From 2ee31816ec447ad8aca5ed20e1793f248204d0ed Mon Sep 17 00:00:00 2001

From: Alan Coopersmith <[email protected]>

Date: Tue, 29 Dec 2015 17:22:36 -0800

Subject: [PATCH 09/19] xauth-directory

Bug 15620655/SUNBT6923733 gdm create user writable directories under /var/run

Original date:2010-02-19 owner:yippi type:feature bugster:6923733

---

 daemon/gdm-display-access-file.c | 128 ++++++++++++++++++++++++++++++++++-----

 daemon/gdm-display-access-file.h |   1 +

 daemon/main.c                    |   3 +

 data/Makefile.am                 |  12 ++--

 4 files changed, 124 insertions(+), 20 deletions(-)

diff --git a/daemon/gdm-display-access-file.c b/daemon/gdm-display-access-file.c

index 02ec0a0..90e4eed 100644

--- a/daemon/gdm-display-access-file.c

+++ b/daemon/gdm-display-access-file.c

@@ -41,6 +41,8 @@

 #include "gdm-display-access-file.h"

 #include "gdm-common.h"

+static const char *xauth_dir_name = NULL;

+

 struct _GdmDisplayAccessFilePrivate

 {

         char *username;

@@ -221,13 +223,24 @@ _get_uid_and_gid_for_user (const char *username,

         return TRUE;

 }

+void

+gdm_display_access_file_cleanup_xauth (void)

+{

+        /* Clean up any xauth_dir_name when shutting down */

+        if (strcmp (GDM_XAUTH_DIR, "/tmp") == 0 && xauth_dir_name != NULL) {

+                g_remove (xauth_dir_name);

+                g_debug ("GdmDisplayAccessFile: Unlinking xauth directory %s", xauth_dir_name);

+                xauth_dir_name = NULL;

+        }

+}

+

 static void

-clean_up_stale_auth_subdirs (void)

+clean_up_stale_auth_subdirs (const char * xauth_dir_name)

 {

         GDir *dir;

         const char *filename;

-        dir = g_dir_open (GDM_XAUTH_DIR, 0, NULL);

+        dir = g_dir_open (xauth_dir_name, 0, NULL);

         if (dir == NULL) {

                 return;

@@ -236,7 +249,7 @@ clean_up_stale_auth_subdirs (void)

         while ((filename = g_dir_read_name (dir)) != NULL) {

                 char *path;

-                path = g_build_filename (GDM_XAUTH_DIR, filename, NULL);

+                path = g_build_filename (xauth_dir_name, filename, NULL);

                 /* Will only succeed if the directory is empty

                  */

@@ -251,10 +264,13 @@ _create_xauth_file_for_user (const char  *username,

                              char       **filename,

                              GError     **error)

 {

+        struct stat statbuf;

+        gboolean dir_exists;

         char   *template;

         const char *dir_name;

         char   *auth_filename;

         int     fd;

+        int     xauth_dir_fp = -1;

         FILE   *fp;

         uid_t   uid;

         gid_t   gid;

@@ -268,10 +284,37 @@ _create_xauth_file_for_user (const char  *username,

         fp = NULL;

         fd = -1;

+        dir_exists = TRUE;

+

+        if (xauth_dir_name == NULL) {

+                if (strcmp (GDM_XAUTH_DIR, "/tmp") == 0) {

+                        dir_exists = FALSE;

+                        template = g_strdup_printf ("/tmp/gdm-auth-cookies-XXXXXX");

+                        xauth_dir_name = gdm_make_temp_dir (template);

+

+                        g_debug ("GdmDisplayAccessFile: Creating xauth directory %s", xauth_dir_name);

+                        g_chmod (xauth_dir_name, 0711);

+                        _get_uid_and_gid_for_user (GDM_USERNAME, &uid, &gid);

+                        if (chown (xauth_dir_name, 0, gid) != 0) {

+                                g_warning ("Unable to change owner of '%s'",

+                                           xauth_dir_name);

+                        }

+                } else {

+                        xauth_dir_name = GDM_XAUTH_DIR;

+                }

+        }

+

+        /*

+         * Note: if GDM_XAUTH_DIR is "/tmp", we never fall into the next if-case, since

+         * gdm_make_temp_dir calls mkdtemp() which creates the directory.

+         */

+

         /* Create directory if not exist, then set permission 0711 and ownership root:gdm */

-        if (g_file_test (GDM_XAUTH_DIR, G_FILE_TEST_IS_DIR) == FALSE) {

-                g_remove (GDM_XAUTH_DIR);

-                if (g_mkdir (GDM_XAUTH_DIR, 0711) != 0) {

+

+        if (g_file_test (xauth_dir_name, G_FILE_TEST_IS_DIR) == FALSE) {

+                dir_exists = FALSE;

+                g_remove (xauth_dir_name);

+                if (g_mkdir (xauth_dir_name, 0711) != 0) {

                         g_set_error (error,

                                      G_FILE_ERROR,

                                      g_file_error_from_errno (errno),

@@ -279,18 +322,70 @@ _create_xauth_file_for_user (const char  *username,

                         goto out;

                 }

-                g_chmod (GDM_XAUTH_DIR, 0711);

+                g_chmod (xauth_dir_name, 0711);

                 _get_uid_and_gid_for_user (GDM_USERNAME, &uid, &gid);

-                if (chown (GDM_XAUTH_DIR, 0, gid) != 0) {

+                if (chown (xauth_dir_name, 0, gid) != 0) {

                         g_warning ("Unable to change owner of '%s'",

-                                   GDM_XAUTH_DIR);

+                                   xauth_dir_name);

+                }

+        }

+

+        /* Do sanity testing on the Xauth directory */

+        if ((xauth_dir_fp = open (xauth_dir_name, O_RDONLY | O_NOFOLLOW)) == -1) {

+                /* If it is a symlink, open fails with O_NOFOLLOW. */

+                g_set_error (error,

+                     GDM_DISPLAY_ACCESS_FILE_ERROR,

+                     GDM_DISPLAY_ACCESS_FILE_ERROR_FINDING_AUTH_ENTRY,

+                     _("GDM authorization directory %s cannot be opened."),

+                     xauth_dir_name);

+                goto out;

+        }

+

+        if (fstat (xauth_dir_fp, &statbuf) == 0) {

+                if (! S_ISDIR (statbuf.st_mode)) {

+                        g_set_error (error,

+                             GDM_DISPLAY_ACCESS_FILE_ERROR,

+                             GDM_DISPLAY_ACCESS_FILE_ERROR_FINDING_AUTH_ENTRY,

+                             _("GDM authorization directory %s is not a directory."),

+                             xauth_dir_name);

+                        goto out;

+                }

+

+                if (statbuf.st_uid != 0) {

+                        g_set_error (error,

+                             GDM_DISPLAY_ACCESS_FILE_ERROR,

+                             GDM_DISPLAY_ACCESS_FILE_ERROR_FINDING_AUTH_ENTRY,

+                             _("GDM authorization directory %s: uid is not root"),

+                             xauth_dir_name);

+                        goto out;

+                }

+

+                _get_uid_and_gid_for_user (GDM_USERNAME, &uid, &gid);

+                if (statbuf.st_gid != gid) {

+                        g_set_error (error,

+                             GDM_DISPLAY_ACCESS_FILE_ERROR,

+                             GDM_DISPLAY_ACCESS_FILE_ERROR_FINDING_AUTH_ENTRY,

+                             _("GDM authorization directory %s: gid is not the GDM user"),

+                             xauth_dir_name);

+                        goto out;

                 }

         } else {

-                /* if it does exist make sure it has correct mode 0711 */

-                g_chmod (GDM_XAUTH_DIR, 0711);

+                g_set_error (error,

+                     GDM_DISPLAY_ACCESS_FILE_ERROR,

+                     GDM_DISPLAY_ACCESS_FILE_ERROR_FINDING_AUTH_ENTRY,

+                     _("Cannot fstat() the GDM authorization directory %s"),

+                     xauth_dir_name);

+                goto out;

+        }

+

+        if (dir_exists == TRUE) {

+                /* If we did not create the directory, do some cleanup */

+

+                /* Make sure it has correct mode 0711 */

+                g_chmod (xauth_dir_name, 0711);

                 /* and clean up any stale auth subdirs */

-                clean_up_stale_auth_subdirs ();

+                clean_up_stale_auth_subdirs (xauth_dir_name);

         }

         if (!_get_uid_and_gid_for_user (username, &uid, &gid)) {

@@ -303,9 +398,8 @@ _create_xauth_file_for_user (const char  *username,

         }

-        template = g_strdup_printf (GDM_XAUTH_DIR

-                                    "/auth-for-%s-XXXXXX",

-                                    username);

+        template = g_strdup_printf ("%s/auth-for-%s-XXXXXX",

+                                    xauth_dir_name, username);

         g_debug ("GdmDisplayAccessFile: creating xauth directory %s", template);

         /* Initially create with mode 01700 then later chmod after we create database */

@@ -394,7 +488,9 @@ out:

         if (fd != -1) {

                 close (fd);

         }

-

+        if (xauth_dir_fp != -1) {

+		close (xauth_dir_fp);

+        }

         return fp;

 }

diff --git a/daemon/gdm-display-access-file.h b/daemon/gdm-display-access-file.h

index cc7de9e..091b31f 100644

--- a/daemon/gdm-display-access-file.h

+++ b/daemon/gdm-display-access-file.h

@@ -83,6 +83,7 @@ gboolean              gdm_display_access_file_remove_display          (GdmDispla

 void                  gdm_display_access_file_close                   (GdmDisplayAccessFile  *file);

 char                 *gdm_display_access_file_get_path                (GdmDisplayAccessFile  *file);

+void                  gdm_display_access_file_cleanup_xauth           (void);

 G_END_DECLS

 #endif /* __GDM_DISPLAY_ACCESS_FILE_H__ */

diff --git a/daemon/main.c b/daemon/main.c

index 50f6e94..65f34c8 100644

--- a/daemon/main.c

+++ b/daemon/main.c

@@ -47,6 +47,7 @@

 #include "gdm-settings.h"

 #include "gdm-settings-direct.h"

 #include "gdm-settings-keys.h"

+#include "gdm-display-access-file.h"

 #define GDM_DBUS_NAME "org.gnome.DisplayManager"

@@ -426,6 +427,8 @@ main (int    argc,

         gdm_settings_direct_shutdown ();

         gdm_log_shutdown ();

+        gdm_display_access_file_cleanup_xauth ();

+

         g_main_loop_unref (main_loop);

         ret = 0;

diff --git a/data/Makefile.am b/data/Makefile.am

index 81cde22..a05fc14 100644

--- a/data/Makefile.am

+++ b/data/Makefile.am

@@ -212,8 +212,10 @@ uninstall-hook:

 	$(DESTDIR)$(sysconfdir)/dconf/profile/gdm \

 	-rf \

 	$(DESTDIR)$(screenshotdir) \

-	$(DESTDIR)$(xauthdir) \

 	$(DESTDIR)$(PAM_PREFIX)/pam.d

+	if test "x$(xauthdir)" -ne "x/tmp"; then \

+		rm -rf $(DESTDIR)$(xauthdir) \

+	fi

 	if test -n "$(systemdsystemunit)"; then \

 		rm -f $(DESTDIR)$(SYSTEMD_SYSTEM_UNIT_DIR)/$(systemdsystemunit); \

@@ -292,9 +294,11 @@ endif

 	fi

 	if test '!' -d $(DESTDIR)$(xauthdir); then \

-		$(mkinstalldirs) $(DESTDIR)$(xauthdir); \

-		chmod 0711 $(DESTDIR)$(xauthdir); \

-		chown root:gdm $(DESTDIR)$(xauthdir) || : ; \

+		if test "x$(xauthdir)" -ne "x/tmp"; then \

+			$(mkinstalldirs) $(DESTDIR)$(xauthdir); \

+			chmod 0711 $(DESTDIR)$(xauthdir); \

+			chown root:gdm $(DESTDIR)$(xauthdir) || : ; \

+		fi \

 	fi

 	if test -n "$(systemdsystemunit)" -a '!' -d $(DESTDIR)$(SYSTEMD_SYSTEM_UNIT_DIR); then \

-- 

2.7.4