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adding a few checks to the audio packet descrambling, this should hopefully catch all related out of array accesses

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note, the original code might have been exploitable

Originally committed as revision 7640 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Michael Niedermayer 2007-01-22 03:19:00 +00:00
parent 2c86a5786a
commit 0521946359
1 changed files with 9 additions and 1 deletions
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10
libavformat/asf.c
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@ -244,7 +244,8 @@ static int asf_read_header(AVFormatContext *s, AVFormatParameters *ap)
// asf_st->ds_data_size, asf_st->ds_span, asf_st->ds_silence_data);
if (asf_st->ds_span > 1) {
if (!asf_st->ds_chunk_size
|| (asf_st->ds_packet_size/asf_st->ds_chunk_size <= 1))
|| (asf_st->ds_packet_size/asf_st->ds_chunk_size <= 1)
|| asf_st->ds_packet_size % asf_st->ds_chunk_size)
asf_st->ds_span = 0; // disable descrambling
}
switch (st->codec->codec_id) {
@ -702,6 +703,9 @@ static int asf_read_packet(AVFormatContext *s, AVPacket *pkt)
if (asf_st->frag_offset == asf_st->pkt.size) {
/* return packet */
if (asf_st->ds_span > 1) {
if(asf_st->pkt.size != asf_st->ds_packet_size * asf_st->ds_span){
av_log(s, AV_LOG_ERROR, "pkt.size != ds_packet_size * ds_span\n");
}else{
/* packet descrambling */
uint8_t *newdata = av_malloc(asf_st->pkt.size);
if (newdata) {
@ -712,6 +716,9 @@ static int asf_read_packet(AVFormatContext *s, AVPacket *pkt)
int col = off % asf_st->ds_span;
int idx = row + col * asf_st->ds_packet_size / asf_st->ds_chunk_size;
//printf("off:%d row:%d col:%d idx:%d\n", off, row, col, idx);
assert(offset + asf_st->ds_chunk_size <= asf_st->pkt.size);
assert(idx+1 <= asf_st->pkt.size / asf_st->ds_chunk_size);
memcpy(newdata + offset,
asf_st->pkt.data + idx * asf_st->ds_chunk_size,
asf_st->ds_chunk_size);
@ -720,6 +727,7 @@ static int asf_read_packet(AVFormatContext *s, AVPacket *pkt)
av_free(asf_st->pkt.data);
asf_st->pkt.data = newdata;
}
}
}
asf_st->frag_offset = 0;
*pkt= asf_st->pkt;