[FFmpeg-cvslog] avcodec/tiff: Check frame parameters before blit for DNG

[Michael Niedermayer]

ffmpeg | branch: release/4.3 | Michael Niedermayer <michael at niedermayer.cc> | Sat Jul  4 14:17:05 2020 +0200| [b228e0c5f6a854d2ba3d5b4e3b88ab47380aacf1] | committer: Michael Niedermayer

avcodec/tiff: Check frame parameters before blit for DNG

Fixes: out of array access
Fixes: 23888/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_TIFF_fuzzer-6021365974171648.fuzz

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 4091f4f78012d1a7eb1e04b69cf65d5ef3afee3a)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=b228e0c5f6a854d2ba3d5b4e3b88ab47380aacf1
---

 libavcodec/tiff.c | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/libavcodec/tiff.c b/libavcodec/tiff.c
index d93a02b07e..6a3ec3ef95 100644
--- a/libavcodec/tiff.c
+++ b/libavcodec/tiff.c
@@ -911,12 +911,23 @@ static int dng_decode_jpeg(AVCodecContext *avctx, AVFrame *frame,
             return 0;
     }
 
+    is_u16 = (s->bpp > 8);
+
     /* Copy the outputted tile's pixels from 'jpgframe' to 'frame' (final buffer) */
 
     /* See dng_blit for explanation */
-    is_single_comp = (s->avctx_mjpeg->width == w * 2 && s->avctx_mjpeg->height == h / 2);
+    if (s->avctx_mjpeg->width  == w * 2 &&
+        s->avctx_mjpeg->height == h / 2 &&
+        s->avctx_mjpeg->pix_fmt == AV_PIX_FMT_GRAY16LE) {
+        is_single_comp = 1;
+    } else if (s->avctx_mjpeg->width  == w &&
+               s->avctx_mjpeg->height == h &&
+               s->avctx_mjpeg->pix_fmt == (is_u16 ? AV_PIX_FMT_GRAY16 : AV_PIX_FMT_GRAY8)
+              ) {
+        is_single_comp = 0;
+    } else
+        return AVERROR_INVALIDDATA;
 
-    is_u16 = (s->bpp > 8);
     pixel_size = (is_u16 ? sizeof(uint16_t) : sizeof(uint8_t));
 
     if (is_single_comp && !is_u16) {