[FFmpeg-cvslog] avcodec/4xm: Check frame_4cc before allocation

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Sun May 11 19:41:18 2025 +0200| [4a9d907b5eb93c0efe09ddd947ae5f462689f6f2] | committer: Michael Niedermayer

avcodec/4xm: Check frame_4cc before allocation

Fixes: Timeout
Fixes: 403402798/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_FOURXM_fuzzer-5012819292782592

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

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=4a9d907b5eb93c0efe09ddd947ae5f462689f6f2
---

 libavcodec/4xm.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/libavcodec/4xm.c b/libavcodec/4xm.c
index fd3a45f093..94f4268127 100644
--- a/libavcodec/4xm.c
+++ b/libavcodec/4xm.c
@@ -927,8 +927,11 @@ static int decode_frame(AVCodecContext *avctx, AVFrame *picture,
         frame_size = buf_size - 12;
     }
 
-    if ((ret = ff_get_buffer(avctx, picture, 0)) < 0)
-        return ret;
+    if (   frame_4cc == AV_RL32("ifr2") || frame_4cc == AV_RL32("ifrm")
+        || frame_4cc == AV_RL32("pfrm") || frame_4cc == AV_RL32("pfr2")) {
+        if ((ret = ff_get_buffer(avctx, picture, 0)) < 0)
+            return ret;
+    }
 
     if (frame_4cc == AV_RL32("ifr2")) {
         picture->pict_type = AV_PICTURE_TYPE_I;