linux-kernel - Re: [PATCH v4] ARM: Implement SLS mitigation

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: <20210221101317.GN1463@shell.armlinux.org.uk>
Date:   Sun, 21 Feb 2021 10:13:17 +0000
From:   Russell King - ARM Linux admin <linux@...linux.org.uk>
To:     Jian Cai <jiancai@...gle.com>
Cc:     Mark Rutland <mark.rutland@....com>,
        Catalin Marinas <catalin.marinas@....com>,
        Linus Walleij <linus.walleij@...aro.org>,
        James Morris <jmorris@...ei.org>, manojgupta@...gle.com,
        Will Deacon <will@...nel.org>, Ingo Molnar <mingo@...nel.org>,
        Marc Zyngier <maz@...nel.org>,
        Masahiro Yamada <masahiroy@...nel.org>,
        Ard Biesheuvel <ardb@...nel.org>,
        clang-built-linux@...glegroups.com, llozano@...gle.com,
        David Brazdil <dbrazdil@...gle.com>,
        "Serge E. Hallyn" <serge@...lyn.com>,
        Kees Cook <keescook@...omium.org>,
        Arnd Bergmann <arnd@...db.de>,
        Nathan Chancellor <nathan@...nel.org>,
        linux-arm-kernel@...ts.infradead.org, ndesaulniers@...gle.com,
        linux-kernel@...r.kernel.org,
        linux-security-module@...r.kernel.org,
        David Laight <David.Laight@...lab.com>,
        James Morse <james.morse@....com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Andreas Färber <afaerber@...e.de>,
        Mike Rapoport <rppt@...nel.org>
Subject: Re: [PATCH v4] ARM: Implement SLS mitigation

On Fri, Feb 19, 2021 at 03:08:13PM -0800, Jian Cai wrote:
> diff --git a/security/Kconfig.hardening b/security/Kconfig.hardening
> index 269967c4fc1b..146b75a79d9e 100644
> --- a/security/Kconfig.hardening
> +++ b/security/Kconfig.hardening
> @@ -121,6 +121,16 @@ choice
>  
>  endchoice
>  
> +config HARDEN_SLS_ALL
> +	bool "enable SLS vulnerability hardening"
> +	default n

Please get rid of this useless "default n"

> +	depends on $(cc-option,-mharden-sls=all)
> +	help
> +	  Enables straight-line speculation vulnerability hardening on ARM and ARM64
> +	  architectures. It inserts speculation barrier sequences (SB or DSB+ISB
> +	  depending on the target architecture) after RET and BR, and replacing
> +	  BLR with BL+BR sequence.

Given that this is in an architecture independent Kconfig file, and it
detects support in CC for this feature, why should this help text be
written to be specific to a couple of architectures? Will this feature
only ever be available on these two architectures? What if someone adds
support for another architecture?

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!