[FFmpeg-devel] [PATCH] avdevice/lavfi: fix crash on unconnected outpads

metamuffin metamuffin at disroot.org
Sun May 7 13:34:47 EEST 2023


Nameless outpads would cause an invocation to sscanf with NULL.
Example: ffmpeg -f lavfi -i 'nullsrc;nullsrc' -
Changed to throwing an error instead.
---
 libavdevice/lavfi.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/libavdevice/lavfi.c b/libavdevice/lavfi.c
index 9c1fcf334b..21f33ade0e 100644
--- a/libavdevice/lavfi.c
+++ b/libavdevice/lavfi.c
@@ -174,6 +174,11 @@ av_cold static int lavfi_read_header(AVFormatContext *avctx)
      * create a mapping between them and the streams */
     for (i = 0, inout = output_links; inout; i++, inout = inout->next) {
         int stream_idx = 0, suffix = 0, use_subcc = 0;
+        if (!inout->name) {
+            av_log(avctx,  AV_LOG_ERROR,
+                   "Filtergraph has nameless outpads\n");
+            FAIL(AVERROR(EINVAL));    
+        }
         sscanf(inout->name, "out%n%d%n", &suffix, &stream_idx, &suffix);
         if (!suffix) {
             av_log(avctx,  AV_LOG_ERROR,
-- 
2.40.1



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