From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.19]) (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 F0EB279CF for ; Tue, 12 Mar 2024 02:56:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.19 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1710212174; cv=none; b=nvWW6ZD4OA2temcn5+9ThUuL+aRLnCFpxjJuWFBuIP2TxwRMWSOiVjl5QLU6bczhPbVvLOsg9SCQiUpEWGeFWgnK4fCGSPur4upu4jCgaNLBR9kBGBwdOwabgTvEun//pHZhh6E/l5scYdnl6r3FK897ZpHwSVvWYOa3LLzKN5g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1710212174; c=relaxed/simple; bh=Byby3dPab9clHdBpqGNxzWvALlnFyqoIXHFndqlr3zc=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=AnqCdGqfDrtA0wG1X3Lttyl3QeoDJ2iZy+XimsSP1wUv69S7bBsJGnoJaP1Y8Mp/nCULSSJ70DrKQDdOm4xiDbuydiYSWjUxzrJP6sbMHToNVXW2cTsX8TXzDUg3Ft9Vo0x09AkMv4y9y4gn18pBkR8BEbrtYPxuazxVtk+AunQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=none smtp.mailfrom=linux.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=TI6RKdtH; arc=none smtp.client-ip=198.175.65.19 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="TI6RKdtH" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1710212173; x=1741748173; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=Byby3dPab9clHdBpqGNxzWvALlnFyqoIXHFndqlr3zc=; b=TI6RKdtHYFAADlZ20p78s6EnKUM1JO1Kdp3ORiB7yW+OCEVBX8CXfey3 zQ5h5g3nPreCzW6i3VCTGPnzYTHPStdF8M99r1L9V9Ts1qhHSRL7+cwBm g6WfLqjvzqDHi92IyKWJNQxJhYWsNSrmU/eyiECLDpB9upN5zYUDA/nqI 33XYKRhy14ttWWq2kV4gPQOq2HKx7nPghxDaCg6Csf7XXAiZlRcNIlPZJ TBl1xAGsX4/LdOEVAZLODzQ9eMi5B1ROzNdRBuPTNyrUE+8/M49lmTCIb DldAwBqLg/e0d8b7sAoDT0Lq6Tb6OTKYkVvBnCnrR42ItXjlRq5xuqV/S Q==; X-IronPort-AV: E=McAfee;i="6600,9927,11010"; a="4762031" X-IronPort-AV: E=Sophos;i="6.07,118,1708416000"; d="scan'208";a="4762031" Received: from fmviesa008.fm.intel.com ([10.60.135.148]) by orvoesa111.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 11 Mar 2024 19:56:12 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.07,118,1708416000"; d="scan'208";a="11478107" Received: from sbrowne-mobl.amr.corp.intel.com (HELO [10.209.68.239]) ([10.209.68.239]) by fmviesa008-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 11 Mar 2024 19:56:11 -0700 Message-ID: Date: Mon, 11 Mar 2024 19:56:10 -0700 Precedence: bulk X-Mailing-List: linux-coco@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 1/5] Drivers: hv: vmbus: Leak pages if set_memory_encrypted() fails Content-Language: en-US To: mhklinux@outlook.com, rick.p.edgecombe@intel.com, kys@microsoft.com, haiyangz@microsoft.com, wei.liu@kernel.org, decui@microsoft.com, gregkh@linuxfoundation.org, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, kirill.shutemov@linux.intel.com, dave.hansen@linux.intel.com, linux-kernel@vger.kernel.org, linux-hyperv@vger.kernel.org, netdev@vger.kernel.org, linux-coco@lists.linux.dev Cc: elena.reshetova@intel.com References: <20240311161558.1310-1-mhklinux@outlook.com> <20240311161558.1310-2-mhklinux@outlook.com> From: Kuppuswamy Sathyanarayanan In-Reply-To: <20240311161558.1310-2-mhklinux@outlook.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Hi, On 3/11/24 9:15 AM, mhkelley58@gmail.com wrote: > From: Rick Edgecombe > > In CoCo VMs it is possible for the untrusted host to cause > set_memory_encrypted() or set_memory_decrypted() to fail such that an > error is returned and the resulting memory is shared. Callers need to > take care to handle these errors to avoid returning decrypted (shared) > memory to the page allocator, which could lead to functional or security > issues. > > VMBus code could free decrypted pages if set_memory_encrypted()/decrypted() > fails. Leak the pages if this happens. > > Signed-off-by: Rick Edgecombe > Signed-off-by: Michael Kelley > --- LGTM Reviewed-by: Kuppuswamy Sathyanarayanan > drivers/hv/connection.c | 29 ++++++++++++++++++++++------- > 1 file changed, 22 insertions(+), 7 deletions(-) > > diff --git a/drivers/hv/connection.c b/drivers/hv/connection.c > index 3cabeeabb1ca..f001ae880e1d 100644 > --- a/drivers/hv/connection.c > +++ b/drivers/hv/connection.c > @@ -237,8 +237,17 @@ int vmbus_connect(void) > vmbus_connection.monitor_pages[0], 1); > ret |= set_memory_decrypted((unsigned long) > vmbus_connection.monitor_pages[1], 1); > - if (ret) > + if (ret) { > + /* > + * If set_memory_decrypted() fails, the encryption state > + * of the memory is unknown. So leak the memory instead > + * of risking returning decrypted memory to the free list. > + * For simplicity, always handle both pages the same. > + */ > + vmbus_connection.monitor_pages[0] = NULL; > + vmbus_connection.monitor_pages[1] = NULL; > goto cleanup; > + } > > /* > * Set_memory_decrypted() will change the memory contents if > @@ -337,13 +346,19 @@ void vmbus_disconnect(void) > vmbus_connection.int_page = NULL; > } > > - set_memory_encrypted((unsigned long)vmbus_connection.monitor_pages[0], 1); > - set_memory_encrypted((unsigned long)vmbus_connection.monitor_pages[1], 1); > + if (vmbus_connection.monitor_pages[0]) { > + if (!set_memory_encrypted( > + (unsigned long)vmbus_connection.monitor_pages[0], 1)) > + hv_free_hyperv_page(vmbus_connection.monitor_pages[0]); > + vmbus_connection.monitor_pages[0] = NULL; > + } > > - hv_free_hyperv_page(vmbus_connection.monitor_pages[0]); > - hv_free_hyperv_page(vmbus_connection.monitor_pages[1]); > - vmbus_connection.monitor_pages[0] = NULL; > - vmbus_connection.monitor_pages[1] = NULL; > + if (vmbus_connection.monitor_pages[1]) { > + if (!set_memory_encrypted( > + (unsigned long)vmbus_connection.monitor_pages[1], 1)) > + hv_free_hyperv_page(vmbus_connection.monitor_pages[1]); > + vmbus_connection.monitor_pages[1] = NULL; > + } > } > > /* -- Sathyanarayanan Kuppuswamy Linux Kernel Developer