TOMOYO: Allow specifying domain transition preference.

I got an opinion that it is difficult to use exception policy's domain
transition control directives because they need to match the pathname specified
to "file execute" directives. For example, if "file execute /bin/\*\-ls\-cat"
is given, corresponding domain transition control directive needs to be like
"no_keep_domain /bin/\*\-ls\-cat from any".

If we can specify like below, it will become more convenient.

  file execute /bin/ls keep exec.realpath="/bin/ls" exec.argv[0]="ls"
  file execute /bin/cat keep exec.realpath="/bin/cat" exec.argv[0]="cat"
  file execute /bin/\*\-ls\-cat child
  file execute /usr/sbin/httpd <apache> exec.realpath="/usr/sbin/httpd" exec.argv[0]="/usr/sbin/httpd"

In above examples, "keep" works as if keep_domain is specified, "child" works
as if "no_reset_domain" and "no_initialize_domain" and "no_keep_domain" are
specified, "<apache>" causes domain transition to <apache> domain upon
successful execve() operation.

Moreover, we can also allow transition to different domains based on conditions
like below example.

  <kernel> /usr/sbin/sshd
  file execute /bin/bash <kernel> /usr/sbin/sshd //batch-session exec.argc=2 exec.argv[1]="-c"
  file execute /bin/bash <kernel> /usr/sbin/sshd //root-session task.uid=0
  file execute /bin/bash <kernel> /usr/sbin/sshd //nonroot-session task.uid!=0

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

1 files changed, 4 insertions, 0 deletions

diff --git a/security/tomoyo/common.h b/security/tomoyo/common.h
index 471c9f9afc18..a2bc33fc60b6 100644
--- a/security/tomoyo/common.h
+++ b/security/tomoyo/common.h
@@ -615,6 +615,7 @@ struct tomoyo_execve {
         struct tomoyo_request_info r;
         struct tomoyo_obj_info obj;
         struct linux_binprm *bprm;
+        const struct tomoyo_path_info *transition;
         /* For dumping argv[] and envp[]. */
         struct tomoyo_page_dump dump;
         /* For temporary use. */
@@ -650,6 +651,7 @@ struct tomoyo_condition {
         u16 argc; /* Number of "struct tomoyo_argv". */
         u16 envc; /* Number of "struct tomoyo_envp". */
         u8 grant_log; /* One of values in "enum tomoyo_grant_log". */
+        const struct tomoyo_path_info *transit; /* Maybe NULL. */
         /*
          * struct tomoyo_condition_element condition[condc];
          * struct tomoyo_number_union values[numbers_count];
@@ -956,6 +958,8 @@ int tomoyo_check_open_permission(struct tomoyo_domain_info *domain,
                                  struct path *path, const int flag);
 int tomoyo_close_control(struct tomoyo_io_buffer *head);
 int tomoyo_env_perm(struct tomoyo_request_info *r, const char *env);
+int tomoyo_execute_permission(struct tomoyo_request_info *r,
+                              const struct tomoyo_path_info *filename);
 int tomoyo_find_next_domain(struct linux_binprm *bprm);
 int tomoyo_get_mode(const struct tomoyo_policy_namespace *ns, const u8 profile,
                     const u8 index);