From fff4ecc82f2bcfa7427596e7ad9c3769fcab040b Mon Sep 17 00:00:00 2001
From: Perberos <perberos@gmail.com>
Date: Fri, 4 Nov 2011 22:16:15 -0300
Subject: first commit

---
 src/gs-auth-helper.c.orig | 213 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 213 insertions(+)
 create mode 100644 src/gs-auth-helper.c.orig

(limited to 'src/gs-auth-helper.c.orig')

diff --git a/src/gs-auth-helper.c.orig b/src/gs-auth-helper.c.orig
new file mode 100644
index 0000000..946aef3
--- /dev/null
+++ b/src/gs-auth-helper.c.orig
@@ -0,0 +1,213 @@
+/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 8 -*-
+ *
+ * written by Olaf Kirch <okir@suse.de>
+ * xscreensaver, Copyright (c) 1993-2004 Jamie Zawinski <jwz@jwz.org>
+ *
+ * Permission to use, copy, modify, distribute, and sell this software and its
+ * documentation for any purpose is hereby granted without fee, provided that
+ * the above copyright notice appear in all copies and that both that
+ * copyright notice and this permission notice appear in supporting
+ * documentation.  No representations are made about the suitability of this
+ * software for any purpose.  It is provided "as is" without express or
+ * implied warranty.
+ */
+
+/* The idea here is to be able to run mate-screensaver-dialog without any setuid bits.
+ * Password verification happens through an external program that you feed
+ * your password to on stdin.  The external command is invoked with a user
+ * name argument.
+ *
+ * The external helper does whatever authentication is necessary.  Currently,
+ * SuSE uses "unix2_chkpwd", which is a variation of "unix_chkpwd" from the
+ * PAM distribution.
+ *
+ * Normally, the password helper should just authenticate the calling user
+ * (i.e. based on the caller's real uid).  This is in order to prevent
+ * brute-forcing passwords in a shadow environment.  A less restrictive
+ * approach would be to allow verifying other passwords as well, but always
+ * with a 2 second delay or so.  (Not sure what SuSE's "unix2_chkpwd"
+ * currently does.)
+ *                         -- Olaf Kirch <okir@suse.de>, 16-Dec-2003
+ */
+
+#include "config.h"
+
+#include <stdlib.h>
+#ifdef HAVE_UNISTD_H
+# include <unistd.h>
+#endif
+
+#include <stdio.h>
+#include <string.h>
+#include <sys/types.h>
+#include <pwd.h>
+#include <errno.h>
+#include <sys/wait.h>
+
+#include <glib.h>
+#include <glib/gstdio.h>
+
+#include "gs-auth.h"
+#include "subprocs.h"
+
+static gboolean verbose_enabled = FALSE;
+
+GQuark
+gs_auth_error_quark (void)
+{
+    static GQuark quark = 0;
+    if (! quark)
+    {
+        quark = g_quark_from_static_string ("gs_auth_error");
+    }
+
+    return quark;
+}
+
+void
+gs_auth_set_verbose (gboolean enabled)
+{
+    verbose_enabled = enabled;
+}
+
+gboolean
+gs_auth_get_verbose (void)
+{
+    return verbose_enabled;
+}
+
+static gboolean
+ext_run (const char *user,
+         const char *typed_passwd,
+         gboolean    verbose)
+{
+    int   pfd[2], status;
+    pid_t pid;
+
+    if (pipe (pfd) < 0)
+    {
+        return 0;
+    }
+
+    if (verbose)
+    {
+        g_message ("ext_run (%s, %s)",
+                   PASSWD_HELPER_PROGRAM, user);
+    }
+
+    block_sigchld ();
+
+    if ((pid = fork ()) < 0)
+    {
+        close (pfd [0]);
+        close (pfd [1]);
+        return FALSE;
+    }
+
+    if (pid == 0)
+    {
+        close (pfd [1]);
+        if (pfd [0] != 0)
+        {
+            dup2 (pfd [0], 0);
+        }
+
+        /* Helper is invoked as helper service-name [user] */
+        execlp (PASSWD_HELPER_PROGRAM, PASSWD_HELPER_PROGRAM, "mate-screensaver", user, NULL);
+        if (verbose)
+        {
+            g_message ("%s: %s", PASSWD_HELPER_PROGRAM, g_strerror (errno));
+        }
+
+        exit (1);
+    }
+
+    close (pfd [0]);
+
+    /* Write out password to helper process */
+    if (!typed_passwd)
+    {
+        typed_passwd = "";
+    }
+    write (pfd [1], typed_passwd, strlen (typed_passwd));
+    close (pfd [1]);
+
+    while (waitpid (pid, &status, 0) < 0)
+    {
+        if (errno == EINTR)
+        {
+            continue;
+        }
+
+        if (verbose)
+        {
+            g_message ("ext_run: waitpid failed: %s\n",
+                       g_strerror (errno));
+        }
+
+        unblock_sigchld ();
+        return FALSE;
+    }
+
+    unblock_sigchld ();
+
+    if (! WIFEXITED (status) || WEXITSTATUS (status) != 0)
+    {
+        return FALSE;
+    }
+
+    return TRUE;
+}
+
+gboolean
+gs_auth_verify_user (const char       *username,
+                     const char       *display,
+                     GSAuthMessageFunc func,
+                     gpointer          data,
+                     GError          **error)
+{
+    gboolean       res = FALSE;
+    char          *password;
+
+    password = NULL;
+
+    /* ask for the password for user */
+    if (func != NULL)
+    {
+        func (GS_AUTH_MESSAGE_PROMPT_ECHO_OFF,
+              "Password: ",
+              &password,
+              data);
+    }
+
+    if (password == NULL)
+    {
+        return FALSE;
+    }
+
+    res = ext_run (username, password, gs_auth_get_verbose ());
+
+    return res;
+}
+
+gboolean
+gs_auth_init (void)
+{
+    return TRUE;
+}
+
+gboolean
+gs_auth_priv_init (void)
+{
+    /* Make sure the passwd helper exists */
+    if (g_access (PASSWD_HELPER_PROGRAM, X_OK) < 0)
+    {
+        g_warning ("%s does not exist. "
+                   "password authentication via "
+                   "external helper will not work.",
+                   PASSWD_HELPER_PROGRAM);
+        return FALSE;
+    }
+
+    return TRUE;
+}
-- 
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