* Copyright (c) 2007 Reimar Doeffinger
* This is a rewrite of code contained in freeme/freeme2
*
- * This file is part of FFmpeg.
+ * This file is part of Libav.
*
- * FFmpeg is free software; you can redistribute it and/or
+ * Libav is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
- * FFmpeg is distributed in the hope that it will be useful,
+ * Libav is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
- * License along with FFmpeg; if not, write to the Free Software
+ * License along with Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
-#include "libavutil/common.h"
-#include "libavutil/intreadwrite.h"
#include "libavutil/bswap.h"
+#include "libavutil/common.h"
#include "libavutil/des.h"
+#include "libavutil/intreadwrite.h"
#include "libavutil/rc4.h"
#include "asfcrypt.h"
/**
- * \brief find multiplicative inverse modulo 2 ^ 32
- * \param v number to invert, must be odd!
- * \return number so that result * v = 1 (mod 2^32)
+ * @brief find multiplicative inverse modulo 2 ^ 32
+ * @param v number to invert, must be odd!
+ * @return number so that result * v = 1 (mod 2^32)
*/
-static uint32_t inverse(uint32_t v) {
+static uint32_t inverse(uint32_t v)
+{
// v ^ 3 gives the inverse (mod 16), could also be implemented
// as table etc. (only lowest 4 bits matter!)
uint32_t inverse = v * v * v;
}
/**
- * \brief read keys from keybuf into keys
- * \param keybuf buffer containing the keys
- * \param keys output key array containing the keys for encryption in
+ * @brief read keys from keybuf into keys
+ * @param keybuf buffer containing the keys
+ * @param keys output key array containing the keys for encryption in
* native endianness
*/
-static void multiswap_init(const uint8_t keybuf[48], uint32_t keys[12]) {
+static void multiswap_init(const uint8_t keybuf[48], uint32_t keys[12])
+{
int i;
for (i = 0; i < 12; i++)
keys[i] = AV_RL32(keybuf + (i << 2)) | 1;
}
/**
- * \brief invert the keys so that encryption become decryption keys and
+ * @brief invert the keys so that encryption become decryption keys and
* the other way round.
- * \param keys key array of ints to invert
+ * @param keys key array of ints to invert
*/
-static void multiswap_invert_keys(uint32_t keys[12]) {
+static void multiswap_invert_keys(uint32_t keys[12])
+{
int i;
for (i = 0; i < 5; i++)
keys[i] = inverse(keys[i]);
keys[i] = inverse(keys[i]);
}
-static uint32_t multiswap_step(const uint32_t keys[12], uint32_t v) {
+static uint32_t multiswap_step(const uint32_t keys[12], uint32_t v)
+{
int i;
v *= keys[0];
for (i = 1; i < 5; i++) {
- v = (v >> 16) | (v << 16);
+ v = (v >> 16) | (v << 16);
v *= keys[i];
}
v += keys[5];
return v;
}
-static uint32_t multiswap_inv_step(const uint32_t keys[12], uint32_t v) {
+static uint32_t multiswap_inv_step(const uint32_t keys[12], uint32_t v)
+{
int i;
v -= keys[5];
for (i = 4; i > 0; i--) {
v *= keys[i];
- v = (v >> 16) | (v << 16);
+ v = (v >> 16) | (v << 16);
}
v *= keys[0];
return v;
}
/**
- * \brief "MultiSwap" encryption
- * \param keys 32 bit numbers in machine endianness,
+ * @brief "MultiSwap" encryption
+ * @param keys 32 bit numbers in machine endianness,
* 0-4 and 6-10 must be inverted from decryption
- * \param key another key, this one must be the same for the decryption
- * \param data data to encrypt
- * \return encrypted data
+ * @param key another key, this one must be the same for the decryption
+ * @param data data to encrypt
+ * @return encrypted data
*/
-static uint64_t multiswap_enc(const uint32_t keys[12], uint64_t key, uint64_t data) {
+static uint64_t multiswap_enc(const uint32_t keys[12],
+ uint64_t key, uint64_t data)
+{
uint32_t a = data;
uint32_t b = data >> 32;
uint32_t c;
uint32_t tmp;
- a += key;
- tmp = multiswap_step(keys , a);
- b += tmp;
- c = (key >> 32) + tmp;
+ a += key;
+ tmp = multiswap_step(keys, a);
+ b += tmp;
+ c = (key >> 32) + tmp;
tmp = multiswap_step(keys + 6, b);
- c += tmp;
+ c += tmp;
return ((uint64_t)c << 32) | tmp;
}
/**
- * \brief "MultiSwap" decryption
- * \param keys 32 bit numbers in machine endianness,
+ * @brief "MultiSwap" decryption
+ * @param keys 32 bit numbers in machine endianness,
* 0-4 and 6-10 must be inverted from encryption
- * \param key another key, this one must be the same as for the encryption
- * \param data data to decrypt
- * \return decrypted data
+ * @param key another key, this one must be the same as for the encryption
+ * @param data data to decrypt
+ * @return decrypted data
*/
-static uint64_t multiswap_dec(const uint32_t keys[12], uint64_t key, uint64_t data) {
+static uint64_t multiswap_dec(const uint32_t keys[12],
+ uint64_t key, uint64_t data)
+{
uint32_t a;
uint32_t b;
- uint32_t c = data >> 32;
+ uint32_t c = data >> 32;
uint32_t tmp = data;
- c -= tmp;
- b = multiswap_inv_step(keys + 6, tmp);
+ c -= tmp;
+ b = multiswap_inv_step(keys + 6, tmp);
tmp = c - (key >> 32);
- b -= tmp;
- a = multiswap_inv_step(keys , tmp);
- a -= key;
+ b -= tmp;
+ a = multiswap_inv_step(keys, tmp);
+ a -= key;
return ((uint64_t)b << 32) | a;
}
-void ff_asfcrypt_dec(const uint8_t key[20], uint8_t *data, int len) {
+void ff_asfcrypt_dec(const uint8_t key[20], uint8_t *data, int len)
+{
struct AVDES des;
struct AVRC4 rc4;
- int num_qwords = len >> 3;
- uint64_t *qwords = (uint64_t *)data;
- uint64_t rc4buff[8];
+ int num_qwords = len >> 3;
+ uint8_t *qwords = data;
+ uint64_t rc4buff[8] = { 0 };
uint64_t packetkey;
uint32_t ms_keys[12];
uint64_t ms_state;
return;
}
- memset(rc4buff, 0, sizeof(rc4buff));
av_rc4_init(&rc4, key, 12 * 8, 1);
av_rc4_crypt(&rc4, (uint8_t *)rc4buff, NULL, sizeof(rc4buff), NULL, 1);
multiswap_init((uint8_t *)rc4buff, ms_keys);
- packetkey = AV_RN64(&qwords[num_qwords - 1]);
+ packetkey = AV_RN64(&qwords[num_qwords * 8 - 8]);
packetkey ^= rc4buff[7];
av_des_init(&des, key + 12, 64, 1);
av_des_crypt(&des, (uint8_t *)&packetkey, (uint8_t *)&packetkey, 1, NULL, 1);
av_rc4_crypt(&rc4, data, data, len, NULL, 1);
ms_state = 0;
- for (i = 0; i < num_qwords - 1; i++, qwords++)
+ for (i = 0; i < num_qwords - 1; i++, qwords += 8)
ms_state = multiswap_enc(ms_keys, ms_state, AV_RL64(qwords));
multiswap_invert_keys(ms_keys);
packetkey = (packetkey << 32) | (packetkey >> 32);
projects / ffmpeg / blobdiff