From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (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 B01AE21018F for ; Thu, 8 May 2025 07:52:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746690735; cv=none; b=ReWKOkoI4K5xVe4mtwMAvmbekvnC6pE7AOwTHWr/tN0j2v2jBCKUt39ix3PF3czrNeyRJ8nOWmgbxaDxcjW/hDJnwmaeCBN9LTQSbeZ8P1lDHdX/+GzJd3shG0jBEuqz7ARHU+KlAd/Rm48kd6VaAmfIrdiAYny4vzWywVIpJqs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746690735; c=relaxed/simple; bh=WCRZByRUZpxmsXzHGVCvKrD10+f8Bu3lRPM31G4RUNU=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Ew/rLTlanccAMUEhJov0RGjzs+dI0IwehDRhcL6ZogdplBrmTpKh9Ha+0Sz9knv1wOQXriT1wwH7JjphyX0LDnvSxora9XL9IezREjmZW9Lslie16xGC/4+YrZGAWpE6Q5FVVfiFX8P1p56k0LV1oCQOBGp1uLFvvz/tWZr/j0E= 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=e02cnDo+; arc=none smtp.client-ip=170.10.129.124 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="e02cnDo+" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1746690732; 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=9Ym5IsgJPELXlmxVUiqqeE5x95LD2/wvG6YGV47RIG4=; b=e02cnDo+8Ut2CE4yePcuv5/M81XElr+h2fAEf6DGcAYl/obIIcp7e6ik3QHcSO3aolfO2w W8FXBFC+4CHDvvCA9Ehu4jzlI5f8HoQH8WSVEU9+3Y+xzXtKkeTJS86XGnsu6Jef7AzHIm hrVl+sk1ziYkAcAkNmR2L0hNIgHkHsE= 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-221-uoOCdMg9OBicCzW3qE3Qrw-1; Thu, 08 May 2025 03:52:09 -0400 X-MC-Unique: uoOCdMg9OBicCzW3qE3Qrw-1 X-Mimecast-MFC-AGG-ID: uoOCdMg9OBicCzW3qE3Qrw_1746690728 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 396331956089; Thu, 8 May 2025 07:52:08 +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 8A9551955F24; Thu, 8 May 2025 07:52:06 +0000 (UTC) Date: Thu, 8 May 2025 15:52:01 +0800 From: Baoquan He To: fuqiang wang Cc: Vivek Goyal , Dave Young , kexec@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [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-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Scanned-By: MIMEDefang 3.0 on 10.30.177.15 On 05/08/25 at 03:38pm, Baoquan He wrote: > 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. Sorry, this should be from fuqiang wang, when I edited the patch to reply to his patch, I forgot that. Please help makes change to set Fuqiang as the patch author, I just adapted the content based on Coiby's patches. > > 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 > 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 += 2; > + nr_ranges += 3; > cmem = 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; > > /* > - * 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 = 2; > + nr_ranges = 3; > cmem = vzalloc(struct_size(cmem, ranges, nr_ranges)); > if (!cmem) > return -ENOMEM; > -- > 2.41.0 >