TOMOYO: Remove alias keyword.

Some programs behave differently depending on argv[0] passed to execve().
TOMOYO has "alias" keyword in order to allow administrators to define different
domains if requested pathname passed to execve() is a symlink. But "alias"
keyword is incomplete because this keyword assumes that requested pathname and
argv[0] are identical. Thus, remove "alias" keyword (by this patch) and add
syntax for checking argv[0] (by future patches).

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

security/tomoyo/common.c

@@ -1177,8 +1177,6 @@ static int tomoyo_write_exception_policy(struct tomoyo_io_buffer *head)
 							      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))
 		return tomoyo_write_globally_readable_policy(data, is_delete);
 	if (tomoyo_str_starts(&data, TOMOYO_KEYWORD_FILE_PATTERN))
@@ -1334,16 +1332,6 @@ static bool tomoyo_read_policy(struct tomoyo_io_buffer *head, const int idx)
 				w[1] = ptr->filename->name;
 			}
 			break;
-		case TOMOYO_ID_ALIAS:
-			{
-				struct tomoyo_alias_entry *ptr =
-					container_of(acl, typeof(*ptr), head);
-				w[0] = TOMOYO_KEYWORD_ALIAS;
-				w[1] = ptr->original_name->name;
-				w[2] = " ";
-				w[3] = ptr->aliased_name->name;
-			}
-			break;
 		case TOMOYO_ID_AGGREGATOR:
 			{
 				struct tomoyo_aggregator_entry *ptr =

security/tomoyo/common.h

@@ -53,7 +53,6 @@ enum tomoyo_policy_id {
 	TOMOYO_ID_DOMAIN_INITIALIZER,
 	TOMOYO_ID_DOMAIN_KEEPER,
 	TOMOYO_ID_AGGREGATOR,
-	TOMOYO_ID_ALIAS,
 	TOMOYO_ID_GLOBALLY_READABLE,
 	TOMOYO_ID_PATTERN,
 	TOMOYO_ID_NO_REWRITE,
@@ -72,7 +71,6 @@ enum tomoyo_group_id {
 
 /* 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 "
 #define TOMOYO_KEYWORD_DELETE                    "delete "
@@ -682,20 +680,6 @@ struct tomoyo_aggregator_entry {
 	const struct tomoyo_path_info *aggregated_name;
 };
 
-/*
- * tomoyo_alias_entry is a structure which is used for holding "alias" entries.
- * It has following fields.
- *
- *  (1) "head" is "struct tomoyo_acl_head".
- *  (2) "original_name" which is a dereferenced pathname.
- *  (3) "aliased_name" which is a symlink's pathname.
- */
-struct tomoyo_alias_entry {
-	struct tomoyo_acl_head head;
-	const struct tomoyo_path_info *original_name;
-	const struct tomoyo_path_info *aliased_name;
-};
-
 /*
  * tomoyo_policy_manager_entry is a structure which is used for holding list of
  * domainnames or programs which are permitted to modify configuration via
@@ -809,8 +793,6 @@ 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);
 /*
  * Create "initialize_domain" and "no_initialize_domain" entry
  * in exception policy.
@@ -868,16 +850,14 @@ void tomoyo_put_number_union(struct tomoyo_number_union *ptr);
 char *tomoyo_encode(const char *str);
 
 /*
- * Returns realpath(3) of the given pathname but ignores chroot'ed root.
- * These functions use kzalloc(), so the caller must call kfree()
- * if these functions didn't return NULL.
+ * Returns realpath(3) of the given pathname except that
+ * ignores chroot'ed root and does not follow the final symlink.
  */
-char *tomoyo_realpath(const char *pathname);
+char *tomoyo_realpath_nofollow(const char *pathname);
 /*
- * Same with tomoyo_realpath() except that it doesn't follow the final symlink.
+ * Returns realpath(3) of the given pathname except that
+ * ignores chroot'ed root and the pathname is already solved.
  */
-char *tomoyo_realpath_nofollow(const char *pathname);
-/* Same with tomoyo_realpath() except that the pathname is already solved. */
 char *tomoyo_realpath_from_path(struct path *path);
 /* Get patterned pathname. */
 const char *tomoyo_file_pattern(const struct tomoyo_path_info *filename);

security/tomoyo/domain.c

@@ -467,72 +467,6 @@ int tomoyo_write_aggregator_policy(char *data, const bool is_delete)
 	return tomoyo_update_aggregator_entry(data, cp, is_delete);
 }
 
-static bool tomoyo_same_alias_entry(const struct tomoyo_acl_head *a,
-				    const struct tomoyo_acl_head *b)
-{
-	const struct tomoyo_alias_entry *p1 = container_of(a, typeof(*p1),
-							   head);
-	const struct tomoyo_alias_entry *p2 = container_of(b, typeof(*p2),
-							   head);
-	return p1->original_name == p2->original_name &&
-		p1->aliased_name == p2->aliased_name;
-}
-
-/**
- * tomoyo_update_alias_entry - Update "struct tomoyo_alias_entry" list.
- *
- * @original_name: The original program's real name.
- * @aliased_name:  The symbolic program's symbolic link's name.
- * @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_alias_entry(const char *original_name,
-				     const char *aliased_name,
-				     const bool is_delete)
-{
-	struct tomoyo_alias_entry e = { };
-	int error = is_delete ? -ENOENT : -ENOMEM;
-
-	if (!tomoyo_correct_path(original_name) ||
-	    !tomoyo_correct_path(aliased_name))
-		return -EINVAL;
-	e.original_name = tomoyo_get_name(original_name);
-	e.aliased_name = tomoyo_get_name(aliased_name);
-	if (!e.original_name || !e.aliased_name ||
-	    e.original_name->is_patterned || e.aliased_name->is_patterned)
-		goto out; /* No patterns allowed. */
-	error = tomoyo_update_policy(&e.head, sizeof(e), is_delete,
-				     &tomoyo_policy_list[TOMOYO_ID_ALIAS],
-				     tomoyo_same_alias_entry);
- out:
-	tomoyo_put_name(e.original_name);
-	tomoyo_put_name(e.aliased_name);
-	return error;
-}
-
-/**
- * tomoyo_write_alias_policy - Write "struct tomoyo_alias_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_alias_policy(char *data, const bool is_delete)
-{
-	char *cp = strchr(data, ' ');
-
-	if (!cp)
-		return -EINVAL;
-	*cp++ = '\0';
-	return tomoyo_update_alias_entry(data, cp, is_delete);
-}
-
 /**
  * tomoyo_find_or_assign_new_domain - Create a domain.
  *
@@ -606,7 +540,6 @@ int tomoyo_find_next_domain(struct linux_binprm *bprm)
 	int retval = -ENOMEM;
 	bool need_kfree = false;
 	struct tomoyo_path_info rn = { }; /* real name */
-	struct tomoyo_path_info sn = { }; /* symlink name */
 	struct tomoyo_path_info ln; /* last name */
 
 	ln.name = tomoyo_get_last_name(old_domain);
@@ -621,39 +554,14 @@ int tomoyo_find_next_domain(struct linux_binprm *bprm)
 		kfree(rn.name);
 		need_kfree = false;
 	}
-	/* Get tomoyo_realpath of program. */
+	/* Get symlink's pathname of program. */
 	retval = -ENOENT;
-	rn.name = tomoyo_realpath(original_name);
+	rn.name = tomoyo_realpath_nofollow(original_name);
 	if (!rn.name)
 		goto out;
 	tomoyo_fill_path_info(&rn);
 	need_kfree = true;
 
-	/* Get tomoyo_realpath of symbolic link. */
-	sn.name = tomoyo_realpath_nofollow(original_name);
-	if (!sn.name)
-		goto out;
-	tomoyo_fill_path_info(&sn);
-
-	/* Check 'alias' directive. */
-	if (tomoyo_pathcmp(&rn, &sn)) {
-		struct tomoyo_alias_entry *ptr;
-		/* Is this program allowed to be called via symbolic links? */
-		list_for_each_entry_rcu(ptr,
-					&tomoyo_policy_list[TOMOYO_ID_ALIAS],
-					head.list) {
-			if (ptr->head.is_deleted ||
-			    tomoyo_pathcmp(&rn, ptr->original_name) ||
-			    tomoyo_pathcmp(&sn, ptr->aliased_name))
-				continue;
-			kfree(rn.name);
-			need_kfree = false;
-			/* This is OK because it is read only. */
-			rn = *ptr->aliased_name;
-			break;
-		}
-	}
-
 	/* Check 'aggregator' directive. */
 	{
 		struct tomoyo_aggregator_entry *ptr;
@@ -663,8 +571,7 @@ int tomoyo_find_next_domain(struct linux_binprm *bprm)
 			    !tomoyo_path_matches_pattern(&rn,
 							 ptr->original_name))
 				continue;
-			if (need_kfree)
-				kfree(rn.name);
+			kfree(rn.name);
 			need_kfree = false;
 			/* This is OK because it is read only. */
 			rn = *ptr->aggregated_name;
@@ -729,7 +636,6 @@ int tomoyo_find_next_domain(struct linux_binprm *bprm)
 	bprm->cred->security = domain;
 	if (need_kfree)
 		kfree(rn.name);
-	kfree(sn.name);
 	kfree(tmp);
 	return retval;
 }

security/tomoyo/gc.c

@@ -77,14 +77,6 @@ static void tomoyo_del_aggregator(struct list_head *element)
 	tomoyo_put_name(ptr->aggregated_name);
 }
 
-static void tomoyo_del_alias(struct list_head *element)
-{
-	struct tomoyo_alias_entry *ptr =
-		container_of(element, typeof(*ptr), head.list);
-	tomoyo_put_name(ptr->original_name);
-	tomoyo_put_name(ptr->aliased_name);
-}
-
 static void tomoyo_del_manager(struct list_head *element)
 {
 	struct tomoyo_policy_manager_entry *ptr =
@@ -309,9 +301,6 @@ static void tomoyo_kfree_entry(void)
 		case TOMOYO_ID_AGGREGATOR:
 			tomoyo_del_aggregator(element);
 			break;
-		case TOMOYO_ID_ALIAS:
-			tomoyo_del_alias(element);
-			break;
 		case TOMOYO_ID_GLOBALLY_READABLE:
 			tomoyo_del_allow_read(element);
 			break;

security/tomoyo/realpath.c

@@ -161,25 +161,6 @@ char *tomoyo_realpath_from_path(struct path *path)
 	return name;
 }
 
-/**
- * tomoyo_realpath - Get realpath of a pathname.
- *
- * @pathname: The pathname to solve.
- *
- * Returns the realpath of @pathname on success, NULL otherwise.
- */
-char *tomoyo_realpath(const char *pathname)
-{
-	struct path path;
-
-	if (pathname && kern_path(pathname, LOOKUP_FOLLOW, &path) == 0) {
-		char *buf = tomoyo_realpath_from_path(&path);
-		path_put(&path);
-		return buf;
-	}
-	return NULL;
-}
-
 /**
  * tomoyo_realpath_nofollow - Get realpath of a pathname.
  *