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 7324E49CF22 for ; Tue, 15 Sep 2026 16:33:06 +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=1789489987; cv=none; b=RK7NRReFYsU2FLxETZXERtI8AWBhLFqvHTVfiunvW2zCRZ4ZoVGiGASBggSSceDcGU5o7jBWiqbXQS7YUHxd3JymvNuDkAT5rKJ3yW6bsQug3q7X66jBpVerWlGa/QdMrrd8+GgRV0naxcbUnux7yJ2t3jvt3OKsb4eeYPHNguY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789489987; c=relaxed/simple; bh=Xzgz+4tsqdIJiJ44u0qBX2B1GLvXUOfXVH0aIZzJ9Ts=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=JlY6CpprEvf0KFVAszzvDjd5vneyYlQohnFatFLVlJbu1oAnAsrZI6hCAP1S6FM8oojGdeGlUrWllkAnCEl1uU9mJrH5bBA78uMd+YfA5CxXteM7fKkVrorGCBdtAgUP2P+oZtvkK4Mt/0qAVPtQdT237eq9ookPi9OJi4RQflM= 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=EMuy/4E5; dkim=pass (2048-bit key) header.d=redhat.com header.i=@redhat.com header.b=NiyXGILZ; 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="EMuy/4E5"; dkim=pass (2048-bit key) header.d=redhat.com header.i=@redhat.com header.b="NiyXGILZ" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1789489985; 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=zGgRa3VPDYgehvQnqiC0LfcNhzBWNqGieMYcbjfd6B4=; b=EMuy/4E5cIH/zpPjsfVnZ+f5iluwYV677C8HfFeKeG3iEOEdWFUFD6XYcEO4kVRTG365m4 tj52mKho/n8mdZIwPPwwDHwU7AxHJQjeaIWqZ4mkS7XEEONP4wlsRoL+EmcSGTYq1blYZ9 cY1wlFYBiMLi0iA7CLJkoK0mpSb6GHI= Received: from mail-wm1-f69.google.com (mail-wm1-f69.google.com [209.85.128.69]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-621-04Xvd8jCOleJ-NgpK0hqGg-1; Tue, 15 Sep 2026 12:33:03 -0400 X-MC-Unique: 04Xvd8jCOleJ-NgpK0hqGg-1 X-Mimecast-MFC-AGG-ID: 04Xvd8jCOleJ-NgpK0hqGg_1789489983 Received: by mail-wm1-f69.google.com with SMTP id 5b1f17b1804b1-49e65ecd557so30686335e9.1 for ; Tue, 15 Sep 2026 09:33:03 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=google; t=1789489983; x=1790094783; 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=zGgRa3VPDYgehvQnqiC0LfcNhzBWNqGieMYcbjfd6B4=; b=NiyXGILZXXkYsKiUM8gekg0NdAkMrNWfZPRNbtbyW0Jch4fUcvZyglEloXy0rv3pmg fjTxNQAxhRHszyeHFb53qxpBptHq1S+TL73LcZ8Mmprmzjt2kd8xVqN1oRPcw0loo1JT Y++A4c5bTIrSGd1vjjI1mIDIRhZh92dXxs/T7TyKmYNqMmW6LBqVnffvpvK4NYQiCncs IxjWdBOIfo0s5uB6DyklvFZWg8iXUfenDDoOK7p2jo6YbcAK5XmooCbDw1qLiN6Z/S3M dkjLid/MZfcr4KGHRvmdPpOWFRxZ8P7bPMdWByyUzKFIrFhE7p56InXjyfjlNLtzb2oQ H9fg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1789489983; x=1790094783; 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=zGgRa3VPDYgehvQnqiC0LfcNhzBWNqGieMYcbjfd6B4=; b=Ev519R27l8DRZ0As/9gJGQHBXrHA3SUZ6+v5OJDHJpRQErFSbHqGdeCS1CnL2DfjUQ NDpgVWMf3YWCt/Jd2eZ6HxSVt3hByM9pMgJ3sbmXXWJDO95CMUPd1ZRlnNYFQ/l2rnAR Txdo6gnI67lFtDvotg+xSAtEMQxTLd6gsx3g9y1M4n58gUTRp3PeCTfPoc6RyHix8i8q l+HOsc5W7AOdh3/s4lFwLqxlY/bImZfADbTyovZaRsHzekE8utwXkpP5TBRuTmKNFQt3 VfKwAsXOeSc0i6+yGa7FM9rbwxbSXDqmAlQ5qKuwGHLHMGmHBwcfaMzZesFeSv3v1SgM IZDA== X-Forwarded-Encrypted: i=1; AKwUvBzlfbc8sDK964KldBctScGtJfHhvXfHbCjWIFjH4ueLB2GBX9you66a7nLNKGnk2UM3EO8uFTc=@vger.kernel.org X-Gm-Message-State: AFuF++mzouuHzSuOnAndi7acH1Xa8j0bNJl5bYfYrLmc4tqwCX2Td6vt x5X07n175vaEtUO5+FnqyDp2H6dYd4tbfAduL3yEyR1iFYla2wjonGxltmJ2Ma+yXz2KgsOOqgj 0t7gpjs1WTIgqikeBXCbJlwi/FkVnuFKaNFJ1dc4VstcFO4VaDbcO1xJCWw== X-Gm-Gg: AYBFou2XBUFkaKOaoSIR2oH6WGO4/aE8AMFbkAeErUiGG/eXwgGnh3hLV3XIAhvkMTZ LLRg+iFnoECBQXuN9xcHgY6Vxp4p4LyZnxEByk5NUl8l/qpIoG4xnTI2cxNyDxHGJbXQZm6SnU3 Cmm+gC77+Ms9gQ1yCMoNADWIlZRQ16nN6pHXfeKy08Q1vDFVtgw9KQRzOHY2y6cAAJ6obHVUmOh gDuMcgO8sV+iXeTMT5ZkAEkidsTCovd5++8XQanxQ8BzLKAggVW0VOMuAk4+2oEMiLYFQmBs68T gJ4EUBl1y8JH3xVRZ6cIeqiRv94O+A3EnEpo7v6cU2hl4grQ9HKcTEnuF/g5elKAJ8he5YQ+2fD Y2pfu8tY0HzOmkK35LW3btxirF/MK9CWKORM= X-Received: by 2002:a05:600c:548b:b0:49c:fc6e:8caf with SMTP id 5b1f17b1804b1-49e8227eb75mr26724365e9.19.1789489982805; Tue, 15 Sep 2026 09:33:02 -0700 (PDT) X-Received: by 2002:a05:600c:548b:b0:49c:fc6e:8caf with SMTP id 5b1f17b1804b1-49e8227eb75mr26723975e9.19.1789489982463; Tue, 15 Sep 2026 09:33:02 -0700 (PDT) Received: from leonardi-redhat ([151.29.41.106]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-49e83dba8f4sm1920305e9.13.2026.09.15.09.33.00 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 15 Sep 2026 09:33:02 -0700 (PDT) Date: Tue, 15 Sep 2026 18:32:59 +0200 From: Luigi Leonardi To: Aldo Ariel Panzardo Cc: Stefano Garzarella , virtualization@lists.linux.dev, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH v2] vsock: ignore empty child namespace mode writes Message-ID: References: <20260915111417.2726515-1-qwe.aldo@gmail.com> <20260915141547.3010692-1-qwe.aldo@gmail.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: <20260915141547.3010692-1-qwe.aldo@gmail.com> Hi Aldo, On Tue, Sep 15, 2026 at 11:15:47AM -0300, Aldo Ariel Panzardo wrote: >__vsock_net_mode_string() returns success without updating new_mode when >the transfer length is zero. Its caller then reads the uninitialized enum >and may permanently store a stack-derived value in the write-once child >mode. > >Return before inspecting or storing new_mode when no bytes were >transferred. This also prevents an empty write from locking the current >mode. > >Fixes: eafb64f40ca4 ("vsock: add netns to vsock core") >Cc: stable@vger.kernel.org >Signed-off-by: Aldo Ariel Panzardo >--- > net/vmw_vsock/af_vsock.c | 2 ++ > 1 file changed, 2 insertions(+) > >diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c >index 622dbd0467..816d25b314 100644 >--- a/net/vmw_vsock/af_vsock.c >+++ b/net/vmw_vsock/af_vsock.c >@@ -2883,6 +2883,8 @@ static int vsock_net_child_mode_string(const struct ctl_table *table, int write, > vsock_net_child_mode(net), &new_mode); > if (ret) > return ret; >+ if (!*lenp) >+ return 0; > > if (write) { > /* Prevent a "local" namespace from escalating to "global", >-- >2.43.0 > Code LGTM. Reviewed-by: Luigi Leonardi To reproduce it, I suppose we need a kernel that does not come with `CONFIG_INIT_STACK_ALL_ZERO` set. @Stefano do you think it's worth adding a test for this case? Just out of curiosity, how did you find this bug? Thanks, Luigi