linux-kernel - Re: [PATCH v5 0/3] selftests/lam: get_user additions and LAM enabled check

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] [day] [month] [year] [list]

Message-ID: <7qymrv7tfyt65dtqf6jhy7afkvtqftmpsa4y2hn5u65tusn7h2@3qw5dythjswm>
Date: Wed, 15 Jan 2025 10:06:36 +0100
From: Maciej Wieczor-Retman <maciej.wieczor-retman@...el.com>
To: <shuah@...nel.org>
CC: <linux-kernel@...r.kernel.org>, <linux-kselftest@...r.kernel.org>,
	<kirill@...temov.name>, <hpa@...or.com>, <x86@...nel.org>,
	<dave.hansen@...ux.intel.com>, <bp@...en8.de>, <mingo@...hat.com>,
	<tglx@...utronix.de>
Subject: Re: [PATCH v5 0/3] selftests/lam: get_user additions and LAM enabled
 check

Hello Shuah, I'd like to bump this series for visibility and ask if you still
consider these patches okay to merge?

Just checked and there were no conflicts after applying it on the newest
kselftest-next.

On 2024-11-27 at 18:35:28 +0100, Maciej Wieczor-Retman wrote:
>Recent change in how get_user() handles pointers [1] has a specific case
>for LAM. It assigns a different bitmask that's later used to check
>whether a pointer comes from userland in get_user().
>
>While currently commented out (until LASS [2] is merged into the kernel)
>it's worth making changes to the LAM selftest ahead of time.
>
>Modify cpu_has_la57() so it provides current paging level information
>instead of the cpuid one.
>
>Add test case to LAM that utilizes a ioctl (FIOASYNC) syscall which uses
>get_user() in its implementation. Execute the syscall with differently
>tagged pointers to verify that valid user pointers are passing through
>and invalid kernel/non-canonical pointers are not.
>
>Also to avoid unhelpful test failures add a check in main() to skip
>running tests if LAM was not compiled into the kernel.
>
>Code was tested on a Sierra Forest Xeon machine that's LAM capable. The
>test was ran without issues with both the LAM lines from [1] untouched
>and commented out. The test was also ran without issues with LAM_SUP
>both enabled and disabled.
>
>4/5 level pagetables code paths were also successfully tested in Simics
>on a 5-level capable machine.
>
>[1] https://lore.kernel.org/all/20241024013214.129639-1-torvalds@linux-foundation.org/
>[2] https://lore.kernel.org/all/20241028160917.1380714-1-alexander.shishkin@linux.intel.com/
>
>Maciej Wieczor-Retman (3):
>  selftests/lam: Move cpu_has_la57() to use cpuinfo flag
>  selftests/lam: Skip test if LAM is disabled
>  selftests/lam: Test get_user() LAM pointer handling
>
> tools/testing/selftests/x86/lam.c | 120 ++++++++++++++++++++++++++++--
> 1 file changed, 115 insertions(+), 5 deletions(-)
>
>-- 
>2.47.1
>

-- 
Kind regards
Maciej Wieczór-Retman