linux-kernel - Re: [PATCH][v4] virt: tdx-guest: Don't free decrypted memory

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <bd072a45a755eb2be1fe4c1c95c27f7cd0635a27.camel@intel.com>
Date: Mon, 2 Dec 2024 18:10:13 +0000
From: "Edgecombe, Rick P" <rick.p.edgecombe@...el.com>
To: "kirill.shutemov@...ux.intel.com" <kirill.shutemov@...ux.intel.com>,
	"linux-coco@...ts.linux.dev" <linux-coco@...ts.linux.dev>, "Hansen, Dave"
	<dave.hansen@...el.com>, "Li, Rongqing" <lirongqing@...du.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"dave.hansen@...ux.intel.com" <dave.hansen@...ux.intel.com>, "x86@...nel.org"
	<x86@...nel.org>
Subject: Re: [PATCH][v4] virt: tdx-guest: Don't free decrypted memory

On Mon, 2024-12-02 at 10:05 -0800, Dave Hansen wrote:
> On 11/27/24 08:48, Edgecombe, Rick P wrote:
> > On Wed, 2024-06-19 at 19:18 +0800, Li RongQing wrote:
> > > In CoCo VMs it is possible for the untrusted host to cause
> > > 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.
> > > 
> > > Leak the decrypted memory when set_memory_decrypted() fails,
> > > and don't need to print an error since set_memory_decrypted()
> > > will call WARN_ONCE().
> > > 
> > > Reviewed-by: Rick Edgecombe <rick.p.edgecombe@...el.com>
> > > Reviewed-by: Kirill A. Shutemov <kirill.shutemov@...ux.intel.com>
> > > Signed-off-by: Li RongQing <lirongqing@...du.com>
> > It needs a Fixes tag.
> > Fixes: f4738f56d1dc ("virt: tdx-guest: Add Quote generation support using
> > TSM_REPORTS")
> > 
> > I think it is a worthwhile fix. Without it the guest can be tricked into freeing
> > shared pages, or trying to execute from them and crashing.
> 
> Does this need a "Fixes" and cc:stable@?

Oh yea, probably worth a cc:stable too.