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imxtools/sbtools: switch AES implementation to Crypto++

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Instead of having our own copy of the AES code, use a good library to do that.
Crypto++ is well-maintained, supports a lot of ciphers, works on many OSes, and
is optimized for many architectures.

Change-Id: I7d7d24b47993206d7338c5f9bac8bbdd3915a667
This commit is contained in:
Amaury Pouly 2017-01-03 13:56:48 +01:00
parent 5ff3a3a98f
commit 8b3f5a8ad7
5 changed files with 84 additions and 312 deletions
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83
utils/imxtools/sbtools/crypto.cpp
View file

@ -20,9 +20,81 @@
****************************************************************************/
#include "crypto.h"
#include "misc.h"
#include <cryptopp/modes.h>
#include <cryptopp/aes.h>
static enum crypto_method_t g_cur_method = CRYPTO_NONE;
static byte g_key[16];
using namespace CryptoPP;
namespace
{
enum crypto_method_t g_cur_method = CRYPTO_NONE;
byte g_key[16];
CBC_Mode<AES>::Encryption g_aes_enc;
CBC_Mode<AES>::Decryption g_aes_dec;
bool g_aes_enc_key_dirty; /* true of g_aes_enc key needs to be updated */
bool g_aes_dec_key_dirty; /* same for g_aes_dec */
int cbc_mac2(
const byte *in_data, /* Input data */
byte *out_data, /* Output data (or NULL) */
int nr_blocks, /* Number of blocks to encrypt/decrypt (one block=16 bytes) */
byte key[16], /* Key */
byte iv[16], /* Initialisation Vector */
byte (*out_cbc_mac)[16], /* CBC-MAC of the result (or NULL) */
bool encrypt /* 1 to encrypt, 0 to decrypt */
)
{
/* encrypt */
if(encrypt)
{
/* update keys if neeeded */
if(g_aes_enc_key_dirty)
{
/* we need to provide an IV with the key, although we change it
* everytime we run the cipher anyway */
g_aes_enc.SetKeyWithIV(g_key, 16, iv, 16);
g_aes_enc_key_dirty = false;
}
g_aes_enc.Resynchronize(iv, 16);
byte tmp[16];
/* we need some output buffer, either a temporary one if we are CBC-MACing
* only, or use output buffer if available */
byte *out_ptr = (out_data == NULL) ? tmp : out_data;
while(nr_blocks-- > 0)
{
g_aes_enc.ProcessData(out_ptr, in_data, 16);
/* if this is the last block, copy CBC-MAC */
if(nr_blocks == 0 && out_cbc_mac)
memcpy(out_cbc_mac, out_ptr, 16);
/* if we are writing data to the output buffer, advance output pointer */
if(out_data != NULL)
out_ptr += 16;
in_data += 16;
}
return CRYPTO_ERROR_SUCCESS;
}
/* decrypt */
else
{
/* update keys if neeeded */
if(g_aes_dec_key_dirty)
{
/* we need to provide an IV with the key, although we change it
* everytime we run the cipher anyway */
g_aes_dec.SetKeyWithIV(g_key, 16, iv, 16);
g_aes_dec_key_dirty = false;
}
/* we cannot produce a CBC-MAC in decrypt mode, output buffer exists */
if(out_cbc_mac || out_data == NULL)
return CRYPTO_ERROR_INVALID_OP;
g_aes_dec.Resynchronize(iv, 16);
g_aes_dec.ProcessData(out_data, in_data, nr_blocks * 16);
return CRYPTO_ERROR_SUCCESS;
}
}
}
int crypto_setup(struct crypto_key_t *key)
{
@ -31,6 +103,8 @@ int crypto_setup(struct crypto_key_t *key)
{
case CRYPTO_KEY:
memcpy(g_key, key->u.key, 16);
g_aes_dec_key_dirty = true;
g_aes_enc_key_dirty = true;
return CRYPTO_ERROR_SUCCESS;
default:
return CRYPTO_ERROR_BADSETUP;
@ -46,10 +120,7 @@ int crypto_apply(
bool encrypt)
{
if(g_cur_method == CRYPTO_KEY)
{
cbc_mac(in_data, out_data, nr_blocks, g_key, iv, out_cbc_mac, encrypt);
return CRYPTO_ERROR_SUCCESS;
}
return cbc_mac2(in_data, out_data, nr_blocks, g_key, iv, out_cbc_mac, encrypt);
else
return CRYPTO_ERROR_BADSETUP;
}