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=-19.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_RED,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 3467DC43600 for ; Mon, 26 Apr 2021 07:49:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1D39B61029 for ; Mon, 26 Apr 2021 07:49:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234114AbhDZHtl (ORCPT ); Mon, 26 Apr 2021 03:49:41 -0400 Received: from mail.kernel.org ([198.145.29.99]:56330 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233342AbhDZHlh (ORCPT ); Mon, 26 Apr 2021 03:41:37 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 7CF6061360; Mon, 26 Apr 2021 07:38:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1619422735; bh=vR086/OtZmjhhp5C+vQyX2/QF1h1eIf1xXETMKsRN5g=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=WCGNKyH4zYGCrmJ9T4le0cPaAqwGULRhzZa+KKEtR+kKX+PimHRhOKDox307PsKoH ioS5HiwWoMyi45ZnFckgPc3quWlbi8ckROEPf8KP/z54KYfupxlYGhi0/JEpFkgWo8 qUt97W6cRsaTt+/QsOa4t+vGHrMJ5ciN0O1DzBZo= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Mike Galbraith , Borislav Petkov , Dave Young Subject: [PATCH 5.4 20/20] x86/crash: Fix crash_setup_memmap_entries() out-of-bounds access Date: Mon, 26 Apr 2021 09:30:11 +0200 Message-Id: <20210426072817.360292254@linuxfoundation.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210426072816.686976183@linuxfoundation.org> References: <20210426072816.686976183@linuxfoundation.org> User-Agent: quilt/0.66 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 From: Mike Galbraith commit 5849cdf8c120e3979c57d34be55b92d90a77a47e upstream. Commit in Fixes: added support for kexec-ing a kernel on panic using a new system call. As part of it, it does prepare a memory map for the new kernel. However, while doing so, it wrongly accesses memory it has not allocated: it accesses the first element of the cmem->ranges[] array in memmap_exclude_ranges() but it has not allocated the memory for it in crash_setup_memmap_entries(). As KASAN reports: BUG: KASAN: vmalloc-out-of-bounds in crash_setup_memmap_entries+0x17e/0x3a0 Write of size 8 at addr ffffc90000426008 by task kexec/1187 (gdb) list *crash_setup_memmap_entries+0x17e 0xffffffff8107cafe is in crash_setup_memmap_entries (arch/x86/kernel/crash.c:322). 317 unsigned long long mend) 318 { 319 unsigned long start, end; 320 321 cmem->ranges[0].start = mstart; 322 cmem->ranges[0].end = mend; 323 cmem->nr_ranges = 1; 324 325 /* Exclude elf header region */ 326 start = image->arch.elf_load_addr; (gdb) Make sure the ranges array becomes a single element allocated. [ bp: Write a proper commit message. ] Fixes: dd5f726076cc ("kexec: support for kexec on panic using new system call") Signed-off-by: Mike Galbraith Signed-off-by: Borislav Petkov Reviewed-by: Dave Young Cc: Link: https://lkml.kernel.org/r/725fa3dc1da2737f0f6188a1a9701bead257ea9d.camel@gmx.de Signed-off-by: Greg Kroah-Hartman --- arch/x86/kernel/crash.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/arch/x86/kernel/crash.c +++ b/arch/x86/kernel/crash.c @@ -364,7 +364,7 @@ int crash_setup_memmap_entries(struct ki struct crash_memmap_data cmd; struct crash_mem *cmem; - cmem = vzalloc(sizeof(struct crash_mem)); + cmem = vzalloc(struct_size(cmem, ranges, 1)); if (!cmem) return -ENOMEM;