/* $OpenBSD: evp_aead.c,v 1.4 2014/06/12 15:49:29 deraadt Exp $ */ /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) * All rights reserved. * * This package is an SSL implementation written * by Eric Young (eay@cryptsoft.com). * The implementation was written so as to conform with Netscapes SSL. * * This library is free for commercial and non-commercial use as long as * the following conditions are aheared to. The following conditions * apply to all code found in this distribution, be it the RC4, RSA, * lhash, DES, etc., code; not just the SSL code. The SSL documentation * included with this distribution is covered by the same copyright terms * except that the holder is Tim Hudson (tjh@cryptsoft.com). * * Copyright remains Eric Young's, and as such any Copyright notices in * the code are not to be removed. * If this package is used in a product, Eric Young should be given attribution * as the author of the parts of the library used. * This can be in the form of a textual message at program startup or * in documentation (online or textual) provided with the package. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * "This product includes cryptographic software written by * Eric Young (eay@cryptsoft.com)" * The word 'cryptographic' can be left out if the rouines from the library * being used are not cryptographic related :-). * 4. If you include any Windows specific code (or a derivative thereof) from * the apps directory (application code) you must include an acknowledgement: * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)" * * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * The licence and distribution terms for any publically available version or * derivative of this code cannot be changed. i.e. this code cannot simply be * copied and put under another distribution licence * [including the GNU Public Licence.] */ #include #include #include #include #include "evp_locl.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; } int EVP_AEAD_CTX_init(EVP_AEAD_CTX *ctx, const EVP_AEAD *aead, const unsigned char *key, size_t key_len, size_t tag_len, ENGINE *impl) { ctx->aead = aead; if (key_len != aead->key_len) { EVPerr(EVP_F_EVP_AEAD_CTX_INIT, EVP_R_UNSUPPORTED_KEY_SIZE); return 0; } return aead->init(ctx, key, key_len, tag_len); } void EVP_AEAD_CTX_cleanup(EVP_AEAD_CTX *ctx) { if (ctx->aead == NULL) return; ctx->aead->cleanup(ctx); ctx->aead = NULL; } /* check_alias returns 0 if out points within the buffer determined by in * and in_len and 1 otherwise. * * When processing, there's only an issue if out points within in[:in_len] * and isn't equal to in. If that's the case then writing the output will * stomp input that hasn't been read yet. * * This function checks for that case. */ static int check_alias(const unsigned char *in, size_t in_len, const unsigned char *out) { if (out <= in) return 1; if (in + in_len <= out) return 1; return 0; } int EVP_AEAD_CTX_seal(const EVP_AEAD_CTX *ctx, unsigned char *out, size_t *out_len, size_t max_out_len, const unsigned char *nonce, size_t nonce_len, const unsigned char *in, size_t in_len, const unsigned char *ad, size_t ad_len) { size_t possible_out_len = in_len + ctx->aead->overhead; /* Overflow. */ if (possible_out_len < in_len) { EVPerr(EVP_F_AEAD_CTX_SEAL, EVP_R_TOO_LARGE); goto error; } if (!check_alias(in, in_len, out)) { EVPerr(EVP_F_AEAD_CTX_SEAL, EVP_R_OUTPUT_ALIASES_INPUT); goto error; } if (ctx->aead->seal(ctx, out, out_len, max_out_len, nonce, nonce_len, in, 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. */ memset(out, 0, max_out_len); *out_len = 0; return 0; } int EVP_AEAD_CTX_open(const EVP_AEAD_CTX *ctx, unsigned char *out, size_t *out_len, size_t max_out_len, const unsigned char *nonce, size_t nonce_len, const unsigned char *in, size_t in_len, const unsigned char *ad, size_t ad_len) { if (!check_alias(in, in_len, out)) { EVPerr(EVP_F_AEAD_CTX_OPEN, EVP_R_OUTPUT_ALIASES_INPUT); goto error; } if (ctx->aead->open(ctx, out, out_len, max_out_len, nonce, nonce_len, in, 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 try and process bad * data. */ memset(out, 0, max_out_len); *out_len = 0; return 0; }