From 87ddf9f1ef17726fd4235f2e7aed8334d0ff231b Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Tue, 17 Sep 2019 19:53:45 +0200 Subject: [PATCH] avcodec/4xm: Check index in decode_i_block() also in the path where its not used. Fixes: Infinite loop Fixes: signed integer overflow: 2147483644 + 16 cannot be represented in type 'int' Fixes: 16169/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_FOURXM_fuzzer-5662570416963584 Fixes: 16782/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_FOURXM_fuzzer-5743163859271680 Fixes: 17641/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_FOURXM_fuzzer-5711603562971136 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 --- libavcodec/4xm.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/libavcodec/4xm.c b/libavcodec/4xm.c index 1f4e2aee24..336c651d31 100644 --- a/libavcodec/4xm.c +++ b/libavcodec/4xm.c @@ -525,6 +525,10 @@ static int decode_i_block(FourXContext *f, int16_t *block) break; if (code == 0xf0) { i += 16; + if (i >= 64) { + av_log(f->avctx, AV_LOG_ERROR, "run %d overflow\n", i); + return 0; + } } else { if (code & 0xf) { level = get_xbits(&f->gb, code & 0xf);