X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=libavformat%2Fasfcrypt.c;h=c26147584865124d62b8bf3f25c099d9c88ff4cf;hb=c11e33a3d9665dd1fc5dbdecdd03a4860ac6a622;hp=993c9dac911242fa6d6bfa4cfd609c4ad6224da5;hpb=e6b22522c94cfccda97018e52ab65da8c69d8a56;p=ffmpeg diff --git a/libavformat/asfcrypt.c b/libavformat/asfcrypt.c index 993c9dac911..c2614758486 100644 --- a/libavformat/asfcrypt.c +++ b/libavformat/asfcrypt.c @@ -3,36 +3,37 @@ * 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; @@ -45,23 +46,25 @@ static uint32_t inverse(uint32_t 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]); @@ -69,78 +72,85 @@ static void multiswap_invert_keys(uint32_t keys[12]) { 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; @@ -151,12 +161,11 @@ void ff_asfcrypt_dec(const uint8_t key[20], uint8_t *data, int len) { 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 = 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); @@ -166,11 +175,11 @@ void ff_asfcrypt_dec(const uint8_t key[20], uint8_t *data, int len) { 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); - packetkey = le2ne_64(packetkey); + packetkey = av_le2ne64(packetkey); packetkey = multiswap_dec(ms_keys, ms_state, packetkey); AV_WL64(qwords, packetkey); }