From f76d7352e05526fde7c607b9a9db536a5760af29 Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Sat, 22 Jun 2019 19:21:50 +0200 Subject: [PATCH] avcodec/iff: Check ham vs bpp This checks the ham value much stricter and avoids hitting cases which cannot be reached with data from the libavformat demuxer. Fixes: out of array access Fixes: 15320/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_IFF_ILBM_fuzzer-5080476840099840 Fixes: 15423/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_IFF_ILBM_fuzzer-5630765833912320 Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg Signed-off-by: Michael Niedermayer --- libavcodec/iff.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) diff --git a/libavcodec/iff.c b/libavcodec/iff.c index 4099d118e4..c6e2359b00 100644 --- a/libavcodec/iff.c +++ b/libavcodec/iff.c @@ -280,6 +280,16 @@ static int extract_header(AVCodecContext *const avctx, for (i = 0; i < 16; i++) s->tvdc[i] = bytestream_get_be16(&buf); + if (s->ham) { + if (s->bpp > 8) { + av_log(avctx, AV_LOG_ERROR, "Invalid number of hold bits for HAM: %u\n", s->ham); + return AVERROR_INVALIDDATA; + } if (s->ham != (s->bpp > 6 ? 6 : 4)) { + av_log(avctx, AV_LOG_ERROR, "Invalid number of hold bits for HAM: %u, BPP: %u\n", s->ham, s->bpp); + return AVERROR_INVALIDDATA; + } + } + if (s->masking == MASK_HAS_MASK) { if (s->bpp >= 8 && !s->ham) { avctx->pix_fmt = AV_PIX_FMT_RGB32; @@ -307,9 +317,6 @@ static int extract_header(AVCodecContext *const avctx, if (!s->bpp || s->bpp > 32) { av_log(avctx, AV_LOG_ERROR, "Invalid number of bitplanes: %u\n", s->bpp); return AVERROR_INVALIDDATA; - } else if (s->ham >= 8) { - av_log(avctx, AV_LOG_ERROR, "Invalid number of hold bits for HAM: %u\n", s->ham); - return AVERROR_INVALIDDATA; } av_freep(&s->ham_buf);