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=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, 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 B194EC3F2C6 for ; Tue, 3 Mar 2020 22:12:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8CEC820870 for ; Tue, 3 Mar 2020 22:12:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727912AbgCCWMN (ORCPT ); Tue, 3 Mar 2020 17:12:13 -0500 Received: from mail-qt1-f195.google.com ([209.85.160.195]:35453 "EHLO mail-qt1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727870AbgCCWMM (ORCPT ); Tue, 3 Mar 2020 17:12:12 -0500 Received: by mail-qt1-f195.google.com with SMTP id v15so1343497qto.2; Tue, 03 Mar 2020 14:12:10 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=vQx7FGziZfvZ+uJJoZ5T61fhrPtNY4KnIrK1LWeACyQ=; b=F2fHwcupiv+9VppG5BuYyxiA3sygvouUnZTyEbe4MafyardHB/vL6353Ly9WjviBRa eVyXoJCmpBNetNUcru9Pxkdf27DKy6P4AJG6Zy+ryl4WfzLhDLfdaImoXCpJEU2GtdxJ 5xPHjnZCkDPjxKw/eWRpMlFouiniK55nVRSj2czKgtAXW6kL1Rwacgjy3yIKlnIILReE lSAjDrmhbP2K6ljafCGVvuIDnF/DYwD5ckcOQwMbbiiY3x2W2ljAf/tpTjkSxX6TBXjm 49+h6EbTlydJR3P0tRKzqB4U5VmYvQDawxZtOuxoB/n2c4zEvxAkVg3HYs0namua0jOU zk2g== X-Gm-Message-State: ANhLgQ0rhgTMWm3KZdCu73Xe4LgGl2qLwnJUZ427spMzAiSavqyQClCP lPXTZxXOo0bnfOiNads7U0E= X-Google-Smtp-Source: ADFU+vshsB9lMkvhs9h+psMOIx/jhLBmuNrFpZxVybguzxUf9II1jZKtl8D8QMql12UAP4mzuoNLIw== X-Received: by 2002:aed:308a:: with SMTP id 10mr6647996qtf.221.1583273529360; Tue, 03 Mar 2020 14:12:09 -0800 (PST) Received: from rani.riverdale.lan ([2001:470:1f07:5f3::b55f]) by smtp.gmail.com with ESMTPSA id i91sm13267378qtd.70.2020.03.03.14.12.08 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 03 Mar 2020 14:12:09 -0800 (PST) From: Arvind Sankar To: Ard Biesheuvel Cc: linux-efi@vger.kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v2 4/5] efi/x86: Remove extra headroom for setup block Date: Tue, 3 Mar 2020 17:12:04 -0500 Message-Id: <20200303221205.4048668-5-nivedita@alum.mit.edu> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20200303221205.4048668-1-nivedita@alum.mit.edu> References: <20200301230537.2247550-1-nivedita@alum.mit.edu> <20200303221205.4048668-1-nivedita@alum.mit.edu> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 --- 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(); -- 2.24.1