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 X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A0C00C3A589 for ; Thu, 15 Aug 2019 15:45:16 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 726DF20665 for ; Thu, 15 Aug 2019 15:45:16 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="q4S0V7ak" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 726DF20665 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=Ej+Yw6UZAoHBB2VqhPT/WMc2zANYG2uMcrz/FiDBHTM=; b=q4S0V7akOBIOY1 C7vpNBdhXTvAypLsYyJH69Q4mN/WEBWrU/re8PTMSlQG81bYmzcDLcNqwWJx7RhRC2vROF7nvw7e9 vAqwjNZBcdv0RkILjKlNeG/giKcSEVePStZBFdouNbbAMw23Er3UEX3/VBs1uerfAsrjwugPzhrUv cGrnJO3s/k/mLI1TkTKBlFec8k9yI5sOl+VpGtfuTqKwlofdsDoq/rdYhhFB/AX/9tmGUNQLb4pIa NARPjBF9lFts9eXDAUikSDtTMaCGeHznZMZAtGimB5P/+sfQyWABjKtOeCH1jpO37/8DcH2em/8a8 BhPFg6RGsy/7QqJY6+1A==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92 #3 (Red Hat Linux)) id 1hyHw4-0003kB-Gd; Thu, 15 Aug 2019 15:45:08 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.92 #3 (Red Hat Linux)) id 1hyHvC-0002IS-Jl for linux-arm-kernel@lists.infradead.org; Thu, 15 Aug 2019 15:44:20 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 956C81596; Thu, 15 Aug 2019 08:44:13 -0700 (PDT) Received: from arrakis.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id E56B43F706; Thu, 15 Aug 2019 08:44:11 -0700 (PDT) From: Catalin Marinas To: linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org Subject: [PATCH v8 3/5] arm64: Change the tagged_addr sysctl control semantics to only prevent the opt-in Date: Thu, 15 Aug 2019 16:44:01 +0100 Message-Id: <20190815154403.16473-4-catalin.marinas@arm.com> X-Mailer: git-send-email 2.23.0.rc0 In-Reply-To: <20190815154403.16473-1-catalin.marinas@arm.com> References: <20190815154403.16473-1-catalin.marinas@arm.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190815_084414_687714_90AA310D X-CRM114-Status: GOOD ( 13.13 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-arch@vger.kernel.org, linux-doc@vger.kernel.org, Szabolcs Nagy , Andrey Konovalov , Kevin Brodsky , Will Deacon , Dave Hansen , Andrew Morton , Vincenzo Frascino , Dave P Martin Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org First rename the sysctl control to abi.tagged_addr_disabled and make it default off (zero). When abi.tagged_addr_disabled == 1, only block the enabling of the TBI ABI via prctl(PR_SET_TAGGED_ADDR_CTRL, PR_TAGGED_ADDR_ENABLE). Getting the status of the ABI or disabling it is still allowed. Signed-off-by: Catalin Marinas --- arch/arm64/kernel/process.c | 17 ++++++++++------- 1 file changed, 10 insertions(+), 7 deletions(-) diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c index 76b7c55026aa..03689c0beb34 100644 --- a/arch/arm64/kernel/process.c +++ b/arch/arm64/kernel/process.c @@ -579,17 +579,22 @@ void arch_setup_new_exec(void) /* * Control the relaxed ABI allowing tagged user addresses into the kernel. */ -static unsigned int tagged_addr_prctl_allowed = 1; +static unsigned int tagged_addr_disabled; long set_tagged_addr_ctrl(unsigned long arg) { - if (!tagged_addr_prctl_allowed) - return -EINVAL; if (is_compat_task()) return -EINVAL; if (arg & ~PR_TAGGED_ADDR_ENABLE) return -EINVAL; + /* + * Do not allow the enabling of the tagged address ABI if globally + * disabled via sysctl abi.tagged_addr_disabled. + */ + if (arg & PR_TAGGED_ADDR_ENABLE && tagged_addr_disabled) + return -EINVAL; + update_thread_flag(TIF_TAGGED_ADDR, arg & PR_TAGGED_ADDR_ENABLE); return 0; @@ -597,8 +602,6 @@ long set_tagged_addr_ctrl(unsigned long arg) long get_tagged_addr_ctrl(void) { - if (!tagged_addr_prctl_allowed) - return -EINVAL; if (is_compat_task()) return -EINVAL; @@ -618,9 +621,9 @@ static int one = 1; static struct ctl_table tagged_addr_sysctl_table[] = { { - .procname = "tagged_addr", + .procname = "tagged_addr_disabled", .mode = 0644, - .data = &tagged_addr_prctl_allowed, + .data = &tagged_addr_disabled, .maxlen = sizeof(int), .proc_handler = proc_dointvec_minmax, .extra1 = &zero, _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel