From: Linus Torvalds <torvalds@linux-foundation.org>
To: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andy Lutomirski <luto@amacapital.net>,
Andrew Lutomirski <luto@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Linux API <linux-api@vger.kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Paul McKenney <paulmck@linux.vnet.ibm.com>,
Boqun Feng <boqun.feng@gmail.com>,
Dave Watson <davejwatson@fb.com>, Paul Turner <pjt@google.com>,
Andrew Morton <akpm@linux-foundation.org>,
Russell King - ARM Linux <linux@arm.linux.org.uk>,
Ingo Molnar <mingo@redhat.com>, Peter Anvin <hpa@zytor.com>,
Andi Kleen <andi@firstfloor.org>,
Christoph Lameter <cl@linux.com>, Ben Maurer <bmaurer@fb.com>,
Steven Rostedt <rostedt@goodmis.org>,
Josh Triplett <josh@joshtriplett.org>,
Catalin Marinas <catalin.marinas@arm.com>
Subject: Re: [RFC PATCH for 4.18 1/2] rseq: validate rseq_cs fields are < TASK_SIZE
Date: Fri, 29 Jun 2018 10:03:10 -0700 [thread overview]
Message-ID: <CA+55aFz8KyVqFsVnp-6g+thz7vmm5nK_FSdRTPSks7gsNVNRdQ@mail.gmail.com> (raw)
In-Reply-To: <247789350.9741.1530288432573.JavaMail.zimbra@efficios.com>
On Fri, Jun 29, 2018 at 9:07 AM Mathieu Desnoyers
<mathieu.desnoyers@efficios.com> wrote:
>
> This code is not invoked from syscalls, but rather on return from
> interrupt/trap after a preemption.
But when we register the rseq, we could easily check that the top bits
of the IP is clear, no?
Sure, user space can change it after the fact, but at that point it's
literally "user space is being intentionally stupid".
The real worry is that 32-bit compat code never initializes those bits
at all, no?
Linus
next prev parent reply other threads:[~2018-06-29 17:03 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-28 16:23 [RFC PATCH for 4.18 1/2] rseq: validate rseq_cs fields are < TASK_SIZE Mathieu Desnoyers
2018-06-28 16:23 ` [RFC PATCH for 4.18 2/2] rseq: check that rseq->rseq_cs padding is zero Mathieu Desnoyers
2018-06-28 16:53 ` Will Deacon
2018-06-28 20:55 ` Mathieu Desnoyers
2018-06-28 20:22 ` [RFC PATCH for 4.18 1/2] rseq: validate rseq_cs fields are < TASK_SIZE Andy Lutomirski
2018-06-28 20:56 ` Mathieu Desnoyers
2018-06-28 21:22 ` Linus Torvalds
2018-06-28 22:29 ` Mathieu Desnoyers
2018-06-28 23:29 ` Andy Lutomirski
2018-06-29 0:18 ` Linus Torvalds
2018-06-29 0:54 ` Mathieu Desnoyers
2018-06-29 1:08 ` Andy Lutomirski
2018-06-29 14:02 ` Linus Torvalds
2018-06-29 14:05 ` Mathieu Desnoyers
2018-06-29 14:17 ` Linus Torvalds
2018-06-29 15:03 ` Mathieu Desnoyers
[not found] ` <CA+55aFw==YnFJn7iGnKMW=RbPT74YHNa0QDF96mEdMPA2oX9SA@mail.gmail.com>
2018-06-29 15:54 ` Linus Torvalds
2018-06-29 16:07 ` Mathieu Desnoyers
2018-06-29 17:03 ` Linus Torvalds [this message]
2018-06-29 19:48 ` Mathieu Desnoyers
2018-06-29 20:39 ` Andy Lutomirski
2018-07-02 14:32 ` Mathieu Desnoyers
2018-07-02 16:04 ` Mathieu Desnoyers
2018-07-02 17:11 ` Andy Lutomirski
2018-07-02 19:00 ` Mathieu Desnoyers
2018-07-02 19:02 ` Andy Lutomirski
2018-07-02 19:31 ` Linus Torvalds
2018-07-02 20:12 ` Andy Lutomirski
2018-07-02 20:22 ` Linus Torvalds
2018-06-29 16:07 ` Andy Lutomirski
2018-06-29 13:55 ` Mathieu Desnoyers
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