From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pg1-f181.google.com (mail-pg1-f181.google.com [209.85.215.181]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 93C576BB25 for ; Fri, 1 Mar 2024 09:26:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.215.181 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709285202; cv=none; b=Tpv1/dVz2hvpNwConaEgRhO/1p8nBhLaDCoo4KxUNzPzYz0IIA8r7swEEQ8vaEYFVjSlUxnwXNqyADUHB1BzpMk7fHVbcTqglnJ31VxzFy5XJZJaoVIsfRBKDnrExMJBEotpCX+2hvnhYYzGY8T1x5u90LnzSU67FEj8BR8ZTj8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709285202; c=relaxed/simple; bh=0wdFpKbEyNhuu/RpjYvuz8KPZKT0kttiGp+cGiKwHZk=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Uq1Uhv/kX4HOYZfg2hSTmyY5DZtbb94XbzEPjtnO78rFUI/jWwbWzLhTutYhh9QfQcpkEdLCYoGOZWBLdj5eM1lGMRjupXZx1CrUqcQKdj1DUuEsk8sxRjzJeYxrIc/gqhfjtkpy9NdqR2hCVC/9dtJBfC9BY6D/bMzu9biuVcs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org; spf=pass smtp.mailfrom=gmail.com; arc=none smtp.client-ip=209.85.215.181 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Received: by mail-pg1-f181.google.com with SMTP id 41be03b00d2f7-5cddc5455aeso1497154a12.1 for ; Fri, 01 Mar 2024 01:26:41 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1709285201; x=1709890001; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=7fp76SLNrOitLz2IPJZxtYaUARyA39f42XEHvT3cwYM=; b=FOLZMPvm3gXe0QthMa7dqW59wCCY5pT21HnvmQE9G1iaZ76vuq52T8TzotegvIoKMh p1bDSrYhUsMu0nTYoqAWIcRi2hPHhwMgsaA/wnHdfNIkhpizDOiKA+p2xsSQMvW9TKag 1dQIrlAyD5gWH2rEx/IlmSF6ci2XixHngLUpKXItyYYSSHUkfoeAHi9gyBLRk6CHLrZO pe+UjAOMgJ2hL/TawnE7Dm8hZEROLJ+3GrL1V8htHf5+c85hQ9rEFZuHVKRbXNd8Cx3s Tbz1bmBM8+ULv1iH24f+Bf3w12e3EWfjIcI8PD0OvvoB+Y4XGuKe2z/zv/NzgszckARp VP/w== X-Forwarded-Encrypted: i=1; AJvYcCWYLjrMUD5T55am8tKvyCwibMLpvU10D/bbmoAvx83jreekj/nBZSC1yyHXZoyrKa20uH2hPPgo7yLvjBw+HYztMld4WvvNVc05Cg== X-Gm-Message-State: AOJu0YwrXIWL4Ia7RRrm4Zj6S4YQEDP8UUTOHq0peaG4IEz31VpI1Yh9 ArQgJuQq91I9bPClycwGybLsHQyV9uWjZuWIXhOYaGnbiiDF4cVs X-Google-Smtp-Source: AGHT+IFzP30XgcgRz16jjeqSQMfVBbG9kjUBn2FuxIWeyBnM+Cs+BqPA7eeqULcAd7TXur4Xy4bBMg== X-Received: by 2002:a05:6a20:7343:b0:1a1:2f17:1bc2 with SMTP id v3-20020a056a20734300b001a12f171bc2mr989042pzc.35.1709285200822; Fri, 01 Mar 2024 01:26:40 -0800 (PST) Received: from liuwe-devbox-debian-v2 ([20.69.120.36]) by smtp.gmail.com with ESMTPSA id d11-20020a170902cecb00b001d739667fc3sm2947317plg.207.2024.03.01.01.26.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 01 Mar 2024 01:26:40 -0800 (PST) Date: Fri, 1 Mar 2024 09:26:38 +0000 From: Wei Liu To: Rick Edgecombe Cc: kys@microsoft.com, haiyangz@microsoft.com, wei.liu@kernel.org, decui@microsoft.com, mhklinux@outlook.com, linux-hyperv@vger.kernel.org, gregkh@linuxfoundation.org, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, netdev@vger.kernel.org, kirill.shutemov@linux.intel.com, dave.hansen@linux.intel.com, linux-coco@lists.linux.dev, linux-kernel@vger.kernel.org, sathyanarayanan.kuppuswamy@linux.intel.com, elena.reshetova@intel.com Subject: Re: [RFC RFT PATCH 1/4] hv: Leak pages if set_memory_encrypted() fails Message-ID: References: <20240222021006.2279329-1-rick.p.edgecombe@intel.com> <20240222021006.2279329-2-rick.p.edgecombe@intel.com> Precedence: bulk X-Mailing-List: linux-coco@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240222021006.2279329-2-rick.p.edgecombe@intel.com> On Wed, Feb 21, 2024 at 06:10:03PM -0800, Rick Edgecombe wrote: > On TDX 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. > > Hyperv could free decrypted/shared pages if set_memory_encrypted() fails. "Hyper-V" throughout. > Leak the pages if this happens. > > Only compile tested. > > Cc: "K. Y. Srinivasan" > Cc: Haiyang Zhang > Cc: Wei Liu > Cc: Dexuan Cui > Cc: linux-hyperv@vger.kernel.org > Signed-off-by: Rick Edgecombe > --- > drivers/hv/connection.c | 11 +++++++---- > 1 file changed, 7 insertions(+), 4 deletions(-) > > diff --git a/drivers/hv/connection.c b/drivers/hv/connection.c > index 3cabeeabb1ca..e39493421bbb 100644 > --- a/drivers/hv/connection.c > +++ b/drivers/hv/connection.c > @@ -315,6 +315,7 @@ int vmbus_connect(void) > > void vmbus_disconnect(void) > { > + int ret; > /* > * First send the unload request to the host. > */ > @@ -337,11 +338,13 @@ 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); > + ret = set_memory_encrypted((unsigned long)vmbus_connection.monitor_pages[0], 1); > + ret |= set_memory_encrypted((unsigned long)vmbus_connection.monitor_pages[1], 1); > > - hv_free_hyperv_page(vmbus_connection.monitor_pages[0]); > - hv_free_hyperv_page(vmbus_connection.monitor_pages[1]); > + if (!ret) { > + hv_free_hyperv_page(vmbus_connection.monitor_pages[0]); > + hv_free_hyperv_page(vmbus_connection.monitor_pages[1]); > + } This silently leaks the pages if set_memory_encrypted() fails. I think there should print some warning or error messages here. Thanks, Wei. > vmbus_connection.monitor_pages[0] = NULL; > vmbus_connection.monitor_pages[1] = NULL; > } > -- > 2.34.1 >