1 /* $OpenBSD: evp_aead.c,v 1.6 2017/01/29 17:49:23 beck Exp $ */
3 * Copyright (c) 2014, Google Inc.
5 * Permission to use, copy, modify, and/or distribute this software for any
6 * purpose with or without fee is hereby granted, provided that the above
7 * copyright notice and this permission notice appear in all copies.
9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
12 * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
14 * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
15 * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
21 #include <openssl/evp.h>
22 #include <openssl/err.h>
27 EVP_AEAD_key_length(const EVP_AEAD *aead)
33 EVP_AEAD_nonce_length(const EVP_AEAD *aead)
35 return aead->nonce_len;
39 EVP_AEAD_max_overhead(const EVP_AEAD *aead)
41 return aead->overhead;
45 EVP_AEAD_max_tag_len(const EVP_AEAD *aead)
47 return aead->max_tag_len;
51 EVP_AEAD_CTX_init(EVP_AEAD_CTX *ctx, const EVP_AEAD *aead,
52 const unsigned char *key, size_t key_len, size_t tag_len, ENGINE *impl)
55 if (key_len != aead->key_len) {
56 EVPerror(EVP_R_UNSUPPORTED_KEY_SIZE);
59 return aead->init(ctx, key, key_len, tag_len);
63 EVP_AEAD_CTX_cleanup(EVP_AEAD_CTX *ctx)
65 if (ctx->aead == NULL)
67 ctx->aead->cleanup(ctx);
71 /* check_alias returns 0 if out points within the buffer determined by in
72 * and in_len and 1 otherwise.
74 * When processing, there's only an issue if out points within in[:in_len]
75 * and isn't equal to in. If that's the case then writing the output will
76 * stomp input that hasn't been read yet.
78 * This function checks for that case. */
80 check_alias(const unsigned char *in, size_t in_len, const unsigned char *out)
84 if (in + in_len <= out)
90 EVP_AEAD_CTX_seal(const EVP_AEAD_CTX *ctx, unsigned char *out, size_t *out_len,
91 size_t max_out_len, const unsigned char *nonce, size_t nonce_len,
92 const unsigned char *in, size_t in_len, const unsigned char *ad,
95 size_t possible_out_len = in_len + ctx->aead->overhead;
98 if (possible_out_len < in_len) {
99 EVPerror(EVP_R_TOO_LARGE);
103 if (!check_alias(in, in_len, out)) {
104 EVPerror(EVP_R_OUTPUT_ALIASES_INPUT);
108 if (ctx->aead->seal(ctx, out, out_len, max_out_len, nonce, nonce_len,
109 in, in_len, ad, ad_len)) {
114 /* In the event of an error, clear the output buffer so that a caller
115 * that doesn't check the return value doesn't send raw data. */
116 memset(out, 0, max_out_len);
122 EVP_AEAD_CTX_open(const EVP_AEAD_CTX *ctx, unsigned char *out, size_t *out_len,
123 size_t max_out_len, const unsigned char *nonce, size_t nonce_len,
124 const unsigned char *in, size_t in_len, const unsigned char *ad,
127 if (!check_alias(in, in_len, out)) {
128 EVPerror(EVP_R_OUTPUT_ALIASES_INPUT);
132 if (ctx->aead->open(ctx, out, out_len, max_out_len, nonce, nonce_len,
133 in, in_len, ad, ad_len)) {
138 /* In the event of an error, clear the output buffer so that a caller
139 * that doesn't check the return value doesn't try and process bad
141 memset(out, 0, max_out_len);