From: "H. Peter Anvin" <hpa@zytor.com>
To: Roland McGrath <mcgrathr@google.com>
Cc: Kees Cook <keescook@chromium.org>, Will Drewry <wad@chromium.org>,
Andrew Lutomirski <luto@mit.edu>, Indan Zupancic <indan@nul.nu>,
linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
linux-doc@vger.kernel.org, kernel-hardening@lists.openwall.com,
netdev@vger.kernel.org, x86@kernel.org, arnd@arndb.de,
davem@davemloft.net, mingo@redhat.com, oleg@redhat.com,
peterz@infradead.org, rdunlap@xenotime.net, tglx@linutronix.de,
eparis@redhat.com, serge.hallyn@canonical.com, djm@mindrot.org,
scarybeasts@gmail.com, pmoore@redhat.com,
akpm@linux-foundation.org, corbet@lwn.net,
eric.dumazet@gmail.com, markus@chromium.org
Subject: [kernel-hardening] Re: [PATCH v10 07/11] signal, x86: add SIGSYS info and make it synchronous.
Date: Wed, 22 Feb 2012 17:06:17 -0800 [thread overview]
Message-ID: <4F459109.1060205@zytor.com> (raw)
In-Reply-To: <CAB=4xhq1sm_ewZ_8Kerf2aN7nGx+DEENse7Lqg5N0wuvqtzUAw@mail.gmail.com>
On 02/22/2012 04:50 PM, Roland McGrath wrote:
> On Wed, Feb 22, 2012 at 4:29 PM, H. Peter Anvin <hpa@zytor.com> wrote:
>> Can we really introduce force-kill semantics for a POSIX-defined signal?
>> Other user space programs might use it for other purposes.
>
> The semantics are based on how the signal was generated, not what signal
> number it was. The only thing that depends on the signal number is
> SYNCHRONOUS_MASK, which just determines in which order pending signals are
> dequeued (POSIX says it may be any order). We only have that so your state
> doesn't get unhelpfully warped to another signal handler entry point
> (including fiddling the stack) before you dump core.
>
> No use of SIGSYS is specified by POSIX at all, of course, since "system
> call" is an implementation concept below the level POSIX specifies.
I meant whether or not a signal can be blocked/caught and the fact that
the signal exists at all.
Now I guess we could have "blockable" and "unblockable" SIGSYS, but that
would seem to have its own set of issues...
-hpa
--
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel. I don't speak on their behalf.
WARNING: multiple messages have this Message-ID (diff)
From: "H. Peter Anvin" <hpa@zytor.com>
To: Roland McGrath <mcgrathr@google.com>
Cc: Kees Cook <keescook@chromium.org>, Will Drewry <wad@chromium.org>,
Andrew Lutomirski <luto@mit.edu>, Indan Zupancic <indan@nul.nu>,
linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
linux-doc@vger.kernel.org, kernel-hardening@lists.openwall.com,
netdev@vger.kernel.org, x86@kernel.org, arnd@arndb.de,
davem@davemloft.net, mingo@redhat.com, oleg@redhat.com,
peterz@infradead.org, rdunlap@xenotime.net, tglx@linutronix.de,
eparis@redhat.com, serge.hallyn@canonical.com, djm@mindrot.org,
scarybeasts@gmail.com, pmoore@redhat.com,
akpm@linux-foundation.org, corbet@lwn.net,
eric.dumazet@gmail.com, markus@chromium.org
Subject: Re: [PATCH v10 07/11] signal, x86: add SIGSYS info and make it synchronous.
Date: Wed, 22 Feb 2012 17:06:17 -0800 [thread overview]
Message-ID: <4F459109.1060205@zytor.com> (raw)
In-Reply-To: <CAB=4xhq1sm_ewZ_8Kerf2aN7nGx+DEENse7Lqg5N0wuvqtzUAw@mail.gmail.com>
On 02/22/2012 04:50 PM, Roland McGrath wrote:
> On Wed, Feb 22, 2012 at 4:29 PM, H. Peter Anvin <hpa@zytor.com> wrote:
>> Can we really introduce force-kill semantics for a POSIX-defined signal?
>> Other user space programs might use it for other purposes.
>
> The semantics are based on how the signal was generated, not what signal
> number it was. The only thing that depends on the signal number is
> SYNCHRONOUS_MASK, which just determines in which order pending signals are
> dequeued (POSIX says it may be any order). We only have that so your state
> doesn't get unhelpfully warped to another signal handler entry point
> (including fiddling the stack) before you dump core.
>
> No use of SIGSYS is specified by POSIX at all, of course, since "system
> call" is an implementation concept below the level POSIX specifies.
I meant whether or not a signal can be blocked/caught and the fact that
the signal exists at all.
Now I guess we could have "blockable" and "unblockable" SIGSYS, but that
would seem to have its own set of issues...
-hpa
--
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel. I don't speak on their behalf.
next prev parent reply other threads:[~2012-02-23 1:06 UTC|newest]
Thread overview: 112+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-02-21 17:30 [kernel-hardening] [PATCH v10 01/11] sk_run_filter: add support for custom load_pointer Will Drewry
2012-02-21 17:30 ` Will Drewry
2012-02-21 17:30 ` [kernel-hardening] [PATCH v10 02/11] seccomp: kill the seccomp_t typedef Will Drewry
2012-02-21 17:30 ` Will Drewry
2012-02-21 17:30 ` [kernel-hardening] [PATCH v10 03/11] asm/syscall.h: add syscall_get_arch Will Drewry
2012-02-21 17:30 ` Will Drewry
2012-02-21 18:46 ` [kernel-hardening] " Roland McGrath
2012-02-21 18:46 ` Roland McGrath
2012-02-21 18:57 ` [kernel-hardening] " Will Drewry
2012-02-21 18:57 ` Will Drewry
2012-02-21 19:01 ` [kernel-hardening] [PATCH v11 " Will Drewry
2012-02-21 19:01 ` Will Drewry
2012-02-21 17:30 ` [kernel-hardening] [PATCH v10 04/11] arch/x86: add syscall_get_arch to syscall.h Will Drewry
2012-02-21 17:30 ` Will Drewry
2012-02-21 17:30 ` [kernel-hardening] [PATCH v10 05/11] seccomp: add system call filtering using BPF Will Drewry
2012-02-21 17:30 ` Will Drewry
2012-02-22 6:32 ` [kernel-hardening] " H. Peter Anvin
2012-02-22 6:32 ` H. Peter Anvin
2012-02-22 19:48 ` [kernel-hardening] " Will Drewry
2012-02-22 19:48 ` Will Drewry
2012-02-22 8:19 ` [kernel-hardening] " Indan Zupancic
2012-02-22 8:19 ` Indan Zupancic
2012-02-22 8:19 ` Indan Zupancic
2012-02-22 8:19 ` Indan Zupancic
2012-02-22 14:23 ` [kernel-hardening] " Ben Hutchings
2012-02-22 14:23 ` Ben Hutchings
2012-02-22 14:23 ` Ben Hutchings
2012-02-22 19:47 ` [kernel-hardening] " Will Drewry
2012-02-22 19:47 ` Will Drewry
2012-02-22 23:46 ` [kernel-hardening] " Indan Zupancic
2012-02-22 23:46 ` Indan Zupancic
2012-02-22 23:51 ` [kernel-hardening] " Andrew Lutomirski
2012-02-22 23:51 ` Andrew Lutomirski
2012-02-23 0:08 ` [kernel-hardening] " Indan Zupancic
2012-02-23 0:08 ` Indan Zupancic
2012-02-23 1:07 ` [kernel-hardening] " H. Peter Anvin
2012-02-23 1:07 ` H. Peter Anvin
2012-02-22 23:03 ` [kernel-hardening] " Indan Zupancic
2012-02-22 23:03 ` Indan Zupancic
2012-02-22 19:47 ` [kernel-hardening] " Will Drewry
2012-02-22 19:47 ` Will Drewry
2012-02-22 19:53 ` [kernel-hardening] " H. Peter Anvin
2012-02-22 19:53 ` H. Peter Anvin
2012-02-22 20:01 ` [kernel-hardening] " Will Drewry
2012-02-22 20:01 ` Will Drewry
2012-02-23 0:25 ` [kernel-hardening] " Indan Zupancic
2012-02-23 0:25 ` Indan Zupancic
2012-02-21 17:30 ` [kernel-hardening] [PATCH v10 06/11] seccomp: add SECCOMP_RET_ERRNO Will Drewry
2012-02-21 17:30 ` Will Drewry
2012-02-21 22:41 ` [kernel-hardening] " Kees Cook
2012-02-21 22:41 ` Kees Cook
2012-02-21 22:48 ` [kernel-hardening] " Will Drewry
2012-02-21 22:48 ` Will Drewry
2012-02-21 17:30 ` [kernel-hardening] [PATCH v10 07/11] signal, x86: add SIGSYS info and make it synchronous Will Drewry
2012-02-21 17:30 ` Will Drewry
2012-02-22 8:34 ` [kernel-hardening] " Indan Zupancic
2012-02-22 8:34 ` Indan Zupancic
2012-02-22 8:34 ` Indan Zupancic
2012-02-22 8:34 ` Indan Zupancic
2012-02-22 19:48 ` [kernel-hardening] " Will Drewry
2012-02-22 19:48 ` Will Drewry
2012-02-22 23:38 ` [kernel-hardening] " Andrew Lutomirski
2012-02-22 23:38 ` Andrew Lutomirski
2012-02-22 23:53 ` [kernel-hardening] " Kees Cook
2012-02-22 23:53 ` Kees Cook
2012-02-23 0:05 ` [kernel-hardening] " Will Drewry
2012-02-23 0:05 ` Will Drewry
2012-02-23 0:08 ` [kernel-hardening] " Kees Cook
2012-02-23 0:08 ` Kees Cook
2012-02-23 0:29 ` [kernel-hardening] " H. Peter Anvin
2012-02-23 0:29 ` H. Peter Anvin
2012-02-23 0:50 ` [kernel-hardening] " Roland McGrath
2012-02-23 0:50 ` Roland McGrath
2012-02-23 1:06 ` H. Peter Anvin [this message]
2012-02-23 1:06 ` H. Peter Anvin
2012-02-23 17:38 ` [kernel-hardening] " Roland McGrath
2012-02-23 17:38 ` Roland McGrath
2012-02-23 19:26 ` [kernel-hardening] " Will Drewry
2012-02-23 19:26 ` Will Drewry
2012-02-23 22:15 ` [kernel-hardening] " Indan Zupancic
2012-02-23 22:15 ` Indan Zupancic
2012-02-23 22:33 ` [kernel-hardening] " Markus Gutschke
2012-02-23 22:33 ` Markus Gutschke
2012-02-23 22:36 ` [kernel-hardening] " Will Drewry
2012-02-23 22:36 ` Will Drewry
2012-02-27 12:32 ` [kernel-hardening] " Indan Zupancic
2012-02-27 12:32 ` Indan Zupancic
2012-02-27 16:21 ` [kernel-hardening] " Will Drewry
2012-02-27 16:21 ` Will Drewry
2012-02-23 22:34 ` [kernel-hardening] " Will Drewry
2012-02-23 16:44 ` Will Drewry
2012-02-23 16:44 ` Will Drewry
2012-02-23 0:11 ` [kernel-hardening] " Roland McGrath
2012-02-23 0:11 ` Roland McGrath
2012-02-21 17:30 ` [kernel-hardening] [PATCH v10 08/11] seccomp: Add SECCOMP_RET_TRAP Will Drewry
2012-02-21 17:30 ` Will Drewry
2012-02-21 17:30 ` [kernel-hardening] [PATCH v10 09/11] ptrace,seccomp: Add PTRACE_SECCOMP support Will Drewry
2012-02-21 17:30 ` Will Drewry
2012-02-22 12:22 ` [kernel-hardening] " Indan Zupancic
2012-02-22 12:22 ` Indan Zupancic
2012-02-22 12:22 ` Indan Zupancic
2012-02-22 12:22 ` Indan Zupancic
2012-02-22 19:47 ` [kernel-hardening] " Will Drewry
2012-02-22 19:47 ` Will Drewry
2012-02-21 17:30 ` [kernel-hardening] [PATCH v10 10/11] x86: Enable HAVE_ARCH_SECCOMP_FILTER Will Drewry
2012-02-21 17:30 ` Will Drewry
2012-02-21 17:30 ` [kernel-hardening] [PATCH v10 11/11] Documentation: prctl/seccomp_filter Will Drewry
2012-02-21 17:30 ` Will Drewry
2012-02-21 23:12 ` [kernel-hardening] " Kees Cook
2012-02-21 23:12 ` Kees Cook
2012-02-22 3:41 ` [kernel-hardening] " Will Drewry
2012-02-22 3:41 ` Will Drewry
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