TOMOYO: Add interactive enforcing mode.

Since the behavior of the system is restricted by policy, we may need to update
policy when you update packages.

We need to update policy in the following cases.

    * The pathname of files has changed.
    * The dependency of files has changed.
    * The access permissions required has increased.

The ideal way to update policy is to rebuild from the scratch using learning
mode. But it is not desirable to change from enforcing mode to other mode if
the system has once entered in production state. Suppose MAC could support
per-application enforcing mode, the MAC becomes useless if an application that
is not running in enforcing mode was cracked. For example, the whole system
becomes vulnerable if only HTTP server application is running in learning mode
to rebuild policy for the application. So, in TOMOYO Linux, updating policy is
done while the system is running in enforcing mode.

This patch implements "interactive enforcing mode" which allows administrators
to judge whether to accept policy violation in enforcing mode or not.
A demo movie is available at http://www.youtube.com/watch?v=b9q1Jo25LPA .

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

1 files changed, 29 insertions, 18 deletions

diff --git a/security/tomoyo/domain.c b/security/tomoyo/domain.c
index afdf26128bf..7e242d27da5 100644
--- a/security/tomoyo/domain.c
+++ b/security/tomoyo/domain.c
@@ -678,6 +678,7 @@ struct tomoyo_domain_info *tomoyo_find_or_assign_new_domain(const char *
  */
 int tomoyo_find_next_domain(struct linux_binprm *bprm)
 {
+	struct tomoyo_request_info r;
 	/*
 	 * This function assumes that the size of buffer returned by
 	 * tomoyo_realpath() = TOMOYO_MAX_PATHNAME_LEN.
@@ -693,11 +694,12 @@ int tomoyo_find_next_domain(struct linux_binprm *bprm)
 	const u8 mode = tomoyo_check_flags(old_domain, TOMOYO_MAC_FOR_FILE);
 	const bool is_enforce = (mode == TOMOYO_CONFIG_ENFORCING);
 	int retval = -ENOMEM;
-	struct tomoyo_path_info r; /* real name */
-	struct tomoyo_path_info s; /* symlink name */
-	struct tomoyo_path_info l; /* last name */
+	struct tomoyo_path_info rn; /* real name */
+	struct tomoyo_path_info sn; /* symlink name */
+	struct tomoyo_path_info ln; /* last name */
 	static bool initialized;
 
+	tomoyo_init_request_info(&r, NULL);
 	if (!tmp)
 		goto out;
 
@@ -713,6 +715,7 @@ int tomoyo_find_next_domain(struct linux_binprm *bprm)
 		initialized = true;
 	}
 
+ retry:
 	/* Get tomoyo_realpath of program. */
 	retval = -ENOENT;
 	/* I hope tomoyo_realpath() won't fail with -ENOMEM. */
@@ -724,37 +727,39 @@ int tomoyo_find_next_domain(struct linux_binprm *bprm)
 	if (!symlink_program_name)
 		goto out;
 
-	r.name = real_program_name;
-	tomoyo_fill_path_info(&r);
-	s.name = symlink_program_name;
-	tomoyo_fill_path_info(&s);
-	l.name = tomoyo_get_last_name(old_domain);
-	tomoyo_fill_path_info(&l);
+	rn.name = real_program_name;
+	tomoyo_fill_path_info(&rn);
+	sn.name = symlink_program_name;
+	tomoyo_fill_path_info(&sn);
+	ln.name = tomoyo_get_last_name(old_domain);
+	tomoyo_fill_path_info(&ln);
 
 	/* Check 'alias' directive. */
-	if (tomoyo_pathcmp(&r, &s)) {
+	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_alias_list, list) {
 			if (ptr->is_deleted ||
-			    tomoyo_pathcmp(&r, ptr->original_name) ||
-			    tomoyo_pathcmp(&s, ptr->aliased_name))
+			    tomoyo_pathcmp(&rn, ptr->original_name) ||
+			    tomoyo_pathcmp(&sn, ptr->aliased_name))
 				continue;
 			memset(real_program_name, 0, TOMOYO_MAX_PATHNAME_LEN);
 			strncpy(real_program_name, ptr->aliased_name->name,
 				TOMOYO_MAX_PATHNAME_LEN - 1);
-			tomoyo_fill_path_info(&r);
+			tomoyo_fill_path_info(&rn);
 			break;
 		}
 	}
 
 	/* Check execute permission. */
-	retval = tomoyo_check_exec_perm(old_domain, &r);
+	retval = tomoyo_check_exec_perm(old_domain, &rn);
+	if (retval == TOMOYO_RETRY_REQUEST)
+		goto retry;
 	if (retval < 0)
 		goto out;
 
 	new_domain_name = tmp->buffer;
-	if (tomoyo_is_domain_initializer(old_domain->domainname, &r, &l)) {
+	if (tomoyo_is_domain_initializer(old_domain->domainname, &rn, &ln)) {
 		/* Transit to the child of tomoyo_kernel_domain domain. */
 		snprintf(new_domain_name, TOMOYO_MAX_PATHNAME_LEN + 1,
 			 TOMOYO_ROOT_NAME " " "%s", real_program_name);
@@ -766,7 +771,7 @@ int tomoyo_find_next_domain(struct linux_binprm *bprm)
 		 * initializers because they might start before /sbin/init.
 		 */
 		domain = old_domain;
-	} else if (tomoyo_is_domain_keeper(old_domain->domainname, &r, &l)) {
+	} else if (tomoyo_is_domain_keeper(old_domain->domainname, &rn, &ln)) {
 		/* Keep current domain. */
 		domain = old_domain;
 	} else {
@@ -779,8 +784,14 @@ int tomoyo_find_next_domain(struct linux_binprm *bprm)
 	domain = tomoyo_find_domain(new_domain_name);
 	if (domain)
 		goto done;
-	if (is_enforce)
-		goto done;
+	if (is_enforce) {
+		int error = tomoyo_supervisor(&r, "# wants to create domain\n"
+					      "%s\n", new_domain_name);
+		if (error == TOMOYO_RETRY_REQUEST)
+			goto retry;
+		if (error < 0)
+			goto done;
+	}
 	domain = tomoyo_find_or_assign_new_domain(new_domain_name,
 						  old_domain->profile);
  done: