Re: [kernel-hardening] [RFC] [PATCH 2/5] task_unshare LSM hook

From: Jann Horn <jann@thejh.net>
To: kernel-hardening@lists.openwall.com
Cc: linux-security-module@vger.kernel.org, keescook@chromium.org,
	spender@grsecurity.net, jmorris@namei.org,
	casey.schaufler@intel.com, michael.leibowitz@intel.com,
	william.c.roberts@intel.com,
	Elena Reshetova <elena.reshetova@intel.com>
Subject: Re: [kernel-hardening] [RFC] [PATCH 2/5] task_unshare LSM hook
Date: Fri, 29 Jul 2016 19:58:19 +0200	[thread overview]
Message-ID: <20160729175819.GA11621@pc.thejh.net> (raw)
In-Reply-To: <1469777680-3687-3-git-send-email-elena.reshetova@intel.com>

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On Fri, Jul 29, 2016 at 10:34:37AM +0300, Elena Reshetova wrote:
> This adds a new security_task_unshare() LSM hook.
> It can be used by LSMs concerned about unshare
> system call.
> 
> Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
> ---
[...]
> @@ -2052,6 +2052,11 @@ SYSCALL_DEFINE1(unshare, unsigned long, unshare_flags)
>  	if (err)
>  		goto bad_unshare_cleanup_cred;
>  
> +	err = security_task_unshare(unshare_flags, new_fs, new_fd,
> +			new_cred, new_nsproxy);
> +	if (err)
> +		goto bad_unshare_cleanup_cred;
> +
>  	if (new_fs || new_fd || do_sysvsem || new_cred || new_nsproxy) {
>  		if (do_sysvsem) {
>  			/*

Why would you have an LSM hook just for the unshare() syscall given
that clone() exposes nearly the same functionality?

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