From 08d2df41538b583932c1a6772e3c8978a2334107 Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Wed, 28 Apr 2021 16:58:50 +0200 Subject: [PATCH] avcodec/faxcompr: Check for end of bitstream in decode_group3_1d_line() and decode_group3_2d_line() Fixes: infinite loop Fixes: 33674/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_TIFF_fuzzer-4816457818046464 Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg Signed-off-by: Michael Niedermayer --- libavcodec/faxcompr.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/libavcodec/faxcompr.c b/libavcodec/faxcompr.c index 7bf11d80ca..d44de2485d 100644 --- a/libavcodec/faxcompr.c +++ b/libavcodec/faxcompr.c @@ -209,6 +209,8 @@ static int decode_group3_1d_line(AVCodecContext *avctx, GetBitContext *gb, unsigned int run = 0; unsigned int t; for (;;) { + if (get_bits_left(gb) <= 0) + return AVERROR_INVALIDDATA; t = get_vlc2(gb, ccitt_vlc[mode].table, 9, 2); run += t; if (t < 64) { @@ -254,7 +256,10 @@ static int decode_group3_2d_line(AVCodecContext *avctx, GetBitContext *gb, unsigned int offs = 0, run = 0; while (offs < width) { - int cmode = get_vlc2(gb, ccitt_group3_2d_vlc.table, 9, 1); + int cmode; + if (get_bits_left(gb) <= 0) + return AVERROR_INVALIDDATA; + cmode = get_vlc2(gb, ccitt_group3_2d_vlc.table, 9, 1); if (cmode == -1) { av_log(avctx, AV_LOG_ERROR, "Incorrect mode VLC\n"); return AVERROR_INVALIDDATA;