEAD_CTX_cleanup(ctx);
OPENSSL_free(ctx);
}
int EVP_AEAD_CTX_init(EVP_AEAD_CTX *ctx, const EVP_AEAD *aead,
const uint8_t *key, size_t key_len, size_t tag_len,
ENGINE *impl) {
if (!aead->init) {
OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_NO_DIRECTION_SET);
ctx->aead = NULL;
return 0;
}
return EVP_AEAD_CTX_init_with_direction(ctx, aead, key, key_len, tag_len,
evp_aead_open);
}
int EVP_AEAD_CTX_init_with_direction(EVP_AEAD_CTX *ctx, const EVP_AEAD *aead,
const uint8_t *key, size_t key_len,
size_t tag_len,
enum evp_aead_direction_t dir) {
if (key_len != aead->key_len) {
OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_UNSUPPORTED_KEY_SIZE);
ctx->aead = NULL;
return 0;
}
ctx->aead = aead;
int ok;
if (aead->init) {
ok = aead->init(ctx, key, key_len, tag_len);
} else {
ok = aead->init_with_direction(ctx, key, key_len, tag_len, dir);
}
if (!ok) {
ctx->aead = NULL;
}
return ok;
}
void EVP_AEAD_CTX_cleanup(EVP_AEAD_CTX *ctx) {
if (ctx->aead == NULL) {
return;
}
ctx->aead->cleanup(ctx);
ctx->aead = NULL;
}
// check_alias returns 1 if |out| is compatible with |in| and 0 otherwise. If
// |in| and |out| alias, we require that |in| == |out|.
static int check_alias(const uint8_t *in, size_t in_len, const uint8_t *out,
size_t out_len) {
if (!buffers_alias(in, in_len, out, out_len)) {
return 1;
}
return in == out;
}
int EVP_AEAD_CTX_seal(const EVP_AEAD_CTX *ctx, uint8_t *out, size_t *out_len,
size_t max_out_len, const uint8_t *nonce,
size_t nonce_len, const uint8_t *in, size_t in_len,
const uint8_t *ad, size_t ad_len) {
if (in_len + ctx->aead->overhead < in_len /* overflow */) {
OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_TOO_LARGE);
goto error;
}
if (max_out_len < in_len) {
OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_BUFFER_TOO_SMALL);
goto error;
}
if (!check_alias(in, in_len, out, max_out_len)) {
OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_OUTPUT_ALIASES_INPUT);
goto error;
}
size_t out_tag_len;
if (ctx->aead->seal_scatter(ctx, out, out + in_len, &out_tag_len,
max_out_len - in_len, nonce, nonce_len, in,
in_len, NULL, 0, ad, ad_len)) {
*out_len = in_len + out_tag_len;
return 1;
}
error:
// In the event of an error, clear the output buffer so that a caller
// that doesn't check the return value doesn't send raw data.
OPENSSL_memset(out, 0, max_out_len);
*out_len = 0;
return 0;
}
int EVP_AEAD_CTX_seal_scatter(
const EVP_AEAD_CTX *ctx, uint8_t *out, uint8_t *out_tag, size_t
*out_tag_len, size_t max_out_tag_len, const uint8_t *nonce, size_t
nonce_len, const uint8_t *in, size_t in_len, const uint8_t *extra_in,
size_t extra_in_len, const uint8_t *ad, size_t ad_len) {
// |in| and |out| may alias exactly, |out_tag| may not alias.
if (!check_alias(in, in_len, out, in_len) ||
buffers_alias(out, in_len, out_tag, max_out_tag_len) ||
buffers_alias(in, in_len, out_tag, max_out_tag_len)) {
OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_OUTPUT_ALIASES_INPUT);
goto error;
}
if (!ctx->aead->seal_scatter_supports_extra_in && extra_in_len) {
OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_INVALID_OPERATION);
goto error;
}
if (ctx->aead->seal_scatter(ctx, out, out_tag, out_tag_len, max_out_tag_len,
nonce, nonce_len, in, in_len, extra_in,
extra_in_len, ad, ad_len)) {
return 1;
}
error:
// In the event of an error, clear the output buffer so that a caller
// that doesn't check the return value doesn't send raw data.
OPENSSL_memset(out, 0, in_len);
OPENSSL_memset(out_tag, 0, max_out_tag_len);
*out_tag_len = 0;
return 0;
}
int EVP_AEAD_CTX_open(const EVP_AEAD_CTX *ctx, uint8_t *out, size_t *out_len,
size_t max_out_len, const uint8_t *nonce,
size_t nonce_len, const uint8_t *in, size_t in_len,
const uint8_t *ad, size_t ad_len) {
if (!check_alias(in, in_len, out, max_out_len)) {
OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_OUTPUT_ALIASES_INPUT);
goto error;
}
if (ctx->aead->open) {
if (!ctx->aead->open(ctx, out, out_len, max_out_len, nonce, nonce_len, in,
in_len, ad, ad_len)) {
goto error;
}
return 1;
}
// AEADs that use the default implementation of open() must set |tag_len| at
// initialization time.
assert(ctx->tag_len);
if (in_len < ctx->tag_len) {
OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_BAD_DECRYPT);
goto error;
}
size_t plaintext_len = in_len - ctx->tag_len;
if (max_out_len < plaintext_len) {
OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_BUFFER_TOO_SMALL);
goto error;
}
if (EVP_AEAD_CTX_open_gather(ctx, out, nonce, nonce_len, in, plaintext_len,
in + plaintext_len, ctx->tag_len, ad, ad_len)) {
*out_len = plaintext_len;
return 1;
}
error:
// In the event of an error, clear the output buffer so that a caller
// that doesn't check the return value doesn't try and process bad
// data.
OPENSSL_memset(out, 0, max_out_len);
*out_len = 0;
return 0;
}
int EVP_AEAD_CTX_open_gather(const EVP_AEAD_CTX *ctx, uint8_t *out,
const uint8_t *nonce, size_t nonce_len,
const uint8_t *in, size_t in_len,
const uint8_t *in_tag, size_t in_tag_len,
const uint8_t *ad, size_t ad_len) {
if (!check_alias(in, in_len, out, in_len)) {
OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_OUTPUT_ALIASES_INPUT);
goto error;
}
if (!ctx->aead->open_gather) {
OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_CTRL_NOT_IMPLEMENTED);
goto error;
}
if (ctx->aead->open_gather(ctx, out, nonce, nonce_len, in, in_len, in_tag,
in_tag_len, ad, ad_len)) {
return 1;
}
error:
// In the event of an error, clear the output buffer so that a caller
// that doesn't check the return value doesn't try and process bad
// data.
OPENSSL_memset(out, 0, in_len);
return 0;
}
const EVP_AEAD *EVP_AEAD_CTX_aead(const EVP_AEAD_CTX *ctx) { return ctx->aead; }
int EVP_AEAD_CTX_get_iv(const EVP_AEAD_CTX *ctx, const uint8_t **out_iv,
size_t *out_len) {
if (ctx->aead->get_iv == NULL) {
return 0;
}
return ctx->aead->get_iv(ctx, out_iv, out_len);
}
int EVP_AEAD_CTX_tag_len(const EVP_AEAD_CTX *ctx, size_t *out_tag_len,
const size_t in_len, const size_t extra_in_len) {
assert(ctx->aead->seal_scatter_supports_extra_in || !extra_in_len);
if (ctx->aead->tag_len) {
*out_tag_len = ctx->aead->tag_len(ctx, in_len, extra_in_len);
return 1;
}
if (extra_in_len + ctx->tag_len < extra_in_len) {
OPENSSL_PUT_ERROR(CIPHER, ERR_R_OVERFLOW);
*out_tag_len = 0;
return 0;
}
*out_tag_len = extra_in_len + ctx->tag_len;
return 1;
}