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>

1 files changed, 147 insertions, 0 deletions

diff --git a/security/tomoyo/domain.c b/security/tomoyo/domain.c
index 50f6e7972174..a07ca6dc1a08 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)