linux-kernel - Re: [PATCH 6/9] x86, pkeys: add pkey set/get syscalls

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <578D19AF.3020204@sr71.net>
Date:	Mon, 18 Jul 2016 11:02:23 -0700
From:	Dave Hansen <dave@...1.net>
To:	Ingo Molnar <mingo@...nel.org>
Cc:	Mel Gorman <mgorman@...hsingularity.net>,
	linux-kernel@...r.kernel.org, x86@...nel.org,
	linux-api@...r.kernel.org, linux-arch@...r.kernel.org,
	linux-mm@...ck.org, torvalds@...ux-foundation.org,
	akpm@...ux-foundation.org, dave.hansen@...ux.intel.com,
	arnd@...db.de, hughd@...gle.com, viro@...iv.linux.org.uk,
	Thomas Gleixner <tglx@...utronix.de>,
	"H. Peter Anvin" <hpa@...or.com>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>
Subject: Re: [PATCH 6/9] x86, pkeys: add pkey set/get syscalls

On 07/09/2016 01:37 AM, Ingo Molnar wrote:
>    I.e. this pattern:
> 
>      ret = pkey_mprotect(NULL, PAGE_SIZE, real_prot, pkey);
> 
>    ... would validate the pkey and we'd return -EOPNOTSUPP for pkey that is not 
>    available? This would allow maximum future flexibility as it would not define 
>    kernel allocated pkeys as a 'range'.

Isn't this  multiplexing an otherwise straightforward system call?  In
addition to providing pkey assignment to memory, it would also being
used to pass pkey allocation information independently from any use for
memory assignment.

The complexity of the ABI comes from its behavior, not from the raw
number of system calls that are needed to implement it.  IOW, this makes
the ABI *more* complicated.