Re: [PATCH] bugfix: was Re: [ linus-git ] prctl(PR_SET_KEEPCAPS, ...) is broken for some configs, e.g. CONFIG_SECURITY_SELINUX

[Chris Wright <chrisw@sous-sol.org>]

* Andrew G. Morgan (morgan@kernel.org) wrote:
> --- a/security/dummy.c
> +++ b/security/dummy.c
> @@ -27,6 +27,8 @@
>  #include <linux/hugetlb.h>
>  #include <linux/ptrace.h>
>  #include <linux/file.h>
> +#include <linux/prctl.h>
> +#include <linux/securebits.h>
>  
>  static int dummy_ptrace (struct task_struct *parent, struct task_struct *child)
>  {
> @@ -607,7 +609,27 @@ static int dummy_task_kill (struct task_struct *p, struct siginfo *info,
>  static int dummy_task_prctl (int option, unsigned long arg2, unsigned long arg3,
>  			     unsigned long arg4, unsigned long arg5, long *rc_p)
>  {
> -	return 0;
> +	switch (option) {
> +	case PR_CAPBSET_READ:
> +		*rc_p = (cap_valid(arg2) ? 1 : -EINVAL);
> +		break;

Do we need this one?  It's new to 2.6.25, so I think we could not
worry about emulating it here.

> +	case PR_GET_KEEPCAPS:
> +		*rc_p = issecure(SECURE_KEEP_CAPS);
> +		break;
> +	case PR_SET_KEEPCAPS:
> +		if (arg2 > 1)
> +			*rc_p = -EINVAL;
> +		else if (arg2)
> +			current->securebits |= issecure_mask(SECURE_KEEP_CAPS);
> +		else
> +			current->securebits &=
> +				~issecure_mask(SECURE_KEEP_CAPS);
> +		break;
> +	default:
> +		return 0;
> +	}
> +
> +	return 1;
>  }
>  
>  static void dummy_task_reparent_to_init (struct task_struct *p)