Messages in this thread | | | Date | Mon, 31 Jul 2023 10:33:12 -0700 | From | Dan Williams <> | Subject | Re: [PATCH 0/4] keys: Introduce a keys frontend for attestation reports |
| |
Jarkko Sakkinen wrote: > On Fri Jul 28, 2023 at 7:44 PM UTC, Dan Williams wrote: > > Jarkko Sakkinen wrote: > > > On Fri Jul 28, 2023 at 7:30 PM UTC, Dan Williams wrote: > > > > The bulk of the justification for this patch kit is in "[PATCH 1/4] > > > > > > /patch kit/patch set/ > > > > > > > keys: Introduce tsm keys". The short summary is that the current > > > > approach of adding new char devs and new ioctls, for what amounts to the > > > > same functionality with minor formatting differences across vendors, is > > > > untenable. Common concepts and the community benefit from common > > > > infrastructure. > > > > > > > > Use Keys to build common infrastructure for confidential computing > > > > > > /Keys/Linux keyring/ > > > > > > > attestation report blobs, convert sevguest to use it (leaving the > > > > deprecation question alone for now), and pave the way for tdx-guest and > > > > the eventual risc-v equivalent to use it in lieu of new ioctls. > > > > > > > > The sevguest conversion is only compile-tested. > > > > > > > > This submission is To:David since he needs to sign-off on the idea of a > > > > new Keys type, the rest is up to the confidential-computing driver > > > > maintainers to adopt. > > > > > > > > Changes from / credit for internal review: > > > > - highlight copy_{to,from}_sockptr() as a common way to mix > > > > copy_user() and memcpy() paths (Andy) > > > > - add MODULE_DESCRIPTION() (Andy) > > > > - clarify how the user-defined portion blob might be used (Elena) > > > > - clarify the key instantiation options (Sathya) > > > > - drop usage of a list for registering providers (Sathya) > > > > - drop list.h include from tsm.h (Andy) > > > > - add a comment for how TSM_DATA_MAX was derived (Andy) > > > > - stop open coding kmemdup_nul() (Andy) > > > > - add types.h to tsm.h (Andy) > > > > - fix punctuation in comment (Andy) > > > > - reorder security/keys/Makefile (Andy) > > > > - add some missing includes to tsm.c (Andy) > > > > - undo an 81 column clang-format line break (Andy) > > > > - manually reflow tsm_token indentation (Andy) > > > > - move allocations after input validation in tsm_instantiate() (Andy) > > > > - switch to bin2hex() in tsm_read() (Andy) > > > > - move init/exit declarations next to their functions (Andy) > > > > > > > > > > > > --- > > > > > > > > Dan Williams (4): > > > > keys: Introduce tsm keys > > > > virt: sevguest: Prep for kernel internal {get,get_ext}_report() > > > > mm/slab: Add __free() support for kvfree > > > > virt: sevguest: Add TSM key support for SNP_{GET,GET_EXT}_REPORT > > > > > > > > > > > > drivers/virt/coco/sev-guest/Kconfig | 2 > > > > drivers/virt/coco/sev-guest/sev-guest.c | 135 ++++++++++++++- > > > > include/keys/tsm.h | 71 ++++++++ > > > > include/linux/slab.h | 2 > > > > security/keys/Kconfig | 12 + > > > > security/keys/Makefile | 1 > > > > security/keys/tsm.c | 282 +++++++++++++++++++++++++++++++ > > > > 7 files changed, 494 insertions(+), 11 deletions(-) > > > > create mode 100644 include/keys/tsm.h > > > > create mode 100644 security/keys/tsm.c > > > > > > > > base-commit: 06c2afb862f9da8dc5efa4b6076a0e48c3fbaaa5 > > > > > > So how does this scale? Does it scale to TDX, SGX, TPM's or even TEE's > > > (ARM SM, RISC-V Keystone etc.). I'm not sure about the scope but we want > > > of course something that adapts to multiple use cases, right? > > > > TPMs and TEEs are covered by trusted-keys. I do think a "TSM" flavor of > > trusted-keys is in scope for where some of these implementations are > > headed, but that comes later. I talk about that in the changelog that > > functionality like SNP_GET_DERIVED_KEY likely wants to have a > > trusted-keys frontend and not isolated behind a vendor-specific ioctl > > interface. > > TEE's and TPM's are not the exact same thing. Are we sure that any > future ARM SMC like TEE interface what you say will hold?
Agree, they are not the same thing, I assume that's why trusted-keys has a TEE and a TPM backend. Also that's the point of common interface proposals for the per vendor experts to take a look and make sure it fits their needs. If you have contacts there, please highlight this thread to them.
> Why do we need a new key type, when we have already trusted keys?
As I mentioned to James to the comment from him about vTPM, if that ends up just looking like a standard TPM to Linux then nothing new is needed.
> This whole territory should be better defined so that everything > will fit together.
Yes, the per-vendor differentiation in this space is an impediment to kernel interface design.
> > This facility is different, it is just aiming to unify this attestation > > report flow. It scales to any driver that can provide the ->auth_new() > > operation. I have the sev-guest conversion in this set, and Sathya has > > tested this with tdx-guest. I am hoping Samuel can evaluate it for > > cove-guest or whatever that driver ends up being called. > > What about SGX without TDX?
My hope would be that anything that can not be fronted by TPM2_Quote directly can by frontend by this "TSM" class device (as I will be switching from Keyring to sysfs).
| |