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asfcrypt: fix unaligned accesses with armcc

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Compilers may assume a pointer has natural alignment, even if it was
assigned from a pointer type with weaker alignment requirements.  It
is thus not safe to assign a possibly unaligned value to a pointer,
regardless of how it is subsequently dereferenced.

Originally committed as revision 24897 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Måns Rullgård 2010-08-24 13:42:28 +00:00
parent 7f1af825f8
commit ac9c19da66
1 changed files with 3 additions and 3 deletions
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6
libavformat/asfcrypt.c
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@ -139,7 +139,7 @@ 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;
uint8_t *qwords = data;
uint64_t rc4buff[8];
uint64_t packetkey;
uint32_t ms_keys[12];
@ -156,7 +156,7 @@ void ff_asfcrypt_dec(const uint8_t key[20], uint8_t *data, int len) {
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);
@ -166,7 +166,7 @@ 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);