X-Git-Url: https://tinc-vpn.org/git/browse?a=blobdiff_plain;f=src%2Fopenssl%2Fcipher.c;h=974fbeb2e9966e1d189fa6c7737aa63aa1e1a025;hb=2b0aeec02d64bb4724da9ff1dbc19b7d35d7c904;hp=7f73cb1bbc22e53f7b34025521783986e2b190d7;hpb=5b07039b0712bee0f19749d63116a10fb08a2d8b;p=tinc diff --git a/src/openssl/cipher.c b/src/openssl/cipher.c index 7f73cb1b..974fbeb2 100644 --- a/src/openssl/cipher.c +++ b/src/openssl/cipher.c @@ -1,6 +1,6 @@ /* cipher.c -- Symmetric block cipher handling - Copyright (C) 2007-2013 Guus Sliepen + Copyright (C) 2007-2017 Guus Sliepen This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by @@ -28,27 +28,25 @@ #include "../xalloc.h" struct cipher { - EVP_CIPHER_CTX ctx; + EVP_CIPHER_CTX *ctx; const EVP_CIPHER *cipher; - struct cipher_counter *counter; }; -typedef struct cipher_counter { - unsigned char counter[CIPHER_MAX_IV_SIZE]; - unsigned char block[CIPHER_MAX_IV_SIZE]; - int n; -} cipher_counter_t; - static cipher_t *cipher_open(const EVP_CIPHER *evp_cipher) { - cipher_t *cipher = xzalloc(sizeof *cipher); + cipher_t *cipher = xzalloc(sizeof(*cipher)); cipher->cipher = evp_cipher; - EVP_CIPHER_CTX_init(&cipher->ctx); + cipher->ctx = EVP_CIPHER_CTX_new(); + + if(!cipher->ctx) { + abort(); + } return cipher; } cipher_t *cipher_open_by_name(const char *name) { const EVP_CIPHER *evp_cipher = EVP_get_cipherbyname(name); + if(!evp_cipher) { logger(DEBUG_ALWAYS, LOG_ERR, "Unknown cipher name '%s'!", name); return NULL; @@ -59,6 +57,7 @@ cipher_t *cipher_open_by_name(const char *name) { cipher_t *cipher_open_by_nid(int nid) { const EVP_CIPHER *evp_cipher = EVP_get_cipherbynid(nid); + if(!evp_cipher) { logger(DEBUG_ALWAYS, LOG_ERR, "Unknown cipher nid %d!", nid); return NULL; @@ -67,130 +66,105 @@ cipher_t *cipher_open_by_nid(int nid) { return cipher_open(evp_cipher); } -cipher_t *cipher_open_blowfish_ofb(void) { - return cipher_open(EVP_bf_ofb()); -} - void cipher_close(cipher_t *cipher) { - if(!cipher) + if(!cipher) { return; + } - EVP_CIPHER_CTX_cleanup(&cipher->ctx); - free(cipher->counter); + EVP_CIPHER_CTX_free(cipher->ctx); free(cipher); } size_t cipher_keylength(const cipher_t *cipher) { - return cipher->cipher->key_len + cipher->cipher->block_size; + if(!cipher || !cipher->cipher) { + return 0; + } + + return EVP_CIPHER_key_length(cipher->cipher) + EVP_CIPHER_iv_length(cipher->cipher); } -bool cipher_set_key(cipher_t *cipher, void *key, bool encrypt) { - bool result; +uint64_t cipher_budget(const cipher_t *cipher) { + /* Hopefully some failsafe way to calculate the maximum amount of bytes to + send/receive with a given cipher before we might run into birthday paradox + attacks. Because we might use different modes, the block size of the mode + might be 1 byte. In that case, use the IV length. Ensure the whole thing + is limited to what can be represented with a 64 bits integer. + */ - if(encrypt) - result = EVP_EncryptInit_ex(&cipher->ctx, cipher->cipher, NULL, (unsigned char *)key, (unsigned char *)key + cipher->cipher->key_len); - else - result = EVP_DecryptInit_ex(&cipher->ctx, cipher->cipher, NULL, (unsigned char *)key, (unsigned char *)key + cipher->cipher->key_len); + if(!cipher || !cipher->cipher) { + return UINT64_MAX; // NULL cipher + } - if(result) - return true; + int ivlen = EVP_CIPHER_iv_length(cipher->cipher); + int blklen = EVP_CIPHER_block_size(cipher->cipher); + int len = blklen > 1 ? blklen : ivlen > 1 ? ivlen : 8; + int bits = len * 4 - 1; + return bits < 64 ? UINT64_C(1) << bits : UINT64_MAX; +} - logger(DEBUG_ALWAYS, LOG_ERR, "Error while setting key: %s", ERR_error_string(ERR_get_error(), NULL)); - return false; +size_t cipher_blocksize(const cipher_t *cipher) { + if(!cipher || !cipher->cipher) { + return 1; + } + + return EVP_CIPHER_block_size(cipher->cipher); } -bool cipher_set_key_from_rsa(cipher_t *cipher, void *key, size_t len, bool encrypt) { +bool cipher_set_key(cipher_t *cipher, void *key, bool encrypt) { bool result; - if(encrypt) - result = EVP_EncryptInit_ex(&cipher->ctx, cipher->cipher, NULL, (unsigned char *)key + len - cipher->cipher->key_len, (unsigned char *)key + len - cipher->cipher->iv_len - cipher->cipher->key_len); - else - result = EVP_DecryptInit_ex(&cipher->ctx, cipher->cipher, NULL, (unsigned char *)key + len - cipher->cipher->key_len, (unsigned char *)key + len - cipher->cipher->iv_len - cipher->cipher->key_len); + if(encrypt) { + result = EVP_EncryptInit_ex(cipher->ctx, cipher->cipher, NULL, (unsigned char *)key, (unsigned char *)key + EVP_CIPHER_key_length(cipher->cipher)); + } else { + result = EVP_DecryptInit_ex(cipher->ctx, cipher->cipher, NULL, (unsigned char *)key, (unsigned char *)key + EVP_CIPHER_key_length(cipher->cipher)); + } - if(result) + if(result) { return true; + } logger(DEBUG_ALWAYS, LOG_ERR, "Error while setting key: %s", ERR_error_string(ERR_get_error(), NULL)); return false; } -bool cipher_set_counter(cipher_t *cipher, const void *counter, size_t len) { - if(len > cipher->cipher->block_size - 4) { - logger(DEBUG_ALWAYS, LOG_ERR, "Counter too long"); - abort(); - } - - memcpy(cipher->counter->counter + cipher->cipher->block_size - len, counter, len); - memset(cipher->counter->counter, 0, 4); - cipher->counter->n = 0; - - return true; -} - -bool cipher_set_counter_key(cipher_t *cipher, void *key) { - int result = EVP_EncryptInit_ex(&cipher->ctx, cipher->cipher, NULL, (unsigned char *)key, NULL); - if(!result) { - logger(DEBUG_ALWAYS, LOG_ERR, "Error while setting key: %s", ERR_error_string(ERR_get_error(), NULL)); - return false; - } - - if(!cipher->counter) - cipher->counter = xzalloc(sizeof *cipher->counter); - else - cipher->counter->n = 0; - - memcpy(cipher->counter->counter, (unsigned char *)key + cipher->cipher->key_len, cipher->cipher->block_size); - - return true; -} +bool cipher_set_key_from_rsa(cipher_t *cipher, void *key, size_t len, bool encrypt) { + bool result; -bool cipher_counter_xor(cipher_t *cipher, const void *indata, size_t inlen, void *outdata) { - if(!cipher->counter) { - logger(DEBUG_ALWAYS, LOG_ERR, "Counter not initialized"); - return false; + if(encrypt) { + result = EVP_EncryptInit_ex(cipher->ctx, cipher->cipher, NULL, (unsigned char *)key + len - EVP_CIPHER_key_length(cipher->cipher), (unsigned char *)key + len - EVP_CIPHER_iv_length(cipher->cipher) - EVP_CIPHER_key_length(cipher->cipher)); + } else { + result = EVP_DecryptInit_ex(cipher->ctx, cipher->cipher, NULL, (unsigned char *)key + len - EVP_CIPHER_key_length(cipher->cipher), (unsigned char *)key + len - EVP_CIPHER_iv_length(cipher->cipher) - EVP_CIPHER_key_length(cipher->cipher)); } - const unsigned char *in = indata; - unsigned char *out = outdata; - - while(inlen--) { - // Encrypt the new counter value if we need it - if(!cipher->counter->n) { - int len; - if(!EVP_EncryptUpdate(&cipher->ctx, cipher->counter->block, &len, cipher->counter->counter, cipher->cipher->block_size)) { - logger(DEBUG_ALWAYS, LOG_ERR, "Error while encrypting: %s", ERR_error_string(ERR_get_error(), NULL)); - return false; - } - - // Increase the counter value - for(int i = 0; i < cipher->cipher->block_size; i++) - if(++cipher->counter->counter[i]) - break; - } - - *out++ = *in++ ^ cipher->counter->counter[cipher->counter->n++]; - - if(cipher->counter->n >= cipher->cipher->block_size) - cipher->counter->n = 0; + if(result) { + return true; } - return true; + logger(DEBUG_ALWAYS, LOG_ERR, "Error while setting key: %s", ERR_error_string(ERR_get_error(), NULL)); + return false; } - bool cipher_encrypt(cipher_t *cipher, const void *indata, size_t inlen, void *outdata, size_t *outlen, bool oneshot) { if(oneshot) { int len, pad; - if(EVP_EncryptInit_ex(&cipher->ctx, NULL, NULL, NULL, NULL) - && EVP_EncryptUpdate(&cipher->ctx, (unsigned char *)outdata, &len, indata, inlen) - && EVP_EncryptFinal(&cipher->ctx, (unsigned char *)outdata + len, &pad)) { - if(outlen) *outlen = len + pad; + + if(EVP_EncryptInit_ex(cipher->ctx, NULL, NULL, NULL, NULL) + && EVP_EncryptUpdate(cipher->ctx, (unsigned char *)outdata, &len, indata, inlen) + && EVP_EncryptFinal_ex(cipher->ctx, (unsigned char *)outdata + len, &pad)) { + if(outlen) { + *outlen = len + pad; + } + return true; } } else { int len; - if(EVP_EncryptUpdate(&cipher->ctx, outdata, &len, indata, inlen)) { - if(outlen) *outlen = len; + + if(EVP_EncryptUpdate(cipher->ctx, outdata, &len, indata, inlen)) { + if(outlen) { + *outlen = len; + } + return true; } } @@ -202,16 +176,24 @@ bool cipher_encrypt(cipher_t *cipher, const void *indata, size_t inlen, void *ou bool cipher_decrypt(cipher_t *cipher, const void *indata, size_t inlen, void *outdata, size_t *outlen, bool oneshot) { if(oneshot) { int len, pad; - if(EVP_DecryptInit_ex(&cipher->ctx, NULL, NULL, NULL, NULL) - && EVP_DecryptUpdate(&cipher->ctx, (unsigned char *)outdata, &len, indata, inlen) - && EVP_DecryptFinal(&cipher->ctx, (unsigned char *)outdata + len, &pad)) { - if(outlen) *outlen = len + pad; + + if(EVP_DecryptInit_ex(cipher->ctx, NULL, NULL, NULL, NULL) + && EVP_DecryptUpdate(cipher->ctx, (unsigned char *)outdata, &len, indata, inlen) + && EVP_DecryptFinal_ex(cipher->ctx, (unsigned char *)outdata + len, &pad)) { + if(outlen) { + *outlen = len + pad; + } + return true; } } else { int len; - if(EVP_EncryptUpdate(&cipher->ctx, outdata, &len, indata, inlen)) { - if(outlen) *outlen = len; + + if(EVP_DecryptUpdate(cipher->ctx, outdata, &len, indata, inlen)) { + if(outlen) { + *outlen = len; + } + return true; } } @@ -221,9 +203,13 @@ bool cipher_decrypt(cipher_t *cipher, const void *indata, size_t inlen, void *ou } int cipher_get_nid(const cipher_t *cipher) { - return cipher->cipher ? cipher->cipher->nid : 0; + if(!cipher || !cipher->cipher) { + return 0; + } + + return EVP_CIPHER_nid(cipher->cipher); } bool cipher_active(const cipher_t *cipher) { - return cipher && cipher->cipher && cipher->cipher->nid != 0; + return cipher && cipher->cipher && EVP_CIPHER_nid(cipher->cipher) != 0; }