/* crypto/aes/aes_wrap.c */ /* Written by Dr Stephen N Henson ([email protected]) for the OpenSSL * project. */ /* ==================================================================== * Copyright (c) 2008 The OpenSSL Project. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in * the documentation and/or other materials provided with the * distribution. * * 3. All advertising materials mentioning features or use of this * software must display the following acknowledgment: * "This product includes software developed by the OpenSSL Project * for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)" * * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to * endorse or promote products derived from this software without * prior written permission. For written permission, please contact * [email protected]. * * 5. Products derived from this software may not be called "OpenSSL" * nor may "OpenSSL" appear in their names without prior written * permission of the OpenSSL Project. * * 6. Redistributions of any form whatsoever must retain the following * acknowledgment: * "This product includes software developed by the OpenSSL Project * for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)" * * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED * OF THE POSSIBILITY OF SUCH DAMAGE. * ==================================================================== */
#include "cryptlib.h"
#include <openssl/aes.h>
#include <openssl/bio.h>
static const unsigned char default_iv[] = {
0xA6, 0xA6, 0xA6, 0xA6, 0xA6, 0xA6, 0xA6, 0xA6,
};
int AES_wrap_key(AES_KEY *key, const unsigned char *iv,
unsigned char *out,
const unsigned char *in, unsigned int inlen)
{
unsigned char *A, B[16], *R;
unsigned int i, j, t;
if ((inlen & 0x7) || (inlen < 8))
return -1;
A = B;
t = 1;
memcpy(out + 8, in, inlen);
if (!iv)
iv = default_iv;
memcpy(A, iv, 8);
for (j = 0; j < 6; j++)
{
R = out + 8;
for (i = 0; i < inlen; i += 8, t++, R += 8)
{
memcpy(B + 8, R, 8);
AES_encrypt(B, B, key);
A[7] ^= (unsigned char)(t & 0xff);
if (t > 0xff)
{
A[6] ^= (unsigned char)((t >> 8) & 0xff);
A[5] ^= (unsigned char)((t >> 16) & 0xff);
A[4] ^= (unsigned char)((t >> 24) & 0xff);
}
memcpy(R, B + 8, 8);
}
}
memcpy(out, A, 8);
return inlen + 8;
}
int AES_unwrap_key(AES_KEY *key, const unsigned char *iv,
unsigned char *out,
const unsigned char *in, unsigned int inlen)
{
unsigned char *A, B[16], *R;
unsigned int i, j, t;
inlen -= 8;
if (inlen & 0x7)
return -1;
if (inlen < 8)
return -1;
A = B;
t = 6 * (inlen >> 3);
memcpy(A, in, 8);
memcpy(out, in + 8, inlen);
for (j = 0; j < 6; j++)
{
R = out + inlen - 8;
for (i = 0; i < inlen; i += 8, t--, R -= 8)
{
A[7] ^= (unsigned char)(t & 0xff);
if (t > 0xff)
{
A[6] ^= (unsigned char)((t >> 8) & 0xff);
A[5] ^= (unsigned char)((t >> 16) & 0xff);
A[4] ^= (unsigned char)((t >> 24) & 0xff);
}
memcpy(B + 8, R, 8);
AES_decrypt(B, B, key);
memcpy(R, B + 8, 8);
}
}
if (!iv)
iv = default_iv;
if (memcmp(A, iv, 8))
{
OPENSSL_cleanse(out, inlen);
return 0;
}
return inlen;
}
#ifdef AES_WRAP_TEST
int AES_wrap_unwrap_test(const unsigned char *kek, int keybits,
const unsigned char *iv,
const unsigned char *eout,
const unsigned char *key, int keylen)
{
unsigned char *otmp = NULL, *ptmp = NULL;
int r, ret = 0;
AES_KEY wctx;
otmp = OPENSSL_malloc(keylen + 8);
ptmp = OPENSSL_malloc(keylen);
if (!otmp || !ptmp)
return 0;
if (AES_set_encrypt_key(kek, keybits, &wctx))
goto err;
r = AES_wrap_key(&wctx, iv, otmp, key, keylen);
if (r <= 0)
goto err;
if (eout && memcmp(eout, otmp, keylen))
goto err;
if (AES_set_decrypt_key(kek, keybits, &wctx))
goto err;
r = AES_unwrap_key(&wctx, iv, ptmp, otmp, r);
if (memcmp(key, ptmp, keylen))
goto err;
ret = 1;
err:
if (otmp)
OPENSSL_free(otmp);
if (ptmp)
OPENSSL_free(ptmp);
return ret;
}
int main(int argc, char **argv)
{
static const unsigned char kek[] = {
0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f
};
static const unsigned char key[] = {
0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77,
0x88, 0x99, 0xaa, 0xbb, 0xcc, 0xdd, 0xee, 0xff,
0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f
};
static const unsigned char e1[] = {
0x1f, 0xa6, 0x8b, 0x0a, 0x81, 0x12, 0xb4, 0x47,
0xae, 0xf3, 0x4b, 0xd8, 0xfb, 0x5a, 0x7b, 0x82,
0x9d, 0x3e, 0x86, 0x23, 0x71, 0xd2, 0xcf, 0xe5
};
static const unsigned char e2[] = {
0x96, 0x77, 0x8b, 0x25, 0xae, 0x6c, 0xa4, 0x35,
0xf9, 0x2b, 0x5b, 0x97, 0xc0, 0x50, 0xae, 0xd2,
0x46, 0x8a, 0xb8, 0xa1, 0x7a, 0xd8, 0x4e, 0x5d
};
static const unsigned char e3[] = {
0x64, 0xe8, 0xc3, 0xf9, 0xce, 0x0f, 0x5b, 0xa2,
0x63, 0xe9, 0x77, 0x79, 0x05, 0x81, 0x8a, 0x2a,
0x93, 0xc8, 0x19, 0x1e, 0x7d, 0x6e, 0x8a, 0xe7
};
static const unsigned char e4[] = {
0x03, 0x1d, 0x33, 0x26, 0x4e, 0x15, 0xd3, 0x32,
0x68, 0xf2, 0x4e, 0xc2, 0x60, 0x74, 0x3e, 0xdc,
0xe1, 0xc6, 0xc7, 0xdd, 0xee, 0x72, 0x5a, 0x93,
0x6b, 0xa8, 0x14, 0x91, 0x5c, 0x67, 0x62, 0xd2
};
static const unsigned char e5[] = {
0xa8, 0xf9, 0xbc, 0x16, 0x12, 0xc6, 0x8b, 0x3f,
0xf6, 0xe6, 0xf4, 0xfb, 0xe3, 0x0e, 0x71, 0xe4,
0x76, 0x9c, 0x8b, 0x80, 0xa3, 0x2c, 0xb8, 0x95,
0x8c, 0xd5, 0xd1, 0x7d, 0x6b, 0x25, 0x4d, 0xa1
};
static const unsigned char e6[] = {
0x28, 0xc9, 0xf4, 0x04, 0xc4, 0xb8, 0x10, 0xf4,
0xcb, 0xcc, 0xb3, 0x5c, 0xfb, 0x87, 0xf8, 0x26,
0x3f, 0x57, 0x86, 0xe2, 0xd8, 0x0e, 0xd3, 0x26,
0xcb, 0xc7, 0xf0, 0xe7, 0x1a, 0x99, 0xf4, 0x3b,
0xfb, 0x98, 0x8b, 0x9b, 0x7a, 0x02, 0xdd, 0x21
};
AES_KEY wctx, xctx;
int ret;
ret = AES_wrap_unwrap_test(kek, 128, NULL, e1, key, 16);
fprintf(stderr, "Key test result %d\n", ret);
ret = AES_wrap_unwrap_test(kek, 192, NULL, e2, key, 16);
fprintf(stderr, "Key test result %d\n", ret);
ret = AES_wrap_unwrap_test(kek, 256, NULL, e3, key, 16);
fprintf(stderr, "Key test result %d\n", ret);
ret = AES_wrap_unwrap_test(kek, 192, NULL, e4, key, 24);
fprintf(stderr, "Key test result %d\n", ret);
ret = AES_wrap_unwrap_test(kek, 256, NULL, e5, key, 24);
fprintf(stderr, "Key test result %d\n", ret);
ret = AES_wrap_unwrap_test(kek, 256, NULL, e6, key, 32);
fprintf(stderr, "Key test result %d\n", ret);
}
#endif
Hi ,
I have found a bug in Open SSL - aes_wrap.c.
The XORing logic in both AES_wrap_key and AES_unwrap_key functions is flawed in
that all the XORs inside the "if" block happens with 0 . This bug impacts
when the input size is greater than 336.
Current code in aes_wrap.c :
A[7] ^= (unsigned char)(t & 0xff);
if (t > 0xff)
{
A[6] ^= (unsigned char)((t & 0xff) >> 8);
A[5] ^= (unsigned char)((t & 0xff) >> 16);
A[4] ^= (unsigned char)((t & 0xff) >> 24);
}
The corrected logic is as follows :
A[7] ^= (unsigned char)(t & 0xff);
if (t > 0xff)
{
A[6] ^= (unsigned char)((t >> 8) & 0xff);
A[5] ^= (unsigned char)((t >> 16) & 0xff);
A[4] ^= (unsigned char)((t >> 24) & 0xff);
}
The .c file with the corrected code is attached.
Thanks and Regards,
Benoy Antony
Application security | Desk - 408 967 3390 | Cell - 408 420 9499 | skype -
benoyantony
PayPal - The safer, easier way to pay online
Hi ,
I have found a bug in Open SSL - aes_wrap.c.
The XORing logic in both AES_wrap_key and AES_unwrap_key functions is flawed in that all the XORs inside the “if” block happens with 0 . This bug impacts when the input size is greater than 336.
Current code in aes_wrap.c :
A[7] ^= (unsigned char)(t & 0xff);
if (t > 0xff)
{
A[6] ^= (unsigned char)((t & 0xff) >> 8);
A[5] ^= (unsigned char)((t & 0xff) >> 16);
A[4] ^= (unsigned char)((t & 0xff) >> 24);
}
The corrected logic is as follows :
A[7] ^= (unsigned char)(t & 0xff);
if (t > 0xff)
{
A[6] ^= (unsigned char)((t >> 8) & 0xff);
A[5] ^= (unsigned char)((t >> 16) & 0xff);
A[4] ^= (unsigned char)((t >> 24) & 0xff);
}
The .c file with the corrected code is attached.
Thanks and Regards,
Benoy Antony
Application security | Desk - 408 967 3390 | Cell - 408 420 9499 | skype - benoyantony
PayPal - The safer, easier
way to pay online
