From: Mark Rutland <mark.rutland@arm.com>
To: Sami Tolvanen <samitolvanen@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>, Kees Cook <keescook@chromium.org>,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] arm64: fix function types in COND_SYSCALL
Date: Wed, 11 Sep 2019 16:15:46 +0100 [thread overview]
Message-ID: <20190911151545.GD3360@blommer> (raw)
In-Reply-To: <20190910224044.100388-1-samitolvanen@google.com>
On Tue, Sep 10, 2019 at 03:40:44PM -0700, Sami Tolvanen wrote:
> Define a weak function in COND_SYSCALL instead of a weak alias to
> sys_ni_syscall, which has an incompatible type. This fixes indirect
> call mismatches with Control-Flow Integrity (CFI) checking.
>
> Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
This looks correct to me, builds fine, and I asume has been tested, so FWIW:
Acked-by: Mark Rutland <mark.rutland@arm.com>
In looking at this, I came to the conclusion that we can drop the ifdeffery
around our SYSCALL_DEFINE0(), COND_SYSCALL(), and SYS_NI(), which I evidently
cargo-culted from x86 (where the ifdeffery is actually necessary).
I can send a follow up for that.
Thanks,
Mark.
> ---
> arch/arm64/include/asm/syscall_wrapper.h | 15 ++++++++++++---
> 1 file changed, 12 insertions(+), 3 deletions(-)
>
> diff --git a/arch/arm64/include/asm/syscall_wrapper.h b/arch/arm64/include/asm/syscall_wrapper.h
> index 507d0ee6bc69..06d880b3526c 100644
> --- a/arch/arm64/include/asm/syscall_wrapper.h
> +++ b/arch/arm64/include/asm/syscall_wrapper.h
> @@ -8,6 +8,8 @@
> #ifndef __ASM_SYSCALL_WRAPPER_H
> #define __ASM_SYSCALL_WRAPPER_H
>
> +struct pt_regs;
> +
> #define SC_ARM64_REGS_TO_ARGS(x, ...) \
> __MAP(x,__SC_ARGS \
> ,,regs->regs[0],,regs->regs[1],,regs->regs[2] \
> @@ -35,8 +37,11 @@
> ALLOW_ERROR_INJECTION(__arm64_compat_sys_##sname, ERRNO); \
> asmlinkage long __arm64_compat_sys_##sname(const struct pt_regs *__unused)
>
> -#define COND_SYSCALL_COMPAT(name) \
> - cond_syscall(__arm64_compat_sys_##name);
> +#define COND_SYSCALL_COMPAT(name) \
> + asmlinkage long __weak __arm64_compat_sys_##name(const struct pt_regs *regs) \
> + { \
> + return sys_ni_syscall(); \
> + }
>
> #define COMPAT_SYS_NI(name) \
> SYSCALL_ALIAS(__arm64_compat_sys_##name, sys_ni_posix_timers);
> @@ -70,7 +75,11 @@
> #endif
>
> #ifndef COND_SYSCALL
> -#define COND_SYSCALL(name) cond_syscall(__arm64_sys_##name)
> +#define COND_SYSCALL(name) \
> + asmlinkage long __weak __arm64_sys_##name(const struct pt_regs *regs) \
> + { \
> + return sys_ni_syscall(); \
> + }
> #endif
>
> #ifndef SYS_NI
> --
> 2.23.0.162.g0b9fbb3734-goog
>
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2019-09-11 15:16 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-10 22:40 [PATCH] arm64: fix function types in COND_SYSCALL Sami Tolvanen
2019-09-11 15:15 ` Mark Rutland [this message]
2019-09-12 13:11 ` Will Deacon
2019-09-13 11:33 ` Mark Rutland
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20190911151545.GD3360@blommer \
--to=mark.rutland@arm.com \
--cc=catalin.marinas@arm.com \
--cc=keescook@chromium.org \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=samitolvanen@google.com \
--cc=will@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).