[FFmpeg-cvslog] avcodec/agm: Test remaining data in decode_raw_intra_rgb()

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Sat Feb  8 21:17:01 2020 +0100| [5c151e1491dd609ac5c8a8fbea42f21178a682db] | committer: Michael Niedermayer

avcodec/agm: Test remaining data in decode_raw_intra_rgb()

Fixes: Timeout (270sec -> 25ms)
Fixes: 20485/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_AGM_fuzzer-5636954207289344

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Reviewed-by: Paul B Mahol <onemda at gmail.com>
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=5c151e1491dd609ac5c8a8fbea42f21178a682db
---

 libavcodec/agm.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/libavcodec/agm.c b/libavcodec/agm.c
index 80f4697ee5..c5c9a88dd9 100644
--- a/libavcodec/agm.c
+++ b/libavcodec/agm.c
@@ -573,13 +573,16 @@ static int decode_raw_intra_rgb(AVCodecContext *avctx, GetByteContext *gbyte, AV
     uint8_t *dst = frame->data[0] + (avctx->height - 1) * frame->linesize[0];
     uint8_t r = 0, g = 0, b = 0;
 
+    if (bytestream2_get_bytes_left(gbyte) < 3 * avctx->width * avctx->height)
+        return AVERROR_INVALIDDATA;
+
     for (int y = 0; y < avctx->height; y++) {
         for (int x = 0; x < avctx->width; x++) {
-            dst[x*3+0] = bytestream2_get_byte(gbyte) + r;
+            dst[x*3+0] = bytestream2_get_byteu(gbyte) + r;
             r = dst[x*3+0];
-            dst[x*3+1] = bytestream2_get_byte(gbyte) + g;
+            dst[x*3+1] = bytestream2_get_byteu(gbyte) + g;
             g = dst[x*3+1];
-            dst[x*3+2] = bytestream2_get_byte(gbyte) + b;
+            dst[x*3+2] = bytestream2_get_byteu(gbyte) + b;
             b = dst[x*3+2];
         }
         dst -= frame->linesize[0];