X-Git-Url: https://www.tinc-vpn.org/git/browse?a=blobdiff_plain;f=src%2Fopenssl%2Fcipher.c;h=a8032ea02a68a7459bb26e3caada3952da12a078;hb=1be0c284c7c8d34c2dd6c2160ce49aeae468e867;hp=9b39a28836c151a81d039ce74c80694e5fddb51a;hpb=b78436ff1e9afd767c3da473d34b7553d8411b6a;p=tinc

diff --git a/src/openssl/cipher.c b/src/openssl/cipher.c
index 9b39a288..a8032ea0 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 <guus@tinc-vpn.org>
+    Copyright (C) 2007-2016 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
@@ -28,14 +28,16 @@
 #include "../xalloc.h"
 
 struct cipher {
-	EVP_CIPHER_CTX ctx;
+	EVP_CIPHER_CTX *ctx;
 	const EVP_CIPHER *cipher;
 };
 
 static cipher_t *cipher_open(const EVP_CIPHER *evp_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;
 }
@@ -60,15 +62,11 @@ 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)
 		return;
 
-	EVP_CIPHER_CTX_cleanup(&cipher->ctx);
+	EVP_CIPHER_CTX_free(cipher->ctx);
 	free(cipher);
 }
 
@@ -76,16 +74,41 @@ size_t cipher_keylength(const cipher_t *cipher) {
 	if(!cipher || !cipher->cipher)
 		return 0;
 
-	return cipher->cipher->key_len + cipher->cipher->iv_len;
+	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)
+		return 1;
+
+	return EVP_CIPHER_block_size(cipher->cipher);
 }
 
 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, (unsigned char *)key + cipher->cipher->key_len);
+		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 + cipher->cipher->key_len);
+		result = EVP_DecryptInit_ex(cipher->ctx, cipher->cipher, NULL, (unsigned char *)key, (unsigned char *)key + EVP_CIPHER_key_length(cipher->cipher));
 
 	if(result)
 		return true;
@@ -98,9 +121,9 @@ bool cipher_set_key_from_rsa(cipher_t *cipher, void *key, size_t len, bool encry
 	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);
+		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 - cipher->cipher->key_len, (unsigned char *)key + len - cipher->cipher->iv_len - cipher->cipher->key_len);
+		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)
 		return true;
@@ -112,15 +135,15 @@ bool cipher_set_key_from_rsa(cipher_t *cipher, void *key, size_t len, bool encry
 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(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(EVP_EncryptUpdate(cipher->ctx, outdata, &len, indata, inlen)) {
 			if(outlen) *outlen = len;
 			return true;
 		}
@@ -133,15 +156,15 @@ 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(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(EVP_EncryptUpdate(cipher->ctx, outdata, &len, indata, inlen)) {
 			if(outlen) *outlen = len;
 			return true;
 		}
@@ -155,9 +178,9 @@ int cipher_get_nid(const cipher_t *cipher) {
 	if(!cipher || !cipher->cipher)
 		return 0;
 
-	return cipher->cipher->nid;
+	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;
 }