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=-13.1 required=3.0 tests=BAYES_00,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=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 3EFDBC56201 for ; Thu, 12 Nov 2020 17:27:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C680F21556 for ; Thu, 12 Nov 2020 17:27:36 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="g/uHxEx1" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726201AbgKLR1f (ORCPT ); Thu, 12 Nov 2020 12:27:35 -0500 Received: from mail.kernel.org ([198.145.29.99]:50272 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725987AbgKLR1f (ORCPT ); Thu, 12 Nov 2020 12:27:35 -0500 Received: from localhost.localdomain (NE2965lan1.rev.em-net.ne.jp [210.141.244.193]) (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 0C3C0206E3; Thu, 12 Nov 2020 17:27:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1605202055; bh=urU3aH0It6scRF1tkqFLeTyV8ysZWvq0v8UlroBr8Os=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=g/uHxEx13+TaKej0WaPFvrkDuQCUiZ2sQzBRKI5tLFCj9VuJ8RDgYEBeTov2e81MB q1epoKj3tmae+JCzeKYjj+vt0vsgUX3Sqjhbusgwn8bd8NA5ZCbQfAiFQvRlhx6m5F M5ZFiY4eHsWqrlzaAQkKTf/CkGljMvbo0cz5U6Ks= From: Masami Hiramatsu To: Steven Rostedt Cc: Chen Yu , Chen Yu , Masami Hiramatsu , linux-kernel@vger.kernel.org Subject: [PATCH] bootconfig: Extend the magic check range to the preceding 3 bytes Date: Fri, 13 Nov 2020 02:27:31 +0900 Message-Id: <160520205132.303174.4876760192433315429.stgit@devnote2> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20201113003633.8db2b4e4c5fecf8de0adfa65@kernel.org> References: <20201113003633.8db2b4e4c5fecf8de0adfa65@kernel.org> User-Agent: StGit/0.19 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Since Grub may align the size of initrd to 4 if user pass initrd from cpio, we have to check the preceding 3 bytes as well. Fixes: 85c46b78da58 ("bootconfig: Add bootconfig magic word for indicating bootconfig explicitly") Reported-by: Chen Yu Signed-off-by: Masami Hiramatsu --- init/main.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) diff --git a/init/main.c b/init/main.c index 130376ec10ba..20baced721ad 100644 --- a/init/main.c +++ b/init/main.c @@ -269,14 +269,24 @@ static void * __init get_boot_config_from_initrd(u32 *_size, u32 *_csum) u32 size, csum; char *data; u32 *hdr; + int i; if (!initrd_end) return NULL; data = (char *)initrd_end - BOOTCONFIG_MAGIC_LEN; - if (memcmp(data, BOOTCONFIG_MAGIC, BOOTCONFIG_MAGIC_LEN)) - return NULL; + /* + * Since Grub may align the size of initrd to 4, we must + * check the preceding 3 bytes as well. + */ + for (i = 0; i < 4; i++) { + if (!memcmp(data, BOOTCONFIG_MAGIC, BOOTCONFIG_MAGIC_LEN)) + goto found; + data--; + } + return NULL; +found: hdr = (u32 *)(data - 8); size = hdr[0]; csum = hdr[1];