From nobody Mon Dec 15 21:50:42 2025 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3D81621A44B for ; Thu, 8 May 2025 07:38:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746689932; cv=none; b=HxJmhSkcuTw0wEUC726KBgEzi0sIZ7HJC+1WRvq51RWha4aGr7Ae6OrFUbNpJSNgyNQZc5txcWXLyedaQp0WeDdHeye4b8hdyTwtsssAzvHf4NYt2Nfg495b6BV9JTQmczKSILs5Cr6H1up05LRIgEImZqt0YJRK6c7juhk+0Pc= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746689932; c=relaxed/simple; bh=k+C8E7fjxwPOS+3bQbBZwOzttwQoEn9g/Fznc0zc04s=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=QcImeM5uY3ClsHkTzVePxMc8aLIzz8/euujuaHXUZywdY30AfBbKcIN4UVwaEgt5xxIHdxSkYrec0PfkF151gx6Nq/1+TN9P82a2DdbFY4u6uG+qXAga7vGbYFd5ONziPaOp0+2+UXunqi/NZ0TupEhIkSazTf7ZdvK8hDUI8nU= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=KrL3BBrq; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="KrL3BBrq" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1746689929; 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=NNm/GVsc/U/JM9udHFGbUagWNhhVtJjmOoQfrIgRWUM=; b=KrL3BBrqXuRt5/H6gx4XljHC1avwG/fPr6DyEqUq+qr84JcM/fEJS4vRiYTgcnk/IWh6kn XrlZlBD7qFwiDKTnWORmq9M00BK7jnhExKDN/DgIEnvijfoyW8VDr+Lbgrr9LKpCBRNg1m m3n/mg711tFK7Yo7FRBQTISiJS+egxo= Received: from mx-prod-mc-02.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-10-6Xf9rjE3MSqDfkMdgcAf0Q-1; Thu, 08 May 2025 03:38:45 -0400 X-MC-Unique: 6Xf9rjE3MSqDfkMdgcAf0Q-1 X-Mimecast-MFC-AGG-ID: 6Xf9rjE3MSqDfkMdgcAf0Q_1746689925 Received: from mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.15]) (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 mx-prod-mc-02.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id C88D6195608A; Thu, 8 May 2025 07:38:44 +0000 (UTC) Received: from localhost (unknown [10.72.112.8]) by mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 6FDC21955F24; Thu, 8 May 2025 07:38:43 +0000 (UTC) Date: Thu, 8 May 2025 15:38:38 +0800 From: Baoquan He To: fuqiang wang Cc: Vivek Goyal , Dave Young , kexec@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH v5] x86/kexec: fix potential cmem->ranges out of bounds Message-ID: References: <20240108130720.228478-1-fuqiang.wang@easystack.cn> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20240108130720.228478-1-fuqiang.wang@easystack.cn> X-Scanned-By: MIMEDefang 3.0 on 10.30.177.15 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" 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. And using random kexec_buf for passing dm crypt keys may cause a range split too, add another extra slot here. 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@easy= stack.cn/ [3] https://lore.kernel.org/kexec/ZYQ6O%2F57sHAPxTHm@MiWiFi-R3L-srv/ Signed-off-by: fuqiang wang Signed-off-by: Baoquan He --- v4->v5: - This is on top of Coiby's LUKS patchset in branch mm-nonmm-unstable of akpm/mm.git. I did some adaption based on Coiby's patches. - [PATCH v9 0/8] Support kdump with LUKS encryption by reusing LUKS volume = keys arch/x86/kernel/crash.c | 23 +++++++++++++++++++---- 1 file changed, 19 insertions(+), 4 deletions(-) diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c index bcb534688dfe..749a60ce8b7f 100644 --- a/arch/x86/kernel/crash.c +++ b/arch/x86/kernel/crash.c @@ -165,8 +165,18 @@ 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 +=3D 2; + nr_ranges +=3D 3; cmem =3D vzalloc(struct_size(cmem, ranges, nr_ranges)); if (!cmem) return NULL; @@ -313,10 +323,15 @@ int crash_setup_memmap_entries(struct kimage *image, = struct boot_params *params) struct crash_mem *cmem; =20 /* - * Using random kexec_buf for passing dm crypt keys may cause a range - * split. So use two slots here. + * 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 an extra slot. + * + * And using random kexec_buf for passing dm crypt keys may cause a + * range split too, add another extra slot here. */ - nr_ranges =3D 2; + nr_ranges =3D 3; cmem =3D vzalloc(struct_size(cmem, ranges, nr_ranges)); if (!cmem) return -ENOMEM; --=20 2.41.0