[FFmpeg-cvslog] avcodec/allcodecs: Dont play with NULLs

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Mon Mar 21 21:19:43 2022 +0100| [dd1ce72e68f77c88fe8d258d83f7315c34b1eb11] | committer: Michael Niedermayer

avcodec/allcodecs: Dont play with NULLs

Fixes: member access within null pointer of type 'const FFCodec' (aka 'const struct FFCodec')
Fixes: 45726/clusterfuzz-testcase-minimized-ffmpeg_DEMUXER_fuzzer-6554445419249664

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Reviewed-by: Andreas Rheinhardt <andreas.rheinhardt at outlook.com>
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=dd1ce72e68f77c88fe8d258d83f7315c34b1eb11
---

 libavcodec/allcodecs.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/libavcodec/allcodecs.c b/libavcodec/allcodecs.c
index b1aa7e266b..22d56760ec 100644
--- a/libavcodec/allcodecs.c
+++ b/libavcodec/allcodecs.c
@@ -882,10 +882,11 @@ const AVCodec *av_codec_iterate(void **opaque)
 
     ff_thread_once(&av_codec_static_init, av_codec_init_static);
 
-    if (c)
+    if (c) {
         *opaque = (void*)(i + 1);
-
-    return &c->p;
+        return &c->p;
+    }
+    return NULL;
 }
 
 static enum AVCodecID remap_deprecated_codec_id(enum AVCodecID id)