TOMOYO: Allow domain transition without execve().

[pandora-kernel.git] / security / tomoyo / securityfs_if.c

diff --git a/security/tomoyo/securityfs_if.c b/security/tomoyo/securityfs_if.c
index a49c3bf..d08296a 100644 (file)
--- a/security/tomoyo/securityfs_if.c
+++ b/security/tomoyo/securityfs_if.c
@@ -7,6 +7,124 @@
 #include <linux/security.h>
 #include "common.h"
 
+/**
+ * tomoyo_check_task_acl - Check permission for task operation.
+ *
+ * @r:   Pointer to "struct tomoyo_request_info".
+ * @ptr: Pointer to "struct tomoyo_acl_info".
+ *
+ * Returns true if granted, false otherwise.
+ */
+static bool tomoyo_check_task_acl(struct tomoyo_request_info *r,
+                                 const struct tomoyo_acl_info *ptr)
+{
+       const struct tomoyo_task_acl *acl = container_of(ptr, typeof(*acl),
+                                                        head);
+       return !tomoyo_pathcmp(r->param.task.domainname, acl->domainname);
+}
+
+/**
+ * tomoyo_write_self - write() for /sys/kernel/security/tomoyo/self_domain interface.
+ *
+ * @file:  Pointer to "struct file".
+ * @buf:   Domainname to transit to.
+ * @count: Size of @buf.
+ * @ppos:  Unused.
+ *
+ * Returns @count on success, negative value otherwise.
+ *
+ * If domain transition was permitted but the domain transition failed, this
+ * function returns error rather than terminating current thread with SIGKILL.
+ */
+static ssize_t tomoyo_write_self(struct file *file, const char __user *buf,
+                             size_t count, loff_t *ppos)
+{
+       char *data;
+       int error;
+       if (!count || count >= TOMOYO_EXEC_TMPSIZE - 10)
+               return -ENOMEM;
+       data = kzalloc(count + 1, GFP_NOFS);
+       if (!data)
+               return -ENOMEM;
+       if (copy_from_user(data, buf, count)) {
+               error = -EFAULT;
+               goto out;
+       }
+       tomoyo_normalize_line(data);
+       if (tomoyo_correct_domain(data)) {
+               const int idx = tomoyo_read_lock();
+               struct tomoyo_path_info name;
+               struct tomoyo_request_info r;
+               name.name = data;
+               tomoyo_fill_path_info(&name);
+               /* Check "task manual_domain_transition" permission. */
+               tomoyo_init_request_info(&r, NULL, TOMOYO_MAC_FILE_EXECUTE);
+               r.param_type = TOMOYO_TYPE_MANUAL_TASK_ACL;
+               r.param.task.domainname = &name;
+               tomoyo_check_acl(&r, tomoyo_check_task_acl);
+               if (!r.granted)
+                       error = -EPERM;
+               else {
+                       struct tomoyo_domain_info *new_domain =
+                               tomoyo_assign_domain(data, true);
+                       if (!new_domain) {
+                               error = -ENOENT;
+                       } else {
+                               struct cred *cred = prepare_creds();
+                               if (!cred) {
+                                       error = -ENOMEM;
+                               } else {
+                                       struct tomoyo_domain_info *old_domain =
+                                               cred->security;
+                                       cred->security = new_domain;
+                                       atomic_inc(&new_domain->users);
+                                       atomic_dec(&old_domain->users);
+                                       commit_creds(cred);
+                                       error = 0;
+                               }
+                       }
+               }
+               tomoyo_read_unlock(idx);
+       } else
+               error = -EINVAL;
+out:
+       kfree(data);
+       return error ? error : count;
+}
+
+/**
+ * tomoyo_read_self - read() for /sys/kernel/security/tomoyo/self_domain interface.
+ *
+ * @file:  Pointer to "struct file".
+ * @buf:   Domainname which current thread belongs to.
+ * @count: Size of @buf.
+ * @ppos:  Bytes read by now.
+ *
+ * Returns read size on success, negative value otherwise.
+ */
+static ssize_t tomoyo_read_self(struct file *file, char __user *buf,
+                               size_t count, loff_t *ppos)
+{
+       const char *domain = tomoyo_domain()->domainname->name;
+       loff_t len = strlen(domain);
+       loff_t pos = *ppos;
+       if (pos >= len || !count)
+               return 0;
+       len -= pos;
+       if (count < len)
+               len = count;
+       if (copy_to_user(buf, domain + pos, len))
+               return -EFAULT;
+       *ppos += len;
+       return len;
+}
+
+/* Operations for /sys/kernel/security/tomoyo/self_domain interface. */
+static const struct file_operations tomoyo_self_operations = {
+       .write = tomoyo_write_self,
+       .read  = tomoyo_read_self,
+};
+
 /**
  * tomoyo_open - open() for /sys/kernel/security/tomoyo/ interface.
  *
@@ -135,8 +253,6 @@ static int __init tomoyo_initerface_init(void)
                            TOMOYO_EXCEPTIONPOLICY);
        tomoyo_create_entry("audit",            0400, tomoyo_dir,
                            TOMOYO_AUDIT);
-       tomoyo_create_entry("self_domain",      0400, tomoyo_dir,
-                           TOMOYO_SELFDOMAIN);
        tomoyo_create_entry(".process_status",  0600, tomoyo_dir,
                            TOMOYO_PROCESS_STATUS);
        tomoyo_create_entry("stat",             0644, tomoyo_dir,
@@ -147,6 +263,8 @@ static int __init tomoyo_initerface_init(void)
                            TOMOYO_MANAGER);
        tomoyo_create_entry("version",          0400, tomoyo_dir,
                            TOMOYO_VERSION);
+       securityfs_create_file("self_domain", 0666, tomoyo_dir, NULL,
+                              &tomoyo_self_operations);
        return 0;
 }