Hi Jens,
thanks for your patch!
On Tue, Feb 27, 2024 at 4:31 PM Jens Wiklander jens.wiklander@linaro.org wrote:
A number of storage technologies support a specialised hardware partition designed to be resistant to replay attacks. The underlying HW protocols differ but the operations are common. The RPMB partition cannot be accessed via standard block layer, but by a set of specific RPMB commands: WRITE, READ, GET_WRITE_COUNTER, and PROGRAM_KEY.
Such a
partition provides authenticated and replay protected access, hence suitable as a secure storage.
The initial aim of this patch is to provide a simple RPMB driver interface which can be accessed by the optee driver to facilitate early RPMB access to OP-TEE OS (secure OS) during the boot time.
A TEE device driver can claim the RPMB interface, for example, via rpmb_interface_register() or rpmb_dev_find_device(). The RPMB driver provides a callback to route RPMB frames to the RPMB device accessible via rpmb_route_frames().
The detailed operation of implementing the access is left to the TEE device driver itself.
Signed-off-by: Tomas Winkler tomas.winkler@intel.com Signed-off-by: Alex Bennée alex.bennee@linaro.org Signed-off-by: Shyam Saini shyamsaini@linux.microsoft.com Signed-off-by: Jens Wiklander jens.wiklander@linaro.org
I would mention in the commit that the subsystem is currently only used with eMMC but is designed to be used also by UFS and NVME. Nevertheless, no big deal so:
Moreover, as the years went by, the differences between mmc and ufs grew: In mmc there are 7 rpmb operations, in ufs 9. In mmc the rpmb frame is 512Bytes, also in legacy ufs (up to including ufs3.1), but in ufs4.0 onward it can be 4k with extended header. See e.g. https://patchwork.kernel.org/project/linux-scsi/patch/20221107131038.201724-... In mmc the rpmb sequence is atomic, in ufs not. In ufs rpmb is a wlun in mmc a partition. Both protocols support in multi-region rpmb, but there are some differences there. Etc.
Thanks, Avri
Reviewed-by: Linus Walleij linus.walleij@linaro.org
+config RPMB
tristate "RPMB partition interface"depends on MMCdepends on MMC || SCSI_UFSHCD || NVME_CORE ?
Or do we want to hold it off until we implement the backends?
Yours, Linus Walleij