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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D57C8C4167B for ; Thu, 30 Nov 2023 07:45:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229688AbjK3Ho4 (ORCPT ); Thu, 30 Nov 2023 02:44:56 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44868 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231687AbjK3Hoy (ORCPT ); Thu, 30 Nov 2023 02:44:54 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0D964D6C for ; Wed, 29 Nov 2023 23:44:59 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1701330299; 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=kFX81jkgr22XnPLJhetZKt46F/xnkz4cCCAQykO/SFc=; b=XyVIkhwzl+zGAxLTEjzT3p1UETgjn0DwdeHUjPXRBdq8z9LL0B8l041jaHQpG8IKBRxrQt zF8Y+L3tsVebLSKBiyyt+LeEV6PrXCOgIQEzpyUoV7Cg4l2jZxspr98E+v1/aScW1lG7Px hDefYpjQL15tdJh8lY3V9GOxiFTfDnA= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-417-AHfMViECMDaF78Bs7fn4Uw-1; Thu, 30 Nov 2023 02:44:56 -0500 X-MC-Unique: AHfMViECMDaF78Bs7fn4Uw-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.rdu2.redhat.com [10.11.54.8]) (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 CD3E6185A781; Thu, 30 Nov 2023 07:44:55 +0000 (UTC) Received: from localhost (unknown [10.72.113.121]) by smtp.corp.redhat.com (Postfix) with ESMTPS id D7468C1596F; Thu, 30 Nov 2023 07:44:44 +0000 (UTC) Date: Thu, 30 Nov 2023 15:44:41 +0800 From: Baoquan He To: fuqiang wang Cc: Vivek Goyal , Dave Young , kexec@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] kexec: avoid out of bounds in crash_exclude_mem_range() Message-ID: References: <20231127025641.62210-1-fuqiang.wang@easystack.cn> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20231127025641.62210-1-fuqiang.wang@easystack.cn> X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.8 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/27/23 at 10:56am, fuqiang wang wrote: > When the split happened, judge whether mem->nr_ranges is equal to > mem->max_nr_ranges. If it is true, return -ENOMEM. > > The advantage of doing this is that it can avoid array bounds caused by > some bugs. E.g., Before commit 4831be702b95 ("arm64/kexec: Fix missing > extra range for crashkres_low."), reserve both high and low memories for > the crashkernel may cause out of bounds. > > On the other hand, move this code before the split to ensure that the > array will not be changed when return error. If out of array boundary is caused, means the laoding failed, whether the out of boundary happened or not. I don't see how this code change makes sense. Do I miss anything? Thanks Baoquan > > Signed-off-by: fuqiang wang > --- > kernel/crash_core.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/kernel/crash_core.c b/kernel/crash_core.c > index efe87d501c8c..ffdc246cf425 100644 > --- a/kernel/crash_core.c > +++ b/kernel/crash_core.c > @@ -611,6 +611,9 @@ int crash_exclude_mem_range(struct crash_mem *mem, > } > > if (p_start > start && p_end < end) { > + /* Split happened */ > + if (mem->nr_ranges == mem->max_nr_ranges) > + return -ENOMEM; > /* Split original range */ > mem->ranges[i].end = p_start - 1; > temp_range.start = p_end + 1; > @@ -626,9 +629,6 @@ int crash_exclude_mem_range(struct crash_mem *mem, > if (!temp_range.end) > return 0; > > - /* Split happened */ > - if (i == mem->max_nr_ranges - 1) > - return -ENOMEM; > > /* Location where new range should go */ > j = i + 1; > -- > 2.42.0 > > > _______________________________________________ > kexec mailing list > kexec@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/kexec >