From patchwork Sun Mar 8 08:08:49 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ard Biesheuvel X-Patchwork-Id: 206473 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 3CE0CC18E5F for ; Sun, 8 Mar 2020 08:10:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0B41722B48 for ; Sun, 8 Mar 2020 08:10:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1583655016; bh=t0zvztmSKZBoKnmOYnVnakURJ8XSfvQMNh6AI9EG5U4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=RR10sxvpQuGEajHTy/8GaamPgYKJLJooB3OS5ythndFFU1PfI/3Wx1faCqpsTYXIx bv+hGNMMElPyH0evfQhyErvoZDuSODXZ+Ndn93hXuJ4w3xdXMOXyibfqfVIHq0nFAJ +za2ealQto9ibuc8OeBw/fAc+YEgog6UAkvyF4/Q= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726438AbgCHIKM (ORCPT ); Sun, 8 Mar 2020 04:10:12 -0400 Received: from mail.kernel.org ([198.145.29.99]:37878 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726271AbgCHIKL (ORCPT ); Sun, 8 Mar 2020 04:10:11 -0400 Received: from e123331-lin.home (amontpellier-657-1-18-247.w109-210.abo.wanadoo.fr [109.210.65.247]) (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 668F02084E; Sun, 8 Mar 2020 08:10:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1583655010; bh=t0zvztmSKZBoKnmOYnVnakURJ8XSfvQMNh6AI9EG5U4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=HTgQG5AXw5GRdnhwSuCXacqg1T8fwvrsfRvDN7h/XavfpT75YOP3jQUC8HXm3r8S1 syj1PmSvVHIhQvV1l9dcjcuEi/mpKvHCY1I1vmo0Hc8go6UbLTIlW0Nb72Og7kMlFy 3SuLGoaJHpGSO/MTR/gmgGARKeXDzGU2Ws74gWzM= From: Ard Biesheuvel To: linux-efi@vger.kernel.org, Ingo Molnar , Thomas Gleixner Cc: Ard Biesheuvel , linux-kernel@vger.kernel.org, Arvind Sankar , Christoph Hellwig , David Hildenbrand , Davidlohr Bueso , Guenter Roeck , Heinrich Schuchardt , Jonathan Corbet , Lukas Bulwahn , Masahiro Yamada , Nikolai Merinov , Tom Lendacky , Vladis Dronov Subject: [PATCH 18/28] efi/x86: Remove extra headroom for setup block Date: Sun, 8 Mar 2020 09:08:49 +0100 Message-Id: <20200308080859.21568-19-ardb@kernel.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200308080859.21568-1-ardb@kernel.org> References: <20200308080859.21568-1-ardb@kernel.org> Sender: linux-efi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-efi@vger.kernel.org From: Arvind Sankar commit 223e3ee56f77 ("efi/x86: add headroom to decompressor BSS to account for setup block") added headroom to the PE image to account for the setup block, which wasn't used for the decompression buffer. Now that the decompression buffer is located at the start of the image, and includes the setup block, this is no longer required. Add a check to make sure that the head section of the compressed kernel won't overwrite itself while relocating. This is only for future-proofing as with current limits on the setup and the actual size of the head section, this can never happen. Signed-off-by: Arvind Sankar Link: https://lore.kernel.org/r/20200303221205.4048668-5-nivedita@alum.mit.edu Signed-off-by: Ard Biesheuvel --- arch/x86/boot/tools/build.c | 28 ++++++++++++++++++++++++++-- 1 file changed, 26 insertions(+), 2 deletions(-) diff --git a/arch/x86/boot/tools/build.c b/arch/x86/boot/tools/build.c index 90d403dfec80..3d03ad753ed5 100644 --- a/arch/x86/boot/tools/build.c +++ b/arch/x86/boot/tools/build.c @@ -65,6 +65,8 @@ unsigned long efi_pe_entry; unsigned long efi32_pe_entry; unsigned long kernel_info; unsigned long startup_64; +unsigned long _ehead; +unsigned long _end; /*----------------------------------------------------------------------*/ @@ -232,7 +234,7 @@ static void update_pecoff_text(unsigned int text_start, unsigned int file_sz, { unsigned int pe_header; unsigned int text_sz = file_sz - text_start; - unsigned int bss_sz = init_sz + text_start - file_sz; + unsigned int bss_sz = init_sz - file_sz; pe_header = get_unaligned_le32(&buf[0x3c]); @@ -259,7 +261,7 @@ static void update_pecoff_text(unsigned int text_start, unsigned int file_sz, put_unaligned_le32(file_sz - 512 + bss_sz, &buf[pe_header + 0x1c]); /* Size of image */ - put_unaligned_le32(init_sz + text_start, &buf[pe_header + 0x50]); + put_unaligned_le32(init_sz, &buf[pe_header + 0x50]); /* * Address of entry point for PE/COFF executable @@ -360,6 +362,8 @@ static void parse_zoffset(char *fname) PARSE_ZOFS(p, efi32_pe_entry); PARSE_ZOFS(p, kernel_info); PARSE_ZOFS(p, startup_64); + PARSE_ZOFS(p, _ehead); + PARSE_ZOFS(p, _end); p = strchr(p, '\n'); while (p && (*p == '\r' || *p == '\n')) @@ -444,6 +448,26 @@ int main(int argc, char ** argv) put_unaligned_le32(sys_size, &buf[0x1f4]); init_sz = get_unaligned_le32(&buf[0x260]); +#ifdef CONFIG_EFI_STUB + /* + * The decompression buffer will start at ImageBase. When relocating + * the compressed kernel to its end, we must ensure that the head + * section does not get overwritten. The head section occupies + * [i, i + _ehead), and the destination is [init_sz - _end, init_sz). + * + * At present these should never overlap, because i is at most 32k + * because of SETUP_SECT_MAX, _ehead is less than 1k, and the + * calculation of INIT_SIZE in boot/header.S ensures that + * init_sz - _end is at least 64k. + * + * For future-proofing, increase init_sz if necessary. + */ + + if (init_sz - _end < i + _ehead) { + init_sz = (i + _ehead + _end + 4095) & ~4095; + put_unaligned_le32(init_sz, &buf[0x260]); + } +#endif update_pecoff_text(setup_sectors * 512, i + (sys_size * 16), init_sz); efi_stub_entry_update();