From: Christian Brauner <christian.brauner@ubuntu.com>
To: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>,
LKML <linux-kernel@vger.kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Kees Cook <keescook@chromium.org>, Will Drewry <wad@chromium.org>,
Oleg Nesterov <oleg@redhat.com>,
linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
Parisc List <linux-parisc@vger.kernel.org>,
linux-s390 <linux-s390@vger.kernel.org>,
linux-um@lists.infradead.org, X86 ML <x86@kernel.org>
Subject: Re: [PATCH] seccomp: remove unused arg from secure_computing()
Date: Tue, 24 Sep 2019 08:30:36 +0200 [thread overview]
Message-ID: <20190924063035.n3dmryhn6cb52ida@wittgenstein> (raw)
In-Reply-To: <CALCETrU_fs_At-hTpr231kpaAd0z7xJN4ku-DvzhRU6cvcJA_w@mail.gmail.com>
On Mon, Sep 23, 2019 at 11:41:59AM -0700, Andy Lutomirski wrote:
> On Mon, Sep 23, 2019 at 2:49 AM Borislav Petkov <bp@alien8.de> wrote:
> >
> > On Fri, Sep 20, 2019 at 03:19:09PM +0200, Christian Brauner wrote:
> > > While touching seccomp code I realized that the struct seccomp_data
> > > argument to secure_computing() seems to be unused by all current
> > > callers. So let's remove it unless there is some subtlety I missed.
> > > Note, I only tested this on x86.
> >
> > What was amluto thinking in
> >
> > 2f275de5d1ed ("seccomp: Add a seccomp_data parameter secure_computing()")
>
> IIRC there was a period of time in which x86 used secure_computing()
> for normal syscalls, and it was a good deal faster to have the arch
> code supply seccomp_data. x86 no longer works like this, and syscalls
> aren't fast anymore ayway :(
I started looking at this and actually had a slightly bigger cleanup in
mind. It seems odd that we have secure_computing() and
__secure_computing(). Especially in the mips and x86 case. From what I
can tell they could both rely on secure_computing() and don't need
__secure_computing().
If I can make those changes, we can make __secure_computing() static and
have only a single function secure_computing() that is used by all
arches which would make this code simpler.
Apparenly mips once switched from secure_computing() to
__secure_computing() because of bpf and tracepoints. The last change to
this was:
commit 3d729deaf287c43e415c5d791c9ac8414dbeff70
Author: James Hogan <jhogan@kernel.org>
Date: Fri Aug 11 21:56:50 2017 +0100
MIPS: seccomp: Fix indirect syscall args
which references a broken samples/bpf/tracex5 test. But in the thread to
this last change Kees and others were less than sure that this makes
sense. So I'm not sure. Maybe I should just try and send it out...
Christian
WARNING: multiple messages have this Message-ID (diff)
From: Christian Brauner <christian.brauner@ubuntu.com>
To: Andy Lutomirski <luto@kernel.org>
Cc: linux-s390 <linux-s390@vger.kernel.org>,
Will Drewry <wad@chromium.org>, Kees Cook <keescook@chromium.org>,
Parisc List <linux-parisc@vger.kernel.org>,
X86 ML <x86@kernel.org>,
linux-um@lists.infradead.org, LKML <linux-kernel@vger.kernel.org>,
Oleg Nesterov <oleg@redhat.com>, Borislav Petkov <bp@alien8.de>,
Thomas Gleixner <tglx@linutronix.de>,
linux-arm-kernel <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH] seccomp: remove unused arg from secure_computing()
Date: Tue, 24 Sep 2019 08:30:36 +0200 [thread overview]
Message-ID: <20190924063035.n3dmryhn6cb52ida@wittgenstein> (raw)
In-Reply-To: <CALCETrU_fs_At-hTpr231kpaAd0z7xJN4ku-DvzhRU6cvcJA_w@mail.gmail.com>
On Mon, Sep 23, 2019 at 11:41:59AM -0700, Andy Lutomirski wrote:
> On Mon, Sep 23, 2019 at 2:49 AM Borislav Petkov <bp@alien8.de> wrote:
> >
> > On Fri, Sep 20, 2019 at 03:19:09PM +0200, Christian Brauner wrote:
> > > While touching seccomp code I realized that the struct seccomp_data
> > > argument to secure_computing() seems to be unused by all current
> > > callers. So let's remove it unless there is some subtlety I missed.
> > > Note, I only tested this on x86.
> >
> > What was amluto thinking in
> >
> > 2f275de5d1ed ("seccomp: Add a seccomp_data parameter secure_computing()")
>
> IIRC there was a period of time in which x86 used secure_computing()
> for normal syscalls, and it was a good deal faster to have the arch
> code supply seccomp_data. x86 no longer works like this, and syscalls
> aren't fast anymore ayway :(
I started looking at this and actually had a slightly bigger cleanup in
mind. It seems odd that we have secure_computing() and
__secure_computing(). Especially in the mips and x86 case. From what I
can tell they could both rely on secure_computing() and don't need
__secure_computing().
If I can make those changes, we can make __secure_computing() static and
have only a single function secure_computing() that is used by all
arches which would make this code simpler.
Apparenly mips once switched from secure_computing() to
__secure_computing() because of bpf and tracepoints. The last change to
this was:
commit 3d729deaf287c43e415c5d791c9ac8414dbeff70
Author: James Hogan <jhogan@kernel.org>
Date: Fri Aug 11 21:56:50 2017 +0100
MIPS: seccomp: Fix indirect syscall args
which references a broken samples/bpf/tracex5 test. But in the thread to
this last change Kees and others were less than sure that this makes
sense. So I'm not sure. Maybe I should just try and send it out...
Christian
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next prev parent reply other threads:[~2019-09-24 6:30 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-20 13:19 [PATCH] seccomp: remove unused arg from secure_computing() Christian Brauner
2019-09-20 13:19 ` Christian Brauner
2019-09-23 9:49 ` Borislav Petkov
2019-09-23 9:49 ` Borislav Petkov
2019-09-23 18:41 ` Andy Lutomirski
2019-09-23 18:41 ` Andy Lutomirski
2019-09-23 19:34 ` Borislav Petkov
2019-09-23 19:34 ` Borislav Petkov
2019-09-23 23:51 ` Kees Cook
2019-09-23 23:51 ` Kees Cook
2019-09-24 6:19 ` Christian Brauner
2019-09-24 6:19 ` Christian Brauner
2019-09-24 6:30 ` Christian Brauner [this message]
2019-09-24 6:30 ` Christian Brauner
2019-09-24 6:44 ` [PATCH v1] seccomp: simplify secure_computing() Christian Brauner
2019-09-24 6:44 ` Christian Brauner
2019-09-24 9:51 ` Borislav Petkov
2019-09-24 9:51 ` Borislav Petkov
2019-09-24 17:11 ` Andy Lutomirski
2019-09-24 17:11 ` Andy Lutomirski
2019-10-10 21:53 ` Kees Cook
2019-10-10 21:53 ` Kees Cook
2019-10-11 9:45 ` Christian Brauner
2019-10-11 9:45 ` Christian Brauner
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