kdxcxs
/
n2n
mirror of https://github.com/ntop/n2n.git
1
0
Fork 0
Code Issues Releases Wiki Activity
Browse Source

Merge pull request #213 from Logan007/evp 

AES -- (better) hardware acceleration using openssl's evp interface
pull/232/head
Luca Deri 4 years ago
committed by GitHub
parent
2636c65999 fb1dfdbdf2
commit
3c8837cfa3
No known key found for this signature in database GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 82 additions and 17 deletions
Whitespace
Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL
Split View
Diff Options
Show Stats Download Patch File Download Diff File
  1. 99
      transform_aes.c

99
transform_aes.c
View File

@ -23,6 +23,8 @@
#include <openssl/aes.h>
#include <openssl/sha.h>
#include <openssl/evp.h>
#include <openssl/err.h>
#define N2N_AES_TRANSFORM_VERSION 1 /* version of the transform encoding */
#define N2N_AES_IVEC_SIZE (AES_BLOCK_SIZE)
@ -41,8 +43,10 @@
typedef unsigned char n2n_aes_ivec_t[N2N_AES_IVEC_SIZE];
typedef struct transop_aes {
AES_KEY enc_key; /* tx key */
AES_KEY dec_key; /* tx key */
EVP_CIPHER_CTX *enc_ctx; /* openssl's reusable evp_* encryption context */
EVP_CIPHER_CTX *dec_ctx; /* openssl's reusable evp_* decryption context */
const EVP_CIPHER *cipher; /* cipher to use: e.g. EVP_aes_128_cbc */
uint8_t key[32]; /* the pure key data for payload encryption & decryption */
AES_KEY iv_enc_key; /* key used to encrypt the IV */
uint8_t iv_pad_val[TRANSOP_AES_IV_PADDING_SIZE]; /* key used to pad the random IV seed to full block size */
} transop_aes_t;
@ -50,12 +54,29 @@ typedef struct transop_aes {
static int transop_deinit_aes(n2n_trans_op_t *arg) {
transop_aes_t *priv = (transop_aes_t *)arg->priv;
EVP_CIPHER_CTX_free(priv->enc_ctx);
EVP_CIPHER_CTX_free(priv->dec_ctx);
if(priv)
free(priv);
return 0;
}
/* get any erorr message out of openssl
taken from https://en.wikibooks.org/wiki/OpenSSL/Error_handling */
char *openssl_err_as_string (void) {
BIO *bio = BIO_new (BIO_s_mem ());
ERR_print_errors (bio);
char *buf = NULL;
size_t len = BIO_get_mem_data (bio, &buf);
char *ret = (char *) calloc (1, 1 + len);
if (ret)
memcpy (ret, buf, len);
BIO_free (bio);
return ret;
}
static void set_aes_cbc_iv(transop_aes_t *priv, n2n_aes_ivec_t ivec, uint64_t iv_seed) {
uint8_t iv_full[N2N_AES_IVEC_SIZE];
@ -129,10 +150,27 @@ static int transop_encode_aes( n2n_trans_op_t * arg,
set_aes_cbc_iv(priv, enc_ivec, iv_seed);
AES_cbc_encrypt( assembly, /* source */
outbuf + TRANSOP_AES_PREAMBLE_SIZE, /* dest */
len2, /* enc size */
&(priv->enc_key), enc_ivec, AES_ENCRYPT);
EVP_CIPHER_CTX *ctx = priv->enc_ctx;
int evp_len;
int evp_ciphertext_len;
if (1 == EVP_EncryptInit_ex(ctx, priv->cipher, NULL, priv->key, enc_ivec)) {
if (1 == EVP_CIPHER_CTX_set_padding(ctx, 0)) {
if (1 == EVP_EncryptUpdate(ctx, outbuf + TRANSOP_AES_PREAMBLE_SIZE, &evp_len, assembly, len2)) {
evp_ciphertext_len = evp_len;
if (1 == EVP_EncryptFinal_ex(ctx, outbuf + TRANSOP_AES_PREAMBLE_SIZE + evp_len, &evp_len)) {
evp_ciphertext_len += evp_len;
if ( evp_ciphertext_len != len2)
traceEvent (TRACE_ERROR, "encode_aes openssl encryption: encrypted %u bytes where %u were expected.\n",
evp_ciphertext_len, len2);
} else
traceEvent(TRACE_ERROR, "encode_aes openssl final encryption: %s\n", openssl_err_as_string());
} else
traceEvent(TRACE_ERROR, "encode_aes openssl encrpytion: %s\n", openssl_err_as_string());
} else
traceEvent(TRACE_ERROR, "encode_aes openssl padding setup: %s\n", openssl_err_as_string());
} else
traceEvent(TRACE_ERROR, "encode_aes openssl init: %s\n", openssl_err_as_string());
EVP_CIPHER_CTX_reset(ctx);
len2 += TRANSOP_AES_PREAMBLE_SIZE; /* size of data carried in UDP. */
} else
@ -180,11 +218,27 @@ static int transop_decode_aes( n2n_trans_op_t * arg,
set_aes_cbc_iv(priv, dec_ivec, iv_seed);
AES_cbc_encrypt( (inbuf + TRANSOP_AES_PREAMBLE_SIZE),
assembly, /* destination */
len,
&(priv->dec_key),
dec_ivec, AES_DECRYPT);
EVP_CIPHER_CTX *ctx = priv->dec_ctx;
int evp_len;
int evp_plaintext_len;
if (1 == EVP_DecryptInit_ex(ctx, priv->cipher, NULL, priv->key, dec_ivec)) {
if (1 == EVP_CIPHER_CTX_set_padding(ctx, 0)) {
if (1 == EVP_DecryptUpdate(ctx, assembly, &evp_len, inbuf + TRANSOP_AES_PREAMBLE_SIZE, len)) {
evp_plaintext_len = evp_len;
if (1 == EVP_DecryptFinal_ex(ctx, assembly + evp_len, &evp_len)) {
evp_plaintext_len += evp_len;
if ( evp_plaintext_len != len)
traceEvent (TRACE_ERROR, "decode_aes openssl decryption: decrypted %u bytes where %u were expected.\n",
evp_plaintext_len, len);
} else
traceEvent(TRACE_ERROR, "decode_aes openssl final decryption: %s\n", openssl_err_as_string());
} else
traceEvent(TRACE_ERROR, "decode_aes openssl decrpytion: %s\n", openssl_err_as_string());
} else
traceEvent(TRACE_ERROR, "decode_aes openssl padding setup: %s\n", openssl_err_as_string());
} else
traceEvent(TRACE_ERROR, "decode_aes openssl init: %s\n", openssl_err_as_string());
EVP_CIPHER_CTX_reset(ctx);
/* last byte is how much was padding: max value should be
* AES_BLOCKSIZE-1 */
@ -223,8 +277,7 @@ static int setup_aes_key(transop_aes_t *priv, const uint8_t *key, ssize_t key_si
size_t key_mat_buf_length;
/* Clear out any old possibly longer key matter. */
memset( &(priv->enc_key), 0, sizeof(priv->enc_key) );
memset( &(priv->dec_key), 0, sizeof(priv->dec_key) );
memset( &(priv->key), 0, sizeof(priv->key) );
memset( &(priv->iv_enc_key), 0, sizeof(priv->iv_enc_key) );
memset( &(priv->iv_pad_val), 0, sizeof(priv->iv_pad_val) );
@ -245,12 +298,14 @@ static int setup_aes_key(transop_aes_t *priv, const uint8_t *key, ssize_t key_si
if (key_size >= 65)
{
priv->cipher = EVP_aes_256_cbc();
aes_key_size_bytes = AES256_KEY_BYTES;
SHA512(key, key_size, key_mat_buf);
key_mat_buf_length = SHA512_DIGEST_LENGTH;
}
else if (key_size >= 44)
{
priv->cipher = EVP_aes_192_cbc();
aes_key_size_bytes = AES192_KEY_BYTES;
SHA384(key, key_size, key_mat_buf);
/* append a hash of the first hash to create enough material for IV padding */
@ -259,6 +314,7 @@ static int setup_aes_key(transop_aes_t *priv, const uint8_t *key, ssize_t key_si
}
else
{
priv->cipher = EVP_aes_128_cbc();
aes_key_size_bytes = AES128_KEY_BYTES;
SHA256(key, key_size, key_mat_buf);
/* append a hash of the first hash to create enough material for IV padding */
@ -275,10 +331,9 @@ static int setup_aes_key(transop_aes_t *priv, const uint8_t *key, ssize_t key_si
return(1);
}
/* setup of enc_key/dec_key, used for the CBC encryption */
/* setup of key, used for the CBC encryption */
aes_key_size_bits = 8 * aes_key_size_bytes;
AES_set_encrypt_key(key_mat_buf, aes_key_size_bits, &(priv->enc_key));
AES_set_decrypt_key(key_mat_buf, aes_key_size_bits, &(priv->dec_key));
memcpy (priv->key, key_mat_buf, aes_key_size_bytes);
/* setup of iv_enc_key (AES128 key) and iv_pad_val, used for generating the CBC IV */
AES_set_encrypt_key(key_mat_buf + aes_key_size_bytes, TRANSOP_AES_IV_KEY_BYTES * 8, &(priv->iv_enc_key));
@ -313,7 +368,17 @@ int n2n_transop_aes_cbc_init(const n2n_edge_conf_t *conf, n2n_trans_op_t *ttt) {
}
ttt->priv = priv;
/* Setup the key */
/* Setup openssl's reusable evp_* contexts for encryption and decryption*/
if (!(priv->enc_ctx = EVP_CIPHER_CTX_new())) {
traceEvent(TRACE_ERROR, "openssl's evp_* encryption context creation: %s\n", openssl_err_as_string());
return(-1);
}
if (!(priv->dec_ctx = EVP_CIPHER_CTX_new())) {
traceEvent(TRACE_ERROR, "openssl's evp_* decryption context creation: %s\n", openssl_err_as_string());
return(-1);
}
/* Setup the cipher and key */
return(setup_aes_key(priv, encrypt_key, encrypt_key_len));
}

Write Preview
Loading…
Cancel
Save