From: Christian Brauner <christian.brauner@ubuntu.com>
To: Gabriel Krisman Bertazi <krisman@collabora.com>
Cc: luto@kernel.org, tglx@linutronix.de, keescook@chromium.org,
x86@kernel.org, linux-kernel@vger.kernel.org,
linux-api@vger.kernel.org, willy@infradead.org,
linux-kselftest@vger.kernel.org, shuah@kernel.org,
kernel@collabora.com
Subject: Re: [PATCH v6 2/9] kernel: entry: Support TIF_SYSCAL_INTERCEPT on common entry code
Date: Mon, 7 Sep 2020 12:16:18 +0200 [thread overview]
Message-ID: <20200907101618.dnxv5n4x4vty73hr@wittgenstein> (raw)
In-Reply-To: <20200904203147.2908430-3-krisman@collabora.com>
On Fri, Sep 04, 2020 at 04:31:40PM -0400, Gabriel Krisman Bertazi wrote:
> Syscalls that use common entry code (x86 at the moment of this writing)
> need to have their defines updated inside this commit. This added a
> measureable overhead of 1ns to seccomp_benchmark selftests on a
> bare-metal AMD system.
>
> Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>
> ---
> arch/x86/include/asm/thread_info.h | 4 ++--
> include/linux/entry-common.h | 6 +-----
> kernel/entry/common.c | 24 +++++++++++++++++++++---
> 3 files changed, 24 insertions(+), 10 deletions(-)
>
> diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h
> index 267701ae3d86..cf723181e1f2 100644
> --- a/arch/x86/include/asm/thread_info.h
> +++ b/arch/x86/include/asm/thread_info.h
> @@ -82,7 +82,7 @@ struct thread_info {
> #define TIF_SSBD 5 /* Speculative store bypass disable */
> #define TIF_SYSCALL_EMU 6 /* syscall emulation active */
> #define TIF_SYSCALL_AUDIT 7 /* syscall auditing active */
> -#define TIF_SECCOMP 8 /* secure computing */
> +#define TIF_SYSCALL_INTERCEPT 8 /* Intercept system call */
> #define TIF_SPEC_IB 9 /* Indirect branch speculation mitigation */
> #define TIF_SPEC_FORCE_UPDATE 10 /* Force speculation MSR update in context switch */
> #define TIF_USER_RETURN_NOTIFY 11 /* notify kernel of userspace return */
> @@ -112,7 +112,7 @@ struct thread_info {
> #define _TIF_SSBD (1 << TIF_SSBD)
> #define _TIF_SYSCALL_EMU (1 << TIF_SYSCALL_EMU)
> #define _TIF_SYSCALL_AUDIT (1 << TIF_SYSCALL_AUDIT)
> -#define _TIF_SECCOMP (1 << TIF_SECCOMP)
> +#define _TIF_SYSCALL_INTERCEPT (1 << TIF_SYSCALL_INTERCEPT)
> #define _TIF_SPEC_IB (1 << TIF_SPEC_IB)
> #define _TIF_SPEC_FORCE_UPDATE (1 << TIF_SPEC_FORCE_UPDATE)
> #define _TIF_USER_RETURN_NOTIFY (1 << TIF_USER_RETURN_NOTIFY)
> diff --git a/include/linux/entry-common.h b/include/linux/entry-common.h
> index efebbffcd5cc..72ce9ca860c6 100644
> --- a/include/linux/entry-common.h
> +++ b/include/linux/entry-common.h
> @@ -21,10 +21,6 @@
> # define _TIF_SYSCALL_TRACEPOINT (0)
> #endif
>
> -#ifndef _TIF_SECCOMP
> -# define _TIF_SECCOMP (0)
> -#endif
> -
> #ifndef _TIF_SYSCALL_AUDIT
> # define _TIF_SYSCALL_AUDIT (0)
> #endif
> @@ -45,7 +41,7 @@
> #endif
>
> #define SYSCALL_ENTER_WORK \
> - (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | _TIF_SECCOMP | \
> + (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | _TIF_SYSCALL_INTERCEPT | \
> _TIF_SYSCALL_TRACEPOINT | _TIF_SYSCALL_EMU | \
> ARCH_SYSCALL_ENTER_WORK)
>
> diff --git a/kernel/entry/common.c b/kernel/entry/common.c
> index fcae019158ca..44fd089d59da 100644
> --- a/kernel/entry/common.c
> +++ b/kernel/entry/common.c
> @@ -4,6 +4,7 @@
> #include <linux/entry-common.h>
> #include <linux/livepatch.h>
> #include <linux/audit.h>
> +#include <linux/syscall_intercept.h>
>
> #define CREATE_TRACE_POINTS
> #include <trace/events/syscalls.h>
> @@ -41,6 +42,20 @@ static inline void syscall_enter_audit(struct pt_regs *regs, long syscall)
> }
> }
>
> +static inline long do_syscall_intercept(struct pt_regs *regs)
Hey Gabriel,
I think you can drop the pt_regs argument and just have this be
static inline do_syscall_intercept(void)
otherwise
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
> +{
> + int sysint_work = READ_ONCE(current->syscall_intercept);
> + int ret;
> +
> + if (sysint_work & SYSINT_SECCOMP) {
> + ret = __secure_computing(NULL);
> + if (ret == -1L)
> + return ret;
> + }
> +
> + return 0;
> +}
> +
> static long syscall_trace_enter(struct pt_regs *regs, long syscall,
> unsigned long ti_work)
> {
> @@ -53,9 +68,12 @@ static long syscall_trace_enter(struct pt_regs *regs, long syscall,
> return -1L;
> }
>
> - /* Do seccomp after ptrace, to catch any tracer changes. */
> - if (ti_work & _TIF_SECCOMP) {
> - ret = __secure_computing(NULL);
> + /*
> + * Do syscall interception like seccomp after ptrace, to catch
> + * any tracer changes.
> + */
> + if (ti_work & _TIF_SYSCALL_INTERCEPT) {
> + ret = do_syscall_intercept(regs);
> if (ret == -1L)
> return ret;
> }
> --
> 2.28.0
next prev parent reply other threads:[~2020-09-07 10:26 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-04 20:31 [PATCH v6 0/9] Syscall User Dispatch Gabriel Krisman Bertazi
2020-09-04 20:31 ` [PATCH v6 1/9] kernel: Support TIF_SYSCALL_INTERCEPT flag Gabriel Krisman Bertazi
2020-09-07 10:16 ` Christian Brauner
2020-09-08 4:59 ` Gabriel Krisman Bertazi
2020-09-22 19:42 ` Kees Cook
2020-09-23 20:28 ` Gabriel Krisman Bertazi
2020-09-11 9:32 ` peterz
2020-09-11 20:08 ` Gabriel Krisman Bertazi
2020-09-24 11:24 ` Peter Zijlstra
2020-09-22 19:44 ` Kees Cook
2020-09-23 20:18 ` Gabriel Krisman Bertazi
2020-09-23 20:49 ` Kees Cook
2020-09-25 8:00 ` Thomas Gleixner
2020-09-25 16:15 ` Gabriel Krisman Bertazi
2020-09-25 20:30 ` Kees Cook
2020-09-04 20:31 ` [PATCH v6 2/9] kernel: entry: Support TIF_SYSCAL_INTERCEPT on common entry code Gabriel Krisman Bertazi
2020-09-07 10:16 ` Christian Brauner [this message]
2020-09-11 9:35 ` peterz
2020-09-11 20:11 ` Gabriel Krisman Bertazi
2020-09-04 20:31 ` [PATCH v6 3/9] x86: vdso: Expose sigreturn address on vdso to the kernel Gabriel Krisman Bertazi
2020-09-22 19:40 ` Kees Cook
2020-09-04 20:31 ` [PATCH v6 4/9] signal: Expose SYS_USER_DISPATCH si_code type Gabriel Krisman Bertazi
2020-09-07 10:15 ` Christian Brauner
2020-09-22 19:39 ` Kees Cook
2020-09-04 20:31 ` [PATCH v6 5/9] kernel: Implement selective syscall userspace redirection Gabriel Krisman Bertazi
2020-09-05 11:24 ` Matthew Wilcox
2020-09-11 9:44 ` peterz
2020-09-04 20:31 ` [PATCH v6 6/9] kernel: entry: Support Syscall User Dispatch for common syscall entry Gabriel Krisman Bertazi
2020-09-07 10:15 ` Christian Brauner
2020-09-07 14:15 ` Andy Lutomirski
2020-09-07 14:25 ` Christian Brauner
2020-09-07 20:20 ` Andy Lutomirski
2020-09-11 9:46 ` peterz
2020-09-04 20:31 ` [PATCH v6 7/9] x86: Enable Syscall User Dispatch Gabriel Krisman Bertazi
2020-09-22 19:37 ` Kees Cook
2020-09-23 20:23 ` Gabriel Krisman Bertazi
2020-09-04 20:31 ` [PATCH v6 8/9] selftests: Add kselftest for syscall user dispatch Gabriel Krisman Bertazi
2020-09-22 19:35 ` Kees Cook
2020-09-04 20:31 ` [PATCH v6 9/9] doc: Document Syscall User Dispatch Gabriel Krisman Bertazi
2020-09-22 19:35 ` Kees Cook
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=20200907101618.dnxv5n4x4vty73hr@wittgenstein \
--to=christian.brauner@ubuntu.com \
--cc=keescook@chromium.org \
--cc=kernel@collabora.com \
--cc=krisman@collabora.com \
--cc=linux-api@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-kselftest@vger.kernel.org \
--cc=luto@kernel.org \
--cc=shuah@kernel.org \
--cc=tglx@linutronix.de \
--cc=willy@infradead.org \
--cc=x86@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).