[FFmpeg-devel] [PATCH] examples: fix memory leaks, zombie processes and integer overflows

[FFmpeg-devel] [PATCH] examples: fix memory leaks, zombie processes and integer overflows

[Baptiste Bd via ffmpeg-devel]

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>From 78bb1086f99b6ba234a9874246feb15360c8496c Mon Sep 17 00:00:00 2001
From: OxBat <monsterbat02@gmail.com>
Date: Sat, 3 Jan 2026 19:23:35 +0100
Subject: [PATCH] examples: fix memory leaks, zombie processes and integer
 overflows

---
 doc/examples/avio_http_serve_files.c |  2 ++
 doc/examples/extract_mvs.c           |  3 ++-
 doc/examples/filter_audio.c          |  6 ++++++
 doc/examples/hw_decode.c             |  6 ++++--
 doc/examples/qsv_transcode.c         |  5 +++++
 doc/examples/transcode.c             | 14 ++++++++------
 6 files changed, 27 insertions(+), 9 deletions(-)

diff --git a/doc/examples/avio_http_serve_files.c
b/doc/examples/avio_http_serve_files.c
index 2aae3870c2..9aaf4b273b 100644
--- a/doc/examples/avio_http_serve_files.c
+++ b/doc/examples/avio_http_serve_files.c
@@ -31,6 +31,7 @@
 #include <libavformat/avformat.h>
 #include <libavutil/opt.h>
 #include <unistd.h>
+#include <signal.h>  /* NEW */

 static void process_client(AVIOContext *client, const char *in_uri)
 {
@@ -103,6 +104,7 @@ int main(int argc, char **argv)
     const char *in_uri, *out_uri;
     int ret, pid;
     av_log_set_level(AV_LOG_TRACE);
+    signal(SIGCHLD, SIG_IGN); /* PATCH: Prevent zombie processes */
     if (argc < 3) {
         printf("usage: %s input http://hostname[:port]\n"
                "API example program to serve http to multiple clients.\n"
diff --git a/doc/examples/extract_mvs.c b/doc/examples/extract_mvs.c
index 5603064d72..3052473e81 100644
--- a/doc/examples/extract_mvs.c
+++ b/doc/examples/extract_mvs.c
@@ -105,10 +105,11 @@ static int open_codec_context(AVFormatContext
*fmt_ctx, enum AVMediaType type)
             fprintf(stderr, "Failed to allocate codec\n");
             return AVERROR(EINVAL);
         }
-
+        /* PATCH: Memory leak*/
         ret = avcodec_parameters_to_context(dec_ctx, st->codecpar);
         if (ret < 0) {
             fprintf(stderr, "Failed to copy codec parameters to codec
context\n");
+            avcodec_free_context(&dec_ctx); /* PATCH: Fix leak */
             return ret;
         }

diff --git a/doc/examples/filter_audio.c b/doc/examples/filter_audio.c
index ad77bf1f89..c4673bddef 100644
--- a/doc/examples/filter_audio.c
+++ b/doc/examples/filter_audio.c
@@ -88,6 +88,7 @@ static int init_filter_graph(AVFilterGraph **graph,
AVFilterContext **src,
     abuffer = avfilter_get_by_name("abuffer");
     if (!abuffer) {
         fprintf(stderr, "Could not find the abuffer filter.\n");
+        avfilter_graph_free(&filter_graph); /* PATCH: Fix leak */
         return AVERROR_FILTER_NOT_FOUND;
     }

@@ -279,6 +280,11 @@ int main(int argc, char *argv[])
     }

     duration  = atof(argv[1]);
+/* PATCH: Check for integer overflow */
+    if (duration > (double)2147483647 / INPUT_SAMPLERATE) {
+    fprintf(stderr, "Duration too long\n");
+    return 1;
+    }
     nb_frames = duration * INPUT_SAMPLERATE / FRAME_SIZE;
     if (nb_frames <= 0) {
         fprintf(stderr, "Invalid duration: %s\n", argv[1]);
diff --git a/doc/examples/hw_decode.c b/doc/examples/hw_decode.c
index ac4e445505..caef3e93e3 100644
--- a/doc/examples/hw_decode.c
+++ b/doc/examples/hw_decode.c
@@ -215,8 +215,10 @@ int main(int argc, char *argv[])
         return AVERROR(ENOMEM);

     video = input_ctx->streams[video_stream];
-    if (avcodec_parameters_to_context(decoder_ctx, video->codecpar) < 0)
-        return -1;
+    if (avcodec_parameters_to_context(decoder_ctx, video->codecpar) < 0) {
+    avcodec_free_context(&decoder_ctx); /* PATCH: Fix leak */
+    return -1;
+}

     decoder_ctx->get_format  = get_hw_format;

diff --git a/doc/examples/qsv_transcode.c b/doc/examples/qsv_transcode.c
index 13b4933041..b780a65c79 100644
--- a/doc/examples/qsv_transcode.c
+++ b/doc/examples/qsv_transcode.c
@@ -351,6 +351,11 @@ int main(int argc, char **argv)
     }
     setting_number = (argc - 5) / 2;
     dynamic_setting = av_malloc(setting_number * sizeof(*dynamic_setting));
+    /* PATCH: Check allocation */
+    if (!dynamic_setting) {
+        ret = AVERROR(ENOMEM);
+        goto end;
+    }
     current_setting_number = 0;
     for (int i = 0; i < setting_number; i++) {
         dynamic_setting[i].frame_number = atoi(argv[i*2 + 5]);
diff --git a/doc/examples/transcode.c b/doc/examples/transcode.c
index 1dc1b50502..6dcacc1d4f 100644
--- a/doc/examples/transcode.c
+++ b/doc/examples/transcode.c
@@ -92,12 +92,14 @@ static int open_input_file(const char *filename)
             av_log(NULL, AV_LOG_ERROR, "Failed to allocate the decoder
context for stream #%u\n", i);
             return AVERROR(ENOMEM);
         }
-        ret = avcodec_parameters_to_context(codec_ctx, stream->codecpar);
-        if (ret < 0) {
-            av_log(NULL, AV_LOG_ERROR, "Failed to copy decoder parameters
to input decoder context "
-                   "for stream #%u\n", i);
-            return ret;
-        }
+    /* PATCH: Memory leak - Input Decoder */
+    ret = avcodec_parameters_to_context(codec_ctx, stream->codecpar);
+    if (ret < 0) {
+        av_log(NULL, AV_LOG_ERROR, "Failed to copy decoder parameters to
input decoder context "
+           "for stream #%u\n", i);
+        avcodec_free_context(&codec_ctx); /* PATCH: Fix leak */
+        return ret;
+    }

         /* Inform the decoder about the timebase for the packet timestamps.
          * This is highly recommended, but not mandatory. */
-- 
2.52.0.windows.1

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