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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 D6AD4C2BA83 for ; Fri, 14 Feb 2020 16:57:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B0A1D2067D for ; Fri, 14 Feb 2020 16:57:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581699440; bh=FDLTKae5L6Lt5h3s6D/TeS96VdvhDxPetZvWw6O8jx4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=f5khh69HZr2xtYDGXRiR2vFoHLWIOXZOj827dCXRsKYEMc4P2TiLMW7kuB1t285P3 nnUgZ2U75hinCR0sQDtrRt/uz9jLUEyI3Yhh685KappmGpcUgd9KEQ3QxSEZ0FOUzU 6/yydicY+m84yRBFbIbmOxJBM5m1/pxFROeCEI30= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2394353AbgBNQ5P (ORCPT ); Fri, 14 Feb 2020 11:57:15 -0500 Received: from mail.kernel.org ([198.145.29.99]:49384 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2404556AbgBNQRr (ORCPT ); Fri, 14 Feb 2020 11:17:47 -0500 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (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 72EB5246EB; Fri, 14 Feb 2020 16:17:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581697066; bh=FDLTKae5L6Lt5h3s6D/TeS96VdvhDxPetZvWw6O8jx4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=iQH8ahVm9eNUFCI5tsy5d+sTnguyNMHHA376AvwrBIjwxQQdzOAPaB3BFTdgiraNJ OUvb0cZV90E3/pUgvKHefbmMQwbzTgwUpJxz6W3FkRV7w1z/iqI7WnUPvEPk8Zy4/5 54QRG+yuBQaKYbLmxGkH9l9e1JsDuZ/xTKSkV36k= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Ard Biesheuvel , Andy Lutomirski , Ard Biesheuvel , Arvind Sankar , Matthew Garrett , linux-efi@vger.kernel.org, Ingo Molnar , Sasha Levin , platform-driver-x86@vger.kernel.org, x86@kernel.org Subject: [PATCH AUTOSEL 4.14 023/186] efi/x86: Map the entire EFI vendor string before copying it Date: Fri, 14 Feb 2020 11:14:32 -0500 Message-Id: <20200214161715.18113-23-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200214161715.18113-1-sashal@kernel.org> References: <20200214161715.18113-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-efi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-efi@vger.kernel.org From: Ard Biesheuvel [ Upstream commit ffc2760bcf2dba0dbef74013ed73eea8310cc52c ] Fix a couple of issues with the way we map and copy the vendor string: - we map only 2 bytes, which usually works since you get at least a page, but if the vendor string happens to cross a page boundary, a crash will result - only call early_memunmap() if early_memremap() succeeded, or we will call it with a NULL address which it doesn't like, - while at it, switch to early_memremap_ro(), and array indexing rather than pointer dereferencing to read the CHAR16 characters. Signed-off-by: Ard Biesheuvel Cc: Andy Lutomirski Cc: Ard Biesheuvel Cc: Arvind Sankar Cc: Matthew Garrett Cc: linux-efi@vger.kernel.org Fixes: 5b83683f32b1 ("x86: EFI runtime service support") Link: https://lkml.kernel.org/r/20200103113953.9571-5-ardb@kernel.org Signed-off-by: Ingo Molnar Signed-off-by: Sasha Levin --- arch/x86/platform/efi/efi.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c index 335a62e74a2e9..5b0275310070e 100644 --- a/arch/x86/platform/efi/efi.c +++ b/arch/x86/platform/efi/efi.c @@ -480,7 +480,6 @@ void __init efi_init(void) efi_char16_t *c16; char vendor[100] = "unknown"; int i = 0; - void *tmp; #ifdef CONFIG_X86_32 if (boot_params.efi_info.efi_systab_hi || @@ -505,14 +504,16 @@ void __init efi_init(void) /* * Show what we know for posterity */ - c16 = tmp = early_memremap(efi.systab->fw_vendor, 2); + c16 = early_memremap_ro(efi.systab->fw_vendor, + sizeof(vendor) * sizeof(efi_char16_t)); if (c16) { - for (i = 0; i < sizeof(vendor) - 1 && *c16; ++i) - vendor[i] = *c16++; + for (i = 0; i < sizeof(vendor) - 1 && c16[i]; ++i) + vendor[i] = c16[i]; vendor[i] = '\0'; - } else + early_memunmap(c16, sizeof(vendor) * sizeof(efi_char16_t)); + } else { pr_err("Could not map the firmware vendor!\n"); - early_memunmap(tmp, 2); + } pr_info("EFI v%u.%.02u by %s\n", efi.systab->hdr.revision >> 16, -- 2.20.1