https://gitlab.gnome.org/GNOME/glib/-/merge_requests/3029
https://gitlab.gnome.org/GNOME/glib/-/merge_requests/3039 (backport PR we've used)
https://bugs.gentoo.org/878995
https://bugs.gentoo.org/878351

From e2f283d7c8c5ab3aeb2f281a27ec7c0f24b86868 Mon Sep 17 00:00:00 2001
From: Ray Strode <rstrode@redhat.com>
Date: Fri, 28 Oct 2022 11:21:04 -0400
Subject: [PATCH 1/2] Revert "Handling collision between standard i/o file
 descriptors and newly created ones"

g_unix_open_pipe tries to avoid the standard io fd range
when getting pipe fds. This turns out to be a bad idea because
certain buggy programs rely on it using that range.

This reverts commit d9ba6150909818beb05573f54f26232063492c5b
--- a/glib/glib-unix.c
+++ b/glib/glib-unix.c
@@ -108,17 +108,6 @@ g_unix_open_pipe (int     *fds,
     ecode = pipe2 (fds, pipe2_flags);
     if (ecode == -1 && errno != ENOSYS)
       return g_unix_set_error_from_errno (error, errno);
-    /* Don't reassign pipes to stdin, stdout, stderr if closed meanwhile */
-    else if (fds[0] < 3 || fds[1] < 3)
-      {
-        int old_fds[2] = { fds[0], fds[1] };
-        gboolean result = g_unix_open_pipe (fds, flags, error);
-        close (old_fds[0]);
-        close (old_fds[1]);
-
-        if (!result)
-          g_unix_set_error_from_errno (error, errno);
-      }
     else if (ecode == 0)
       return TRUE;
     /* Fall through on -ENOSYS, we must be running on an old kernel */
@@ -127,19 +116,6 @@ g_unix_open_pipe (int     *fds,
   ecode = pipe (fds);
   if (ecode == -1)
     return g_unix_set_error_from_errno (error, errno);
-  /* Don't reassign pipes to stdin, stdout, stderr if closed meanwhile */
-  else if (fds[0] < 3 || fds[1] < 3)
-    {
-      int old_fds[2] = { fds[0], fds[1] };
-      gboolean result = g_unix_open_pipe (fds, flags, error);
-      close (old_fds[0]);
-      close (old_fds[1]);
-
-      if (!result)
-        g_unix_set_error_from_errno (error, errno);
-
-      return result;
-    }
 
   if (flags == 0)
     return TRUE;
GitLab
From 4526620d8c485f5dfba6ddca33f91670982f82eb Mon Sep 17 00:00:00 2001
From: Ray Strode <rstrode@redhat.com>
Date: Mon, 31 Oct 2022 09:17:55 -0400
Subject: [PATCH 2/2] glib-unix: Add test to make sure g_unix_open_pipe will
 intrude standard range

Now that we know it's a bad idea to avoid the standard io fd range
when getting pipe fds for g_unix_open_pipe, we should test to make sure
we don't inadvertently try to do it again.

This commit adds that test.
--- a/glib/tests/unix.c
+++ b/glib/tests/unix.c
@@ -24,8 +24,11 @@
 #include "config.h"
 
 #include "glib-unix.h"
+#include "gstdio.h"
+
 #include <string.h>
 #include <pwd.h>
+#include <unistd.h>
 
 static void
 test_pipe (void)
@@ -52,6 +55,39 @@ test_pipe (void)
   g_assert (g_str_has_prefix (buf, "hello"));
 }
 
+static void
+test_pipe_stdio_overwrite (void)
+{
+  GError *error = NULL;
+  int pipefd[2], ret;
+  gboolean res;
+  int stdin_fd;
+
+  stdin_fd = dup (STDIN_FILENO);
+  g_assert_cmpint (stdin_fd, >, 0);
+
+  g_close (STDIN_FILENO, &error);
+  g_assert_no_error (error);
+
+  res = g_unix_open_pipe (pipefd, FD_CLOEXEC, &error);
+  g_assert_no_error (error);
+  g_assert_true (res);
+
+  g_assert_cmpint (pipefd[0], ==, STDIN_FILENO);
+
+  g_close (pipefd[0], &error);
+  g_assert_no_error (error);
+
+  g_close (pipefd[1], &error);
+  g_assert_no_error (error);
+
+  ret = dup2 (stdin_fd, STDIN_FILENO);
+  g_assert_cmpint (ret, >=, 0);
+
+  g_close (stdin_fd, &error);
+  g_assert_no_error (error);
+}
+
 static void
 test_error (void)
 {
@@ -337,6 +373,7 @@ main (int   argc,
   g_test_init (&argc, &argv, NULL);
 
   g_test_add_func ("/glib-unix/pipe", test_pipe);
+  g_test_add_func ("/glib-unix/pipe-stdio-overwrite", test_pipe_stdio_overwrite);
   g_test_add_func ("/glib-unix/error", test_error);
   g_test_add_func ("/glib-unix/nonblocking", test_nonblocking);
   g_test_add_func ("/glib-unix/sighup", test_sighup);
GitLab