[FFmpeg-cvslog] tools/target_dem_fuzzer: Check fmt before dereferencing

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Wed Feb 23 23:58:41 2022 +0100| [c900f2e42c6ef4b51b5b9237fa6829a4db544d29] | committer: Michael Niedermayer

tools/target_dem_fuzzer: Check fmt before dereferencing

Fixes: NULL pointer dereference
Fixes: 44884/clusterfuzz-testcase-minimized-ffmpeg_DEMUXER_fuzzer-4656748688965632

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=c900f2e42c6ef4b51b5b9237fa6829a4db544d29
---

 tools/target_dem_fuzzer.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/target_dem_fuzzer.c b/tools/target_dem_fuzzer.c
index 687989ccc8..32767a0182 100644
--- a/tools/target_dem_fuzzer.c
+++ b/tools/target_dem_fuzzer.c
@@ -173,7 +173,7 @@ int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
     }
 
     // HLS uses a loop with sleep, we thus must breakout or we timeout
-    if (!strcmp(fmt->name, "hls"))
+    if (fmt && !strcmp(fmt->name, "hls"))
         interrupt_counter &= 31;
 
     if (!io_buffer_size || size / io_buffer_size > maxblocks)