From: Andy Lutomirski <luto@kernel.org>
To: Arnd Bergmann <arnd@arndb.de>
Cc: Christian Brauner <christian@brauner.io>,
"Eric W. Biederman" <ebiederm@xmission.com>,
Andrew Lutomirski <luto@kernel.org>,
Florian Weimer <fweimer@redhat.com>,
LKML <linux-kernel@vger.kernel.org>,
"Serge E. Hallyn" <serge@hallyn.com>,
Jann Horn <jannh@google.com>,
Andrew Morton <akpm@linux-foundation.org>,
Oleg Nesterov <oleg@redhat.com>, Aleksa Sarai <cyphar@cyphar.com>,
Al Viro <viro@zeniv.linux.org.uk>,
Linux FS Devel <linux-fsdevel@vger.kernel.org>,
Linux API <linux-api@vger.kernel.org>,
Daniel Colascione <dancol@google.com>,
Tim Murray <timmurray@google.com>,
linux-man <linux-man@vger.kernel.org>,
Kees Cook <keescook@chromium.org>
Subject: Re: [PATCH v2] signal: add procfd_signal() syscall
Date: Fri, 30 Nov 2018 08:35:45 -0800 [thread overview]
Message-ID: <CALCETrW2aphWwEY4=hUwo_JBCvkQyMjxzxGd9FCW017kMLaMOQ@mail.gmail.com> (raw)
In-Reply-To: <CAK8P3a0kqPii5TwFAo_JHLX=o_FDMFVKXxgzzbDjLFZ7OQ5QCQ@mail.gmail.com>
On Fri, Nov 30, 2018 at 3:41 AM Arnd Bergmann <arnd@arndb.de> wrote:
> siginfo_t as it is now still has a number of other downsides, and Andy in
> particular didn't like the idea of having three new variants on x86
> (depending on how you count). His alternative suggestion of having
> a single syscall entry point that takes a 'signfo_t __user *' but interprets
> it as compat_siginfo depending on in_compat_syscall()/in_x32_syscall()
> should work correctly, but feels wrong to me, or at least inconsistent
> with how we do this elsewhere.
If everyone else is okay with it, I can get on board with three
variants on x86. What I can't get on board with is *five* variants on
x86, which would be:
procfd_signal via int80 / the 32-bit vDSO: the ia32 structure
syscall64 with nr == 335 (presumably): 64-bit
syscall64 with nr == 548 | 0x40000000: x32
syscall64 with nr == 548: 64-bit entry but in_compat_syscall() ==
true, behavior is arbitrary
syscall64 with nr == 335 | 0x40000000: x32 entry, but
in_compat_syscall() == false, behavior is arbitrary
This mess isn't really Christian's fault -- it's been there for a
while, but it's awful and I don't think we want to perpetuate it.
Obviously, I'd prefer a variant where the structure that's passed in
is always the same.
BTW, do we consider siginfo_t to be extensible? If so, and if we pass
in a pointer, presumably we should pass a length as well.
next prev parent reply other threads:[~2018-11-30 16:36 UTC|newest]
Thread overview: 54+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-20 10:51 [PATCH v2] signal: add procfd_signal() syscall Christian Brauner
2018-11-20 10:51 ` [PATCH v2] procfd_signal.2: document procfd_signal syscall Christian Brauner
2018-11-22 8:00 ` [PATCH v2] signal: add procfd_signal() syscall Serge E. Hallyn
2018-11-22 8:23 ` Aleksa Sarai
2018-11-28 14:05 ` Arnd Bergmann
2018-11-29 12:28 ` Florian Weimer
2018-11-29 16:54 ` Andy Lutomirski
2018-11-29 19:16 ` Christian Brauner
2018-11-29 19:22 ` Andy Lutomirski
2018-11-29 19:55 ` Christian Brauner
2018-11-29 20:14 ` Andy Lutomirski
2018-11-29 21:02 ` Arnd Bergmann
2018-11-29 21:35 ` Christian Brauner
2018-11-29 21:40 ` Arnd Bergmann
2018-11-30 2:40 ` Aleksa Sarai
2018-12-01 1:25 ` Christian Brauner
2018-11-30 5:13 ` Eric W. Biederman
2018-11-30 6:56 ` Christian Brauner
2018-11-30 11:41 ` Arnd Bergmann
2018-11-30 16:35 ` Andy Lutomirski [this message]
2018-11-30 21:57 ` Christian Brauner
2018-11-30 22:09 ` Arnd Bergmann
2018-11-30 22:26 ` Christian Brauner
2018-11-30 23:05 ` Daniel Colascione
2018-11-30 23:12 ` Arnd Bergmann
2018-11-30 23:15 ` Arnd Bergmann
2018-11-30 23:37 ` Christian Brauner
2018-11-30 23:46 ` Andy Lutomirski
2018-12-01 1:20 ` Christian Brauner
2018-11-30 23:53 ` Andy Lutomirski
2018-12-01 8:51 ` Arnd Bergmann
2018-12-01 9:17 ` Christian Brauner
2018-12-01 10:27 ` Arnd Bergmann
2018-12-01 13:41 ` Eric W. Biederman
2018-12-01 14:46 ` Eric W. Biederman
2018-12-01 15:28 ` Eric W. Biederman
2018-12-01 15:52 ` Andy Lutomirski
2018-12-01 16:27 ` Christian Brauner
2018-12-02 0:06 ` Eric W. Biederman
2018-12-02 1:14 ` Andy Lutomirski
2018-12-02 8:52 ` Christian Brauner
2018-11-30 23:52 ` Christian Brauner
2018-12-02 10:03 ` Christian Brauner
2018-12-03 16:57 ` Florian Weimer
2018-12-03 18:02 ` Christian Brauner
2018-12-04 6:03 ` Aleksa Sarai
2018-12-04 12:55 ` Florian Weimer
2018-12-04 13:26 ` Christian Brauner
2018-12-06 18:54 ` Andy Lutomirski
2018-12-06 18:56 ` Florian Weimer
2018-12-06 19:03 ` Christian Brauner
2018-12-25 5:32 ` Lai Jiangshan
2018-12-25 7:11 ` Lai Jiangshan
2018-12-25 12:07 ` Aleksa Sarai
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