[FFmpeg-cvslog] r24897 - trunk/libavformat/asfcrypt.c

[mru]

Author: mru
Date: Tue Aug 24 15:42:28 2010
New Revision: 24897

Log:
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.

Modified:
   trunk/libavformat/asfcrypt.c

Modified: trunk/libavformat/asfcrypt.c
==============================================================================
--- trunk/libavformat/asfcrypt.c	Tue Aug 24 10:38:00 2010	(r24896)
+++ trunk/libavformat/asfcrypt.c	Tue Aug 24 15:42:28 2010	(r24897)
@@ -139,7 +139,7 @@ void ff_asfcrypt_dec(const uint8_t key[2
     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[2
     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[2
     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);