PolicyKit: Branch 'master'

[David Zeuthen]

 src/polkit-grant/polkit-grant-helper-shadow.c |  151 ++++++++++++++++++++++++++
 1 file changed, 151 insertions(+)

New commits:
commit 0d7167147f85f1bc046f8b6024667eec8d2c3dde
Author: Carlos Corbacho <carlos at strangeworlds.co.uk>
Date:   Mon Dec 17 12:14:04 2007 -0500

    also add the new C file for the shadow helper

diff --git a/src/polkit-grant/polkit-grant-helper-shadow.c b/src/polkit-grant/polkit-grant-helper-shadow.c
new file mode 100644
index 0000000..018e30a
--- /dev/null
+++ b/src/polkit-grant/polkit-grant-helper-shadow.c
@@ -0,0 +1,151 @@
+/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 8 -*- */
+/***************************************************************************
+ *
+ * polkit-grant-helper-shadow.c : setuid root shadow helper for PolicyKit
+ *
+ * Copyright (C) 2007 Piter PUNK, <piterpunk at slackware.com>
+ *
+ * Based on polkit-grant-helper-pam.c :
+ *   Copyright (C) 2007 David Zeuthen, <david at fubar.dk>
+ *
+ * Permission is hereby granted, free of charge, to any person
+ * obtaining a copy of this software and associated documentation
+ * files (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use, copy,
+ * modify, merge, publish, distribute, sublicense, and/or sell copies
+ * of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+ * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+ * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ *
+ **************************************************************************/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <syslog.h>
+#include <shadow.h>
+#include <grp.h>
+#include <pwd.h>
+
+/* Development aid: define PGH_DEBUG to get debugging output. Do _NOT_
+ * enable this in production builds; it may leak passwords and other
+ * sensitive information.
+ */
+#undef PGH_DEBUG
+/* #define PGH_DEBUG */
+
+extern char *crypt ();
+static int do_auth (const char *user_to_auth);
+
+int main (int argc, char *argv[])
+{
+        char user_to_auth[256];
+
+        /* clear the entire environment to avoid attacks with
+         * libraries honoring environment variables */
+        if (clearenv () != 0)
+               goto error;
+        /* set a minimal environment */
+        setenv ("PATH", "/usr/sbin:/usr/bin:/sbin:/bin", 1);
+
+        /* check that we are setuid root */
+        if (geteuid () != 0) {
+                fprintf (stderr, "polkit-grant-helper-shadow: needs to be setuid root\n");
+                goto error;
+        }
+
+        openlog ("polkit-grant-helper-shadow", LOG_CONS | LOG_PID, LOG_AUTHPRIV);
+
+        /* check for correct invocation */
+        if (argc != 1) {
+                syslog (LOG_NOTICE, "inappropriate use of helper, wrong number of arguments [uid=%d]", getuid ());
+                fprintf (stderr, "polkit-grant-helper-shadow: wrong number of arguments. This incident has been logged.\n");
+                goto error;
+        }
+
+        if (getuid () != 0) {
+                /* check we're running with a non-tty stdin */
+                if (isatty (STDIN_FILENO) != 0) {
+                        syslog (LOG_NOTICE, "inappropriate use of helper, stdin is a tty [uid=%d]", getuid ());
+                        fprintf (stderr, "polkit-grant-helper-shadow: inappropriate use of helper, stdin is a tty. This incident has been logged.\n");
+                        goto error;
+                }
+        }
+
+        /* get user to auth */
+        if (fgets (user_to_auth, sizeof (user_to_auth), stdin) == NULL)
+                goto error;
+        if (strlen (user_to_auth) > 0 && user_to_auth[strlen (user_to_auth) - 1] == '\n')
+                user_to_auth[strlen(user_to_auth) - 1] = '\0';
+
+#ifdef PGH_DEBUG
+        fprintf (stderr, "polkit-grant-helper-shadow: user to auth is '%s'.\n", user_to_auth);
+#endif /* PGH_DEBUG */
+
+        if(!do_auth (user_to_auth)) {
+                syslog (LOG_NOTICE, "authentication failure [uid=%d] trying to authenticate '%s'", getuid (), user_to_auth);
+                fprintf (stderr, "polkit-grant-helper-shadow: authentication failure. This incident has been logged.\n");
+                goto error;
+        }
+
+#ifdef PGH_DEBUG
+        fprintf (stderr, "polkit-grant-helper-shadow: successfully authenticated user '%s'.\n", user_to_auth);
+#endif /* PGH_DEBUG */
+
+        fprintf (stdout, "SUCCESS\n");
+        fflush (stdout);
+        return 0;
+
+error:
+        sleep (2); /* Discourage brute force attackers */
+        fprintf (stdout, "FAILURE\n");
+        fflush (stdout);
+        return 1;
+}
+/* 
+ * This is the shadow do_auth function. It receives
+ * only the name of user (user_to_auth). Waits for
+ * password in stdin and auth the user. It return success
+ * if the user can be authenticated and unsuccess when
+ * user can't be authenticated.
+ */
+int do_auth (const char *user_to_auth)
+{
+        struct spwd *shadow;
+        char *password;
+        char buf[256];
+
+        if ((shadow = getspnam (user_to_auth)) == NULL)
+                goto error;
+
+        if (fgets (buf, sizeof (buf), stdin) == NULL)
+                goto error;
+
+        if (strlen (buf) > 0 &&
+                buf[strlen (buf) - 1] == '\n')
+                        buf[strlen (buf) - 1] = '\0';
+
+        password = strdup (buf);
+
+        if (strcmp (shadow->sp_pwdp, crypt (password, shadow->sp_pwdp)) != 0)
+                goto error;
+
+        return 1;
+
+error:
+        return 0;
+}