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Add explicit initialization vector to aes_encrypt() #618

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Add explicit initialization vector to aes_encrypt() #618

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daa7298
Add explicit initialization vector to aes_encrypt()
numberten Nov 12, 2018
271bbfb
Restored number of encryption/decryption tests run
numberten Nov 12, 2018
2be09df
Merge branch 'dev' into aes-explicit-initialization-vector
ipapapa Dec 17, 2018
4fb197e
Merge branch 'dev' into aes-explicit-initialization-vector
numberten Jan 10, 2019
d0c355b
Merge branch 'dev' into aes-explicit-initialization-vector
numberten Jan 15, 2019
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44 changes: 34 additions & 10 deletions src/dyn_crypto.c
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Original file line number Diff line number Diff line change
Expand Up @@ -10,6 +10,7 @@
#include <openssl/rsa.h>
#include <openssl/ssl.h>
#include <stdio.h>
#include <string.h>

#include "dyn_core.h"
#include "dyn_crypto.h"
Expand Down Expand Up @@ -264,27 +265,47 @@ base64_decode(const char *b64message, const size_t length, unsigned char
}
*/

rstatus_t aes_encrypt(const unsigned char *msg, size_t msg_len,
unsigned char **enc_msg, unsigned char *arg_aes_key) {
rstatus_t aes_encrypt(const unsigned char *original_msg,
size_t original_msg_len, unsigned char **enc_msg,
unsigned char *arg_aes_key) {
int block_len = 0;
int enc_msg_len = 0;

// Create a new plaintext, with an additional block of randomness prepended
// as an explicit initialization vector.
size_t msg_len = original_msg_len + AES_BLOCK_SIZE;
unsigned char *msg = malloc(msg_len);

if (RAND_bytes(msg, AES_BLOCK_SIZE) == 0) {
log_debug(LOG_VERB,
"RAND_bytes failed to generate an explicit iv for : '%.*s':",
original_msg_len,
original_msg);
return DN_ERROR;
}

int i;
for (i = 0; i < original_msg_len; i++) {
msg[i+AES_BLOCK_SIZE] = original_msg[i];
}

// Malloc enough room for the new plaintext and the final block of padding.
*enc_msg = (unsigned char *)malloc(msg_len + AES_BLOCK_SIZE);
if (*enc_msg == NULL) return DN_ERROR;

// if(!EVP_EncryptInit_ex(aes_encrypt_ctx, aes_cipher, NULL, arg_aes_key,
// aes_iv)) {
if (!EVP_EncryptInit_ex(aes_encrypt_ctx, aes_cipher, NULL, arg_aes_key,
arg_aes_key)) {
log_debug(LOG_VERB, "This is bad data in EVP_EncryptInit_ex : '%.*s'",
msg_len, msg);
free(msg);
return DN_ERROR;
}

if (!EVP_EncryptUpdate(aes_encrypt_ctx, *enc_msg, &block_len,
(unsigned char *)msg, (int)msg_len)) {
log_debug(LOG_VERB, "This is bad data in EVP_EncryptUpdate : '%.*s'",
msg_len, msg);
free(msg);
return DN_ERROR;
}
enc_msg_len += block_len;
Expand All @@ -293,9 +314,12 @@ rstatus_t aes_encrypt(const unsigned char *msg, size_t msg_len,
&block_len)) {
log_debug(LOG_VERB, "This is bad data in EVP_EncryptFinal_ex : '%.*s'",
msg_len, msg);
free(msg);
return DN_ERROR;
}

free(msg);

// EVP_CIPHER_CTX_cleanup(aesEncryptCtx);

return enc_msg_len + block_len;
Expand All @@ -308,8 +332,6 @@ rstatus_t dyn_aes_encrypt(const unsigned char *msg, size_t msg_len,

ASSERT(mbuf != NULL && mbuf->last == mbuf->pos);

// if(!EVP_EncryptInit_ex(aes_encrypt_ctx, aes_cipher, NULL, arg_aes_key,
// aes_iv)) {
if (!EVP_EncryptInit_ex(aes_encrypt_ctx, aes_cipher, NULL, arg_aes_key,
arg_aes_key)) {
loga_hexdump(
Expand Down Expand Up @@ -362,8 +384,6 @@ rstatus_t dyn_aes_decrypt(unsigned char *enc_msg, size_t enc_msg_len,

ASSERT(mbuf != NULL && mbuf->start == mbuf->pos);

// if(!EVP_DecryptInit_ex(aes_decrypt_ctx, aes_cipher, NULL, arg_aes_key,
// aes_iv)) {
if (!EVP_DecryptInit_ex(aes_decrypt_ctx, aes_cipher, NULL, arg_aes_key,
arg_aes_key)) {
loga_hexdump(
Expand Down Expand Up @@ -475,8 +495,6 @@ rstatus_t aes_decrypt(unsigned char *enc_msg, size_t enc_msg_len,
*dec_msg = (unsigned char *)malloc(enc_msg_len);
if (*dec_msg == NULL) return DN_ERROR;

// if(!EVP_DecryptInit_ex(aes_decrypt_ctx, aes_cipher, NULL, arg_aes_key,
// aes_iv)) {
if (!EVP_DecryptInit_ex(aes_decrypt_ctx, aes_cipher, NULL, arg_aes_key,
arg_aes_key)) {
log_debug(LOG_VERB, "This is bad data in EVP_DecryptInit_ex : '%.*s'",
Expand All @@ -500,6 +518,12 @@ rstatus_t aes_decrypt(unsigned char *enc_msg, size_t enc_msg_len,
}
dec_len += block_len;

// Drop the first block of random plaintext by shifting dec_msg over
// by one block.
dec_len -= AES_BLOCK_SIZE;
memmove(*dec_msg, *dec_msg + AES_BLOCK_SIZE, dec_len);
(*dec_msg)[dec_len] = '\0';

// EVP_CIPHER_CTX_cleanup(aesDecryptCtx);

return (int)dec_len;
Expand Down
37 changes: 34 additions & 3 deletions src/dyn_test.c
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Original file line number Diff line number Diff line change
Expand Up @@ -8,6 +8,7 @@
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/utsname.h>
#include <unistd.h>
Expand Down Expand Up @@ -397,7 +398,9 @@ static rstatus_t aes_test(void) {
}
size_t enc_msg_len = (size_t)ret; /* if success, aes_encrypt returns len */

size_t expected_output_len = 16 * (msg_len / 16 + 1);
// Expected output is 2 blocks larger than the original msg_len, due to the
// explicit initialization vector and padding.
size_t expected_output_len = 16 * (msg_len / 16 + 2);
if (enc_msg_len != expected_output_len) {
log_panic("msg:'%s'\nexpected encrypted len: %lu encrypted len %lu\n\n",
msg, expected_output_len, enc_msg_len);
Expand All @@ -415,15 +418,43 @@ static rstatus_t aes_test(void) {
if (strcmp(msg, dec_msg) != 0) {
loga_hexdump(msg, strlen(msg), "Original Message:");
loga_hexdump(dec_msg, strlen(dec_msg), "Decrypted Message:");
log_panic("encryption/Decryption mismatch");
log_panic("encryption/decryption mismatch");
}

free(enc_msg);
free(dec_msg);
if ((i + 1) % 1000000 == 0) {
if ((i + 1) % (count / 10) == 0) {
loga("Completed Running %lu messages", i + 1);
}
}

loga("Making sure encryption is non-deterministic");
gen_random(msg, rand() % MAX_MSG_LEN);
unsigned int msg_len = strlen(msg) + 1;
unsigned char *enc_msg_1 = NULL;
unsigned char *enc_msg_2 = NULL;

rstatus_t ret_1 =
aes_encrypt((const unsigned char *)msg, msg_len, &enc_msg_1, aes_key);
rstatus_t ret_2 =
aes_encrypt((const unsigned char *)msg, msg_len, &enc_msg_2, aes_key);
if (ret_1 == DN_ERROR || ret_2 == DN_ERROR) {
log_panic("msg:'%s'\nencryption failed aes_key '%s'\n", msg,
aes_key_print);
return DN_ERROR;
}

if ((size_t)ret_1 == (size_t)ret_2 &&
!strncmp(enc_msg_1, enc_msg_2, (size_t)ret_1)) {
loga_hexdump(msg, strlen(msg), "Original Message:");
loga_hexdump(enc_msg_1, (size_t)ret_1, "Encrypted Message #1:");
loga_hexdump(enc_msg_2, (size_t)ret_2, "Encrypted Message #2:");
log_panic("Encryption failed to be non-deterministic");
}

free(enc_msg_1);
free(enc_msg_2);

return DN_OK;
}
/**
Expand Down