From ac9c19da66b54e690f17001e7eb855bae5f23d0d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?M=C3=A5ns=20Rullg=C3=A5rd?= <mans@mansr.com>
Date: Tue, 24 Aug 2010 13:42:28 +0000
Subject: [PATCH] asfcrypt: fix unaligned accesses with armcc
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
---
libavformat/asfcrypt.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/libavformat/asfcrypt.c b/libavformat/asfcrypt.c
index cb3516fc500..59986e0a2c3 100644
--- a/libavformat/asfcrypt.c
+++ b/libavformat/asfcrypt.c
@@ -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);
--
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