lkml.org 
[lkml]   [2022]   [Nov]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectRe: [PATCH v4 04/11] security: keys: trusted: Include TPM2 creation data
On Fri, Nov 4, 2022 at 11:33 AM Kees Cook <keescook@chromium.org> wrote:
>
> On Thu, Nov 03, 2022 at 11:01:12AM -0700, Evan Green wrote:
> > In addition to the private key and public key, the TPM2_Create
> > command may also return creation data, a creation hash, and a creation
> > ticket. These fields allow the TPM to attest to the contents of a
> > specified set of PCRs at the time the trusted key was created. Encrypted
> > hibernation will use this to ensure that PCRs settable only by the
> > kernel were set properly at the time of creation, indicating this is an
> > authentic hibernate key.
> >
> > Encode these additional parameters into the ASN.1 created to represent
> > the key blob. The new fields are made optional so that they don't bloat
> > key blobs which don't need them, and to ensure interoperability with
> > old blobs.
> >
> > Signed-off-by: Evan Green <evgreen@chromium.org>
>
> There's a lot of open-coded math for the bounds checking. I didn't
> immediately see any problems, but it'd be nice if there was a way to
> hook a fuzzer up to this, or at least write some KUnit tests to check
> boundary conditions explicitly.
>
> Reviewed-by: Kees Cook <keescook@chromium.org>

Thank you! Yes, agreed about all the bounds checking. I could probably
pull out the "check for src + 2 > end, then get_unaligned_be16()" into
a helper function. Let me see if that makes things look better or ends
up looking the same.
-Evan

\
 
 \ /
  Last update: 2022-11-07 21:13    [W:0.072 / U:0.064 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site