[FFmpeg-cvslog] avcodec/mjpegdec: Check input buffer size.

[Michael Niedermayer]

ffmpeg | branch: release/3.3 | Michael Niedermayer <michael at niedermayer.cc> | Tue Apr 10 16:12:15 2018 +0200| [6de499caed33f26cfce32f0ddd74b2a518f60402] | committer: Michael Niedermayer

avcodec/mjpegdec: Check input buffer size.

Fixes: Timeout
Fixes: 6381/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_JPEGLS_fuzzer-5665032743419904

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 8d381b57fd9d17fb5c3a851ca46c738b3afc33a2)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=6de499caed33f26cfce32f0ddd74b2a518f60402
---

 libavcodec/mjpegdec.c | 4 ++++
 libavcodec/mjpegdec.h | 1 +
 2 files changed, 5 insertions(+)

diff --git a/libavcodec/mjpegdec.c b/libavcodec/mjpegdec.c
index 31c8fb422d..ab326b8e9a 100644
--- a/libavcodec/mjpegdec.c
+++ b/libavcodec/mjpegdec.c
@@ -309,6 +309,8 @@ int ff_mjpeg_decode_sof(MJpegDecodeContext *s)
     av_log(s->avctx, AV_LOG_DEBUG, "sof0: picture: %dx%d\n", width, height);
     if (av_image_check_size(width, height, 0, s->avctx))
         return AVERROR_INVALIDDATA;
+    if (s->buf_size && (width + 7) / 8 * ((height + 7) / 8) > s->buf_size * 4LL)
+        return AVERROR_INVALIDDATA;
 
     nb_components = get_bits(&s->gb, 8);
     if (nb_components <= 0 ||
@@ -2091,6 +2093,8 @@ int ff_mjpeg_decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
     int ret = 0;
     int is16bit;
 
+    s->buf_size = buf_size;
+
     av_dict_free(&s->exif_metadata);
     av_freep(&s->stereo3d);
     s->adobe_transform = -1;
diff --git a/libavcodec/mjpegdec.h b/libavcodec/mjpegdec.h
index 024cedcb5a..0fa5a748a1 100644
--- a/libavcodec/mjpegdec.h
+++ b/libavcodec/mjpegdec.h
@@ -45,6 +45,7 @@ typedef struct MJpegDecodeContext {
     AVClass *class;
     AVCodecContext *avctx;
     GetBitContext gb;
+    int buf_size;
 
     int start_code; /* current start code */
     int buffer_size;