From 2a36bb4b7e46f9ac043561c61f9a790786a5440c 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
Closes: #2795
Reopens: #16
---
glib/glib-unix.c | 24 ------------------------
1 file changed, 24 deletions(-)
diff --git a/glib/glib-unix.c b/glib/glib-unix.c
index 4710c51168..bc152d7663 100644
--- 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 1c1c452ff2030135e4abc2816e81b7078a845580 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.
---
glib/tests/unix.c | 41 +++++++++++++++++++++++++++++++++++++++++
1 file changed, 41 insertions(+)
diff --git a/glib/tests/unix.c b/glib/tests/unix.c
index 2112cab6bf..6c4a59dee7 100644
--- 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 +55,43 @@ 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;
+
+
+ g_test_summary ("Test that g_unix_open_pipe() will use the first available FD, even if it’s stdin/stdout/stderr");
+ g_test_bug ("https://gitlab.gnome.org/GNOME/glib/-/issues/2795");
+
+ 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 +377,7 @@ 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