From patchwork Tue Nov 5 20:58:30 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ard Biesheuvel X-Patchwork-Id: 11228615 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 8DADD1390 for ; Tue, 5 Nov 2019 21:09:25 +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 4FE232087E for ; Tue, 5 Nov 2019 21:09:25 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="p6Greesl"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="uwX4gepQ" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4FE232087E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.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:MIME-Version:Cc:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id: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=pFQIS0T1GEUHuspFy+QluvSpPU6NA7CszVZHNPtJRt0=; b=p6GreeslLewsUJqFkKam55yWoq DVeWzDzNcCifxnUtZne5sqVQPE1G6E9hyKW5CdoUwQParxqtupAqcl6O4ECbcvYFjlhAb0q+HrM3V o5ESqLVnj9N1vfzdRVrbv62tzfVp41JoPi02XxYIBJuKiqbuShE54Kxdaaqwdd/0h7M47xXG74a1s RPYouwJdp7Fffiv8nVbDxeVSuL1R5K8HASkMqta7eaAobetjdnhs5RM6Xh/SqaaDSVH423wz1WqhS N/G/SB/HQs2mY4G11zAlynuj+7UOCSZD9Y4noepD1jltwlE9c4G4vak8I1Fb9O0PDVeSPnaoa2y3Y 1jSdcoeg==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1iS64o-0000EK-WF; Tue, 05 Nov 2019 21:09:23 +0000 Received: from mail.kernel.org ([198.145.29.99]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1iS5wT-0007wj-1L for linux-arm-kernel@lists.infradead.org; Tue, 05 Nov 2019 21:00:46 +0000 Received: from e123331-lin.home (lfbn-mar-1-643-104.w90-118.abo.wanadoo.fr [90.118.215.104]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id EC6ED21D6C; Tue, 5 Nov 2019 21:00:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1572987644; bh=pA/Dm4dtcPygG47J2WY3DC/j1I2HfkxehJVrSXMlYDQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=uwX4gepQHKJFOXLKzZEmzsajx7FhFSW3RmPXNAL/Z3eghqBZR+MZwgxVfuwTgYJqM zLebEsyFNj8TnMkA/9VG2OrtrurnTxOU/chPzrxrMUxSu5dUdDb2j70bAR4HH9dffk whCg9RWXCZiv5PdYbJqsqIbV7nzN36DSrGej1fEo= From: Ard Biesheuvel To: linux-arm-kernel@lists.infradead.org Subject: [PATCH for-stable-v4.4 37/53] ARM: spectre-v1: use get_user() for __get_user() Date: Tue, 5 Nov 2019 21:58:30 +0100 Message-Id: <20191105205846.1394-38-ardb@kernel.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20191105205846.1394-1-ardb@kernel.org> References: <20191105205846.1394-1-ardb@kernel.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20191105_130045_117449_4102B7A1 X-CRM114-Status: GOOD ( 13.04 ) X-Spam-Score: -5.2 (-----) X-Spam-Report: SpamAssassin version 3.4.2 on bombadil.infradead.org summary: Content analysis details: (-5.2 points) pts rule name description ---- ---------------------- -------------------------------------------------- -5.0 RCVD_IN_DNSWL_HI RBL: Sender listed at https://www.dnswl.org/, high trust [198.145.29.99 listed in list.dnswl.org] -0.0 SPF_PASS SPF: sender matches SPF record 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record 0.1 DKIM_SIGNED Message has a DKIM or DK signature, not necessarily valid -0.1 DKIM_VALID_EF Message has a valid DKIM or DK signature from envelope-from domain -0.1 DKIM_VALID Message has at least one valid DKIM or DK signature -0.1 DKIM_VALID_AU Message has a valid DKIM or DK signature from author's domain -0.0 DKIMWL_WL_HIGH DKIMwl.org - Whitelisted High sender 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: Mark Rutland , Florian Fainelli , Greg Kroah-Hartman , Tony Lindgren , Catalin Marinas , Russell King , "David A . Long" , Marc Zyngier , Will Deacon , Ard Biesheuvel MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org From: Russell King Commit b1cd0a14806321721aae45f5446ed83a3647c914 upstream. Fixing __get_user() for spectre variant 1 is not sane: we would have to add address space bounds checking in order to validate that the location should be accessed, and then zero the address if found to be invalid. Since __get_user() is supposed to avoid the bounds check, and this is exactly what get_user() does, there's no point having two different implementations that are doing the same thing. So, when the Spectre workarounds are required, make __get_user() an alias of get_user(). Acked-by: Mark Rutland Signed-off-by: Russell King Signed-off-by: David A. Long Signed-off-by: Greg Kroah-Hartman Signed-off-by: Ard Biesheuvel --- arch/arm/include/asm/uaccess.h | 17 +++++++++++------ 1 file changed, 11 insertions(+), 6 deletions(-) diff --git a/arch/arm/include/asm/uaccess.h b/arch/arm/include/asm/uaccess.h index 99005567fb92..fd33021da6f6 100644 --- a/arch/arm/include/asm/uaccess.h +++ b/arch/arm/include/asm/uaccess.h @@ -288,6 +288,16 @@ static inline void set_fs(mm_segment_t fs) #define user_addr_max() \ (segment_eq(get_fs(), KERNEL_DS) ? ~0UL : get_fs()) +#ifdef CONFIG_CPU_SPECTRE +/* + * When mitigating Spectre variant 1, it is not worth fixing the non- + * verifying accessors, because we need to add verification of the + * address space there. Force these to use the standard get_user() + * version instead. + */ +#define __get_user(x, ptr) get_user(x, ptr) +#else + /* * The "__xxx" versions of the user access functions do not verify the * address space - it must have been done previously with a separate @@ -304,12 +314,6 @@ static inline void set_fs(mm_segment_t fs) __gu_err; \ }) -#define __get_user_error(x, ptr, err) \ -({ \ - __get_user_err((x), (ptr), err); \ - (void) 0; \ -}) - #define __get_user_err(x, ptr, err) \ do { \ unsigned long __gu_addr = (unsigned long)(ptr); \ @@ -369,6 +373,7 @@ do { \ #define __get_user_asm_word(x, addr, err) \ __get_user_asm(x, addr, err, ldr) +#endif #define __put_user_switch(x, ptr, __err, __fn) \