linux-kernel - Re: [PATCH v2 3/3] arm64: use the correct function type for __arm64_sys_ni

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: <20190515114035.GG24357@fuggles.cambridge.arm.com>
Date:   Wed, 15 May 2019 12:40:35 +0100
From:   Will Deacon <will.deacon@....com>
To:     Sami Tolvanen <samitolvanen@...gle.com>
Cc:     Mark Rutland <mark.rutland@....com>,
        Kees Cook <keescook@...omium.org>,
        Catalin Marinas <catalin.marinas@....com>,
        Nick Desaulniers <ndesaulniers@...gle.com>,
        linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v2 3/3] arm64: use the correct function type for
 __arm64_sys_ni_syscall

On Tue, May 07, 2019 at 11:32:27AM -0700, Sami Tolvanen wrote:
> On Tue, May 07, 2019 at 06:25:12PM +0100, Mark Rutland wrote:
> > I strongly think that we cant to fix up the common definition in
> > kernel/sys_ni.c rather than having a point-hack in arm64. Other
> > architectures (e.g. x86, s390) will want the same for CFI, and I'd like
> > to ensure that our approached don't diverge.
> 
> s390 already has the following in arch/s390/kernel/sys_s390.c:
> 
>   SYSCALL_DEFINE0(ni_syscall)
>   {
>         return -ENOSYS;
>   }
> 
> Which, I suppose, is cleaner than calling sys_ni_syscall.
> 
> > I took a quick look, and it looks like it's messy but possible to fix
> > up the core.
> 
> OK. How would you propose fixing this?

In the absence of a patch from Mark, I'd suggest just adding a SYS_NI macro
to our asm/syscall_wrapper.h file which avoids the error injection stuff. It
doesn't preclude moving this to the core later on, but it unblocks the CFI
work.

Will