/*
cipher.c -- Symmetric block cipher handling
- Copyright (C) 2007 Guus Sliepen <guus@tinc-vpn.org>
+ Copyright (C) 2007-2022 Guus Sliepen <guus@tinc-vpn.org>
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
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
-#include "system.h"
+#include "../system.h"
-#include <openssl/rand.h>
#include <openssl/err.h>
+#include <openssl/evp.h>
+#include "log.h"
#include "cipher.h"
-#include "logger.h"
-#include "xalloc.h"
+#include "../cipher.h"
+#include "../logger.h"
-static bool cipher_open(cipher_t *cipher) {
- cipher->keylen = cipher->cipher->key_len;
- cipher->blklen = cipher->cipher->iv_len;
+typedef int (enc_init_t)(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *cipher, ENGINE *impl, const unsigned char *key, const unsigned char *iv);
+typedef int (enc_update_t)(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl, const unsigned char *in, int inl);
+typedef int (enc_final_t)(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl);
- cipher->key = xmalloc(cipher->keylen + cipher->blklen);
+static void cipher_open(cipher_t *cipher, const EVP_CIPHER *evp_cipher) {
+ cipher->cipher = evp_cipher;
+ cipher->ctx = EVP_CIPHER_CTX_new();
- EVP_CIPHER_CTX_init(&cipher->ctx);
-
- return true;
+ if(!cipher->ctx) {
+ abort();
+ }
}
bool cipher_open_by_name(cipher_t *cipher, const char *name) {
- cipher->cipher = EVP_get_cipherbyname(name);
+ const EVP_CIPHER *evp_cipher = EVP_get_cipherbyname(name);
- if(cipher->cipher)
- return cipher_open(cipher);
+ if(!evp_cipher) {
+ logger(DEBUG_ALWAYS, LOG_ERR, "Unknown cipher name '%s'!", name);
+ return false;
+ }
- logger(LOG_DEBUG, "Unknown cipher name '%s'!", name);
- return false;
+ cipher_open(cipher, evp_cipher);
+ return true;
}
bool cipher_open_by_nid(cipher_t *cipher, int nid) {
- cipher->cipher = EVP_get_cipherbynid(nid);
-
- if(cipher->cipher)
- return cipher_open(cipher);
+ const EVP_CIPHER *evp_cipher = EVP_get_cipherbynid(nid);
- logger(LOG_DEBUG, "Unknown cipher nid %d!", nid);
- return false;
-}
+ if(!evp_cipher) {
+ logger(DEBUG_ALWAYS, LOG_ERR, "Unknown cipher nid %d!", nid);
+ return false;
+ }
-bool cipher_open_blowfish_ofb(cipher_t *cipher) {
- cipher->cipher = EVP_bf_ofb();
- return cipher_open(cipher);
+ cipher_open(cipher, evp_cipher);
+ return true;
}
void cipher_close(cipher_t *cipher) {
- EVP_CIPHER_CTX_cleanup(&cipher->ctx);
+ if(!cipher) {
+ return;
+ }
- if(cipher->key) {
- free(cipher->key);
- cipher->key = NULL;
+ if(cipher->ctx) {
+ EVP_CIPHER_CTX_free(cipher->ctx);
}
+
+ memset(cipher, 0, sizeof(*cipher));
}
size_t cipher_keylength(const cipher_t *cipher) {
- return cipher->keylen + cipher->blklen;
-}
+ if(!cipher || !cipher->cipher) {
+ return 0;
+ }
-void cipher_get_key(const cipher_t *cipher, void *key) {
- memcpy(key, cipher->key, cipher->keylen + cipher->blklen);
+ return EVP_CIPHER_key_length(cipher->cipher) + EVP_CIPHER_iv_length(cipher->cipher);
}
-bool cipher_set_key(cipher_t *cipher, void *key, bool encrypt) {
- memcpy(cipher->key, key, cipher->keylen + cipher->blklen);
- 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 *)cipher->key, (unsigned char *)cipher->key + cipher->keylen);
- else
- result = EVP_DecryptInit_ex(&cipher->ctx, cipher->cipher, NULL, (unsigned char *)cipher->key, (unsigned char *)cipher->key + cipher->keylen);
+ 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(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) {
- memcpy(cipher->key, key + len - (size_t)cipher->keylen, cipher->keylen);
- memcpy(cipher->key + cipher->keylen, key + len - (size_t)cipher->keylen - (size_t)cipher->blklen, cipher->blklen);
+static bool cipher_init_ctx(cipher_t *cipher, bool encrypt, const unsigned char *key, const unsigned char *iv) {
bool result;
- if(encrypt)
- result = EVP_EncryptInit_ex(&cipher->ctx, cipher->cipher, NULL, (unsigned char *)cipher->key, (unsigned char *)cipher->key + cipher->keylen);
- else
- result = EVP_DecryptInit_ex(&cipher->ctx, cipher->cipher, NULL, (unsigned char *)cipher->key, (unsigned char *)cipher->key + cipher->keylen);
+ if(encrypt) {
+ result = EVP_EncryptInit_ex(cipher->ctx, cipher->cipher, NULL, key, iv);
+ } else {
+ result = EVP_DecryptInit_ex(cipher->ctx, cipher->cipher, NULL, key, iv);
+ }
- if(result)
+ if(result) {
return true;
+ }
- logger(LOG_ERR, "Error while setting key: %s", ERR_error_string(ERR_get_error(), NULL));
+ openssl_err("set key");
return false;
}
-bool cipher_regenerate_key(cipher_t *cipher, bool encrypt) {
- bool result;
-
- RAND_pseudo_bytes((unsigned char *)cipher->key, cipher->keylen + cipher->blklen);
-
- if(encrypt)
- result = EVP_EncryptInit_ex(&cipher->ctx, cipher->cipher, NULL, (unsigned char *)cipher->key, (unsigned char *)cipher->key + cipher->keylen);
- else
- result = EVP_DecryptInit_ex(&cipher->ctx, cipher->cipher, NULL, (unsigned char *)cipher->key, (unsigned char *)cipher->key + cipher->keylen);
+bool cipher_set_key(cipher_t *cipher, void *key, bool encrypt) {
+ unsigned char *iv = (unsigned char *)key + EVP_CIPHER_key_length(cipher->cipher);
+ return cipher_init_ctx(cipher, encrypt, key, iv);
+}
- if(result)
- return true;
-
- logger(LOG_ERR, "Error while regenerating key: %s", ERR_error_string(ERR_get_error(), NULL));
- return false;
+bool cipher_set_key_from_rsa(cipher_t *cipher, void *key, size_t len, bool encrypt) {
+ unsigned char *k = (unsigned char *)key + len - EVP_CIPHER_key_length(cipher->cipher);
+ unsigned char *iv = k - EVP_CIPHER_iv_length(cipher->cipher);
+ return cipher_init_ctx(cipher, encrypt, k, iv);
}
-bool cipher_encrypt(cipher_t *cipher, const void *indata, size_t inlen, void *outdata, size_t *outlen, bool oneshot) {
+static bool cipher_encrypt_decrypt(cipher_t *cipher, const void *indata, size_t inlen, void *outdata, size_t *outlen, bool oneshot,
+ enc_init_t init, enc_update_t update, enc_final_t final) {
if(oneshot) {
- int len = *outlen, pad;
- if(EVP_EncryptInit_ex(&cipher->ctx, NULL, NULL, NULL, NULL)
- &&EVP_EncryptUpdate(&cipher->ctx, outdata, &len, indata, inlen)
- && EVP_EncryptFinal(&cipher->ctx, outdata + len, &pad)) {
- *outlen = len + pad;
+ int len, pad;
+
+ if(init(cipher->ctx, NULL, NULL, NULL, NULL)
+ && update(cipher->ctx, (unsigned char *)outdata, &len, indata, (int)inlen)
+ && final(cipher->ctx, (unsigned char *)outdata + len, &pad)) {
+ if(outlen) {
+ *outlen = len + pad;
+ }
+
return true;
}
} else {
- int len = *outlen;
- if(EVP_EncryptUpdate(&cipher->ctx, outdata, &len, indata, inlen)) {
- *outlen = len;
+ int len;
+
+ if(update(cipher->ctx, outdata, &len, indata, (int)inlen)) {
+ if(outlen) {
+ *outlen = len;
+ }
+
return true;
}
}
- logger(LOG_ERR, "Error while encrypting: %s", ERR_error_string(ERR_get_error(), NULL));
+ openssl_err("encrypt or decrypt data");
return false;
}
-bool cipher_decrypt(cipher_t *cipher, const void *indata, size_t inlen, void *outdata, size_t *outlen, bool oneshot) {
- if(oneshot) {
- int len = *outlen, pad;
- if(EVP_DecryptInit_ex(&cipher->ctx, NULL, NULL, NULL, NULL)
- && EVP_DecryptUpdate(&cipher->ctx, outdata, &len, indata, inlen)
- && EVP_DecryptFinal(&cipher->ctx, outdata + len, &pad)) {
- *outlen = len + pad;
- return true;
- }
- } else {
- int len = *outlen;
- if(EVP_EncryptUpdate(&cipher->ctx, outdata, &len, indata, inlen)) {
- *outlen = len;
- return true;
- }
- }
+bool cipher_encrypt(cipher_t *cipher, const void *indata, size_t inlen, void *outdata, size_t *outlen, bool oneshot) {
+ return cipher_encrypt_decrypt(cipher, indata, inlen, outdata, outlen, oneshot,
+ EVP_EncryptInit_ex, EVP_EncryptUpdate, EVP_EncryptFinal_ex);
+}
- logger(LOG_ERR, "Error while encrypting: %s", ERR_error_string(ERR_get_error(), NULL));
- return false;
+bool cipher_decrypt(cipher_t *cipher, const void *indata, size_t inlen, void *outdata, size_t *outlen, bool oneshot) {
+ return cipher_encrypt_decrypt(cipher, indata, inlen, outdata, outlen, oneshot,
+ EVP_DecryptInit_ex, EVP_DecryptUpdate, EVP_DecryptFinal_ex);
}
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->nid != 0;
+ return cipher && cipher->cipher && EVP_CIPHER_nid(cipher->cipher) != 0;
}