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 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 39C79C35274 for ; Thu, 21 Dec 2023 13:14:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=5rXGFx+Moo7bmDiYh0q2emqbX1Fr1XKyNC7BAuHHYyw=; b=Z1SQ2rUYAGlUX0 acFkbxmht3tPl121cnul2WdQ2Cc7sXMlZHKGaI4WWbLazfaL1kJf8o+T/g9rMK73mcbFBX6bHEiUJ NHdbCjAU9rqUOcBaxXzs1Oa+yByqnKI1QfPPeqoIXMIQfY7oCjBA5bjjMfvns/Tmjo1USGtfttGCW bR80Oobxq/FnzrVAumZ93BtZNROBrJknqKG0pyFkaiYFWFJ4peGwMnSx5Rg98euU+BktB4mw6nFgn zG1hHE9SC/sPMz0R4xg84dAenr60cwJHPC3ZNdIQFjjQ99Crm5vTZ1ET1OxWHeGOseAjnCtX5L8Zd ne9FDWsZvnogrDuROWpw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1rGIsy-002ucA-2u; Thu, 21 Dec 2023 13:14:48 +0000 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1rGIsw-002ubn-1s for kexec@lists.infradead.org; Thu, 21 Dec 2023 13:14:47 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1703164485; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=1eNoYJka76W6z/XIQNg+OgUP1x/5sVSGmIF7sB3PyIM=; b=H/FcolORCuVhS2HJ1O/k5i0o78ZXGdNSLsUzCJBuDrxPSGe9zSbLSQ8rdtZ7/imGmikIS6 x+kgUIC6DkDc6OOR9Zi0q6s/FFj4J9JYiHWHW+5Fotv27FTG+svXmY9Qo5kQNhBjiKZmlL cLC8gxJk2MC+qltZ6SrG5NJKCIeYI4U= Received: from mimecast-mx02.redhat.com (mx-ext.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-454-9gOrF8nDO3O1s7WKoG1OmQ-1; Thu, 21 Dec 2023 08:14:39 -0500 X-MC-Unique: 9gOrF8nDO3O1s7WKoG1OmQ-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 8B5AD3816B4E; Thu, 21 Dec 2023 13:14:39 +0000 (UTC) Received: from localhost (unknown [10.72.116.38]) by smtp.corp.redhat.com (Postfix) with ESMTPS id D7ACC2166B31; Thu, 21 Dec 2023 13:14:38 +0000 (UTC) Date: Thu, 21 Dec 2023 21:14:35 +0800 From: Baoquan He To: fuqiang wang Cc: Vivek Goyal , Dave Young , Yuntao Wang , kexec@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 1/2] x86/kexec: Fix potential out of bounds in crash_setup_memmap_entries() Message-ID: References: <20231220055733.100325-1-fuqiang.wang@easystack.cn> <20231220055733.100325-2-fuqiang.wang@easystack.cn> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20231220055733.100325-2-fuqiang.wang@easystack.cn> X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.6 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20231221_051446_697985_7E48E92B X-CRM114-Status: GOOD ( 27.46 ) X-BeenThere: kexec@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "kexec" Errors-To: kexec-bounces+kexec=archiver.kernel.org@lists.infradead.org On 12/20/23 at 01:57pm, fuqiang wang wrote: > In memmap_exclude_ranges(), there will exclude elfheader from > crashk_res. In the current x86 architecture code, the elfheader is > always allocated at crashk_res.start. It seems that there won't be a > split a new range. But it depends on the allocation position of > elfheader in crashk_res. To avoid potential out of bounds in future, Set > the array size to 2. If so, I would suggest to add extra slot for low 1M too in fill_up_crash_elf_data() lest the low 1M could be changed in the future, e.g [start, 1M]. > > But similar issue will not exist in fill_up_crash_elf_data(). Because > the range to be excluded is [0, 1M], start (0) is special and will not > appear in the middle of existing cmem->ranges[]. I added a comment to > explain it. > > Signed-off-by: fuqiang wang > --- > arch/x86/kernel/crash.c | 20 ++++++++++++++------ > 1 file changed, 14 insertions(+), 6 deletions(-) > > diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c > index c92d88680dbf..1c15d0884c90 100644 > --- a/arch/x86/kernel/crash.c > +++ b/arch/x86/kernel/crash.c > @@ -149,6 +149,13 @@ static struct crash_mem *fill_up_crash_elf_data(void) > /* > * Exclusion of crash region and/or crashk_low_res may cause > * another range split. So add extra two slots here. > + * > + * Exclusion of low 1M may not cause another range split, because the > + * range of exclude is [0, 1M] and the condition for splitting a new > + * region is that the start, end parameters are both in a certain > + * existing region in cmem and cannot be equal to existing region's > + * start or end. Obviously, the start of [0, 1M] cannot meet this > + * condition. > */ > nr_ranges += 2; > cmem = vzalloc(struct_size(cmem, ranges, nr_ranges)); > @@ -282,9 +289,15 @@ int crash_setup_memmap_entries(struct kimage *image, struct boot_params *params) > struct crash_memmap_data cmd; > struct crash_mem *cmem; > > - cmem = vzalloc(struct_size(cmem, ranges, 1)); > + cmem = vzalloc(struct_size(cmem, ranges, 2)); > if (!cmem) > return -ENOMEM; > + cmem->max_nr_ranges = 2; > + > + /* Exclude some ranges from crashk_res and add rest to memmap */ > + ret = memmap_exclude_ranges(image, cmem, crashk_res.start, crashk_res.end); > + if (ret) > + goto out; > > memset(&cmd, 0, sizeof(struct crash_memmap_data)); > cmd.params = params; > @@ -320,11 +333,6 @@ int crash_setup_memmap_entries(struct kimage *image, struct boot_params *params) > add_e820_entry(params, &ei); > } > > - /* Exclude some ranges from crashk_res and add rest to memmap */ > - ret = memmap_exclude_ranges(image, cmem, crashk_res.start, crashk_res.end); > - if (ret) > - goto out; And you didn't mention moving above code block up in log. I would suggest keeping it as is because it looks more reasonable to be adjacent to the following cmem->ranges[] handling. > - > for (i = 0; i < cmem->nr_ranges; i++) { > ei.size = cmem->ranges[i].end - cmem->ranges[i].start + 1; > > -- > 2.42.0 > _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec