From nobody Tue Nov 26 04:26:58 2024 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D46CF1FEFD2; Mon, 21 Oct 2024 22:16:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=193.142.43.55 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729548975; cv=none; b=RSjq+pxpc5EsRC86hIPbV6+jSldcxzYPAm19SO27saSc/FLr35CWGJ1d0wDoHUzyJt/AOgVKSfA8h9rItNaVbQZ30B+wonMg7TOIxfUYG5ZDBW3YTl6mckk23y8ARQAWQWi8e/iH3JS7MxQKhwmvQ4A+49PLGc/Jz1FmKwBkuZo= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729548975; c=relaxed/simple; bh=o/21IDi3z+3r/CfWZohnh+gwI8lcHwVWkH/yH95StvA=; h=Date:From:To:Subject:Cc:MIME-Version:Message-ID:Content-Type; b=VOOf8tb0jgyKDQeod5TvzmWs0DZ6idZDO1xtJIIHqRQRBRO928D0zrrmVPbfIkr/33Z5tMfnZKHf6TxX1QQpI2uJ5rWIaxQJCV7TlA+ao7lIyFB+rhhYm8eQ5M56rXbFscDEHYEWHqsYZklcN0DgqDCd/ObS5tHKjgRe2M++rkk= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de; spf=pass smtp.mailfrom=linutronix.de; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=cSx5KWTL; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=c0wDeuB8; arc=none smtp.client-ip=193.142.43.55 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linutronix.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="cSx5KWTL"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="c0wDeuB8" Date: Mon, 21 Oct 2024 22:16:09 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1729548970; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=F/VQH6ij6E//+e6oHqxact1RCWdlNziDjscxF7SHn/A=; b=cSx5KWTLQfVlVsanarHTdIPWf0b2r7oSvQGO8goTivqT115Hvof/Xo/jnfWgO1HDZhTxPY YalStZhRT2tYj63JDs+KOhWrwuLVX2Rz8h8ZionNCS/PldjTtDSwyfVbEXrh4XD24x5S2y ti5k2FeAeNIuASee2ZeAIADX9q2irKfg2XAdKP1a393Bm/aozcBKoVrTP2MsPZ/gTKIlYM 5tkUkyuc9OFaCejjhyFGfP2ROkGLpgK6QWhUKOfJpHNlzq4l01dU2hQqMkNp7HyJYayqoV uEozhMY7ukCVrWrQYYIZA3DdeuXw7gNK/jR9f5Vh2bO7JGjX4ARULELTRkQM9w== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1729548970; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=F/VQH6ij6E//+e6oHqxact1RCWdlNziDjscxF7SHn/A=; b=c0wDeuB8QM+B/AbKR/7i28++aq2WdmwkDQW5LAOVemEEL7dJyOOldKtA3pd0erhV5WbJZm WGc4Hzxbfui4cXDQ== From: "tip-bot2 for Pawan Gupta" Sender: tip-bot2@linutronix.de Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: x86/urgent] x86/lam: Disable ADDRESS_MASKING in most cases Cc: Pawan Gupta , Dave Hansen , Sohil Mehta , "Kirill A. Shutemov" , stable@vger.kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-ID: <172954896978.1442.12851270945186118443.tip-bot2@tip-bot2> Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Precedence: bulk Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable The following commit has been merged into the x86/urgent branch of tip: Commit-ID: 3267cb6d3a174ff83d6287dcd5b0047bbd912452 Gitweb: https://git.kernel.org/tip/3267cb6d3a174ff83d6287dcd5b0047bb= d912452 Author: Pawan Gupta AuthorDate: Tue, 23 Jan 2024 19:55:21 -08:00 Committer: Dave Hansen CommitterDate: Mon, 21 Oct 2024 15:05:43 -07:00 x86/lam: Disable ADDRESS_MASKING in most cases Linear Address Masking (LAM) has a weakness related to transient execution as described in the SLAM paper[1]. Unless Linear Address Space Separation (LASS) is enabled this weakness may be exploitable. Until kernel adds support for LASS[2], only allow LAM for COMPILE_TEST, or when speculation mitigations have been disabled at compile time, otherwise keep LAM disabled. There are no processors in market that support LAM yet, so currently nobody is affected by this issue. [1] SLAM: https://download.vusec.net/papers/slam_sp24.pdf [2] LASS: https://lore.kernel.org/lkml/20230609183632.48706-1-alexander.shi= shkin@linux.intel.com/ [ dhansen: update SPECULATION_MITIGATIONS -> CPU_MITIGATIONS ] Signed-off-by: Pawan Gupta Signed-off-by: Dave Hansen Reviewed-by: Sohil Mehta Acked-by: Kirill A. Shutemov Cc:stable@vger.kernel.org Link: https://lore.kernel.org/all/5373262886f2783f054256babdf5a98545dc986b.= 1706068222.git.pawan.kumar.gupta%40linux.intel.com --- arch/x86/Kconfig | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 2852fcd..16354df 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -2257,6 +2257,7 @@ config RANDOMIZE_MEMORY_PHYSICAL_PADDING config ADDRESS_MASKING bool "Linear Address Masking support" depends on X86_64 + depends on COMPILE_TEST || !CPU_MITIGATIONS # wait for LASS help Linear Address Masking (LAM) modifies the checking that is applied to 64-bit linear addresses, allowing software to use of the