From 9701fc0ad609072bf8d0509944da4cd50293d0e6 Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Wed, 24 Jul 2019 22:55:15 +0200 Subject: [PATCH] avcodec/assdec: undefined use of memcpy() Fixes: null pointer passed as argument 2, which is declared to never be null Fixes: 16008/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_SSA_fuzzer-5650582821404672 (this is a separate issue found in this testcase) Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg Reviewed-by: Paul B Mahol Signed-off-by: Michael Niedermayer (cherry picked from commit 47b6ca0b022a413e392707464f2423795aa89bfb) Signed-off-by: Michael Niedermayer --- libavcodec/assdec.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/libavcodec/assdec.c b/libavcodec/assdec.c index 3178f2953c..f0b1069cd2 100644 --- a/libavcodec/assdec.c +++ b/libavcodec/assdec.c @@ -31,7 +31,8 @@ static av_cold int ass_decode_init(AVCodecContext *avctx) avctx->subtitle_header = av_malloc(avctx->extradata_size + 1); if (!avctx->subtitle_header) return AVERROR(ENOMEM); - memcpy(avctx->subtitle_header, avctx->extradata, avctx->extradata_size); + if (avctx->extradata_size) + memcpy(avctx->subtitle_header, avctx->extradata, avctx->extradata_size); avctx->subtitle_header[avctx->extradata_size] = 0; avctx->subtitle_header_size = avctx->extradata_size; return 0;