From: Borislav Petkov <bp@suse.de>
To: speck@linutronix.de
Subject: [MODERATED] Re: [PATCH v3 06/10] [PATCH v3 6/9] Linux Patch #6
Date: Mon, 23 Apr 2018 20:57:55 +0200 [thread overview]
Message-ID: <20180423185755.GM24245@pd.tnic> (raw)
In-Reply-To: <20180423171426.795385641@dhcp-10-159-147-220.vpn.oracle.com>
On Mon, Apr 23, 2018 at 01:11:30PM -0400, speck for konrad.wilk_at_oracle.com wrote:
> x86/spec_store_bypass_disable: Provide boot parameters for the mitigation
>
> Contemporary high performance processors use a common industry-wide
> optimization known as "Speculative Store Bypass" in which loads from
> addresses to which a recent store has occurred may (speculatively)
> see an older value. Intel refers to this feature as "Memory
> Disambiguation", which is part of their "Smart Memory Access"
> capability in Nehalem and later generation processors.
>
> Some processors have an implementation bug that enables a cache
> side-channel attack against such speculatively read values. An
> attacker can create exploit code that allows them to read memory
> outside of a sandbox environment (for example, malicious JavaScript
> in a web page), or to perform more complex attacks against code
> running within the same privilege level, e.g. via the stack.
>
> We provide two command line control knobs:
>
> nospec_store_bypass_disable
> spec_store_bypass_disable=[off,auto,on]
Something's still fishy with this patch. I'm booting a guest with
spec_store_bypass_disable=on
but dmesg still says:
[ 0.044001] Speculative Store Bypass: Vulnerable
and sysfs:
$ grep . /sys/devices/system/cpu/vulnerabilities/*
/sys/devices/system/cpu/vulnerabilities/meltdown:Not affected
/sys/devices/system/cpu/vulnerabilities/spec_store_bypass:Vulnerable
--
Regards/Gruss,
Boris.
SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg)
--
next prev parent reply other threads:[~2018-04-23 18:58 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-23 17:11 [MODERATED] [PATCH v3 06/10] [PATCH v3 6/9] Linux Patch #6 konrad.wilk
2018-04-23 18:34 ` [MODERATED] " Borislav Petkov
2018-04-23 20:45 ` Jiri Kosina
2018-04-23 21:06 ` Borislav Petkov
2018-04-24 0:19 ` Konrad Rzeszutek Wilk
2018-04-23 18:57 ` Borislav Petkov [this message]
2018-04-23 19:08 ` Borislav Petkov
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