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 78AA2C3DA6E for ; Mon, 8 Jan 2024 13:07:58 +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:MIME-Version:Message-ID:Date:Subject:Cc :To:From:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References: List-Owner; bh=kNadNjwd+tRzvilVdVp16QhT3RnAl79xAn7t3vtR0CE=; b=zanUG99fmUSmPI 3II5JXCN+WNahxXInG9yjzGe643jaa8UaU2qekU/NzYR/+omBYUqQWmwsBVBqIA9/y8BhPE1vBnUX KEQQSCYVo6WNM87oEmz/hbIvFeObFWNiALcNKO7i1N015btGf8jS10XEfoesX3KfiSb4hoc+9pCCe /elw1vh0e3X5pbsPtYGZtUrTuyRKWLz2VVpzu6EJcooZpGl7BbotPBQKopmu5G4I31V6GVqxCb8B6 2T6Pwma6T/7vqkg1O8ac38OT3K/82EUlGD4gcMDZ1nRBMcPTOAzIbUz7aCKgpPRW9K2U6DAUXXKtF qx9cESlgt5tVPtjQ7pDw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1rMpMA-005AIc-01; Mon, 08 Jan 2024 13:07:54 +0000 Received: from mail-m12816.netease.com ([103.209.128.16]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1rMpM6-005AGP-2f for kexec@lists.infradead.org; Mon, 08 Jan 2024 13:07:52 +0000 Received: from fedora.. (unknown [211.103.144.18]) by smtp.qiye.163.com (Hmail) with ESMTPA id 386114C0297; Mon, 8 Jan 2024 21:07:33 +0800 (CST) From: fuqiang wang To: Baoquan He , Vivek Goyal , Dave Young Cc: kexec@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH v4] x86/kexec: fix potential cmem->ranges out of bounds Date: Mon, 8 Jan 2024 21:06:47 +0800 Message-ID: <20240108130720.228478-1-fuqiang.wang@easystack.cn> X-Mailer: git-send-email 2.42.0 MIME-Version: 1.0 X-HM-Spam-Status: e1kfGhgUHx5ZQUpXWQgPGg8OCBgUHx5ZQUlOS1dZFg8aDwILHllBWSg2Ly tZV1koWUFJQjdXWS1ZQUlXWQ8JGhUIEh9ZQVkaTkIYVk5OGRhKQxpIGRlOT1UZERMWGhIXJBQOD1 lXWRgSC1lBWUlKSlVKS0hVSk9PVUpDWVdZFhoPEhUdFFlBWU9LSFVKTU9JTE5VSktLVUpCS0tZBg ++ X-HM-Tid: 0a8ce92f7fc0022ekunm386114c0297 X-HM-MType: 1 X-HM-Sender-Digest: e1kMHhlZQR0aFwgeV1kSHx4VD1lBWUc6MhQ6Pww5ITczExAPIwoZIik0 D0wKCg9VSlVKTEtPTEpCSU5PS0lIVTMWGhIXVR0OChIaFRxVDBoVHDseGggCCA8aGBBVGBVFWVdZ EgtZQVlJSkpVSktIVUpPT1VKQ1lXWQgBWUFITk5MNwY+ X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240108_050751_092359_D70B1F04 X-CRM114-Status: GOOD ( 13.78 ) 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 In memmap_exclude_ranges(), elfheader will be excluded 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 new split range. But it depends on the allocation position of elfheader in crashk_res. To avoid potential out of bounds in future, add a extra slot. The similar issue also exists in fill_up_crash_elf_data(). The range to be excluded is [0, 1M], start (0) is special and will not appear in the middle of existing cmem->ranges[]. But in cast the low 1M could be changed in the future, add a extra slot too. Previously discussed link: [1] https://lore.kernel.org/kexec/ZXk2oBf%2FT1Ul6o0c@MiWiFi-R3L-srv/ [2] https://lore.kernel.org/kexec/273284e8-7680-4f5f-8065-c5d780987e59@easystack.cn/ [3] https://lore.kernel.org/kexec/ZYQ6O%2F57sHAPxTHm@MiWiFi-R3L-srv/ Signed-off-by: fuqiang wang --- arch/x86/kernel/crash.c | 21 +++++++++++++++++++-- 1 file changed, 19 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c index b6b044356f1b..d21592ad8952 100644 --- a/arch/x86/kernel/crash.c +++ b/arch/x86/kernel/crash.c @@ -149,8 +149,18 @@ 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. + * + * But in order to lest the low 1M could be changed in the future, + * (e.g. [stare, 1M]), add a extra slot. */ - nr_ranges += 2; + nr_ranges += 3; cmem = vzalloc(struct_size(cmem, ranges, nr_ranges)); if (!cmem) return NULL; @@ -282,9 +292,16 @@ 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)); + /* + * In the current x86 architecture code, the elfheader is always + * allocated at crashk_res.start. But it depends on the allocation + * position of elfheader in crashk_res. To avoid potential out of + * bounds in future, add a extra slot. + */ + cmem = vzalloc(struct_size(cmem, ranges, 2)); if (!cmem) return -ENOMEM; + cmem->max_nr_ranges = 2; memset(&cmd, 0, sizeof(struct crash_memmap_data)); cmd.params = params; -- 2.42.0 _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec