Re: [RFC][PATCH 3/8] init security for init task

[Stephen Smalley]

On Thu, 2006-08-17 at 12:53 -0700, Kylene Jo Hall wrote:
> Added a LSM hook to initialize the security pointer of the init task.
> 
> Signed-off-by: Mimi Zohar <zohar@xxxxxxxxxx> 
> Signed-off-by: Kylene Hall <kjhall@xxxxxxxxxx>
> ---
>  include/linux/security.h |   17 +++++++++++++++++
>  init/main.c              |    1 +
>  security/dummy.c         |    6 ++++++
>  3 files changed, 24 insertions(+)
> 
> --- linux-2.6.18-rc3/include/linux/security.h	2006-07-30 01:15:36.000000000 -0500
> +++ linux-2.6.18-rc3-working/include/linux/security.h	2006-08-08 13:05:48.000000000 -0500
> @@ -516,6 +516,12 @@ struct swap_info_struct;
>   * @task_free_security:
>   *	@p contains the task_struct for process.
>   *	Deallocate and clear the p->security field.
> + * @task_init_alloc_security:
> + *	@p contains the task_struct for init process.
> + *	Allocate and attach a security structure to the p->security field for
> + *	the init task. The security field is initialized to NULL when the task
> + *	structure is allocated.
> + *	Return 0 if operation was successful.
>   * @task_setuid:
>   *	Check permission before setting one or more of the user identity
>   *	attributes of the current process.  The @flags parameter indicates
> @@ -1220,6 +1226,7 @@ struct security_operations {
>  	int (*task_create) (unsigned long clone_flags);
>  	int (*task_alloc_security) (struct task_struct * p);
>  	void (*task_free_security) (struct task_struct * p);
> +	int (*task_init_alloc_security) (struct task_struct * p);
>  	int (*task_setuid) (uid_t id0, uid_t id1, uid_t id2, int flags);
>  	int (*task_post_setuid) (uid_t old_ruid /* or fsuid */ ,
>  				 uid_t old_euid, uid_t old_suid, int flags);
> @@ -1816,6 +1823,11 @@ static inline void security_task_free (s
>  	security_ops->task_free_security (p);
>  }
>  
> +static inline int security_task_init_alloc (struct task_struct *p)
> +{
> +	return security_ops->task_init_alloc_security (p);
> +}
> +
>  static inline int security_task_setuid (uid_t id0, uid_t id1, uid_t id2,
>  					int flags)
>  {
> @@ -2479,6 +2491,11 @@ static inline int security_task_alloc (s
>  static inline void security_task_free (struct task_struct *p)
>  { }
>  
> +static inline int security_task_init_alloc (struct task_struct *p)
> +{
> +	return 0;
> +}
> +
>  static inline int security_task_setuid (uid_t id0, uid_t id1, uid_t id2,
>  					int flags)
>  {
> --- linux-2.6.18-rc3/security/dummy.c	2006-07-30 01:15:36.000000000 -0500
> +++ linux-2.6.18-rc3-working/security/dummy.c	2006-08-04 13:28:34.000000000 -0500
> @@ -474,6 +474,11 @@ static void dummy_task_free_security (st
>  	return;
>  }
>  
> +static int dummy_task_init_alloc_security (struct task_struct *p)
> +{
> +	return 0;
> +}
> +
>  static int dummy_task_setuid (uid_t id0, uid_t id1, uid_t id2, int flags)
>  {
>  	return 0;
> @@ -982,6 +987,7 @@ void security_fixup_ops (struct security
>  	set_to_dummy_if_null(ops, task_create);
>  	set_to_dummy_if_null(ops, task_alloc_security);
>  	set_to_dummy_if_null(ops, task_free_security);
> +	set_to_dummy_if_null(ops, task_init_alloc_security);
>  	set_to_dummy_if_null(ops, task_setuid);
>  	set_to_dummy_if_null(ops, task_post_setuid);
>  	set_to_dummy_if_null(ops, task_setgid);
> --- linux-2.6.18-rc3/init/main.c	2006-07-30 01:15:36.000000000 -0500
> +++ linux-2.6.18-rc3-working/init/main.c	2006-08-04 13:26:12.000000000 -0500
> @@ -698,6 +698,7 @@ static int init(void * unused)
>  	 * can be found.
>  	 */
>  	child_reaper = current;
> +	security_task_init_alloc(current);
>  
>  	smp_prepare_cpus(max_cpus);
>  

Why isn't this handled by upon your module's security initcall?

-- 
Stephen Smalley
National Security Agency

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