From: Andy Lutomirski <luto@amacapital.net>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Arnd Bergmann <arnd@arndb.de>,
christian@brauner.io, Andy Lutomirski <luto@kernel.org>,
Florian Weimer <fweimer@redhat.com>,
Linux Kernel Mailing List <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>,
cyphar@cyphar.com, Al Viro <viro@zeniv.linux.org.uk>,
Linux FS-devel Mailing List <linux-fsdevel@vger.kernel.org>,
Linux API <linux-api@vger.kernel.org>,
Daniel Colascione <dancol@google.com>,
Tim Murray <timmurray@google.com>,
linux-man@vger.kernel.org, Kees Cook <keescook@chromium.org>
Subject: Re: [PATCH v2] signal: add procfd_signal() syscall
Date: Sat, 1 Dec 2018 07:52:37 -0800 [thread overview]
Message-ID: <F53D6D38-3521-4C20-9034-5AF447DF62FF@amacapital.net> (raw)
In-Reply-To: <87tvjxp8pc.fsf@xmission.com>
> On Dec 1, 2018, at 7:28 AM, Eric W. Biederman <ebiederm@xmission.com> wrote:
>
>
> It just occurs to me that the simple way to implement
> procfd_sigqueueinfo info is like:
>
> int copy_siginfo_from_user_any(kernel_siginfo_t *info, siginfo_t *uinfo)
> {
> #ifdef CONFIG_COMPAT
> if (in_compat_syscall)
> return copy_siginfo_from_user32(info, uinfo);
> #endif
> return copy_siginfo_from_user(info, uinfo);
> }
>
> long procfd_sigqueueinfo(int fd, siginfo_t *uinfo)
> {
> kernel_siginfo info;
>
> if (copy_siginfo_from_user_any(&info, uinfo))
> return -EFAULT;
> ...;
> }
>
> It looks like there is already a place in ptrace.c that already
> hand rolls copy_siginfo_from_user_any.
>
> So while I would love to figure out the subset of siginfo_t tha we can
> just pass through, as I think that would make a better more forward
> compatible copy_siginfo_from_user32.
Seems reasonable to me. It’s less code overall than any other suggestion, too.
> I think for this use case we just
> add the in_compat_syscall test and then we just need to ensure this new
> system call is placed in the proper places in the syscall table.
>
> Because we will need 3 call sights: x86_64, x32 and ia32. As the layout
> changes between those three subarchitecuters.
>
>
If it’s done this way, it can just be “common” in the 64-bit table. And we kick the can a bit farther down the road :)
I’m working on patches to clean up x86’s syscall mess. It’s slow because I keep finding new messes. So far I have rt_sigreturn working like every other syscall — whee.
Also, Eric, for your edification, I have a draft patch set to radically simplify x86’s signal delivery and return. Once that’s done, I can trivially speed up delivery by a ton by using sysret.
next prev parent reply other threads:[~2018-12-01 15:52 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
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 [this message]
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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