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avcodec/ccaption_dec: Use simple array instead of AVBuffer 

This is simpler and fixes an out of array read, fixing it with AVBuffers
would be more complex

Fixes: e00d9e6e50e5495cc93fea41147b97bb/asan_heap-oob_12dcdbb_8798_b32a97ea722dd37bb5066812cc674552.mov

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
This commit is contained in:
Michael Niedermayer 2016-09-09 10:26:15 +02:00
parent 7b3bc365f9
commit 752e6dfa3e
1 changed files with 11 additions and 16 deletions
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27
libavcodec/ccaption_dec.c
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@ -247,7 +247,8 @@ typedef struct CCaptionSubContext {
int64_t last_real_time;
char prev_cmd[2];
/* buffer to store pkt data */
AVBufferRef *pktbuf;
uint8_t *pktbuf;
int pktbuf_size;
int readorder;
} CCaptionSubContext;
@ -274,11 +275,7 @@ static av_cold int init_decoder(AVCodecContext *avctx)
if (ret < 0) {
return ret;
}
/* allocate pkt buffer */
ctx->pktbuf = av_buffer_alloc(128);
if (!ctx->pktbuf) {
ret = AVERROR(ENOMEM);
}
return ret;
}
@ -286,7 +283,8 @@ static av_cold int close_decoder(AVCodecContext *avctx)
{
CCaptionSubContext *ctx = avctx->priv_data;
av_bprint_finalize(&ctx->buffer, NULL);
av_buffer_unref(&ctx->pktbuf);
av_freep(&ctx->pktbuf);
ctx->pktbuf_size = 0;
return 0;
}
@ -759,16 +757,13 @@ static int decode(AVCodecContext *avctx, void *data, int *got_sub, AVPacket *avp
int ret = 0;
int i;
if (ctx->pktbuf->size < len) {
ret = av_buffer_realloc(&ctx->pktbuf, len);
if (ret < 0) {
av_log(ctx, AV_LOG_WARNING, "Insufficient Memory of %d truncated to %d\n", len, ctx->pktbuf->size);
len = ctx->pktbuf->size;
ret = 0;
}
av_fast_padded_malloc(&ctx->pktbuf, &ctx->pktbuf_size, len);
if (!ctx->pktbuf) {
av_log(ctx, AV_LOG_WARNING, "Insufficient Memory of %d truncated to %d\n", len, ctx->pktbuf_size);
return AVERROR(ENOMEM);
}
memcpy(ctx->pktbuf->data, avpkt->data, len);
bptr = ctx->pktbuf->data;
memcpy(ctx->pktbuf, avpkt->data, len);
bptr = ctx->pktbuf;
for (i = 0; i < len; i += 3) {
uint8_t cc_type = *(bptr + i) & 3;