From: Oleg Nesterov <oleg@redhat.com>
To: "Dmitry V. Levin" <ldv@altlinux.org>
Cc: Elvira Khabirova <lineprinter@altlinux.org>,
Steven Rostedt <rostedt@goodmis.org>,
Ingo Molnar <mingo@redhat.com>,
Eugene Syromyatnikov <esyr@redhat.com>,
Andy Lutomirski <luto@kernel.org>,
strace-devel@lists.strace.io, linux-api@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH RESEND v3 3/3] ptrace: add PTRACE_EVENT_SECCOMP support to PTRACE_GET_SYSCALL_INFO
Date: Wed, 28 Nov 2018 13:35:46 +0100 [thread overview]
Message-ID: <20181128123545.GA30395@redhat.com> (raw)
In-Reply-To: <20181127232753.GA18755@altlinux.org>
On 11/28, Dmitry V. Levin wrote:
>
> > Just like ptrace_request(PTRACE_LISTEN)
> > does but you can do this lockless (no need to lock_task_sighand()).
>
> Why this can be done lockless? All other places in that file do
> the locking,
PTRACE_LISTEN too doesn't need lock_task_sighand() to access ->last_siginfo,
this code predates ptrace_freeze_traced() which ensures that the tracee can't
go away and clear ->last_siginfo.
However, unlike ptrace_get_syscall(), PTRACE_LISTEN needs spin_lock_irq(siglock),
it modifies ->jobctl and calls signal_wake_up().
> > Of course, debugger can do PTRACE_SETSIGINFO and confuse itself but probably we
> > do not care?
>
> The only potential issue I could think of is whether PTRACE_SETSIGINFO
> could be used this way to cause an information leak by making
> PTRACE_GET_SYSCALL_INFO access some unrelated data.
Well, afaics ptrace_get_syscall() does nothing "special", debugger can use other
PTRACE_ requests to get the same info?
Oleg.
next prev parent reply other threads:[~2018-11-28 12:35 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-25 1:21 [PATCH RESEND v3 0/3] ptrace: add PTRACE_GET_SYSCALL_INFO request Elvira Khabirova
2018-11-25 1:22 ` [PATCH RESEND v3 1/3] ptrace: pass type of a syscall-stop in ptrace_message Elvira Khabirova
2018-11-25 1:54 ` Joey Pabalinas
2018-11-25 2:10 ` Dmitry V. Levin
2018-11-25 6:17 ` Joey Pabalinas
2018-11-26 14:56 ` Oleg Nesterov
2018-11-27 2:53 ` Elvira Khabirova
2018-11-27 3:48 ` Dmitry V. Levin
2018-11-25 1:23 ` [PATCH RESEND v3 2/3] ptrace: add PTRACE_GET_SYSCALL_INFO request Elvira Khabirova
2018-11-25 1:23 ` [RFC PATCH RESEND v3 3/3] ptrace: add PTRACE_EVENT_SECCOMP support to PTRACE_GET_SYSCALL_INFO Elvira Khabirova
2018-11-26 14:35 ` Oleg Nesterov
2018-11-27 3:07 ` Elvira Khabirova
2018-11-27 3:21 ` Dmitry V. Levin
2018-11-27 12:31 ` Oleg Nesterov
2018-11-27 23:27 ` Dmitry V. Levin
2018-11-28 12:35 ` Oleg Nesterov [this message]
2018-11-28 12:44 ` Dmitry V. Levin
2018-11-28 13:13 ` Oleg Nesterov
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