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 void EVP_AEAD_CTX_zero(EVP_AEAD_CTX *ctx) { 34 memset(ctx, 0, sizeof(EVP_AEAD_CTX)); 35 } 36 37 int EVP_AEAD_CTX_init(EVP_AEAD_CTX *ctx, const EVP_AEAD *aead, 38 const uint8_t *key, size_t key_len, size_t tag_len, 39 ENGINE *impl) { 40 if (!aead->init) { 41 OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_NO_DIRECTION_SET); 42 ctx->aead = NULL; 43 return 0; 44 } 45 return EVP_AEAD_CTX_init_with_direction(ctx, aead, key, key_len, tag_len, 46 evp_aead_open); 47 } 48 49 int EVP_AEAD_CTX_init_with_direction(EVP_AEAD_CTX *ctx, const EVP_AEAD *aead, 50 const uint8_t *key, size_t key_len, 51 size_t tag_len, 52 enum evp_aead_direction_t dir) { 53 if (key_len != aead->key_len) { 54 OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_UNSUPPORTED_KEY_SIZE); 55 ctx->aead = NULL; 56 return 0; 57 } 58 59 ctx->aead = aead; 60 61 int ok; 62 if (aead->init) { 63 ok = aead->init(ctx, key, key_len, tag_len); 64 } else { 65 ok = aead->init_with_direction(ctx, key, key_len, tag_len, dir); 66 } 67 68 if (!ok) { 69 ctx->aead = NULL; 70 } 71 72 return ok; 73 } 74 75 void EVP_AEAD_CTX_cleanup(EVP_AEAD_CTX *ctx) { 76 if (ctx->aead == NULL) { 77 return; 78 } 79 ctx->aead->cleanup(ctx); 80 ctx->aead = NULL; 81 } 82 83 /* check_alias returns 0 if |out| points within the buffer determined by |in| 84 * and |in_len| and 1 otherwise. 85 * 86 * When processing, there's only an issue if |out| points within in[:in_len] 87 * and isn't equal to |in|. If that's the case then writing the output will 88 * stomp input that hasn't been read yet. 89 * 90 * This function checks for that case. */ 91 static int check_alias(const uint8_t *in, size_t in_len, const uint8_t *out) { 92 if (out <= in) { 93 return 1; 94 } else if (in + in_len <= out) { 95 return 1; 96 } 97 return 0; 98 } 99 100 int EVP_AEAD_CTX_seal(const EVP_AEAD_CTX *ctx, uint8_t *out, size_t *out_len, 101 size_t max_out_len, const uint8_t *nonce, 102 size_t nonce_len, const uint8_t *in, size_t in_len, 103 const uint8_t *ad, size_t ad_len) { 104 size_t possible_out_len = in_len + ctx->aead->overhead; 105 106 if (possible_out_len < in_len /* overflow */) { 107 OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_TOO_LARGE); 108 goto error; 109 } 110 111 if (!check_alias(in, in_len, out)) { 112 OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_OUTPUT_ALIASES_INPUT); 113 goto error; 114 } 115 116 if (ctx->aead->seal(ctx, out, out_len, max_out_len, nonce, nonce_len, in, 117 in_len, ad, ad_len)) { 118 return 1; 119 } 120 121 error: 122 /* In the event of an error, clear the output buffer so that a caller 123 * that doesn't check the return value doesn't send raw data. */ 124 memset(out, 0, max_out_len); 125 *out_len = 0; 126 return 0; 127 } 128 129 int EVP_AEAD_CTX_open(const EVP_AEAD_CTX *ctx, uint8_t *out, size_t *out_len, 130 size_t max_out_len, const uint8_t *nonce, 131 size_t nonce_len, const uint8_t *in, size_t in_len, 132 const uint8_t *ad, size_t ad_len) { 133 if (!check_alias(in, in_len, out)) { 134 OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_OUTPUT_ALIASES_INPUT); 135 goto error; 136 } 137 138 if (ctx->aead->open(ctx, out, out_len, max_out_len, nonce, nonce_len, in, 139 in_len, ad, ad_len)) { 140 return 1; 141 } 142 143 error: 144 /* In the event of an error, clear the output buffer so that a caller 145 * that doesn't check the return value doesn't try and process bad 146 * data. */ 147 memset(out, 0, max_out_len); 148 *out_len = 0; 149 return 0; 150 } 151 152 int EVP_AEAD_CTX_get_rc4_state(const EVP_AEAD_CTX *ctx, const RC4_KEY **out_key) { 153 if (ctx->aead->get_rc4_state == NULL) { 154 return 0; 155 } 156 157 return ctx->aead->get_rc4_state(ctx, out_key); 158 } 159 160 int EVP_AEAD_CTX_get_iv(const EVP_AEAD_CTX *ctx, const uint8_t **out_iv, 161 size_t *out_len) { 162 if (ctx->aead->get_iv == NULL) { 163 return 0; 164 } 165 166 return ctx->aead->get_iv(ctx, out_iv, out_len); 167 } 168
