1 files changed, 129 insertions, 0 deletions
diff --git a/pam_gdm/pam_gdm.c b/pam_gdm/pam_gdm.c
new file mode 100644
index 0000000..ef77f16
--- /dev/null
+++ b/pam_gdm/pam_gdm.c
@@ -0,0 +1,129 @@
+/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 8 -*-
+ *
+ * Copyright  (C) 2016 Red Hat, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ */
+#include <config.h>
+
+#include <unistd.h>
+
+#include <security/_pam_macros.h>
+#include <security/pam_ext.h>
+#include <security/pam_misc.h>
+#include <security/pam_modules.h>
+#include <security/pam_modutil.h>
+
+#ifdef HAVE_KEYUTILS
+#include <keyutils.h>
+#endif
+
+int
+pam_sm_authenticate (pam_handle_t  *pamh,
+                     int            flags,
+                     int            argc,
+                     const char   **argv)
+{
+#ifdef HAVE_KEYUTILS
+        long r;
+        size_t cached_passwords_length;
+        char *cached_passwords = NULL;
+        char *last_cached_password = NULL;
+        key_serial_t serial;
+        size_t i;
+
+        serial = find_key_by_type_and_desc ("user", "cryptsetup", 0);
+        if (serial == 0)
+                return PAM_AUTHINFO_UNAVAIL;
+
+        r = keyctl_read_alloc (serial, &cached_passwords);
+        if (r < 0)
+                return PAM_AUTHINFO_UNAVAIL;
+        
+        cached_passwords_length = r;
+
+        /*
+            Find the last password in the NUL-separated list of passwords.
+            Multiple passwords are returned either when the user enters an
+            incorrect password or there are multiple encrypted drives.
+            In the case of an incorrect password the last one is correct.
+            In the case of multiple drives, choosing the last drive is as
+            arbitrary a choice as any other, but choosing the last password at
+            least supports multiple attempts on the last drive.
+        */
+        last_cached_password = cached_passwords;
+        for (i = 0; i < cached_passwords_length; i++) {
+                last_cached_password = cached_passwords + i;
+                i += strlen (last_cached_password);
+        }
+
+        r = pam_set_item (pamh, PAM_AUTHTOK, last_cached_password);
+
+        free (cached_passwords);
+
+        if (r < 0)
+                return PAM_AUTH_ERR;
+        else
+                return PAM_SUCCESS;
+#endif
+
+        return PAM_AUTHINFO_UNAVAIL;
+}
+
+int
+pam_sm_setcred (pam_handle_t *pamh,
+                int           flags,
+                int           argc,
+                const char  **argv)
+{
+        return PAM_SUCCESS;
+}
+
+int
+pam_sm_acct_mgmt (pam_handle_t  *pamh,
+                  int            flags,
+                  int            argc,
+                  const char   **argv)
+{
+        return PAM_SUCCESS;
+}
+
+int
+pam_sm_chauthtok (pam_handle_t  *pamh,
+                  int            flags,
+                  int            argc,
+                  const char   **argv)
+{
+        return PAM_SUCCESS;
+}
+
+int
+pam_sm_open_session (pam_handle_t  *pamh,
+                     int            flags,
+                     int            argc,
+                     const char   **argv)
+{
+        return PAM_SUCCESS;
+}
+
+int
+pam_sm_close_session (pam_handle_t  *pamh,
+                      int            flags,
+                      int            argc,
+                      const char   **argv)
+{
+        return PAM_SUCCESS;
+}