From a11aa5f3ed7ee4d2385a7b725d43f6070d790b4c Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Sat, 9 Nov 2019 22:02:50 +0100 Subject: [PATCH] avcodec/alsdec: Discard frames for which no channel could be decoded Fixes: Timeout (80sec -> 33sec) Fixes: 18668/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_ALS_fuzzer-5710836719157248 Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg Signed-off-by: Michael Niedermayer --- libavcodec/alsdec.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/libavcodec/alsdec.c b/libavcodec/alsdec.c index babe30bdc7..62c6036037 100644 --- a/libavcodec/alsdec.c +++ b/libavcodec/alsdec.c @@ -236,6 +236,7 @@ typedef struct ALSDecContext { int **raw_mantissa; ///< decoded mantissa bits of the difference signal unsigned char *larray; ///< buffer to store the output of masked lz decompression int *nbits; ///< contains the number of bits to read for masked lz decompression for all samples + int highest_decoded_channel; } ALSDecContext; @@ -1678,6 +1679,7 @@ static int read_frame_data(ALSDecContext *ctx, unsigned int ra_frame) memmove(ctx->raw_samples[c] - sconf->max_order, ctx->raw_samples[c] - sconf->max_order + sconf->frame_length, sizeof(*ctx->raw_samples[c]) * sconf->max_order); + ctx->highest_decoded_channel = c; } } else { // multi-channel coding ALSBlockData bd = { 0 }; @@ -1746,6 +1748,8 @@ static int read_frame_data(ALSDecContext *ctx, unsigned int ra_frame) if ((ret = decode_block(ctx, &bd)) < 0) return ret; + + ctx->highest_decoded_channel = FFMAX(ctx->highest_decoded_channel, c); } memset(reverted_channels, 0, avctx->channels * sizeof(*reverted_channels)); @@ -1802,11 +1806,15 @@ static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame_ptr, else ctx->cur_frame_length = sconf->frame_length; + ctx->highest_decoded_channel = 0; // decode the frame data if ((invalid_frame = read_frame_data(ctx, ra_frame)) < 0) av_log(ctx->avctx, AV_LOG_WARNING, "Reading frame data failed. Skipping RA unit.\n"); + if (ctx->highest_decoded_channel == 0) + return AVERROR_INVALIDDATA; + ctx->frame_id++; /* get output buffer */