145 lines
3.6 KiB
C
Executable File
145 lines
3.6 KiB
C
Executable File
/* $OpenBSD: evp_aead.c,v 1.6 2017/01/29 17:49:23 beck Exp $ */
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/*
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* Copyright (c) 2014, Google Inc.
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*
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* Permission to use, copy, modify, and/or distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
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* SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
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* OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
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* CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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#include <limits.h>
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#include <string.h>
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#include <openssl/evp.h>
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#include <openssl/err.h>
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#include "evp_locl.h"
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size_t
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EVP_AEAD_key_length(const EVP_AEAD *aead)
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{
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return aead->key_len;
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}
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size_t
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EVP_AEAD_nonce_length(const EVP_AEAD *aead)
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{
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return aead->nonce_len;
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}
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size_t
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EVP_AEAD_max_overhead(const EVP_AEAD *aead)
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{
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return aead->overhead;
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}
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size_t
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EVP_AEAD_max_tag_len(const EVP_AEAD *aead)
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{
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return aead->max_tag_len;
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}
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int
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EVP_AEAD_CTX_init(EVP_AEAD_CTX *ctx, const EVP_AEAD *aead,
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const unsigned char *key, size_t key_len, size_t tag_len, ENGINE *impl)
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{
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ctx->aead = aead;
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if (key_len != aead->key_len) {
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EVPerror(EVP_R_UNSUPPORTED_KEY_SIZE);
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return 0;
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}
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return aead->init(ctx, key, key_len, tag_len);
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}
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void
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EVP_AEAD_CTX_cleanup(EVP_AEAD_CTX *ctx)
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{
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if (ctx->aead == NULL)
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return;
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ctx->aead->cleanup(ctx);
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ctx->aead = NULL;
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}
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/* check_alias returns 0 if out points within the buffer determined by in
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* and in_len and 1 otherwise.
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*
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* When processing, there's only an issue if out points within in[:in_len]
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* and isn't equal to in. If that's the case then writing the output will
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* stomp input that hasn't been read yet.
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*
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* This function checks for that case. */
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static int
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check_alias(const unsigned char *in, size_t in_len, const unsigned char *out)
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{
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if (out <= in)
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return 1;
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if (in + in_len <= out)
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return 1;
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return 0;
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}
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int
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EVP_AEAD_CTX_seal(const EVP_AEAD_CTX *ctx, unsigned char *out, size_t *out_len,
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size_t max_out_len, const unsigned char *nonce, size_t nonce_len,
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const unsigned char *in, size_t in_len, const unsigned char *ad,
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size_t ad_len)
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{
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size_t possible_out_len = in_len + ctx->aead->overhead;
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/* Overflow. */
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if (possible_out_len < in_len) {
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EVPerror(EVP_R_TOO_LARGE);
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goto error;
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}
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if (!check_alias(in, in_len, out)) {
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EVPerror(EVP_R_OUTPUT_ALIASES_INPUT);
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goto error;
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}
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if (ctx->aead->seal(ctx, out, out_len, max_out_len, nonce, nonce_len,
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in, in_len, ad, ad_len)) {
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return 1;
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}
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error:
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/* In the event of an error, clear the output buffer so that a caller
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* that doesn't check the return value doesn't send raw data. */
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memset(out, 0, max_out_len);
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*out_len = 0;
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return 0;
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}
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int
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EVP_AEAD_CTX_open(const EVP_AEAD_CTX *ctx, unsigned char *out, size_t *out_len,
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size_t max_out_len, const unsigned char *nonce, size_t nonce_len,
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const unsigned char *in, size_t in_len, const unsigned char *ad,
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size_t ad_len)
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{
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if (!check_alias(in, in_len, out)) {
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EVPerror(EVP_R_OUTPUT_ALIASES_INPUT);
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goto error;
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}
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if (ctx->aead->open(ctx, out, out_len, max_out_len, nonce, nonce_len,
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in, in_len, ad, ad_len)) {
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return 1;
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}
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error:
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/* In the event of an error, clear the output buffer so that a caller
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* that doesn't check the return value doesn't try and process bad
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* data. */
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memset(out, 0, max_out_len);
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*out_len = 0;
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return 0;
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}
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