1 /* Copyright (c) 2014, Google Inc. 2 * 3 * Permission to use, copy, modify, and/or distribute this software for any 4 * purpose with or without fee is hereby granted, provided that the above 5 * copyright notice and this permission notice appear in all copies. 6 * 7 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 8 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 9 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY 10 * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 11 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION 12 * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN 13 * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */ 14 15 #include <openssl/aead.h> 16 17 #include <string.h> 18 19 #include <openssl/cipher.h> 20 #include <openssl/err.h> 21 22 #include "internal.h" 23 24 25 size_t EVP_AEAD_key_length(const EVP_AEAD *aead) { return aead->key_len; } 26 27 size_t EVP_AEAD_nonce_length(const EVP_AEAD *aead) { return aead->nonce_len; } 28 29 size_t EVP_AEAD_max_overhead(const EVP_AEAD *aead) { return aead->overhead; } 30 31 size_t EVP_AEAD_max_tag_len(const EVP_AEAD *aead) { return aead->max_tag_len; } 32 33 int EVP_AEAD_CTX_init(EVP_AEAD_CTX *ctx, const EVP_AEAD *aead, 34 const uint8_t *key, size_t key_len, size_t tag_len, 35 ENGINE *impl) { 36 ctx->aead = aead; 37 if (key_len != aead->key_len) { 38 OPENSSL_PUT_ERROR(CIPHER, EVP_AEAD_CTX_init, CIPHER_R_UNSUPPORTED_KEY_SIZE); 39 return 0; 40 } 41 return aead->init(ctx, key, key_len, tag_len); 42 } 43 44 void EVP_AEAD_CTX_cleanup(EVP_AEAD_CTX *ctx) { 45 if (ctx->aead == NULL) { 46 return; 47 } 48 ctx->aead->cleanup(ctx); 49 ctx->aead = NULL; 50 } 51 52 /* check_alias returns 0 if |out| points within the buffer determined by |in| 53 * and |in_len| and 1 otherwise. 54 * 55 * When processing, there's only an issue if |out| points within in[:in_len] 56 * and isn't equal to |in|. If that's the case then writing the output will 57 * stomp input that hasn't been read yet. 58 * 59 * This function checks for that case. */ 60 static int check_alias(const uint8_t *in, size_t in_len, const uint8_t *out) { 61 if (out <= in) { 62 return 1; 63 } else if (in + in_len <= out) { 64 return 1; 65 } 66 return 0; 67 } 68 69 int EVP_AEAD_CTX_seal(const EVP_AEAD_CTX *ctx, uint8_t *out, size_t *out_len, 70 size_t max_out_len, const uint8_t *nonce, 71 size_t nonce_len, const uint8_t *in, size_t in_len, 72 const uint8_t *ad, size_t ad_len) { 73 size_t possible_out_len = in_len + ctx->aead->overhead; 74 75 if (possible_out_len < in_len /* overflow */) { 76 OPENSSL_PUT_ERROR(CIPHER, EVP_AEAD_CTX_seal, CIPHER_R_TOO_LARGE); 77 goto error; 78 } 79 80 if (!check_alias(in, in_len, out)) { 81 OPENSSL_PUT_ERROR(CIPHER, EVP_AEAD_CTX_seal, CIPHER_R_OUTPUT_ALIASES_INPUT); 82 goto error; 83 } 84 85 if (ctx->aead->seal(ctx, out, out_len, max_out_len, nonce, nonce_len, in, 86 in_len, ad, ad_len)) { 87 return 1; 88 } 89 90 error: 91 /* In the event of an error, clear the output buffer so that a caller 92 * that doesn't check the return value doesn't send raw data. */ 93 memset(out, 0, max_out_len); 94 *out_len = 0; 95 return 0; 96 } 97 98 int EVP_AEAD_CTX_open(const EVP_AEAD_CTX *ctx, uint8_t *out, size_t *out_len, 99 size_t max_out_len, const uint8_t *nonce, 100 size_t nonce_len, const uint8_t *in, size_t in_len, 101 const uint8_t *ad, size_t ad_len) { 102 if (!check_alias(in, in_len, out)) { 103 OPENSSL_PUT_ERROR(CIPHER, EVP_AEAD_CTX_open, CIPHER_R_OUTPUT_ALIASES_INPUT); 104 goto error; 105 } 106 107 if (ctx->aead->open(ctx, out, out_len, max_out_len, nonce, nonce_len, in, 108 in_len, ad, ad_len)) { 109 return 1; 110 } 111 112 error: 113 /* In the event of an error, clear the output buffer so that a caller 114 * that doesn't check the return value doesn't try and process bad 115 * data. */ 116 memset(out, 0, max_out_len); 117 *out_len = 0; 118 return 0; 119 } 120
