/*
cipher.c -- Symmetric block cipher handling
- Copyright (C) 2007-2013 Guus Sliepen <guus@tinc-vpn.org>
+ Copyright (C) 2007-2017 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
};
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;
cipher->ctx = EVP_CIPHER_CTX_new();
- if(!cipher->ctx)
+
+ 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;
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;
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_free(cipher->ctx);
free(cipher);
}
size_t cipher_keylength(const cipher_t *cipher) {
- if(!cipher || !cipher->cipher)
+ if(!cipher || !cipher->cipher) {
return 0;
+ }
return EVP_CIPHER_key_length(cipher->cipher) + EVP_CIPHER_iv_length(cipher->cipher);
}
+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(!cipher || !cipher->cipher) {
+ return UINT64_MAX; // NULL cipher
+ }
+
+ 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;
+}
+
size_t cipher_blocksize(const cipher_t *cipher) {
- if(!cipher || !cipher->cipher)
+ if(!cipher || !cipher->cipher) {
return 1;
+ }
return EVP_CIPHER_block_size(cipher->cipher);
}
bool cipher_set_key(cipher_t *cipher, void *key, bool encrypt) {
bool result;
- if(encrypt)
+ if(encrypt) {
result = EVP_EncryptInit_ex(cipher->ctx, cipher->cipher, NULL, (unsigned char *)key, (unsigned char *)key + EVP_CIPHER_key_length(cipher->cipher));
- else
+ } 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_key_from_rsa(cipher_t *cipher, void *key, size_t len, bool encrypt) {
bool result;
- if(encrypt)
+ 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
+ } 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));
+ }
- 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_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;
+ && 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(outlen) {
+ *outlen = len;
+ }
+
return true;
}
}
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;
+ && 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;
}
}
}
int cipher_get_nid(const cipher_t *cipher) {
- if(!cipher || !cipher->cipher)
+ if(!cipher || !cipher->cipher) {
return 0;
+ }
return EVP_CIPHER_nid(cipher->cipher);
}
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