From 553fb024d49aa75df40b4f09208f93ce381aa00f Mon Sep 17 00:00:00 2001
From: sfan5 <sfan5@live.de>
Date: Mon, 13 May 2024 21:55:51 +0200
Subject: [PATCH] stream: check file descriptor passed to fd:// or fdclose://

---
 stream/stream_file.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/stream/stream_file.c b/stream/stream_file.c
index 1744fc13a4..d5c2aaa673 100644
--- a/stream/stream_file.c
+++ b/stream/stream_file.c
@@ -299,10 +299,16 @@ static int open_f(stream_t *stream, const struct stream_open_args *args)
     if (strncmp(url, "fd://", 5) == 0 || is_fdclose) {
         char *begin = strstr(stream->url, "://") + 3, *end = NULL;
         p->fd = strtol(begin, &end, 0);
-        if (!end || end == begin || end[0]) {
-            MP_ERR(stream, "Invalid FD: %s\n", stream->url);
+        if (!end || end == begin || end[0] || p->fd < 0) {
+            MP_ERR(stream, "Invalid FD number: %s\n", stream->url);
             return STREAM_ERROR;
         }
+#ifdef F_SETFD
+        if (fcntl(p->fd, F_GETFD) == -1) {
+            MP_ERR(stream, "Invalid FD: %d\n", p->fd);
+            return STREAM_ERROR;
+        }
+#endif
         if (is_fdclose)
             p->close = true;
     } else if (!strict_fs && !strcmp(filename, "-")) {