From: Thomas Gleixner <tglx@linutronix.de>
To: Dave Hansen <dave.hansen@intel.com>, Andrei Vagin <avagin@gmail.com>
Cc: Andrei Vagin <avagin@google.com>, Ingo Molnar <mingo@redhat.com>,
Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
LKML <linux-kernel@vger.kernel.org>,
x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>
Subject: Re: [PATCH] x86/fpu: verify xstate buffer size according with requested features
Date: Thu, 18 Jan 2024 20:54:43 +0100 [thread overview]
Message-ID: <87cytyfmd8.ffs@tglx> (raw)
In-Reply-To: <54bcb902-0fab-4a53-8b8e-85b6e4484b03@intel.com>
On Thu, Jan 18 2024 at 10:27, Dave Hansen wrote:
> If we have nice, reliable fault handling and then decide that we've got
> XRSTOR's running amok reading random memory all over the place that need
> a nicer error message, then we can add that code to predict the future.
> If our "predict the future" code goes wrong, then we lose an error
> message -- not a big deal.
After staring more at it, it's arguable to pass fpstate->user_size to
fault_in_readable() and ignore fx_sw->xstate_size completely.
That's a guaranteed to be reliable size which prevents endless loops
because arguably that's the maximum size which can be touched by XRSTOR,
no?
Thanks,
tglx
next prev parent reply other threads:[~2024-01-18 19:54 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20240116234901.3238852-1-avagin@google.com>
2024-01-17 19:34 ` [PATCH] x86/fpu: verify xstate buffer size according with requested features Dave Hansen
2024-01-17 22:30 ` Andrei Vagin
2024-01-17 23:52 ` Dave Hansen
2024-01-18 7:59 ` Andrei Vagin
2024-01-18 18:27 ` Dave Hansen
2024-01-18 19:54 ` Thomas Gleixner [this message]
2024-01-18 22:02 ` Dave Hansen
2024-01-18 22:11 ` Thomas Gleixner
2024-01-22 3:58 ` Andrei Vagin
2024-01-22 13:26 ` Thomas Gleixner
2024-01-18 19:07 ` Thomas Gleixner
2024-01-22 6:43 ` Andrei Vagin
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