- TF-M - lists.trustedfirmware.org

Key derivation from HUK in NS application

by Kevin Townsend

Hi, I need to derive a new key from the HUK using HKDF, but are we able to request key derivation with the HUK from the NS side, or would we need to create a custom ARoT partittion for that? The requirements are identical to what PS does here with HKDF -- no salt and a fixed 'info' value, resulting in a key that is device-bound and can be regenerated at startup with no storage requirements: https://tf-m-user-guide.trustedfirmware.org/docs/technical_references/desig… (that API usage looks to be out of date, BTW, since "psa_open_key" now takes two params). I tried to do something similar from the NS side, modifying this code https://github.com/zephyrproject-rtos/zephyr/blob/main/samples/tfm_integrat… ..., but get an error when trying to open the HUK with "TFM_CRYPTO_KEY_ID_HUK". That isn't surprising, but is there any alternative to generate keys from the HUK without a custom ARoT service? The fact that no storage is required when deriving from the HUK is significant. Best regards, Kevin

4 years, 1 month

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Using software random generator for FIH library

by Roman.Mazurak＠infineon.com

Hi all, Does anyone know if using software random generator seeded with TRNG to provide random delays for Fault Injection Hardening library is correct from PSA Level 3 certification point of view? The basic idea is to : 1. Use TRNG to provide seed for software random generator on fih_delay_init. 2. Use software random generator to implement fih_delay_random. 3. Periodically reseed software random generator with data from TRNG (optional). Thanks, Roman.

4 years, 1 month

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Commit b8bc0d2a breaks Musca_S1

by Thomas Törnblom

Appears there are more recent breakage. b8bc0d2a "HAL: Expand the scope of tfm_hal_platform_init API" breaks Musca_S1 /Thomas -- *Thomas Törnblom*, /Product Engineer/ IAR Systems AB Box 23051, Strandbodgatan 1 SE-750 23 Uppsala, SWEDEN Mobile: +46 76 180 17 80 Fax: +46 18 16 78 01 E-mail: thomas.tornblom(a)iar.com Website: www.iar.com <http://www.iar.com> Twitter: www.twitter.com/iarsystems <http://www.twitter.com/iarsystems>

4 years, 1 month

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fce78aef breaks psoc64 console output with IARARM and ARMCLANG toolchain

by Thomas Törnblom

The current version breaks console output for the secure partition on psoc64 with IAR or ARMCLANG. Appears to work with GNUARM. It appears that this commit is the culprit: fce78aef Platform: Duplicate the tfm_hal_platform_init The console starts out good, then during tests only garbage is seen. Linker script issues? /Thomas -- *Thomas Törnblom*, /Product Engineer/ IAR Systems AB Box 23051, Strandbodgatan 1 SE-750 23 Uppsala, SWEDEN Mobile: +46 76 180 17 80 Fax: +46 18 16 78 01 E-mail: thomas.tornblom(a)iar.com Website: www.iar.com <http://www.iar.com> Twitter: www.twitter.com/iarsystems <http://www.twitter.com/iarsystems>

4 years, 1 month

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BL2 builds, no "PYTHON_EXECUTABLE" defined

by Thomas Törnblom

While attempting to build for the musca_s1, with mcuboot, on Windows, the build failed very late and brought up a Code Writer window on my screen. I nailed it down to no "PYTHON_EXECUTABLE" being defined while processing bl2/ext/mcuboot/CMakeLists.txt, which caused the build line to just attempt to run wrapper.py, with no interpreter, and windows brought up the appropriate tools to write python code. Adding "-DPYTHON_EXECUTABLE=python" to the cmake line fixed that, but it seems that this shouldn't be needed. The build tools should handle this, or? There is a line: #! /usr/bin/env python3 in wrapper.py, and I assume linux will handle this appropriately, but it doesn't seem windows does. Cheers, Thomas -- *Thomas Törnblom*, /Product Engineer/ IAR Systems AB Box 23051, Strandbodgatan 1 SE-750 23 Uppsala, SWEDEN Mobile: +46 76 180 17 80 Fax: +46 18 16 78 01 E-mail: thomas.tornblom(a)iar.com Website: www.iar.com <http://www.iar.com> Twitter: www.twitter.com/iarsystems <http://www.twitter.com/iarsystems>

4 years, 1 month

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Flash definitions usage

by Bohdan.Hunko＠infineon.com

Hi everyone, I was trying to understand usage of TOTAL_ROM_SIZE and FLASH_TOTAL_SIZE from musca_b1/sse_200/partitions/flash_layout.h file. I haven't found any usage of these definitions. Does anyone know what is the reason to have them defined? Regards, Bohdan Hunko Cypress Semiconductor Ukraine Engineer CSUKR CSS ICW SW FW Mobile: +38099 50 19 714 Bohdan.Hunko(a)infineon.com<mailto:Bohdan.Hunko@infineon.com>

4 years, 1 month

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Inline asm syntax unified and symbol reference in IAR toolchain

by Ken Liu

Hi Thomas and all, I noticed there are some #if !defined(__ICCARM__) ".syntax unified \n" #endif In source code, looks like ".syntax unified" is not support in IAR, is that true? If it could not be supported in a short term, we can define some wrapper such as: #ifdef __ICCARM__ #define CLAIM_SYNTAX_UNIFIED "\n" #else #define CLAIM_SYNTAX_UNIFIED ".syntax unified \n" #endif Another question is about the: #if defined(__ICCARM__) #pragma required = do_schedule #endif If we claim do_schedule in the constraints, is the above "#pragma required" still needed? __asm (".... :: "i"(do_schedule)); We can create a patch to test this - using a constraint looks more proper. Thanks. /Ken

4 years, 1 month

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Re: [TF-M] System reset

by Andrew Thoelke

Hi Sebastian, The section in the Platform Security Model is describing the behavior of a system reset – the recommendation is that any preceding runtime state (in volatile memory, or in CPU or peripheral registers) does not influence the execution of the reboot. This is except for an optional suspend or hibernate state, which explicitly maintains runtime state while powering off most or all of the system and will resume via a CPU reset. System security requirements might require explicit clearing of volatile memory on reset to prevent cold-boot style attacks that could allow an attacker to read any residual RAM contents – although software-based attacks of this kind are partly mitigated by trusted boot, which prevents an attacker from running arbitrary code at reset (unlike devices that boot from untrusted flash memory). The specific bullet list in the PSA Firmware Framework for M (in §3.5.1 on Panics) is describing the challenges for an implementation that does NOT do the recommended action of resetting the system when a Secure Partition panics, which justifies the recommendation to reset the system. If the SPM does reset the system, then the challenges in that bullet list are avoided. The issues listed are: > * An individual Secure Partition cannot be reset and restarted in isolation. > * A Secure Partition may have state maintained on behalf of clients that will be destroyed when restarting the service. There is no mechanism to re-synchronize the clients. > * It is not possible to determine at the point of panic how much corruption has occurred within the Secure Partition and elsewhere in the SPE. If the SPM only restarted the Secure Partition that panicked, then any previous runtime state within that Secure Partition is lost, including any ongoing connections with clients of services within that partition, or any resources that those services were managing for their clients. FF-M does not provide a specified mechanism for such clients to be informed that the connections are broken, and there is no way to provide a general strategy that allows a client to recover from a service failure. This is what is meant by “There is no mechanism to re-synchronize the clients.”. I have just realized that in FF-M 1.1, there may be scenarios in which restarting a Secure Partition could be justified and technically feasible. If a Secure Partition with only Stateless services maintains no client state or resources, and also maintains no connections to other RoT Services (so there are no RoT Services maintaining state for this Secure Partition) – then restarting this Secure Partition might not suffer from the first two complications listed in §3.5.1. The third issue is harder to control: the risks from the data corruption that lead up to the panic depends partly on the SPE isolation policies, and on what this Secure Partition was responsible for. Reset remains the recommended response to a Secure Partition panic in v1.1.0. Regards, Andrew Thoelke Arm Ltd. From: TF-M <tf-m-bounces(a)lists.trustedfirmware.org> On Behalf Of Ken Liu via TF-M Sent: 26 October 2021 10:51 To: tf-m(a)lists.trustedfirmware.org Cc: nd <nd(a)arm.com> Subject: Re: [TF-M] System reset Hi Sebastian, The specification writer looks not here these two days, let me try to explain it based on my understanding. I think two specs both recommend clearing general runtime data while resetting. If the booting runtime clearing code can clear the RAM data for a specific platform, the memory clearing in the 'tfm_spm_hal_system_reset ' can be skipped. Basically, simple hardware reset triggering is just fine. The special-purpose memory to be retained during resetting is not a generic runtime memory, hence they need to be treated specially, such as putting them in a special bank or region and skipping clearing them during booting. This special region can be treated as a private asset of one service, which could NOT be shared between components for direct access. The owner service provides the functionality around this asset. Please put more comments or corrections, thanks. /Ken From: TF-M <mailto:tf-m-bounces@lists.trustedfirmware.org> On Behalf Of Sebastian Bøe via TF-M Sent: Monday, October 25, 2021 3:16 PM To: mailto:tf-m@lists.trustedfirmware.org Subject: [TF-M] System reset Hi, I would like some clarification about system reset. There are these two statements about it in the PSM and PSA-FF: "No run-time state from before the reset should be retained or used, except where necessary if suspend or hibernate are supported, see section 4.6." -- PSM page 22. "A Secure Partition may have state maintained on behalf of clients that will be destroyed when restarting the service." -- PSA-FF page 47. Is it the responsibility of tfm_spm_hal_system_reset to destroy this state or is it OK to destroy it after reset as a part of the C runtime startup procedure? I assume for instance that PRoT .bss is cleared as a part of the C runtime startup procedure, but should it also have been destroyed as a part of tfm_spm_hal_system_reset ? PSM - Platform Security Model. https://developer.arm.com/documentation/den0128/0100/ PSA-FF PSA Firmware Framework https://armkeil.blob.core.windows.net/developer/Files/pdf/PlatformSecurityA… Sebastian Bøe Nordic Semiconductor

4 years, 1 month

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[PLATFORM ATTENTION REQUIRED] Unify the HAL APIs for IPC Model

by Kevin Peng

Hi all, I'm been working to unify the HAL APIs for IPC Model. The IPC Model currently uses two different sets of HAL APIs: * tfm_spm_hal_* - This is mainly used by the Library Model and IPC Model re-uses some of them * tfm_hal_* - This is introduced for IPC Model and some are shared to Library Model This might be confusing for platform vendors. So I'm trying to make it clear for IPC Model by: * Duplicating the shared APIs and rename the IPC copy to tfm_hal_* * Combining several platform init APIs to a single tfm_platform_init for IPC Model * tfm_spm_hal_enable_fault_handlers * tfm_spm_hal_system_reset_cfg * tfm_spm_hal_init_debug * tfm_spm_hal_nvic_interrupt_target_state_cfg * tfm_spm_hal_nvic_interrupt_enable With these changes, IPC Model will use tfm_hal_* APIs only. Please platform owners review these patches<https://review.trustedfirmware.org/q/topic:%22decouple_legacy_hal_for_ipc%2…> to see if any mistakes (the patches mainly move codes around) or any platforms missed in the patches. Plan to have them merged before the end of October. Thanks. Best Regards, Kevin

4 years, 1 month

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System reset

by Sebastian Bøe

Hi, I would like some clarification about system reset. There are these two statements about it in the PSM and PSA-FF: "No run-time state from before the reset should be retained or used, except where necessary if suspend or hibernate are supported, see section 4.6." -- PSM page 22. "A Secure Partition may have state maintained on behalf of clients that will be destroyed when restarting the service." -- PSA-FF page 47. Is it the responsibility of tfm_spm_hal_system_reset to destroy this state or is it OK to destroy it after reset as a part of the C runtime startup procedure? I assume for instance that PRoT .bss is cleared as a part of the C runtime startup procedure, but should it also have been destroyed as a part of tfm_spm_hal_system_reset ? PSM - Platform Security Model. https://developer.arm.com/documentation/den0128/0100/ PSA-FF PSA Firmware Framework https://armkeil.blob.core.windows.net/developer/Files/pdf/PlatformSecurityA… Sebastian Bøe Nordic Semiconductor

4 years, 1 month

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