- OP-TEE - lists.trustedfirmware.org

[PATCH v2 0/2] OP-TEE kernel private shared memory optimizations

by Jens Wiklander

Hi, This patch set optimizes OP-TEE driver private shared memory allocated as dynamic shared memory (not from the static shared memory pool). The first patch handles kernel private RPC allocatations larger than one page and the second changes from alloc_pages_exact() instead of alloc_pages() for more efficient memory usage. v1->v2: * Split into two patches as requested Jens Wiklander (2): optee: add page list to kernel private shared memory optee: allocate shared memory with alloc_pages_exact() drivers/tee/optee/core.c | 59 +++++++++++++++++++++++++------------ drivers/tee/optee/smc_abi.c | 45 +++++++++++++--------------- 2 files changed, 61 insertions(+), 43 deletions(-) base-commit: 05d3ef8bba77c1b5f98d941d8b2d4aeab8118ef1 -- 2.34.1

1 year

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Does OP TEE support golang & JAVA TA?

by Alex Wang

We are considering to provide professional (data security) service for TA, I think that our service software should be TA because it touches sensitive plain text, and our software are in golang & JAVA. Does OP TEE support golang & JAVA TA? If not, any idea of how to make it? Best Regards [defaultAvatar.png] Alex alex(a)surcloud.net References Visible links: Hidden links: 2. https://maas.mail.163.com/dashi-web-extend/html/proSignature.html?ftlId=1&n…

1 year

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[PATCH v12 0/4] tee: introduce TEE system sssion

by Etienne Carriere

This series introduces TEE system sessions for TEE service sessions that require TEE to provision resources to prevent deadlock when clients call the TEE. This deadlock situation can happen when a TEE service is used by low level system resources as for example when Linux kernel uses SCMI service embedded in TEE for clock, reset, regulator, etc... controls. This case is detailled in patch 2/4: > This feature is needed to prevent a system deadlock when several TEE > client applications invoke TEE, consuming all TEE thread contexts > available in the secure world. The deadlock can happen in the OP-TEE > driver for example if all these TEE threads issue an RPC call from TEE > to Linux OS to access an eMMC RPMB partition (TEE secure storage) which > device clock or regulator controller is accessed through an OP-TEE SCMI > services. In that case, Linux SCMI driver must reach OP-TEE SCMI > service without waiting until one of the consumed TEE threads is freed. Etienne Carriere (4): tee: optee: system call property tee: system session tee: optee: support tracking system threads firmware: arm_scmi: optee: use optee system invocation drivers/firmware/arm_scmi/optee.c | 4 + drivers/tee/optee/call.c | 130 ++++++++++++++++++++++++++++-- drivers/tee/optee/core.c | 5 +- drivers/tee/optee/ffa_abi.c | 14 ++-- drivers/tee/optee/optee_private.h | 29 ++++++- drivers/tee/optee/smc_abi.c | 32 +++++--- drivers/tee/tee_core.c | 8 ++ include/linux/tee_drv.h | 16 ++++ 8 files changed, 211 insertions(+), 27 deletions(-) --- Changes since v11: - Fixed inline description comments in patch 1/3 and 3/4, other patches are unchanged. Changes since v10: - Changes patch 3/4, other are unchanged. -- 2.25.1

1 year

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[PATCH] optee: add missing description of RPC argument reference

by Etienne Carriere

Adds missing inline description comment for RPC optional arguments reference. Reported-by: kernel test robot <lkp(a)intel.com> Closes: https://lore.kernel.org/lkml/202310192021.fvb6JDOY-lkp@intel.com/ Signed-off-by: Etienne Carriere <etienne.carriere(a)foss.st.com> --- drivers/tee/optee/smc_abi.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/tee/optee/smc_abi.c b/drivers/tee/optee/smc_abi.c index d5b28fd35d66..67bfa25d6302 100644 --- a/drivers/tee/optee/smc_abi.c +++ b/drivers/tee/optee/smc_abi.c @@ -806,6 +806,7 @@ static void handle_rpc_func_cmd(struct tee_context *ctx, struct optee *optee, /** * optee_handle_rpc() - handle RPC from secure world * @ctx: context doing the RPC + * @rpc_arg: pointer to RPC arguments if any, or NULL if none * @param: value of registers for the RPC * @call_ctx: call context. Preserved during one OP-TEE invocation * -- 2.25.1

1 year

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[PATCH 0/2] OP-TEE FF-A notifications

by Jens Wiklander

Hi all, This patchset adds support for using FF-A notifications as a delivery mechanism of asynchronous notifications from OP-TEE running in the secure world. Support for asynchronous notifications via the SMC ABI was added in [1], here we add the counterpart needed when using the the FF-A ABI. Support for FF-A notifications is added with [2] and this patch set is based on Sudeeps tree at [3]. [1] https://lore.kernel.org/lkml/20211103090255.998070-1-jens.wiklander@linaro.… [2] https://lore.kernel.org/linux-arm-kernel/20231005-ffa_v1-1_notif-v4-0-cddd3… [3] https://git.kernel.org/pub/scm/linux/kernel/git/sudeep.holla/linux.git/tag/… commit bcefd1bf63b1 ("firmware: arm_ffa: Upgrade the driver version to v1.1") Thanks, Jens Jens Wiklander (2): optee: provide optee_do_bottom_half() as a common function optee: ffa_abi: add asynchronous notifications drivers/tee/optee/call.c | 31 ++++++++++- drivers/tee/optee/ffa_abi.c | 91 ++++++++++++++++++++++++++++++- drivers/tee/optee/optee_ffa.h | 28 ++++++++-- drivers/tee/optee/optee_private.h | 9 ++- drivers/tee/optee/smc_abi.c | 36 ++---------- 5 files changed, 153 insertions(+), 42 deletions(-) base-commit: bcefd1bf63b1ec9bb08067021cf47f0fad96f395 -- 2.34.1

1 year

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[PATCH v10 0/5] introduce tee-based EFI Runtime Variable Service

by Masahisa Kojima

This series introduces the tee-based EFI Runtime Variable Service. The eMMC device is typically owned by the non-secure world(linux in this case). There is an existing solution utilizing eMMC RPMB partition for EFI Variables, it is implemented by interacting with OP-TEE, StandaloneMM(as EFI Variable Service Pseudo TA), eMMC driver and tee-supplicant. The last piece is the tee-based variable access driver to interact with OP-TEE and StandaloneMM. This driver depends on the tee-supplicant. When the tee-supplicant stops, this driver needs to be unbound from user-space script or tool, relevant patch is posted[1]. [1] https://lore.kernel.org/all/20231102073056.174480-2-sumit.garg@linaro.org/ Changelog: v9 -> v10 - patch #6 "tee: optee: restore efivars ops when tee-supplicant stops" is removed v8 -> v9 - patch #6 "tee: optee: restore efivars ops when tee-supplicant stops" is newly added - remove !EFI_VARS_PSTORE Kconfig dependency, we have added a non-blocking set_variable and it just returns EFI_UNSUPPORTED. - remove obvious comments v7 -> v8 Only patch #3 "efi: Add tee-based EFI variable driver" is updated. - fix typos - refactor error handling, direct return if applicable - use devm_add_action_or_reset() for closing of tee context/session - remove obvious comment v6 -> v7 Patch #1-#4 are not updated. Patch #5 is added into this series, original patch is here: https://lore.kernel.org/all/20230609094532.562934-1-ilias.apalodimas@linaro… There are two issues in the v6 series and v7 series addresses those. 1) efivar ops is not restored when the tee-supplicant daemon terminates. -> As the following patch says, user must remove the device before terminating tee-supplicant daemon. https://lore.kernel.org/all/20230728134832.326467-1-sumit.garg@linaro.org/ 2) cause panic when someone remounts the efivarfs as RW even if SetVariable is not supported -> The fifth patch addresses this issue. "[PATCH v7 5/5] efivarfs: force RO when remounting if SetVariable is not supported" v5 -> v6 - new patch #4 is added in this series, #1-#3 patches are unchanged. automatically update super block flag when the efivarops support SetVariable runtime service, so that user does not need to manually remount the efivarfs as RW. v4 -> v5 - rebase to efi-next based on v6.4-rc1 - set generic_ops.query_variable_info, it works as expected as follows. $ df -h /sys/firmware/efi/efivars/ Filesystem Size Used Avail Use% Mounted on efivarfs 16K 1.3K 15K 8% /sys/firmware/efi/efivars v3 -> v4: - replace the reference from EDK2 to PI Specification - remove EDK2 source code reference comments - prepare nonblocking variant of set_variable, it just returns EFI_UNSUPPORTED - remove redundant buffer size check - argument name change in mm_communicate - function interface changes in setup_mm_hdr to remove (void **) cast v2 -> v3: - add CONFIG_EFI dependency to TEE_STMM_EFI - add missing return code check for tee_client_invoke_func() - directly call efivars_register/unregister from tee_stmm_efi.c rfc v1 -> v2: - split patch into three patches, one for drivers/tee, one for include/linux/efi.h, and one for the driver/firmware/efi/stmm - context/session management into probe() and remove() same as other tee client driver - StMM variable driver is moved from driver/tee/optee to driver/firmware/efi - use "tee" prefix instead of "optee" in driver/firmware/efi/stmm/tee_stmm_efi.c, this file does not contain op-tee specific code, abstracted by tee layer and StMM variable driver will work on other tee implementation. - PTA_STMM_CMD_COMMUNICATE -> PTA_STMM_CMD_COMMUNICATE - implement query_variable_store() but currently not used - no use of TEEC_SUCCESS, it is defined in driver/tee/optee/optee_private.h. Other tee client drivers use 0 instead of using TEEC_SUCCESS - remove TEEC_ERROR_EXCESS_DATA status, it is referred just to output error message Ilias Apalodimas (1): efivarfs: force RO when remounting if SetVariable is not supported Masahisa Kojima (4): efi: expose efivar generic ops register function efi: Add EFI_ACCESS_DENIED status code efi: Add tee-based EFI variable driver efivarfs: automatically update super block flag drivers/firmware/efi/Kconfig | 15 + drivers/firmware/efi/Makefile | 1 + drivers/firmware/efi/efi.c | 18 + drivers/firmware/efi/stmm/mm_communication.h | 236 +++++++ drivers/firmware/efi/stmm/tee_stmm_efi.c | 616 +++++++++++++++++++ drivers/firmware/efi/vars.c | 8 + fs/efivarfs/super.c | 45 ++ include/linux/efi.h | 12 + 8 files changed, 951 insertions(+) create mode 100644 drivers/firmware/efi/stmm/mm_communication.h create mode 100644 drivers/firmware/efi/stmm/tee_stmm_efi.c base-commit: 5329aa5101f73c451bcd48deaf3f296685849d9c -- 2.39.2

1 year

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HELP for OPTEE Application crash when wakeup from Hiberation

by XiaoXia

Hello All: I have new project for developping TEE in notebook. the system needs to support S4 (Hiberation/STD) in order to reduce the power consume. To make the design simplest, I follow the regular suspend flow as below: 1. the kernel implement suspend flow to freeze thread and store data in swap paritition. then enter into S3 mode 2. system wakeups by pressing poweron event, and boot into kernel as normal. and the TEE OS and Trusted firmware will initialize like in normal boot. Once kernel recover all context, I try to issue CA again, and it prompts the below error message. I know that the context of TEE-OS and TEE driver does not match new after system recovery... I wonder to know if there is way to cleanup TEE driver before entering into S4 to make CA work after wakeup . Thank you for your help . Best Regareds, Vincent Cui

1 year

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[PATCH v3 0/2] tee: optee: Fixes for supplicant dependent enumeration

by Sumit Garg

Currently supplicant dependent optee device enumeration only registers devices whenever tee-supplicant is invoked for the first time. But it forgets to remove devices when tee-supplicant daemon stops running and closes its context gracefully. This leads to following error for fTPM driver during reboot/shutdown: [ 73.466791] tpm tpm0: ftpm_tee_tpm_op_send: SUBMIT_COMMAND invoke error: 0xffff3024 Fix this by separating supplicant dependent devices so that the user-space service can detach supplicant devices before closing the supplicant. While at it use the global system workqueue for OP-TEE bus scanning work rather than our own custom one. Changes in v3: - Split patch into 2 separate ones, one for supplicant fix and other for the workqueue. Changes in v2: - Use device names to separate out tee-supplicant dependent devices via this patch. - Since user-space service is aware about tee-supplicant lifespan, so allow the user-space service to unbind tee-supplicant dependent devices before killing the supplicant. Following command has to be added to the tee-supplicant service file. $ for dev in /sys/bus/tee/devices/*; do if [[ "$dev" == *"optee-ta-supp-"* ]]; \ then echo $(basename "$dev") > $dev/driver/unbind; fi done Sumit Garg (2): tee: optee: Fix supplicant based device enumeration tee: optee: Remove redundant custom workqueue drivers/tee/optee/core.c | 13 ++----------- drivers/tee/optee/device.c | 13 ++++++++++--- drivers/tee/optee/optee_private.h | 2 -- 3 files changed, 12 insertions(+), 16 deletions(-) -- 2.34.1

1 year

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[PATCH 0/3] Introduce DMA APIs to allocate and free TEE shared memory

by jeshwank

From: Jeshwanth Kumar N K <JESHWANTHKUMAR.NK(a)amd.com> At present, the shared memory for TEE ring buffer, command buffer and data buffer is allocated using get_free_pages(). The driver shares the physical address of these buffers with PSP so that it can be mapped by the Trusted OS. In this patch series we have replaced get_free_pages() with dma_alloc_coherent() to allocate shared memory to cleanup the existing allocation method. Rijo Thomas (3): crypto: ccp - Add function to allocate and free memory using DMA APIs crypto: ccp - Use psp_tee_alloc_buffer() and psp_tee_free_buffer() tee: amdtee: Use psp_tee_alloc_buffer() and psp_tee_free_buffer() drivers/crypto/ccp/psp-dev.c | 3 + drivers/crypto/ccp/tee-dev.c | 119 ++++++++++++++++++---------- drivers/crypto/ccp/tee-dev.h | 11 +-- drivers/tee/amdtee/amdtee_private.h | 18 ++--- drivers/tee/amdtee/call.c | 74 ++++++++--------- drivers/tee/amdtee/core.c | 72 ++++++++++------- drivers/tee/amdtee/shm_pool.c | 21 ++--- include/linux/psp-tee.h | 47 +++++++++++ 8 files changed, 221 insertions(+), 144 deletions(-) -- 2.25.1

1 year

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[PATCH] Documentation: Destage TEE subsystem documentation

by Sumit Garg

Add a separate documentation directory for TEE subsystem since it is a standalone subsystem which already offers devices consumed by multiple different subsystem drivers. Split overall TEE subsystem documentation modularly where the first module covers the overview of TEE subsystem itself along with generic features. Then the further modules are dedicated to different TEE implementations like: - OP-TEE - AMD-TEE - and so on for future TEE implementation support. Signed-off-by: Sumit Garg <sumit.garg(a)linaro.org> --- Documentation/staging/index.rst | 1 - Documentation/staging/tee.rst | 364 ------------------------------- Documentation/subsystem-apis.rst | 1 + Documentation/tee/amd-tee.rst | 90 ++++++++ Documentation/tee/index.rst | 19 ++ Documentation/tee/op-tee.rst | 166 ++++++++++++++ Documentation/tee/tee.rst | 122 +++++++++++ MAINTAINERS | 2 +- 8 files changed, 399 insertions(+), 366 deletions(-) delete mode 100644 Documentation/staging/tee.rst create mode 100644 Documentation/tee/amd-tee.rst create mode 100644 Documentation/tee/index.rst create mode 100644 Documentation/tee/op-tee.rst create mode 100644 Documentation/tee/tee.rst diff --git a/Documentation/staging/index.rst b/Documentation/staging/index.rst index ded8254bc0d7..71592f3ce89b 100644 --- a/Documentation/staging/index.rst +++ b/Documentation/staging/index.rst @@ -12,5 +12,4 @@ Unsorted Documentation rpmsg speculation static-keys - tee xz diff --git a/Documentation/staging/tee.rst b/Documentation/staging/tee.rst deleted file mode 100644 index 22baa077a3b9..000000000000 --- a/Documentation/staging/tee.rst +++ /dev/null @@ -1,364 +0,0 @@ -============= -TEE subsystem -============= - -This document describes the TEE subsystem in Linux. - -A TEE (Trusted Execution Environment) is a trusted OS running in some -secure environment, for example, TrustZone on ARM CPUs, or a separate -secure co-processor etc. A TEE driver handles the details needed to -communicate with the TEE. - -This subsystem deals with: - -- Registration of TEE drivers - -- Managing shared memory between Linux and the TEE - -- Providing a generic API to the TEE - -The TEE interface -================= - -include/uapi/linux/tee.h defines the generic interface to a TEE. - -User space (the client) connects to the driver by opening /dev/tee[0-9]* or -/dev/teepriv[0-9]*. - -- TEE_IOC_SHM_ALLOC allocates shared memory and returns a file descriptor - which user space can mmap. When user space doesn't need the file - descriptor any more, it should be closed. When shared memory isn't needed - any longer it should be unmapped with munmap() to allow the reuse of - memory. - -- TEE_IOC_VERSION lets user space know which TEE this driver handles and - its capabilities. - -- TEE_IOC_OPEN_SESSION opens a new session to a Trusted Application. - -- TEE_IOC_INVOKE invokes a function in a Trusted Application. - -- TEE_IOC_CANCEL may cancel an ongoing TEE_IOC_OPEN_SESSION or TEE_IOC_INVOKE. - -- TEE_IOC_CLOSE_SESSION closes a session to a Trusted Application. - -There are two classes of clients, normal clients and supplicants. The latter is -a helper process for the TEE to access resources in Linux, for example file -system access. A normal client opens /dev/tee[0-9]* and a supplicant opens -/dev/teepriv[0-9]. - -Much of the communication between clients and the TEE is opaque to the -driver. The main job for the driver is to receive requests from the -clients, forward them to the TEE and send back the results. In the case of -supplicants the communication goes in the other direction, the TEE sends -requests to the supplicant which then sends back the result. - -The TEE kernel interface -======================== - -Kernel provides a TEE bus infrastructure where a Trusted Application is -represented as a device identified via Universally Unique Identifier (UUID) and -client drivers register a table of supported device UUIDs. - -TEE bus infrastructure registers following APIs: - -match(): - iterates over the client driver UUID table to find a corresponding - match for device UUID. If a match is found, then this particular device is - probed via corresponding probe API registered by the client driver. This - process happens whenever a device or a client driver is registered with TEE - bus. - -uevent(): - notifies user-space (udev) whenever a new device is registered on - TEE bus for auto-loading of modularized client drivers. - -TEE bus device enumeration is specific to underlying TEE implementation, so it -is left open for TEE drivers to provide corresponding implementation. - -Then TEE client driver can talk to a matched Trusted Application using APIs -listed in include/linux/tee_drv.h. - -TEE client driver example -------------------------- - -Suppose a TEE client driver needs to communicate with a Trusted Application -having UUID: ``ac6a4085-0e82-4c33-bf98-8eb8e118b6c2``, so driver registration -snippet would look like:: - - static const struct tee_client_device_id client_id_table[] = { - {UUID_INIT(0xac6a4085, 0x0e82, 0x4c33, - 0xbf, 0x98, 0x8e, 0xb8, 0xe1, 0x18, 0xb6, 0xc2)}, - {} - }; - - MODULE_DEVICE_TABLE(tee, client_id_table); - - static struct tee_client_driver client_driver = { - .id_table = client_id_table, - .driver = { - .name = DRIVER_NAME, - .bus = &tee_bus_type, - .probe = client_probe, - .remove = client_remove, - }, - }; - - static int __init client_init(void) - { - return driver_register(&client_driver.driver); - } - - static void __exit client_exit(void) - { - driver_unregister(&client_driver.driver); - } - - module_init(client_init); - module_exit(client_exit); - -OP-TEE driver -============= - -The OP-TEE driver handles OP-TEE [1] based TEEs. Currently it is only the ARM -TrustZone based OP-TEE solution that is supported. - -Lowest level of communication with OP-TEE builds on ARM SMC Calling -Convention (SMCCC) [2], which is the foundation for OP-TEE's SMC interface -[3] used internally by the driver. Stacked on top of that is OP-TEE Message -Protocol [4]. - -OP-TEE SMC interface provides the basic functions required by SMCCC and some -additional functions specific for OP-TEE. The most interesting functions are: - -- OPTEE_SMC_FUNCID_CALLS_UID (part of SMCCC) returns the version information - which is then returned by TEE_IOC_VERSION - -- OPTEE_SMC_CALL_GET_OS_UUID returns the particular OP-TEE implementation, used - to tell, for instance, a TrustZone OP-TEE apart from an OP-TEE running on a - separate secure co-processor. - -- OPTEE_SMC_CALL_WITH_ARG drives the OP-TEE message protocol - -- OPTEE_SMC_GET_SHM_CONFIG lets the driver and OP-TEE agree on which memory - range to used for shared memory between Linux and OP-TEE. - -The GlobalPlatform TEE Client API [5] is implemented on top of the generic -TEE API. - -Picture of the relationship between the different components in the -OP-TEE architecture:: - - User space Kernel Secure world - ~~~~~~~~~~ ~~~~~~ ~~~~~~~~~~~~ - +--------+ +-------------+ - | Client | | Trusted | - +--------+ | Application | - /\ +-------------+ - || +----------+ /\ - || |tee- | || - || |supplicant| \/ - || +----------+ +-------------+ - \/ /\ | TEE Internal| - +-------+ || | API | - + TEE | || +--------+--------+ +-------------+ - | Client| || | TEE | OP-TEE | | OP-TEE | - | API | \/ | subsys | driver | | Trusted OS | - +-------+----------------+----+-------+----+-----------+-------------+ - | Generic TEE API | | OP-TEE MSG | - | IOCTL (TEE_IOC_*) | | SMCCC (OPTEE_SMC_CALL_*) | - +-----------------------------+ +------------------------------+ - -RPC (Remote Procedure Call) are requests from secure world to kernel driver -or tee-supplicant. An RPC is identified by a special range of SMCCC return -values from OPTEE_SMC_CALL_WITH_ARG. RPC messages which are intended for the -kernel are handled by the kernel driver. Other RPC messages will be forwarded to -tee-supplicant without further involvement of the driver, except switching -shared memory buffer representation. - -OP-TEE device enumeration -------------------------- - -OP-TEE provides a pseudo Trusted Application: drivers/tee/optee/device.c in -order to support device enumeration. In other words, OP-TEE driver invokes this -application to retrieve a list of Trusted Applications which can be registered -as devices on the TEE bus. - -OP-TEE notifications --------------------- - -There are two kinds of notifications that secure world can use to make -normal world aware of some event. - -1. Synchronous notifications delivered with ``OPTEE_RPC_CMD_NOTIFICATION`` - using the ``OPTEE_RPC_NOTIFICATION_SEND`` parameter. -2. Asynchronous notifications delivered with a combination of a non-secure - edge-triggered interrupt and a fast call from the non-secure interrupt - handler. - -Synchronous notifications are limited by depending on RPC for delivery, -this is only usable when secure world is entered with a yielding call via -``OPTEE_SMC_CALL_WITH_ARG``. This excludes such notifications from secure -world interrupt handlers. - -An asynchronous notification is delivered via a non-secure edge-triggered -interrupt to an interrupt handler registered in the OP-TEE driver. The -actual notification value are retrieved with the fast call -``OPTEE_SMC_GET_ASYNC_NOTIF_VALUE``. Note that one interrupt can represent -multiple notifications. - -One notification value ``OPTEE_SMC_ASYNC_NOTIF_VALUE_DO_BOTTOM_HALF`` has a -special meaning. When this value is received it means that normal world is -supposed to make a yielding call ``OPTEE_MSG_CMD_DO_BOTTOM_HALF``. This -call is done from the thread assisting the interrupt handler. This is a -building block for OP-TEE OS in secure world to implement the top half and -bottom half style of device drivers. - -OPTEE_INSECURE_LOAD_IMAGE Kconfig option ----------------------------------------- - -The OPTEE_INSECURE_LOAD_IMAGE Kconfig option enables the ability to load the -BL32 OP-TEE image from the kernel after the kernel boots, rather than loading -it from the firmware before the kernel boots. This also requires enabling the -corresponding option in Trusted Firmware for Arm. The Trusted Firmware for Arm -documentation [8] explains the security threat associated with enabling this as -well as mitigations at the firmware and platform level. - -There are additional attack vectors/mitigations for the kernel that should be -addressed when using this option. - -1. Boot chain security. - - * Attack vector: Replace the OP-TEE OS image in the rootfs to gain control of - the system. - - * Mitigation: There must be boot chain security that verifies the kernel and - rootfs, otherwise an attacker can modify the loaded OP-TEE binary by - modifying it in the rootfs. - -2. Alternate boot modes. - - * Attack vector: Using an alternate boot mode (i.e. recovery mode), the - OP-TEE driver isn't loaded, leaving the SMC hole open. - - * Mitigation: If there are alternate methods of booting the device, such as a - recovery mode, it should be ensured that the same mitigations are applied - in that mode. - -3. Attacks prior to SMC invocation. - - * Attack vector: Code that is executed prior to issuing the SMC call to load - OP-TEE can be exploited to then load an alternate OS image. - - * Mitigation: The OP-TEE driver must be loaded before any potential attack - vectors are opened up. This should include mounting of any modifiable - filesystems, opening of network ports or communicating with external - devices (e.g. USB). - -4. Blocking SMC call to load OP-TEE. - - * Attack vector: Prevent the driver from being probed, so the SMC call to - load OP-TEE isn't executed when desired, leaving it open to being executed - later and loading a modified OS. - - * Mitigation: It is recommended to build the OP-TEE driver as builtin driver - rather than as a module to prevent exploits that may cause the module to - not be loaded. - -AMD-TEE driver -============== - -The AMD-TEE driver handles the communication with AMD's TEE environment. The -TEE environment is provided by AMD Secure Processor. - -The AMD Secure Processor (formerly called Platform Security Processor or PSP) -is a dedicated processor that features ARM TrustZone technology, along with a -software-based Trusted Execution Environment (TEE) designed to enable -third-party Trusted Applications. This feature is currently enabled only for -APUs. - -The following picture shows a high level overview of AMD-TEE:: - - | - x86 | - | - User space (Kernel space) | AMD Secure Processor (PSP) - ~~~~~~~~~~ ~~~~~~~~~~~~~~ | ~~~~~~~~~~~~~~~~~~~~~~~~~~ - | - +--------+ | +-------------+ - | Client | | | Trusted | - +--------+ | | Application | - /\ | +-------------+ - || | /\ - || | || - || | \/ - || | +----------+ - || | | TEE | - || | | Internal | - \/ | | API | - +---------+ +-----------+---------+ +----------+ - | TEE | | TEE | AMD-TEE | | AMD-TEE | - | Client | | subsystem | driver | | Trusted | - | API | | | | | OS | - +---------+-----------+----+------+---------+---------+----------+ - | Generic TEE API | | ASP | Mailbox | - | IOCTL (TEE_IOC_*) | | driver | Register Protocol | - +--------------------------+ +---------+--------------------+ - -At the lowest level (in x86), the AMD Secure Processor (ASP) driver uses the -CPU to PSP mailbox register to submit commands to the PSP. The format of the -command buffer is opaque to the ASP driver. It's role is to submit commands to -the secure processor and return results to AMD-TEE driver. The interface -between AMD-TEE driver and AMD Secure Processor driver can be found in [6]. - -The AMD-TEE driver packages the command buffer payload for processing in TEE. -The command buffer format for the different TEE commands can be found in [7]. - -The TEE commands supported by AMD-TEE Trusted OS are: - -* TEE_CMD_ID_LOAD_TA - loads a Trusted Application (TA) binary into - TEE environment. -* TEE_CMD_ID_UNLOAD_TA - unloads TA binary from TEE environment. -* TEE_CMD_ID_OPEN_SESSION - opens a session with a loaded TA. -* TEE_CMD_ID_CLOSE_SESSION - closes session with loaded TA -* TEE_CMD_ID_INVOKE_CMD - invokes a command with loaded TA -* TEE_CMD_ID_MAP_SHARED_MEM - maps shared memory -* TEE_CMD_ID_UNMAP_SHARED_MEM - unmaps shared memory - -AMD-TEE Trusted OS is the firmware running on AMD Secure Processor. - -The AMD-TEE driver registers itself with TEE subsystem and implements the -following driver function callbacks: - -* get_version - returns the driver implementation id and capability. -* open - sets up the driver context data structure. -* release - frees up driver resources. -* open_session - loads the TA binary and opens session with loaded TA. -* close_session - closes session with loaded TA and unloads it. -* invoke_func - invokes a command with loaded TA. - -cancel_req driver callback is not supported by AMD-TEE. - -The GlobalPlatform TEE Client API [5] can be used by the user space (client) to -talk to AMD's TEE. AMD's TEE provides a secure environment for loading, opening -a session, invoking commands and closing session with TA. - -References -========== - -[1] https://github.com/OP-TEE/optee_os - -[2] http://infocenter.arm.com/help/topic/com.arm.doc.den0028a/index.html - -[3] drivers/tee/optee/optee_smc.h - -[4] drivers/tee/optee/optee_msg.h - -[5] http://www.globalplatform.org/specificationsdevice.asp look for - "TEE Client API Specification v1.0" and click download. - -[6] include/linux/psp-tee.h - -[7] drivers/tee/amdtee/amdtee_if.h - -[8] https://trustedfirmware-a.readthedocs.io/en/latest/threat_model/threat_mode… diff --git a/Documentation/subsystem-apis.rst b/Documentation/subsystem-apis.rst index 90a0535a932a..1666f11de8df 100644 --- a/Documentation/subsystem-apis.rst +++ b/Documentation/subsystem-apis.rst @@ -86,3 +86,4 @@ Storage interfaces misc-devices/index peci/index wmi/index + tee/index diff --git a/Documentation/tee/amd-tee.rst b/Documentation/tee/amd-tee.rst new file mode 100644 index 000000000000..51500fde7038 --- /dev/null +++ b/Documentation/tee/amd-tee.rst @@ -0,0 +1,90 @@ +.. SPDX-License-Identifier: GPL-2.0 + +============================================= +AMD-TEE (AMD's Trusted Execution Environment) +============================================= + +The AMD-TEE driver handles the communication with AMD's TEE environment. The +TEE environment is provided by AMD Secure Processor. + +The AMD Secure Processor (formerly called Platform Security Processor or PSP) +is a dedicated processor that features ARM TrustZone technology, along with a +software-based Trusted Execution Environment (TEE) designed to enable +third-party Trusted Applications. This feature is currently enabled only for +APUs. + +The following picture shows a high level overview of AMD-TEE:: + + | + x86 | + | + User space (Kernel space) | AMD Secure Processor (PSP) + ~~~~~~~~~~ ~~~~~~~~~~~~~~ | ~~~~~~~~~~~~~~~~~~~~~~~~~~ + | + +--------+ | +-------------+ + | Client | | | Trusted | + +--------+ | | Application | + /\ | +-------------+ + || | /\ + || | || + || | \/ + || | +----------+ + || | | TEE | + || | | Internal | + \/ | | API | + +---------+ +-----------+---------+ +----------+ + | TEE | | TEE | AMD-TEE | | AMD-TEE | + | Client | | subsystem | driver | | Trusted | + | API | | | | | OS | + +---------+-----------+----+------+---------+---------+----------+ + | Generic TEE API | | ASP | Mailbox | + | IOCTL (TEE_IOC_*) | | driver | Register Protocol | + +--------------------------+ +---------+--------------------+ + +At the lowest level (in x86), the AMD Secure Processor (ASP) driver uses the +CPU to PSP mailbox register to submit commands to the PSP. The format of the +command buffer is opaque to the ASP driver. It's role is to submit commands to +the secure processor and return results to AMD-TEE driver. The interface +between AMD-TEE driver and AMD Secure Processor driver can be found in [1]. + +The AMD-TEE driver packages the command buffer payload for processing in TEE. +The command buffer format for the different TEE commands can be found in [2]. + +The TEE commands supported by AMD-TEE Trusted OS are: + +* TEE_CMD_ID_LOAD_TA - loads a Trusted Application (TA) binary into + TEE environment. +* TEE_CMD_ID_UNLOAD_TA - unloads TA binary from TEE environment. +* TEE_CMD_ID_OPEN_SESSION - opens a session with a loaded TA. +* TEE_CMD_ID_CLOSE_SESSION - closes session with loaded TA +* TEE_CMD_ID_INVOKE_CMD - invokes a command with loaded TA +* TEE_CMD_ID_MAP_SHARED_MEM - maps shared memory +* TEE_CMD_ID_UNMAP_SHARED_MEM - unmaps shared memory + +AMD-TEE Trusted OS is the firmware running on AMD Secure Processor. + +The AMD-TEE driver registers itself with TEE subsystem and implements the +following driver function callbacks: + +* get_version - returns the driver implementation id and capability. +* open - sets up the driver context data structure. +* release - frees up driver resources. +* open_session - loads the TA binary and opens session with loaded TA. +* close_session - closes session with loaded TA and unloads it. +* invoke_func - invokes a command with loaded TA. + +cancel_req driver callback is not supported by AMD-TEE. + +The GlobalPlatform TEE Client API [3] can be used by the user space (client) to +talk to AMD's TEE. AMD's TEE provides a secure environment for loading, opening +a session, invoking commands and closing session with TA. + +References +========== + +[1] include/linux/psp-tee.h + +[2] drivers/tee/amdtee/amdtee_if.h + +[3] http://www.globalplatform.org/specificationsdevice.asp look for + "TEE Client API Specification v1.0" and click download. diff --git a/Documentation/tee/index.rst b/Documentation/tee/index.rst new file mode 100644 index 000000000000..a23bd08847e5 --- /dev/null +++ b/Documentation/tee/index.rst @@ -0,0 +1,19 @@ +.. SPDX-License-Identifier: GPL-2.0 + +============= +TEE Subsystem +============= + +.. toctree:: + :maxdepth: 1 + + tee + op-tee + amd-tee + +.. only:: subproject and html + + Indices + ======= + + * :ref:`genindex` diff --git a/Documentation/tee/op-tee.rst b/Documentation/tee/op-tee.rst new file mode 100644 index 000000000000..b0ac097d5547 --- /dev/null +++ b/Documentation/tee/op-tee.rst @@ -0,0 +1,166 @@ +.. SPDX-License-Identifier: GPL-2.0 + +==================================================== +OP-TEE (Open Portable Trusted Execution Environment) +==================================================== + +The OP-TEE driver handles OP-TEE [1] based TEEs. Currently it is only the ARM +TrustZone based OP-TEE solution that is supported. + +Lowest level of communication with OP-TEE builds on ARM SMC Calling +Convention (SMCCC) [2], which is the foundation for OP-TEE's SMC interface +[3] used internally by the driver. Stacked on top of that is OP-TEE Message +Protocol [4]. + +OP-TEE SMC interface provides the basic functions required by SMCCC and some +additional functions specific for OP-TEE. The most interesting functions are: + +- OPTEE_SMC_FUNCID_CALLS_UID (part of SMCCC) returns the version information + which is then returned by TEE_IOC_VERSION + +- OPTEE_SMC_CALL_GET_OS_UUID returns the particular OP-TEE implementation, used + to tell, for instance, a TrustZone OP-TEE apart from an OP-TEE running on a + separate secure co-processor. + +- OPTEE_SMC_CALL_WITH_ARG drives the OP-TEE message protocol + +- OPTEE_SMC_GET_SHM_CONFIG lets the driver and OP-TEE agree on which memory + range to used for shared memory between Linux and OP-TEE. + +The GlobalPlatform TEE Client API [5] is implemented on top of the generic +TEE API. + +Picture of the relationship between the different components in the +OP-TEE architecture:: + + User space Kernel Secure world + ~~~~~~~~~~ ~~~~~~ ~~~~~~~~~~~~ + +--------+ +-------------+ + | Client | | Trusted | + +--------+ | Application | + /\ +-------------+ + || +----------+ /\ + || |tee- | || + || |supplicant| \/ + || +----------+ +-------------+ + \/ /\ | TEE Internal| + +-------+ || | API | + + TEE | || +--------+--------+ +-------------+ + | Client| || | TEE | OP-TEE | | OP-TEE | + | API | \/ | subsys | driver | | Trusted OS | + +-------+----------------+----+-------+----+-----------+-------------+ + | Generic TEE API | | OP-TEE MSG | + | IOCTL (TEE_IOC_*) | | SMCCC (OPTEE_SMC_CALL_*) | + +-----------------------------+ +------------------------------+ + +RPC (Remote Procedure Call) are requests from secure world to kernel driver +or tee-supplicant. An RPC is identified by a special range of SMCCC return +values from OPTEE_SMC_CALL_WITH_ARG. RPC messages which are intended for the +kernel are handled by the kernel driver. Other RPC messages will be forwarded to +tee-supplicant without further involvement of the driver, except switching +shared memory buffer representation. + +OP-TEE device enumeration +------------------------- + +OP-TEE provides a pseudo Trusted Application: drivers/tee/optee/device.c in +order to support device enumeration. In other words, OP-TEE driver invokes this +application to retrieve a list of Trusted Applications which can be registered +as devices on the TEE bus. + +OP-TEE notifications +-------------------- + +There are two kinds of notifications that secure world can use to make +normal world aware of some event. + +1. Synchronous notifications delivered with ``OPTEE_RPC_CMD_NOTIFICATION`` + using the ``OPTEE_RPC_NOTIFICATION_SEND`` parameter. +2. Asynchronous notifications delivered with a combination of a non-secure + edge-triggered interrupt and a fast call from the non-secure interrupt + handler. + +Synchronous notifications are limited by depending on RPC for delivery, +this is only usable when secure world is entered with a yielding call via +``OPTEE_SMC_CALL_WITH_ARG``. This excludes such notifications from secure +world interrupt handlers. + +An asynchronous notification is delivered via a non-secure edge-triggered +interrupt to an interrupt handler registered in the OP-TEE driver. The +actual notification value are retrieved with the fast call +``OPTEE_SMC_GET_ASYNC_NOTIF_VALUE``. Note that one interrupt can represent +multiple notifications. + +One notification value ``OPTEE_SMC_ASYNC_NOTIF_VALUE_DO_BOTTOM_HALF`` has a +special meaning. When this value is received it means that normal world is +supposed to make a yielding call ``OPTEE_MSG_CMD_DO_BOTTOM_HALF``. This +call is done from the thread assisting the interrupt handler. This is a +building block for OP-TEE OS in secure world to implement the top half and +bottom half style of device drivers. + +OPTEE_INSECURE_LOAD_IMAGE Kconfig option +---------------------------------------- + +The OPTEE_INSECURE_LOAD_IMAGE Kconfig option enables the ability to load the +BL32 OP-TEE image from the kernel after the kernel boots, rather than loading +it from the firmware before the kernel boots. This also requires enabling the +corresponding option in Trusted Firmware for Arm. The Trusted Firmware for Arm +documentation [6] explains the security threat associated with enabling this as +well as mitigations at the firmware and platform level. + +There are additional attack vectors/mitigations for the kernel that should be +addressed when using this option. + +1. Boot chain security. + + * Attack vector: Replace the OP-TEE OS image in the rootfs to gain control of + the system. + + * Mitigation: There must be boot chain security that verifies the kernel and + rootfs, otherwise an attacker can modify the loaded OP-TEE binary by + modifying it in the rootfs. + +2. Alternate boot modes. + + * Attack vector: Using an alternate boot mode (i.e. recovery mode), the + OP-TEE driver isn't loaded, leaving the SMC hole open. + + * Mitigation: If there are alternate methods of booting the device, such as a + recovery mode, it should be ensured that the same mitigations are applied + in that mode. + +3. Attacks prior to SMC invocation. + + * Attack vector: Code that is executed prior to issuing the SMC call to load + OP-TEE can be exploited to then load an alternate OS image. + + * Mitigation: The OP-TEE driver must be loaded before any potential attack + vectors are opened up. This should include mounting of any modifiable + filesystems, opening of network ports or communicating with external + devices (e.g. USB). + +4. Blocking SMC call to load OP-TEE. + + * Attack vector: Prevent the driver from being probed, so the SMC call to + load OP-TEE isn't executed when desired, leaving it open to being executed + later and loading a modified OS. + + * Mitigation: It is recommended to build the OP-TEE driver as builtin driver + rather than as a module to prevent exploits that may cause the module to + not be loaded. + +References +========== + +[1] https://github.com/OP-TEE/optee_os + +[2] http://infocenter.arm.com/help/topic/com.arm.doc.den0028a/index.html + +[3] drivers/tee/optee/optee_smc.h + +[4] drivers/tee/optee/optee_msg.h + +[5] http://www.globalplatform.org/specificationsdevice.asp look for + "TEE Client API Specification v1.0" and click download. + +[6] https://trustedfirmware-a.readthedocs.io/en/latest/threat_model/threat_mode… diff --git a/Documentation/tee/tee.rst b/Documentation/tee/tee.rst new file mode 100644 index 000000000000..3a5ff925edb5 --- /dev/null +++ b/Documentation/tee/tee.rst @@ -0,0 +1,122 @@ +.. SPDX-License-Identifier: GPL-2.0 + +=================================== +TEE (Trusted Execution Environment) +=================================== + +This document describes the TEE subsystem in Linux. + +Overview +======== + +A TEE is a trusted OS running in some secure environment, for example, +TrustZone on ARM CPUs, or a separate secure co-processor etc. A TEE driver +handles the details needed to communicate with the TEE. + +This subsystem deals with: + +- Registration of TEE drivers + +- Managing shared memory between Linux and the TEE + +- Providing a generic API to the TEE + +The TEE interface +================= + +include/uapi/linux/tee.h defines the generic interface to a TEE. + +User space (the client) connects to the driver by opening /dev/tee[0-9]* or +/dev/teepriv[0-9]*. + +- TEE_IOC_SHM_ALLOC allocates shared memory and returns a file descriptor + which user space can mmap. When user space doesn't need the file + descriptor any more, it should be closed. When shared memory isn't needed + any longer it should be unmapped with munmap() to allow the reuse of + memory. + +- TEE_IOC_VERSION lets user space know which TEE this driver handles and + its capabilities. + +- TEE_IOC_OPEN_SESSION opens a new session to a Trusted Application. + +- TEE_IOC_INVOKE invokes a function in a Trusted Application. + +- TEE_IOC_CANCEL may cancel an ongoing TEE_IOC_OPEN_SESSION or TEE_IOC_INVOKE. + +- TEE_IOC_CLOSE_SESSION closes a session to a Trusted Application. + +There are two classes of clients, normal clients and supplicants. The latter is +a helper process for the TEE to access resources in Linux, for example file +system access. A normal client opens /dev/tee[0-9]* and a supplicant opens +/dev/teepriv[0-9]. + +Much of the communication between clients and the TEE is opaque to the +driver. The main job for the driver is to receive requests from the +clients, forward them to the TEE and send back the results. In the case of +supplicants the communication goes in the other direction, the TEE sends +requests to the supplicant which then sends back the result. + +The TEE kernel interface +======================== + +Kernel provides a TEE bus infrastructure where a Trusted Application is +represented as a device identified via Universally Unique Identifier (UUID) and +client drivers register a table of supported device UUIDs. + +TEE bus infrastructure registers following APIs: + +match(): + iterates over the client driver UUID table to find a corresponding + match for device UUID. If a match is found, then this particular device is + probed via corresponding probe API registered by the client driver. This + process happens whenever a device or a client driver is registered with TEE + bus. + +uevent(): + notifies user-space (udev) whenever a new device is registered on + TEE bus for auto-loading of modularized client drivers. + +TEE bus device enumeration is specific to underlying TEE implementation, so it +is left open for TEE drivers to provide corresponding implementation. + +Then TEE client driver can talk to a matched Trusted Application using APIs +listed in include/linux/tee_drv.h. + +TEE client driver example +------------------------- + +Suppose a TEE client driver needs to communicate with a Trusted Application +having UUID: ``ac6a4085-0e82-4c33-bf98-8eb8e118b6c2``, so driver registration +snippet would look like:: + + static const struct tee_client_device_id client_id_table[] = { + {UUID_INIT(0xac6a4085, 0x0e82, 0x4c33, + 0xbf, 0x98, 0x8e, 0xb8, 0xe1, 0x18, 0xb6, 0xc2)}, + {} + }; + + MODULE_DEVICE_TABLE(tee, client_id_table); + + static struct tee_client_driver client_driver = { + .id_table = client_id_table, + .driver = { + .name = DRIVER_NAME, + .bus = &tee_bus_type, + .probe = client_probe, + .remove = client_remove, + }, + }; + + static int __init client_init(void) + { + return driver_register(&client_driver.driver); + } + + static void __exit client_exit(void) + { + driver_unregister(&client_driver.driver); + } + + module_init(client_init); + module_exit(client_exit); diff --git a/MAINTAINERS b/MAINTAINERS index dd5de540ec0b..81210663770b 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -21130,7 +21130,7 @@ M: Jens Wiklander <jens.wiklander(a)linaro.org> R: Sumit Garg <sumit.garg(a)linaro.org> L: op-tee(a)lists.trustedfirmware.org S: Maintained -F: Documentation/staging/tee.rst +F: Documentation/tee/ F: drivers/tee/ F: include/linux/tee_drv.h F: include/uapi/linux/tee.h -- 2.34.1

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