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* [PATCH v4 0/8] Replay Protected Memory Block (RPMB) subsystem
@ 2016-06-01 21:41 Tomas Winkler
  2016-06-01 21:41 ` [PATCH v4 1/8] rpmb: add " Tomas Winkler
                   ` (8 more replies)
  0 siblings, 9 replies; 17+ messages in thread
From: Tomas Winkler @ 2016-06-01 21:41 UTC (permalink / raw)
  To: Greg Kroah-Hartman, Ulf Hansson, Adrian Hunter, James Bottomley,
	Martin K. Petersen, Vinayak Holikatti, Andy Lutomirski,
	Arve Hjønnevåg, Michael Ryleev, Joao Pinto,
	Christoph Hellwig, Yaniv Gardi
  Cc: linux-kernel, linux-mmc, linux-scsi, Tomas Winkler

Few storage technology such is EMMC, UFS, and NVMe support RPMB
hardware partition with common protocol and frame layout.
The RPMB partition cannot be accessed via standard block layer, but
by a set of specific commands: WRITE, READ, GET_WRITE_COUNTER, and
PROGRAM_KEY.
Such a partition provides authenticated and replay protected access,
hence suitable as a secure storage.

A storage device registers its RPMB hardware (emmc) partition or
RPMB W-LUN (ufs) with the RPMB layer providing an implementation for
send_rpmb_req() handler.
There is as well simulation platform device. This is handy as an RPMB
key can be programmed only once at storage device lifetime.

The RPMB layer aims to provide in-kernel API for Trusted Execution
Environment (TEE) devices that are capable to securely compute block
frame signature. In case a TEE device wish to store a replay protected
data, it creates an RPMB frame with requested data and computes HMAC of
the frame, then it requests the storage device via RPMB layer to store
the data.
A TEE driver can claim rpmb interface, for example,
via  class_interface_register ().

A parallel user space API is provided via /dev/rpmbX character
device with a single IOCTL command similar to the one provided by
mmc/ioctl. h
This API may help applications such as 
https://android.googlesource.com/trusty/app/storage/
To be obliviose to the underlaying HW storage technology.

There is a sample tool under tools/rpmb/ directory that exercises
this interface.

Tomas Winkler (8):
  rpmb: add Replay Protected Memory Block (RPMB) subsystem
  char: rpmb: add sysfs-class ABI documentation
  char: rpmb: add device attributes
  char: rpmb: provide user space interface
  char: rpmb: add RPMB simulation device
  tools rpmb: add RPBM access tool
  mmc: block: register RPMB partition with the RPMB subsystem
  scsi: ufs: connect to RPMB subsystem

 Documentation/ABI/testing/sysfs-class-rpmb |  44 ++
 Documentation/ioctl/ioctl-number.txt       |   1 +
 MAINTAINERS                                |  10 +
 drivers/char/Kconfig                       |   2 +
 drivers/char/Makefile                      |   1 +
 drivers/char/rpmb/Kconfig                  |  25 +
 drivers/char/rpmb/Makefile                 |   6 +
 drivers/char/rpmb/cdev.c                   | 207 +++++++
 drivers/char/rpmb/core.c                   | 408 ++++++++++++++
 drivers/char/rpmb/rpmb-cdev.h              |  31 ++
 drivers/char/rpmb/rpmb_sim.c               | 589 ++++++++++++++++++++
 drivers/mmc/card/Kconfig                   |   1 +
 drivers/mmc/card/block.c                   | 292 ++++++++++
 drivers/scsi/ufs/Kconfig                   |   1 +
 drivers/scsi/ufs/ufshcd.c                  | 219 ++++++++
 drivers/scsi/ufs/ufshcd.h                  |   2 +
 include/linux/rpmb.h                       | 138 +++++
 include/uapi/linux/rpmb.h                  | 120 ++++
 tools/Makefile                             |  14 +-
 tools/rpmb/.gitignore                      |   2 +
 tools/rpmb/Makefile                        |  32 ++
 tools/rpmb/rpmb.c                          | 862 +++++++++++++++++++++++++++++
 22 files changed, 3002 insertions(+), 5 deletions(-)
 create mode 100644 Documentation/ABI/testing/sysfs-class-rpmb
 create mode 100644 drivers/char/rpmb/Kconfig
 create mode 100644 drivers/char/rpmb/Makefile
 create mode 100644 drivers/char/rpmb/cdev.c
 create mode 100644 drivers/char/rpmb/core.c
 create mode 100644 drivers/char/rpmb/rpmb-cdev.h
 create mode 100644 drivers/char/rpmb/rpmb_sim.c
 create mode 100644 include/linux/rpmb.h
 create mode 100644 include/uapi/linux/rpmb.h
 create mode 100644 tools/rpmb/.gitignore
 create mode 100644 tools/rpmb/Makefile
 create mode 100644 tools/rpmb/rpmb.c

-- 
2.5.5

^ permalink raw reply	[flat|nested] 17+ messages in thread
* RE: [PATCH v4 0/8] Replay Protected Memory Block (RPMB) subsystem
@ 2016-06-14 21:05 Winkler, Tomas
  2016-06-15  2:39 ` Arve Hjønnevåg
  0 siblings, 1 reply; 17+ messages in thread
From: Winkler, Tomas @ 2016-06-14 21:05 UTC (permalink / raw)
  To: arve
  Cc: Greg Kroah-Hartman, Ulf Hansson, Hunter, Adrian, James Bottomley,
	Martin K. Petersen, Vinayak Holikatti, Andy Lutomirski,
	Michael Ryleev, Joao Pinto, Christoph Hellwig, Yaniv Gardi, LKML,
	linux-mmc, linux-scsi

>>> wrote:
>>> > Few storage technology such is EMMC, UFS, and NVMe support RPMB
>>> >hardware partition with common protocol and frame layout.
>>> > The RPMB partition cannot be accessed via standard block layer, but
>>> >by a set of specific commands: WRITE, READ, GET_WRITE_COUNTER, and
>>> >PROGRAM_KEY.
>>> >...
>>>
>>> If the same protocol is used by all these standards, why not export it directly
>>> (including the RESULT_READ command or not even knowing the command
>>> types)?
>> The protocol is the  same, but the wrapping of the packets is storage type specific so
>> I believe that the best abstraction is on those  4 operations level. I'm not sure if the code would
>> be simpler if it would be exposed on a lower level.
>
> I disagree. With the two storage types you support, the packets are
> identical. The only difference is the low level commands you use to
> send and receive them.
The packets are identical, but there are these little settings you need to be aware of
like set argument  31 in CMD23 for WRITE and PROGRAM_KEY and for others not so
the storage type transparency is lost, actually the UFS protocol is a bit cleaner in that sense.
I know it can be ironed somehow, but this just stresses the point. 

>> RESULT_READ  is  a command to be issued for getting preceeding write operation status, it's a kind of work around about the fact that you have to issue a read operation
>> in order to retrieve data in this case a  write operation result.  It can be successfully hidden and final result of the operation is delivered
>> to the user.
>>
>
> Yes, it is possible to hide the result read command, but that does not
> mean you should. The rpmb protocol is designed to let two endpoints
> communicate in a way that lets them detect tampering. While the packet
> you inject does not contain any protected data, you can still view it
> as a form of tampering. 

I’m not seeing it like injecting packets, those are merely commands embedded in the packets that need to be performed in order to complete the operation
and there is not security value in them, the only end to end protection is truly given by the MAC verification and this is preserved. 

>If a future rpmb protocol version adds
> features, you could loose the ability to inject packets.

The code will have to change anyhow.  

>
>>> While I would prefer an rpmb specific interface over the existing raw
>>> mmc command interface, all I need is an rpmb operation that lets me send
>>> and receive buffers without interruption.
>>
>> I currently don't see an obstacle on doing the same with proposed interface, what is the issue are seeing.
>>
>
> The main issue is that you are injecting commands, so code that
> follows the mmc spec will not work.

Yes, it should be storage type independent, not mmc spec dependant. 
The interface reduces the number of data passed between user space and kernel, the device power management is simpler. 

>
>>> You can find our exiting user-space code here at
>>> https://android.googlesource.com/platform/system/core/+/master/trusty/s
>>> torage/proxy/rpmb.c.
>>> If you use an interface more similar to this, I think your emmc and ufs
>>> specific code would be simpler. Also, if you don't need the in-kernel
>>> interface, the kernel would not need to know the details of the rpmb
>>> protocol at all.
>>
>> My major interest is the in-kernel protocol the user space API was more intended for debug, but I found it would be even more useful.
>> The store type  access is very RPMB specific  for both MMC and UFS and needs to do special operations for RPMB so I don't see how this awareness can be removed or I'm not reading your proposal correctly.
>
> The interface we use specifies reliable-write, write and read
> operations on an rpmb partition. I don't think you need to know more
> than this in either mmc or ufs. I have not seen the ufs spec, but
> based on your code it looks like reliable-write and write can map to
> the same command there.
Yes, the interface can be also abstract on let’s call it raw rpmb packet read/write level, but I didn’t see the value in at the time as RPMB operations and the steps are well defined.
Maybe there is a place for to support for fing grained access or at leasting adding RESULT_READ command as well,  for the usecases like yours.

>> Accessing RPMB is a multiple stepsoperation, the steps can be driven from the user space as done in EMMC ioctl but hidning would reduce the number of system calls and amount of data passed,
>> in some sense the same as in the  new mmc  MMC_IOC_MULTI_CMD is trying ot achive.
>>
> The main purpose of using the MMC_IOC_MULTI_CMD is not to reduce the
> number of syscalls. It is to prevent other mmc operations from getting
> interleaved with the rpmb packets. Some emmc chips will only respond
> error packet if any other partitions are read from between the write
> and read operation on the rpmb partition.

I didn’t encountered as our interface doesn’t suffer form that issue but yes this just another reason to use the new rpmb interface
>
>>> I have not tested your code, but it looks like we would have to modify the
>>> storage proxy to interpret the data it currently passes through and remove all
>>> RESULT_READ packets.
>> Your proxy driver just sends ioctls so this wouldn't be much difference and the rpmb code on the trusty w need rewrite just rpmb_send () function,
>> actually removing one set of buffer size. I will try to make that modification if it helps?
>>
>
> No I don't want you to modify the code that runs in the secure OS.
> This would require additional code in boot loaders and proxy servers
> using the existing MMC_IOC_MULTI_CMD command as they too would have to
> interpret the packets to inject RESULT_READ packets.

I’ve looked at the proxy and and secure OS, the rewirte is not so hard, though.
I really cannot figure to boo loader and secure OS interactions, you have this notion of TP and TDEA ports but those are not used from the secure OS. 
Is there a software you can point me to? 

Second if it won’t be possible to use the current implementation if the storage type change UFS or NVMe anyhow and on the othernad
I’m not suggesting to kill MMC ioctl, so this won’t be breackages of the existing software. 

In bottom line I will try to add raw read/write access to RPMB to support fine grained access and see if you can work with that.


I really appreciate your feedback.
Thanks
Tomas 

^ permalink raw reply	[flat|nested] 17+ messages in thread

end of thread, other threads:[~2016-06-27 10:17 UTC | newest]

Thread overview: 17+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2016-06-01 21:41 [PATCH v4 0/8] Replay Protected Memory Block (RPMB) subsystem Tomas Winkler
2016-06-01 21:41 ` [PATCH v4 1/8] rpmb: add " Tomas Winkler
2016-06-01 21:41 ` [PATCH v4 2/8] char: rpmb: add sysfs-class ABI documentation Tomas Winkler
2016-06-01 21:41 ` [PATCH v4 3/8] char: rpmb: add device attributes Tomas Winkler
2016-06-01 21:41 ` [PATCH v4 4/8] char: rpmb: provide user space interface Tomas Winkler
2016-06-02 13:44   ` [v4,4/8] " Jérôme Forissier
2016-06-01 21:41 ` [PATCH v4 5/8] char: rpmb: add RPMB simulation device Tomas Winkler
2016-06-01 21:41 ` [PATCH v4 6/8] tools rpmb: add RPBM access tool Tomas Winkler
2016-06-01 21:41 ` [PATCH v4 7/8] mmc: block: register RPMB partition with the RPMB subsystem Tomas Winkler
2016-06-23  6:17   ` Adrian Hunter
2016-06-27 10:17     ` Winkler, Tomas
2016-06-01 21:41 ` [PATCH v4 8/8] scsi: ufs: connect to " Tomas Winkler
2016-06-01 23:21 ` [PATCH v4 0/8] Replay Protected Memory Block (RPMB) subsystem Arve Hjønnevåg
2016-06-02 13:17   ` Winkler, Tomas
2016-06-02 22:35     ` Arve Hjønnevåg
2016-06-14 21:05 Winkler, Tomas
2016-06-15  2:39 ` Arve Hjønnevåg

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