From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B33CEC433F5 for ; Wed, 9 Mar 2022 16:10:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234651AbiCIQK6 (ORCPT ); Wed, 9 Mar 2022 11:10:58 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43626 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234724AbiCIQH7 (ORCPT ); Wed, 9 Mar 2022 11:07:59 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 929F71480C8; Wed, 9 Mar 2022 08:04:15 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 8BBB6B82222; Wed, 9 Mar 2022 16:04:13 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B041BC340E8; Wed, 9 Mar 2022 16:04:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1646841852; bh=YYTxn4Nwrg6CuOgCloYwoSlfT43YKOmCi0fRD30gcL8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=XGXl3okeoLzEPiskxjwJkLwLfOq5VEnqRBYCDaU7zNKO42kDV0+YogiAmOa5ZkpL1 iCD7s1sjDXeok+guEWnXMwQ2eoUG/IAiDdnYGx6vUU/W+/72lqkaWcxocRax1Zar2s 0q0wjZ9KsJ/QrgcJDzwSEfJjlcf8lSu+FxTpwYkA= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "Russell King (Oracle)" Subject: [PATCH 5.4 17/18] ARM: include unprivileged BPF status in Spectre V2 reporting Date: Wed, 9 Mar 2022 17:00:06 +0100 Message-Id: <20220309155857.059352644@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220309155856.552503355@linuxfoundation.org> References: <20220309155856.552503355@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Russell King (Oracle) commit 25875aa71dfefd1959f07e626c4d285b88b27ac2 upstream. The mitigations for Spectre-BHB are only applied when an exception is taken, but when unprivileged BPF is enabled, userspace can load BPF programs that can be used to exploit the problem. When unprivileged BPF is enabled, report the vulnerable status via the spectre_v2 sysfs file. Signed-off-by: Russell King (Oracle) Signed-off-by: Greg Kroah-Hartman --- arch/arm/kernel/spectre.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) --- a/arch/arm/kernel/spectre.c +++ b/arch/arm/kernel/spectre.c @@ -1,9 +1,19 @@ // SPDX-License-Identifier: GPL-2.0-only +#include #include #include #include +static bool _unprivileged_ebpf_enabled(void) +{ +#ifdef CONFIG_BPF_SYSCALL + return !sysctl_unprivileged_bpf_disabled; +#else + return false +#endif +} + ssize_t cpu_show_spectre_v1(struct device *dev, struct device_attribute *attr, char *buf) { @@ -31,6 +41,9 @@ ssize_t cpu_show_spectre_v2(struct devic if (spectre_v2_state != SPECTRE_MITIGATED) return sprintf(buf, "%s\n", "Vulnerable"); + if (_unprivileged_ebpf_enabled()) + return sprintf(buf, "Vulnerable: Unprivileged eBPF enabled\n"); + switch (spectre_v2_methods) { case SPECTRE_V2_METHOD_BPIALL: method = "Branch predictor hardening";