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 3FF58478E49 for ; Wed, 15 Jul 2026 15:57:10 +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=1784131031; cv=none; b=JKW/x2tS+EEgVaVOiTUWoudqTNljolLFt7O9xQt4iXxj8qWOoAmQ+kTME606e/f3gwBc+ykhhCbSm19F0x4Y9xjt6MdcGhyvd4+Z5rZBhIrcO5j0s44dEn0rffBW4Puk9u2+FaNWeF9pteLtO9T+jgf5pd9stjGlwHj3sh+gVJc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784131031; c=relaxed/simple; bh=uv/zLXnCvLIlm5SSXwTVSkUYz8GZAW9tYkJKFd4w0vE=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=bR9fQHH3xBCJJg4yxa6spUNh3ThxbLexobOJcEvR7avWlUICDGAFeOS7BRtmgBpbkhr/ayfgcOVNMwBKACO6/sxVV2OwkgtAs8RxQ2k4wG4kqB/yWw0qugvWkhLpY1NP42L+xeUXPRMh/DLtGM5Zp3GsBF2h5PkrEAtoMWzFod0= 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=VHMTQM0W; dkim=pass (2048-bit key) header.d=redhat.com header.i=@redhat.com header.b=b/DR6Xda; 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="VHMTQM0W"; dkim=pass (2048-bit key) header.d=redhat.com header.i=@redhat.com header.b="b/DR6Xda" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1784131029; 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=QucJ8nQZseawvH/pWqtNGkyG0ZJfjIBnQLKskMGohYU=; b=VHMTQM0W6R1WvgE4ZkB7/IDtR3r1iBMLizrNmqxUV3r9Hi31b+7T08phIKMNnYt5wKnn4u 1BEWtlxR/c76kL8pX9kqWy5SOAiaEvD5EpiQrPnaSEdrIuSE3jEjbIXmgg2H5aOUgr/QsL 0X3yanO9ElOMm0IFlDz6TKSl6g/Rb18= Received: from mail-wm1-f71.google.com (mail-wm1-f71.google.com [209.85.128.71]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-55-hIPfzW6aPqmnYi4ifcpxDg-1; Wed, 15 Jul 2026 11:57:07 -0400 X-MC-Unique: hIPfzW6aPqmnYi4ifcpxDg-1 X-Mimecast-MFC-AGG-ID: hIPfzW6aPqmnYi4ifcpxDg_1784131026 Received: by mail-wm1-f71.google.com with SMTP id 5b1f17b1804b1-493bdaf8549so53551085e9.2 for ; Wed, 15 Jul 2026 08:57:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=google; t=1784131026; x=1784735826; darn=vger.kernel.org; h=in-reply-to:content-disposition:content-type:mime-version :references:message-id:subject:cc:to:from:date:from:to:cc:subject :date:message-id:reply-to:content-type; bh=QucJ8nQZseawvH/pWqtNGkyG0ZJfjIBnQLKskMGohYU=; b=b/DR6XdaajLaL6gRKx+M1hLJEyXDErTNEicTWNKT4QZlj4ZXTfnJP9HfAMhtozJ5CR MwMi2JKPC8Z072Hm8yqt+TdAJABqJdmP2Y5tU7JXUJiHmpcU8OBfdmUnKsjpD1Yg8ubc jJw4kZwtrWbcmkJp6D2enPZys5iNhhcis0Le6Qy+EOh8A5P9gyYWGVp2GVrjZlBwKGUF 52TZoaV1GY7ZpZyWQF4UpqCzRptrMchhl4zOO1OQoEy0h3EX/y52wsqdv9CTf2X8SgSW svneBPKac6XCTtgfyG6xZeYr/1Q3izu4D7uNPb0ommGxaLXTOGAg2gtrFZl3VB8d5gFO IDnQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1784131026; x=1784735826; h=in-reply-to:content-disposition:content-type:mime-version :references:message-id:subject:cc:to:from:date:x-gm-gg :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to :content-type; bh=QucJ8nQZseawvH/pWqtNGkyG0ZJfjIBnQLKskMGohYU=; b=kaGfGcHckaIXxkcGOA07eCI1jeGcjdMKDoVWBi1lMnVWAb/BMezFQmjIL315KLD1al K12Be0jn6CS9x2Uvx7wVLqGwUUDOe9pwtaWuPwz/GFaP1A/eVhO6YUCzW92bZaFzVwDE rtsKmYYDeiAnl40v33qd8Cymw+LNI3E8JSlEGQgA63E+w0VXsL1S+mwWteYlgoyCmPjb xZW4nUHYZxVzpp/BbMra7aj8hGVWR2wLCiCXwHCN4gABzy6VvGT+wTEV1BpzFej5BsaL qkUlg2AnIpDaSVOT6NaXdWe8SCUL5/jD1Ac9PunySYhzkGL6oovxK/pRLDrdE5fugA9x z10Q== X-Forwarded-Encrypted: i=1; AHgh+RpNYhjZp4NW1qV1vFKcXwjAVdl0pCF+MGS56DNogPv+Oye4qSH5jDfJXRoBNSjW7GB1YMIXf4fxL++EjdQ=@vger.kernel.org X-Gm-Message-State: AOJu0YxWKLnQkW2ICjmibfeds2Ty1QjFrsmJ3tNeYeZxSsLnx3we7nQs EU+PFFtPGcmNK8DyhDWg31wnd3BYsjkL0gHq+DtQqImF4moXKml4FeQUqtKvrPQKjqQ//S3Sr85 qpV4zS3UFBExegXy0mdjHI1dZf7E72Tf/+EBWEli83czBSqnFSIBhc3JUugJcW51Wfg== X-Gm-Gg: AfdE7cn3DVEw1npsAlgsm2NDZxnJF3XrcMmdcdSnt455btYzlPYBWWp2z2/ifX9u37l q8In0ggjrBRMWko8qhJN7XdATrz6U0q++ctWy2FXfIJa+pn8sjcC/h+ybvwmYxHST7TKhNUgb2t 7v3WAo3zKoRryZMC9zr1VE0QarbbRcro7nIV241RPabA0p9O031XrRy79Ghp6F7QiDJi0EhSNv5 C5hJO0fZEjMg/Ui8v8EphSD6nz1lG4UCIdzPGcI2E0sEPDJzYNU0h/wCEL1FSKtKEjDumEwa4jO 0ZZrbAZGB89hp+BzVqwzMRr6AZKAK7KzX0dlXwOz+yHeYuEbf6go4+0DZkhBNwqWUrrIgymHBXm gprdupr604cmYGgJDGehsvx1Wp9j+jV8A+7k= X-Received: by 2002:a05:600c:4e93:b0:492:437a:a653 with SMTP id 5b1f17b1804b1-4953c286bbemr40012485e9.26.1784131026029; Wed, 15 Jul 2026 08:57:06 -0700 (PDT) X-Received: by 2002:a05:600c:4e93:b0:492:437a:a653 with SMTP id 5b1f17b1804b1-4953c286bbemr40012045e9.26.1784131025583; Wed, 15 Jul 2026 08:57:05 -0700 (PDT) Received: from redhat.com (IGLD-80-230-24-117.inter.net.il. [80.230.24.117]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-49508731fcdsm140971355e9.4.2026.07.15.08.57.03 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 15 Jul 2026 08:57:05 -0700 (PDT) Date: Wed, 15 Jul 2026 11:57:01 -0400 From: "Michael S. Tsirkin" To: Hari Mishal Cc: Amit Shah , Arnd Bergmann , Greg Kroah-Hartman , Gerd Hoffmann , Jason Wang , David Hildenbrand , Henrik Rydberg , Xuan Zhuo , Eugenio =?iso-8859-1?Q?P=E9rez?= , virtualization@lists.linux.dev, linux-kernel@vger.kernel.org, linux-input@vger.kernel.org Subject: Re: [PATCH 1/4] virtio-mem: validate device-reported block size Message-ID: <20260715115206-mutt-send-email-mst@kernel.org> References: <20260715142337.22811-1-harimishal1@gmail.com> <20260715142337.22811-2-harimishal1@gmail.com> 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: <20260715142337.22811-2-harimishal1@gmail.com> On Wed, Jul 15, 2026 at 04:22:40PM +0200, Hari Mishal wrote: > The device_block_size read from the virtio-mem config space is used > as a divisor and also in ALIGN_DOWN() further down the code path in > the driver without further validation. A zero value leads to a division > by zero, and a non-power-of-two value corrupts the ALIGN_DOWN() bitmask > arithmetic leading to a misreporting of guest usable guest ram, post > crash. Reject both at init time instead of trusting the device. > > Assisted-by: gkh_clanker:t1000 > Signed-off-by: Hari Mishal > --- > drivers/virtio/virtio_mem.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/drivers/virtio/virtio_mem.c b/drivers/virtio/virtio_mem.c > index 11c441501582..43d12ec7c323 100644 > --- a/drivers/virtio/virtio_mem.c > +++ b/drivers/virtio/virtio_mem.c > @@ -2847,6 +2847,13 @@ static int virtio_mem_init(struct virtio_mem *vm) > &vm->plugged_size); > virtio_cread_le(vm->vdev, struct virtio_mem_config, block_size, > &vm->device_block_size); > + if (!vm->device_block_size || > + !is_power_of_2(vm->device_block_size)) { 0 is not a power of 2, why do we need to check twice? > + dev_err(&vm->vdev->dev, > + "invalid device block size: 0x%llx\n", > + (unsigned long long)vm->device_block_size); > + return -EINVAL; > + } > virtio_cread_le(vm->vdev, struct virtio_mem_config, node_id, > &node_id); > vm->nid = virtio_mem_translate_node_id(vm, node_id); > -- > 2.43.0