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dot11decrypt: Let libgcrypt handle AES unwrap 

From version 1.5.0 of libgcrypt there's support for AES unwrap. Use the
libcrypt function when available.

While at it also make AES_unwrap a static function of dot11decrypt.c

Change-Id: I4f69a766df3ea19ce25122e8d2fd1086f440995b
Reviewed-on: https://code.wireshark.org/review/36431
Petri-Dish: Anders Broman <a.broman58@gmail.com>
Tested-by: Petri Dish Buildbot
Reviewed-by: Anders Broman <a.broman58@gmail.com>
This commit is contained in:
Mikael Kanstrup 2020-03-15 09:27:09 +01:00 committed by Anders Broman
parent 1d20a875e4
commit 16c315ca32
5 changed files with 87 additions and 157 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
epan/crypt/CMakeLists.txt
View File

@ -19,7 +19,6 @@ set(CRYPT_HEADER_FILES
dot11decrypt_debug.h
dot11decrypt_int.h
dot11decrypt_interop.h
dot11decrypt_rijndael.h
dot11decrypt_system.h
dot11decrypt_user.h
dot11decrypt_util.h
@ -30,7 +29,6 @@ set(CRYPT_HEADER_FILES
set(CRYPT_FILES
dot11decrypt.c
dot11decrypt_rijndael.c
dot11decrypt_tkip.c
${CUSTOM_CRYPT_SRC}
)

96
epan/crypt/dot11decrypt.c
View File

@ -21,7 +21,6 @@
#include <epan/tvbuff.h>
#include <epan/to_str.h>
#include <epan/strutil.h>
#include <epan/crypt/dot11decrypt_rijndael.h>
#include "dot11decrypt_system.h"
#include "dot11decrypt_int.h"
@ -396,6 +395,91 @@ Dot11DecryptRc4KeyData(const guint8 *decryption_key, guint decryption_key_len,
return decrypted_key;
}
static int
AES_unwrap(
const guint8 *kek,
guint16 kek_len,
const guint8 *cipher_text,
guint16 cipher_len,
guint8 *output,
guint16 *output_len)
{
#if GCRYPT_VERSION_NUMBER >= 0x010500 /* 1.5.0 */
gcry_cipher_hd_t handle;
if (kek == NULL || cipher_len < 16 || cipher_text == NULL) {
return 1; /* "should not happen" */
}
if (gcry_cipher_open(&handle, GCRY_CIPHER_AES, GCRY_CIPHER_MODE_AESWRAP, 0)) {
return 1;
}
if (gcry_cipher_setkey(handle, kek, kek_len)) {
gcry_cipher_close(handle);
return 1;
}
if (gcry_cipher_decrypt(handle, output, cipher_len - 8, cipher_text, cipher_len)) {
gcry_cipher_close(handle);
return 1;
}
*output_len = cipher_len - 8;
gcry_cipher_close(handle);
return 0;
#else /* libcgrypt AES unwrap function not available */
/* Legacy implementation moved from dot11decrypt_rijindael.c */
/* Based on RFC 3394 and NIST AES Key Wrap Specification pseudo-code. */
UCHAR a[8], b[16];
UCHAR *r;
gint16 i, j, n;
gcry_cipher_hd_t rijndael_handle;
if (kek == NULL || cipher_len < 16 || cipher_text == NULL) {
return 1; /* "should not happen" */
}
/* Initialize variables */
memset(output, 0, cipher_len - 8);
n = (cipher_len/8)-1; /* the algorithm works on 64-bits at a time */
memcpy(a, cipher_text, 8);
r = output;
memcpy(r, cipher_text+8, cipher_len - 8);
/* Compute intermediate values */
if (gcry_cipher_open(&rijndael_handle, GCRY_CIPHER_AES, GCRY_CIPHER_MODE_ECB, 0)) {
return 1;
}
if (gcry_cipher_setkey(rijndael_handle, kek, kek_len)) {
gcry_cipher_close(rijndael_handle);
return 1;
}
for (j=5; j >= 0; --j){
r = output + (n - 1) * 8;
/* DEBUG_DUMP("r1", (r-8), 8); */
/* DEBUG_DUMP("r2", r, 8); */
for (i = n; i >= 1; --i){
UINT16 t = (n*j) + i;
/* DEBUG_DUMP("a", a, 8); */
memcpy(b, a, 8);
b[7] ^= t;
/* DEBUG_DUMP("a plus t", b, 8); */
memcpy(b+8, r, 8);
gcry_cipher_decrypt(rijndael_handle, b, 16, NULL, 0);
/* DEBUG_DUMP("aes decrypt", b, 16) */
memcpy(a,b,8);
memcpy(r, b+8, 8);
r -= 8;
}
}
gcry_cipher_close(rijndael_handle);
/* DEBUG_DUMP("a", a, 8); */
/* DEBUG_DUMP("output", output, cipher_len - 8); */
*output_len = cipher_len - 8;
return 0;
#endif
}
INT
Dot11DecryptDecryptKeyData(PDOT11DECRYPT_CONTEXT ctx,
PDOT11DECRYPT_EAPOL_PARSED eapol_parsed,
@ -496,17 +580,11 @@ Dot11DecryptDecryptKeyData(PDOT11DECRYPT_CONTEXT ctx,
/* Though fortunately IEEE802.11-2016 Table 12-8 state that all AKMs use "NIST AES Key Wrap" */
/* algorithm so no AKM lookup is needed. */
/* AES CCMP key */
guint8 *data;
/* Unwrap the key; the result is key_bytes_len in length */
data = AES_unwrap(decryption_key, decryption_key_len, key_data, key_bytes_len);
if (!data) {
if (AES_unwrap(decryption_key, decryption_key_len, key_data, key_bytes_len,
decrypted_data, &key_bytes_len)) {
return DOT11DECRYPT_RET_UNSUCCESS;
}
key_bytes_len -= 8; /* AES-WRAP adds 8 bytes */
memcpy(decrypted_data, data, key_bytes_len);
g_free(data);
}
Dot11DecryptCopyKey(sa, key);

2
epan/crypt/dot11decrypt_ccmp_compat.c
View File

@ -24,8 +24,6 @@
#include "dot11decrypt_system.h"
#include "dot11decrypt_int.h"
#include "dot11decrypt_rijndael.h"
#include "dot11decrypt_debug.h"
#include <glib.h>
#include <wsutil/wsgcrypt.h>

98
epan/crypt/dot11decrypt_rijndael.c
View File

@ -1,98 +0,0 @@
/**
* dot11decrypt_rijndael.c
*
* @version 3.0 (December 2000)
*
* Optimised ANSI C code for the Rijndael cipher (now AES)
*
* @author Vincent Rijmen <vincent.rijmen@esat.kuleuven.ac.be>
* @author Antoon Bosselaers <antoon.bosselaers@esat.kuleuven.ac.be>
* @author Paulo Barreto <paulo.barreto@terra.com.br>
*
* This code is hereby placed in the public domain.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHORS ''AS IS'' AND ANY EXPRESS
* 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 AUTHORS OR 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 "config.h"
#include "dot11decrypt_rijndael.h"
#include "dot11decrypt_debug.h"
#include <glib.h>
#include <wsutil/wsgcrypt.h>
/* Based on RFC 3394 and NIST AES Key Wrap Specification pseudo-code.
This function is used to unwrap an encrypted AES key. One example of its use is
in the WPA-2 protocol to get the group key.
*/
UCHAR *
AES_unwrap(const UCHAR *kek, UINT16 key_len, const UCHAR *cipher_text, UINT16 cipher_len)
{
UCHAR *output;
UCHAR a[8], b[16];
UCHAR *r;
gint16 i, j, n;
gcry_cipher_hd_t rijndael_handle;
if (kek == NULL || cipher_len < 16 || cipher_text == NULL) {
return NULL; /* "should not happen" */
}
/* Allocate buffer for the unwrapped key */
output = (guint8 *) g_malloc0(cipher_len);
/* Initialize variables */
n = (cipher_len/8)-1; /* the algorithm works on 64-bits at a time */
memcpy(a, cipher_text, 8);
r = output;
memcpy(r, cipher_text+8, cipher_len - 8);
/* Compute intermediate values */
if (gcry_cipher_open(&rijndael_handle, GCRY_CIPHER_AES, GCRY_CIPHER_MODE_ECB, 0)) {
return output;
}
if (gcry_cipher_setkey(rijndael_handle, kek, key_len)) {
gcry_cipher_close(rijndael_handle);
return output;
}
for (j=5; j >= 0; --j){
r = output + (n - 1) * 8;
/* DEBUG_DUMP("r1", (r-8), 8); */
/* DEBUG_DUMP("r2", r, 8); */
for (i = n; i >= 1; --i){
UINT16 t = (n*j) + i;
/* DEBUG_DUMP("a", a, 8); */
memcpy(b, a, 8);
b[7] ^= t;
/* DEBUG_DUMP("a plus t", b, 8); */
memcpy(b+8, r, 8);
gcry_cipher_decrypt(rijndael_handle, b, 16, NULL, 0);
/* DEBUG_DUMP("aes decrypt", b, 16) */
memcpy(a,b,8);
memcpy(r, b+8, 8);
r -= 8;
}
}
gcry_cipher_close(rijndael_handle);
/* DEBUG_DUMP("a", a, 8); */
/* DEBUG_DUMP("output", output, cipher_len - 8); */
return output;
}
/* */
/******************************************************************************/

46
epan/crypt/dot11decrypt_rijndael.h
View File

@ -1,46 +0,0 @@
/**
* dot11decrypt_rijndael.h
*
* @version 3.0 (December 2000)
*
* Optimised ANSI C code for the Rijndael cipher (now AES)
*
* @author Vincent Rijmen <vincent.rijmen@esat.kuleuven.ac.be>
* @author Antoon Bosselaers <antoon.bosselaers@esat.kuleuven.ac.be>
* @author Paulo Barreto <paulo.barreto@terra.com.br>
*
* This code is hereby placed in the public domain.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHORS ''AS IS'' AND ANY EXPRESS
* 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 AUTHORS OR 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.
*/
#ifndef _DOT11DECRYPT_RIJNDAEL
#define _DOT11DECRYPT_RIJNDAEL
/******************************************************************************/
/* File includes */
/* */
#include "dot11decrypt_interop.h"
/* */
/* */
/******************************************************************************/
/******************************************************************************/
/* Type definitions */
/* */
UCHAR *AES_unwrap(const UCHAR *kek, UINT16 key_len, const UCHAR *cipher_text, UINT16 cipher_len);
/* */
/******************************************************************************/
#endif