[FFmpeg-cvslog] avcodec/faxcompr: Check for end of bitstream in decode_group3_1d_line() and decode_group3_2d_line()

[Michael Niedermayer]

ffmpeg | branch: release/4.4 | Michael Niedermayer <michael at niedermayer.cc> | Wed Apr 28 16:58:50 2021 +0200| [89d8eae0c618b156361d27200f4629becbdabb1e] | committer: Michael Niedermayer

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 <michael at niedermayer.cc>
(cherry picked from commit 08d2df41538b583932c1a6772e3c8978a2334107)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=89d8eae0c618b156361d27200f4629becbdabb1e
---

 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;