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/* $OpenBSD: evp_aead.c,v 1.5 2014/06/21 15:30:36 jsing 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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✗✓ |
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if (key_len != aead->key_len) { |
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EVPerr(EVP_F_EVP_AEAD_CTX_INIT, 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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✗✓ |
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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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✓✓ |
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if (out <= in) |
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return 1; |
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✓✗ |
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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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✗✓ |
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if (possible_out_len < in_len) { |
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EVPerr(EVP_F_AEAD_CTX_SEAL, EVP_R_TOO_LARGE); |
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goto error; |
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} |
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✗✓ |
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if (!check_alias(in, in_len, out)) { |
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EVPerr(EVP_F_AEAD_CTX_SEAL, EVP_R_OUTPUT_ALIASES_INPUT); |
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goto error; |
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} |
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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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✗✓ |
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if (!check_alias(in, in_len, out)) { |
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EVPerr(EVP_F_AEAD_CTX_OPEN, EVP_R_OUTPUT_ALIASES_INPUT); |
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goto error; |
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} |
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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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} |