TOMOYO: Add pathname aggregation support.

This patch allows users to aggregate programs which provide similar
functionality (e.g. /usr/bin/vi and /usr/bin/emacs ).

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: James Morris <jmorris@namei.org>

4 files changed, 204 insertions, 0 deletions

diff --git a/security/tomoyo/common.c b/security/tomoyo/common.c
index 3f94011c641..bdf1ed7ca45 100644
--- a/security/tomoyo/common.c
+++ b/security/tomoyo/common.c
@@ -1141,6 +1141,8 @@ static int tomoyo_write_exception_policy(struct tomoyo_io_buffer *head)
 	if (tomoyo_str_starts(&data, TOMOYO_KEYWORD_NO_INITIALIZE_DOMAIN))
 		return tomoyo_write_domain_initializer_policy(data, true,
 							      is_delete);
+	if (tomoyo_str_starts(&data, TOMOYO_KEYWORD_AGGREGATOR))
+		return tomoyo_write_aggregator_policy(data, is_delete);
 	if (tomoyo_str_starts(&data, TOMOYO_KEYWORD_ALIAS))
 		return tomoyo_write_alias_policy(data, is_delete);
 	if (tomoyo_str_starts(&data, TOMOYO_KEYWORD_ALLOW_READ))
@@ -1196,6 +1198,8 @@ static int tomoyo_read_exception_policy(struct tomoyo_io_buffer *head)
 			head->read_var2 = NULL;
 			head->read_step = 6;
 		case 6:
+			if (!tomoyo_read_aggregator_policy(head))
+				break;
 			head->read_var2 = NULL;
 			head->read_step = 7;
 		case 7:
diff --git a/security/tomoyo/common.h b/security/tomoyo/common.h
index d1b8d791bff..54db39aa339 100644
--- a/security/tomoyo/common.h
+++ b/security/tomoyo/common.h
@@ -46,6 +46,7 @@ enum tomoyo_mode_index {
 };
 
 /* Keywords for ACLs. */
+#define TOMOYO_KEYWORD_AGGREGATOR                "aggregator "
 #define TOMOYO_KEYWORD_ALIAS                     "alias "
 #define TOMOYO_KEYWORD_ALLOW_MOUNT               "allow_mount "
 #define TOMOYO_KEYWORD_ALLOW_READ                "allow_read "
@@ -593,6 +594,24 @@ struct tomoyo_domain_keeper_entry {
 };
 
 /*
+ * tomoyo_aggregator_entry is a structure which is used for holding
+ * "aggregator" entries.
+ * It has following fields.
+ *
+ *  (1) "list" which is linked to tomoyo_aggregator_list .
+ *  (2) "original_name" which is originally requested name.
+ *  (3) "aggregated_name" which is name to rewrite.
+ *  (4) "is_deleted" is a bool which is true if marked as deleted, false
+ *      otherwise.
+ */
+struct tomoyo_aggregator_entry {
+	struct list_head list;
+	const struct tomoyo_path_info *original_name;
+	const struct tomoyo_path_info *aggregated_name;
+	bool is_deleted;
+};
+
+/*
  * tomoyo_alias_entry is a structure which is used for holding "alias" entries.
  * It has following fields.
  *
@@ -693,6 +712,8 @@ bool tomoyo_print_number_union(struct tomoyo_io_buffer *head,
 			       const struct tomoyo_number_union *ptr);
 bool tomoyo_parse_number_union(char *data, struct tomoyo_number_union *num);
 
+/* Read "aggregator" entry in exception policy. */
+bool tomoyo_read_aggregator_policy(struct tomoyo_io_buffer *head);
 /* Read "alias" entry in exception policy. */
 bool tomoyo_read_alias_policy(struct tomoyo_io_buffer *head);
 /*
@@ -730,6 +751,8 @@ int tomoyo_init_request_info(struct tomoyo_request_info *r,
 /* Check permission for mount operation. */
 int tomoyo_mount_permission(char *dev_name, struct path *path, char *type,
 			    unsigned long flags, void *data_page);
+/* Create "aggregator" entry in exception policy. */
+int tomoyo_write_aggregator_policy(char *data, const bool is_delete);
 /* Create "alias" entry in exception policy. */
 int tomoyo_write_alias_policy(char *data, const bool is_delete);
 /*
@@ -857,6 +880,7 @@ extern struct list_head tomoyo_path_group_list;
 extern struct list_head tomoyo_number_group_list;
 extern struct list_head tomoyo_domain_initializer_list;
 extern struct list_head tomoyo_domain_keeper_list;
+extern struct list_head tomoyo_aggregator_list;
 extern struct list_head tomoyo_alias_list;
 extern struct list_head tomoyo_globally_readable_list;
 extern struct list_head tomoyo_pattern_list;
@@ -1036,6 +1060,14 @@ static inline bool tomoyo_is_same_domain_keeper_entry
 		&& p1->program == p2->program;
 }
 
+static inline bool tomoyo_is_same_aggregator_entry
+(const struct tomoyo_aggregator_entry *p1,
+ const struct tomoyo_aggregator_entry *p2)
+{
+	return p1->original_name == p2->original_name &&
+		p1->aggregated_name == p2->aggregated_name;
+}
+
 static inline bool tomoyo_is_same_alias_entry
 (const struct tomoyo_alias_entry *p1, const struct tomoyo_alias_entry *p2)
 {
diff --git a/security/tomoyo/domain.c b/security/tomoyo/domain.c
index 50f6e797217..a07ca6dc1a0 100644
--- a/security/tomoyo/domain.c
+++ b/security/tomoyo/domain.c
@@ -483,6 +483,136 @@ static bool tomoyo_is_domain_keeper(const struct tomoyo_path_info *domainname,
 }
 
 /*
+ * tomoyo_aggregator_list is used for holding list of rewrite table for
+ * execve() request. Some programs provides similar functionality. This keyword
+ * allows users to aggregate such programs.
+ *
+ * Entries are added by
+ *
+ * # echo 'aggregator /usr/bin/vi /./editor' > \
+ *                            /sys/kernel/security/tomoyo/exception_policy
+ * # echo 'aggregator /usr/bin/emacs /./editor' > \
+ *                            /sys/kernel/security/tomoyo/exception_policy
+ *
+ * and are deleted by
+ *
+ * # echo 'delete aggregator /usr/bin/vi /./editor' > \
+ *                            /sys/kernel/security/tomoyo/exception_policy
+ * # echo 'delete aggregator /usr/bin/emacs /./editor' > \
+ *                            /sys/kernel/security/tomoyo/exception_policy
+ *
+ * and all entries are retrieved by
+ *
+ * # grep ^aggregator /sys/kernel/security/tomoyo/exception_policy
+ *
+ * In the example above, if /usr/bin/vi or /usr/bin/emacs are executed,
+ * permission is checked for /./editor and domainname which the current process
+ * will belong to after execve() succeeds is calculated using /./editor .
+ */
+LIST_HEAD(tomoyo_aggregator_list);
+
+/**
+ * tomoyo_update_aggregator_entry - Update "struct tomoyo_aggregator_entry" list.
+ *
+ * @original_name:   The original program's name.
+ * @aggregated_name: The program name to use.
+ * @is_delete:       True if it is a delete request.
+ *
+ * Returns 0 on success, negative value otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
+ */
+static int tomoyo_update_aggregator_entry(const char *original_name,
+					  const char *aggregated_name,
+					  const bool is_delete)
+{
+	struct tomoyo_aggregator_entry *ptr;
+	struct tomoyo_aggregator_entry e = { };
+	int error = is_delete ? -ENOENT : -ENOMEM;
+
+	if (!tomoyo_is_correct_path(original_name) ||
+	    !tomoyo_is_correct_path(aggregated_name))
+		return -EINVAL;
+	e.original_name = tomoyo_get_name(original_name);
+	e.aggregated_name = tomoyo_get_name(aggregated_name);
+	if (!e.original_name || !e.aggregated_name ||
+	    e.aggregated_name->is_patterned) /* No patterns allowed. */
+		goto out;
+	if (mutex_lock_interruptible(&tomoyo_policy_lock))
+		goto out;
+	list_for_each_entry_rcu(ptr, &tomoyo_aggregator_list, list) {
+		if (!tomoyo_is_same_aggregator_entry(ptr, &e))
+			continue;
+		ptr->is_deleted = is_delete;
+		error = 0;
+		break;
+	}
+	if (!is_delete && error) {
+		struct tomoyo_aggregator_entry *entry =
+			tomoyo_commit_ok(&e, sizeof(e));
+		if (entry) {
+			list_add_tail_rcu(&entry->list,
+					  &tomoyo_aggregator_list);
+			error = 0;
+		}
+	}
+	mutex_unlock(&tomoyo_policy_lock);
+ out:
+	tomoyo_put_name(e.original_name);
+	tomoyo_put_name(e.aggregated_name);
+	return error;
+}
+
+/**
+ * tomoyo_read_aggregator_policy - Read "struct tomoyo_aggregator_entry" list.
+ *
+ * @head: Pointer to "struct tomoyo_io_buffer".
+ *
+ * Returns true on success, false otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
+ */
+bool tomoyo_read_aggregator_policy(struct tomoyo_io_buffer *head)
+{
+	struct list_head *pos;
+	bool done = true;
+
+	list_for_each_cookie(pos, head->read_var2, &tomoyo_aggregator_list) {
+		struct tomoyo_aggregator_entry *ptr;
+
+		ptr = list_entry(pos, struct tomoyo_aggregator_entry, list);
+		if (ptr->is_deleted)
+			continue;
+		done = tomoyo_io_printf(head, TOMOYO_KEYWORD_AGGREGATOR
+					"%s %s\n", ptr->original_name->name,
+					ptr->aggregated_name->name);
+		if (!done)
+			break;
+	}
+	return done;
+}
+
+/**
+ * tomoyo_write_aggregator_policy - Write "struct tomoyo_aggregator_entry" list.
+ *
+ * @data:      String to parse.
+ * @is_delete: True if it is a delete request.
+ *
+ * Returns 0 on success, negative value otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
+ */
+int tomoyo_write_aggregator_policy(char *data, const bool is_delete)
+{
+	char *cp = strchr(data, ' ');
+
+	if (!cp)
+		return -EINVAL;
+	*cp++ = '\0';
+	return tomoyo_update_aggregator_entry(data, cp, is_delete);
+}
+
+/*
  * tomoyo_alias_list is used for holding list of symlink's pathnames which are
  * allowed to be passed to an execve() request. Normally, the domainname which
  * the current process will belong to after execve() succeeds is calculated
@@ -732,6 +862,23 @@ int tomoyo_find_next_domain(struct linux_binprm *bprm)
 		}
 	}
 
+	/* Check 'aggregator' directive. */
+	{
+		struct tomoyo_aggregator_entry *ptr;
+		list_for_each_entry_rcu(ptr, &tomoyo_aggregator_list, list) {
+			if (ptr->is_deleted ||
+			    !tomoyo_path_matches_pattern(&rn,
+							 ptr->original_name))
+				continue;
+			if (need_kfree)
+				kfree(rn.name);
+			need_kfree = false;
+			/* This is OK because it is read only. */
+			rn = *ptr->aggregated_name;
+			break;
+		}
+	}
+
 	/* Check execute permission. */
 	retval = tomoyo_check_exec_perm(old_domain, &rn);
 	if (retval == TOMOYO_RETRY_REQUEST)
diff --git a/security/tomoyo/gc.c b/security/tomoyo/gc.c
index be2d3b93553..8a31f0c628b 100644
--- a/security/tomoyo/gc.c
+++ b/security/tomoyo/gc.c
@@ -18,6 +18,7 @@ enum tomoyo_gc_id {
 	TOMOYO_ID_NUMBER_GROUP_MEMBER,
 	TOMOYO_ID_DOMAIN_INITIALIZER,
 	TOMOYO_ID_DOMAIN_KEEPER,
+	TOMOYO_ID_AGGREGATOR,
 	TOMOYO_ID_ALIAS,
 	TOMOYO_ID_GLOBALLY_READABLE,
 	TOMOYO_ID_PATTERN,
@@ -77,6 +78,12 @@ static void tomoyo_del_domain_keeper(struct tomoyo_domain_keeper_entry *ptr)
 	tomoyo_put_name(ptr->program);
 }
 
+static void tomoyo_del_aggregator(struct tomoyo_aggregator_entry *ptr)
+{
+	tomoyo_put_name(ptr->original_name);
+	tomoyo_put_name(ptr->aggregated_name);
+}
+
 static void tomoyo_del_alias(struct tomoyo_alias_entry *ptr)
 {
 	tomoyo_put_name(ptr->original_name);
@@ -264,6 +271,17 @@ static void tomoyo_collect_entry(void)
 		}
 	}
 	{
+		struct tomoyo_aggregator_entry *ptr;
+		list_for_each_entry_rcu(ptr, &tomoyo_aggregator_list, list) {
+			if (!ptr->is_deleted)
+				continue;
+			if (tomoyo_add_to_gc(TOMOYO_ID_AGGREGATOR, ptr))
+				list_del_rcu(&ptr->list);
+			else
+				break;
+		}
+	}
+	{
 		struct tomoyo_alias_entry *ptr;
 		list_for_each_entry_rcu(ptr, &tomoyo_alias_list, list) {
 			if (!ptr->is_deleted)
@@ -417,6 +435,9 @@ static void tomoyo_kfree_entry(void)
 		case TOMOYO_ID_DOMAIN_KEEPER:
 			tomoyo_del_domain_keeper(p->element);
 			break;
+		case TOMOYO_ID_AGGREGATOR:
+			tomoyo_del_aggregator(p->element);
+			break;
 		case TOMOYO_ID_ALIAS:
 			tomoyo_del_alias(p->element);
 			break;