Console user security policy

* bus/config-parser.c:
(struct PolicyType): Add POLICY_CONSOLE
(struct Element.d.policy): s/gid_or_uid/gid_uid_or_at_console
(start_busconfig_child): Sets up console element when
<policy at_console=""> is encountered in a policy file
(append_rule_from_element): Convert console elements to console
rules.

* bus/policy.c:
(bus_policy_create_client_policy): Add console rules to the client
policy based on if the client is at the console
(bus_policy_append_console_rule): New function for adding a
console rule to a policy
(bus_policy_merge): Handle console rule merging

* dbus/dbus-sysdeps.h: Added the DBUS_CONSOLE_DIR constant
where we check for console user files

* dbus/dbus-sysdeps.c:
(_dbus_file_exists): New function which checks if the given
file exists
(_dbus_user_at_console): New function which does the system
specific process of checking if the user is at the console

* dbus/dbus-userdb.c:
(_dbus_is_console_user): New function converts a UID to user name
and then calls the system specific _dbus_user_at_console to
see if the user is at the console and therefor a console user

3 files changed, 115 insertions, 20 deletions

diff --git a/bus/config-parser.c b/bus/config-parser.c
index 3b8c3ae4..dfc313e3 100644
--- a/bus/config-parser.c
+++ b/bus/config-parser.c
@@ -59,7 +59,8 @@ typedef enum
   POLICY_DEFAULT,
   POLICY_MANDATORY,
   POLICY_USER,
-  POLICY_GROUP
+  POLICY_GROUP,
+  POLICY_CONSOLE
 } PolicyType;
 
 typedef struct
@@ -79,7 +80,7 @@ typedef struct
     struct
     {
       PolicyType type;
-      unsigned long gid_or_uid;      
+      unsigned long gid_uid_or_at_console;      
     } policy;
 
     struct
@@ -775,6 +776,7 @@ start_busconfig_child (BusConfigParser   *parser,
       const char *context;
       const char *user;
       const char *group;
+      const char *at_console;
 
       if ((e = push_element (parser, ELEMENT_POLICY)) == NULL)
         {
@@ -791,16 +793,20 @@ start_busconfig_child (BusConfigParser   *parser,
                               "context", &context,
                               "user", &user,
                               "group", &group,
+                              "at_console", &at_console,
                               NULL))
         return FALSE;
 
       if (((context && user) ||
-           (context && group)) ||
-          (user && group) ||
-          !(context || user || group))
+           (context && group) ||
+           (context && at_console)) ||
+           ((user && group) ||
+           (user && at_console)) ||
+           (group && at_console) ||
+          !(context || user || group || at_console))
         {
           dbus_set_error (error, DBUS_ERROR_FAILED,
-                          "<policy> element must have exactly one of (context|user|group) attributes");
+                          "<policy> element must have exactly one of (context|user|group|at_console) attributes");
           return FALSE;
         }
 
@@ -828,7 +834,7 @@ start_busconfig_child (BusConfigParser   *parser,
           _dbus_string_init_const (&username, user);
 
           if (_dbus_get_user_id (&username,
-                                 &e->d.policy.gid_or_uid))
+                                 &e->d.policy.gid_uid_or_at_console))
             e->d.policy.type = POLICY_USER;
           else
             _dbus_warn ("Unknown username \"%s\" in message bus configuration file\n",
@@ -840,12 +846,30 @@ start_busconfig_child (BusConfigParser   *parser,
           _dbus_string_init_const (&group_name, group);
 
           if (_dbus_get_group_id (&group_name,
-                                  &e->d.policy.gid_or_uid))
+                                  &e->d.policy.gid_uid_or_at_console))
             e->d.policy.type = POLICY_GROUP;
           else
             _dbus_warn ("Unknown group \"%s\" in message bus configuration file\n",
                         group);          
         }
+      else if (at_console != NULL)
+        {
+           dbus_bool_t t;
+           t = (strcmp (at_console, "true") == 0);
+           if (t || strcmp (at_console, "false") == 0)
+             {
+               e->d.policy.gid_uid_or_at_console = t; 
+               e->d.policy.type = POLICY_CONSOLE;
+             }  
+           else
+             {
+               dbus_set_error (error, DBUS_ERROR_FAILED,
+                              "Unknown value \"%s\" for at_console in message bus configuration file",
+                              at_console);
+
+               return FALSE;
+             }
+        }
       else
         {
           _dbus_assert_not_reached ("all <policy> attributes null and we didn't set error");
@@ -936,6 +960,7 @@ append_rule_from_element (BusConfigParser   *parser,
   const char *own;
   const char *user;
   const char *group;
+
   BusPolicyRule *rule;
   
   if (!locate_attributes (parser, element_name,
@@ -1369,7 +1394,7 @@ append_rule_from_element (BusConfigParser   *parser,
               goto failed;
             }
           
-          if (!bus_policy_append_user_rule (parser->policy, pe->d.policy.gid_or_uid,
+          if (!bus_policy_append_user_rule (parser->policy, pe->d.policy.gid_uid_or_at_console,
                                             rule))
             goto nomem;
           break;
@@ -1382,12 +1407,19 @@ append_rule_from_element (BusConfigParser   *parser,
               goto failed;
             }
           
-          if (!bus_policy_append_group_rule (parser->policy, pe->d.policy.gid_or_uid,
+          if (!bus_policy_append_group_rule (parser->policy, pe->d.policy.gid_uid_or_at_console,
+                                             rule))
+            goto nomem;
+          break;
+        
+
+        case POLICY_CONSOLE:
+          if (!bus_policy_append_console_rule (parser->policy, pe->d.policy.gid_uid_or_at_console,
                                              rule))
             goto nomem;
           break;
         }
-      
+ 
       bus_policy_rule_unref (rule);
       rule = NULL;
     }
@@ -2545,7 +2577,7 @@ elements_equal (const Element *a,
     case ELEMENT_POLICY:
       if (a->d.policy.type != b->d.policy.type)
 	return FALSE;
-      if (a->d.policy.gid_or_uid != b->d.policy.gid_or_uid)
+      if (a->d.policy.gid_uid_or_at_console != b->d.policy.gid_uid_or_at_console)
 	return FALSE;
       break;
 
diff --git a/bus/policy.c b/bus/policy.c
index 3de693f7..7759dfad 100644
--- a/bus/policy.c
+++ b/bus/policy.c
@@ -125,10 +125,12 @@ struct BusPolicy
 {
   int refcount;
 
-  DBusList *default_rules;       /**< Default policy rules */
-  DBusList *mandatory_rules;     /**< Mandatory policy rules */
-  DBusHashTable *rules_by_uid;   /**< per-UID policy rules */
-  DBusHashTable *rules_by_gid;   /**< per-GID policy rules */
+  DBusList *default_rules;         /**< Default policy rules */
+  DBusList *mandatory_rules;       /**< Mandatory policy rules */
+  DBusHashTable *rules_by_uid;     /**< per-UID policy rules */
+  DBusHashTable *rules_by_gid;     /**< per-GID policy rules */
+  DBusList *at_console_true_rules; /**< console user policy rules where at_console="true"*/
+  DBusList *at_console_false_rules; /**< console user policy rules where at_console="false"*/
 };
 
 static void
@@ -209,7 +211,13 @@ bus_policy_unref (BusPolicy *policy)
 
       _dbus_list_foreach (&policy->mandatory_rules, free_rule_func, NULL);
       _dbus_list_clear (&policy->mandatory_rules);
-      
+
+      _dbus_list_foreach (&policy->at_console_true_rules, free_rule_func, NULL);
+      _dbus_list_clear (&policy->at_console_true_rules);
+
+      _dbus_list_foreach (&policy->at_console_false_rules, free_rule_func, NULL);
+      _dbus_list_clear (&policy->at_console_false_rules);
+
       if (policy->rules_by_uid)
         {
           _dbus_hash_table_unref (policy->rules_by_uid);
@@ -264,7 +272,8 @@ bus_policy_create_client_policy (BusPolicy      *policy,
                                  DBusError      *error)
 {
   BusClientPolicy *client;
-  unsigned long uid;
+  dbus_uid_t uid;
+  dbus_bool_t at_console;
 
   _dbus_assert (dbus_connection_get_is_authenticated (connection));
   _DBUS_ASSERT_ERROR_IS_CLEAR (error);
@@ -333,6 +342,23 @@ bus_policy_create_client_policy (BusPolicy      *policy,
         }
     }
 
+  /* Add console rules */
+  at_console = _dbus_is_console_user (uid, error);
+
+  if (at_console)
+    {
+      if (!add_list_to_client (&policy->at_console_true_rules, client))
+        goto nomem;
+    }
+  else if (dbus_error_is_set (error) == TRUE)
+    {
+      goto failed;
+    }
+  else if (!add_list_to_client (&policy->at_console_false_rules, client))
+    {
+      goto nomem;
+    }
+
   if (!add_list_to_client (&policy->mandatory_rules,
                            client))
     goto nomem;
@@ -367,7 +393,7 @@ list_allows_user (dbus_bool_t           def,
     {
       BusPolicyRule *rule = link->data;
       link = _dbus_list_get_next_link (list, link);
-      
+
       if (rule->type == BUS_POLICY_RULE_USER)
         {
           _dbus_verbose ("List %p user rule uid="DBUS_UID_FORMAT"\n",
@@ -471,6 +497,8 @@ bus_policy_append_mandatory_rule (BusPolicy      *policy,
   return TRUE;
 }
 
+
+
 static DBusList**
 get_list (DBusHashTable *hash,
           unsigned long  key)
@@ -535,6 +563,28 @@ bus_policy_append_group_rule (BusPolicy      *policy,
   return TRUE;
 }
 
+dbus_bool_t
+bus_policy_append_console_rule (BusPolicy      *policy,
+                                dbus_bool_t     at_console,
+                                BusPolicyRule  *rule)
+{
+  if (at_console)
+    {
+      if (!_dbus_list_append (&policy->at_console_true_rules, rule))
+        return FALSE;
+    }
+    else
+    {
+      if (!_dbus_list_append (&policy->at_console_false_rules, rule))
+        return FALSE;
+    }
+
+  bus_policy_rule_ref (rule);
+
+  return TRUE;
+
+}
+
 static dbus_bool_t
 append_copy_of_policy_list (DBusList **list,
                             DBusList **to_append)
@@ -606,6 +656,14 @@ bus_policy_merge (BusPolicy *policy,
                                    &to_absorb->mandatory_rules))
     return FALSE;
 
+  if (!append_copy_of_policy_list (&policy->at_console_true_rules,
+                                   &to_absorb->at_console_true_rules))
+    return FALSE;
+
+  if (!append_copy_of_policy_list (&policy->at_console_false_rules,
+                                   &to_absorb->at_console_false_rules))
+    return FALSE;
+
   if (!merge_id_hash (policy->rules_by_uid,
                       to_absorb->rules_by_uid))
     return FALSE;
diff --git a/bus/policy.h b/bus/policy.h
index 61e089a7..94b48e6f 100644
--- a/bus/policy.h
+++ b/bus/policy.h
@@ -26,6 +26,7 @@
 
 #include <dbus/dbus.h>
 #include <dbus/dbus-string.h>
+#include <dbus/dbus-list.h>
 #include <dbus/dbus-sysdeps.h>
 #include "bus.h"
 
@@ -96,7 +97,7 @@ struct BusPolicyRule
       /* can be DBUS_GID_UNSET meaning "any" */
       dbus_gid_t gid;
     } group;
-    
+
   } d;
 };
 
@@ -124,6 +125,10 @@ dbus_bool_t      bus_policy_append_user_rule      (BusPolicy        *policy,
 dbus_bool_t      bus_policy_append_group_rule     (BusPolicy        *policy,
                                                    dbus_gid_t        gid,
                                                    BusPolicyRule    *rule);
+dbus_bool_t      bus_policy_append_console_rule   (BusPolicy        *policy,
+                                                   dbus_bool_t        at_console,
+                                                   BusPolicyRule    *rule);
+
 dbus_bool_t      bus_policy_merge                 (BusPolicy        *policy,
                                                    BusPolicy        *to_absorb);