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From: Ingo Molnar <mingo@kernel.org>
To: Jann Horn <jann@thejh.net>
Cc: security@kernel.org, Alexander Viro <viro@zeniv.linux.org.uk>,
	Paul Moore <paul@paul-moore.com>,
	Stephen Smalley <sds@tycho.nsa.gov>,
	Eric Paris <eparis@parisplace.org>,
	James Morris <james.l.morris@oracle.com>,
	"Serge E. Hallyn" <serge@hallyn.com>,
	Nick Kralevich <nnk@google.com>,
	Janis Danisevskis <jdanis@google.com>,
	linux-security-module@vger.kernel.org, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 2/3] mm: add LSM hook for writes to readonly memory
Date: Thu, 29 Sep 2016 08:25:10 +0200	[thread overview]
Message-ID: <20160929062510.GB21794@gmail.com> (raw)
In-Reply-To: <1475103281-7989-3-git-send-email-jann@thejh.net>


* Jann Horn <jann@thejh.net> wrote:

> +/*
> + * subject_cred must be the subjective credentials using which access is
> + * requested.
> + * object_cred must be the objective credentials of the target task at the time
> + * the mm_struct was acquired.
> + * Both of these may be NULL if FOLL_FORCE is unset or FOLL_WRITE is unset.

Hm, I have trouble parsing the first sentence.

> -	return __get_user_pages_locked(current, current->mm, start, nr_pages,
> -				       write, force, pages, vmas, NULL, false,
> -				       FOLL_TOUCH);
> +	return __get_user_pages_locked(current, current->mm, current_cred(),
> +				       current_real_cred(), start,
> +				       nr_pages, write, force, pages, vmas,
> +				       NULL, false, FOLL_TOUCH);

So the parameter passing was disgustig before, and now it became super disgusing! 

Would it improve the code if we added a friendly helper structure (or two if 
that's better) to clean up all the interactions within these various functions?

Thanks,

	Ingo

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WARNING: multiple messages have this Message-ID (diff)
From: Ingo Molnar <mingo@kernel.org>
To: Jann Horn <jann@thejh.net>
Cc: security@kernel.org, Alexander Viro <viro@zeniv.linux.org.uk>,
	Paul Moore <paul@paul-moore.com>,
	Stephen Smalley <sds@tycho.nsa.gov>,
	Eric Paris <eparis@parisplace.org>,
	James Morris <james.l.morris@oracle.com>,
	"Serge E. Hallyn" <serge@hallyn.com>,
	Nick Kralevich <nnk@google.com>,
	Janis Danisevskis <jdanis@google.com>,
	linux-security-module@vger.kernel.org, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 2/3] mm: add LSM hook for writes to readonly memory
Date: Thu, 29 Sep 2016 08:25:10 +0200	[thread overview]
Message-ID: <20160929062510.GB21794@gmail.com> (raw)
In-Reply-To: <1475103281-7989-3-git-send-email-jann@thejh.net>


* Jann Horn <jann@thejh.net> wrote:

> +/*
> + * subject_cred must be the subjective credentials using which access is
> + * requested.
> + * object_cred must be the objective credentials of the target task at the time
> + * the mm_struct was acquired.
> + * Both of these may be NULL if FOLL_FORCE is unset or FOLL_WRITE is unset.

Hm, I have trouble parsing the first sentence.

> -	return __get_user_pages_locked(current, current->mm, start, nr_pages,
> -				       write, force, pages, vmas, NULL, false,
> -				       FOLL_TOUCH);
> +	return __get_user_pages_locked(current, current->mm, current_cred(),
> +				       current_real_cred(), start,
> +				       nr_pages, write, force, pages, vmas,
> +				       NULL, false, FOLL_TOUCH);

So the parameter passing was disgustig before, and now it became super disgusing! 

Would it improve the code if we added a friendly helper structure (or two if 
that's better) to clean up all the interactions within these various functions?

Thanks,

	Ingo

  parent reply	other threads:[~2016-09-29  6:25 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-09-28 22:54 [PATCH v2 0/3] fix SELinux W^X bypass via ptrace Jann Horn
2016-09-28 22:54 ` [PATCH v2 1/3] fs/exec: don't force writing memory access Jann Horn
2016-09-28 22:54   ` Jann Horn
2016-09-29 16:09   ` Oleg Nesterov
2016-09-29 16:09     ` Oleg Nesterov
2016-09-28 22:54 ` [PATCH v2 2/3] mm: add LSM hook for writes to readonly memory Jann Horn
2016-09-28 22:54   ` Jann Horn
2016-09-28 23:22   ` Andy Lutomirski
2016-09-28 23:22     ` Andy Lutomirski
2016-09-28 23:32     ` Jann Horn
2016-09-28 23:44       ` Jann Horn
2016-11-03  2:25       ` Jann Horn
2016-09-29  6:25   ` Ingo Molnar [this message]
2016-09-29  6:25     ` Ingo Molnar
2016-09-28 22:54 ` [PATCH v2 3/3] selinux: require EXECMEM for forced ptrace poke Jann Horn
2016-09-29  6:19   ` Ingo Molnar
2016-09-29  6:19     ` Ingo Molnar
2016-09-29 16:38   ` Stephen Smalley
2016-09-29 16:38     ` Stephen Smalley

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