[FFmpeg-devel] [PATCH 1/7] avcodec/ffv1dec: add missing error messages when a frame is invalid

[Jerome Martinez]

A buggy file (before the patch preventing such issue is applied):
ffmpeg -y -f lavfi -i mandelbrot=s=31x31 -vframes 1 -c ffv1 -slices 961 
a.mkv
Then with:
ffmpeg -y -f lavfi -i mandelbrot=s=31x31 -vframes 1 source.jpg
ffmpeg -y -i a.mkv a.jpg

There is no error message despite the fact the stream was not correctly 
decoded (a.jpg is not like source.jpg), but user is not informed that 
the decoding was not good.
This patch adds error message to the output when relevant.


From 04f7275bdefe56ca2ff5d175de6e392f60c31bc3 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=A9r=C3=B4me=20Martinez?= <jer...@mediaarea.net>
Date: Wed, 7 Mar 2018 10:36:36 +0100
Subject: [PATCH 1/7] avcodec/ffv1dec: add missing error messages when a frame
 is invalid

---
 libavcodec/ffv1dec.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/libavcodec/ffv1dec.c b/libavcodec/ffv1dec.c
index 3d2ee2569f..94bd60ad2b 100644
--- a/libavcodec/ffv1dec.c
+++ b/libavcodec/ffv1dec.c
@@ -296,6 +296,7 @@ static int decode_slice(AVCodecContext *c, void *arg)
         if (decode_slice_header(f, fs) < 0) {
             fs->slice_x = fs->slice_y = fs->slice_height = fs->slice_width = 0;
             fs->slice_damaged = 1;
+            av_log(f->avctx, AV_LOG_ERROR, "Invalid content found while 
parsing slice header\n");
             return AVERROR_INVALIDDATA;
         }
     }
@@ -432,8 +433,10 @@ static int read_extra_header(FFV1Context *f)
     if (f->version > 2) {
         c->bytestream_end -= 4;
         f->micro_version = get_symbol(c, state, 0);
-        if (f->micro_version < 0)
+        if (f->micro_version < 0) {
+            av_log(f->avctx, AV_LOG_ERROR, "Invalid micro_version in global 
header\n");
             return AVERROR_INVALIDDATA;
+        }
     }
     f->ac = get_symbol(c, state, 0);
 
@@ -759,11 +762,15 @@ static int read_header(FFV1Context *f)
             fs->slice_width  = fs->slice_width  / f->num_h_slices - 
fs->slice_x;
             fs->slice_height = fs->slice_height / f->num_v_slices - 
fs->slice_y;
             if ((unsigned)fs->slice_width  > f->width ||
-                (unsigned)fs->slice_height > f->height)
+                (unsigned)fs->slice_height > f->height) {
+                av_log(f->avctx, AV_LOG_ERROR, "Invalid content found while 
parsing header\n");
                 return AVERROR_INVALIDDATA;
+            }
             if (   (unsigned)fs->slice_x + (uint64_t)fs->slice_width  > 
f->width
-                || (unsigned)fs->slice_y + (uint64_t)fs->slice_height > 
f->height)
+                || (unsigned)fs->slice_y + (uint64_t)fs->slice_height > 
f->height) {
+                av_log(f->avctx, AV_LOG_ERROR, "Invalid content found while 
parsing header\n");
                 return AVERROR_INVALIDDATA;
+            }
         }
 
         for (i = 0; i < f->plane_count; i++) {
-- 
2.13.3.windows.1

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