- TF-M - lists.trustedfirmware.org

by vivahavey＠gmail.com

Dear developers, I have a question about interrupt SLIH scheduling in IPC model. Assume that there are two secure partitions P1 and P2, and P1 has higher priority than P2. P1 calls psa_call(), so SPM blocks P1 and wakes up P2 to execute P2's service handler. Now P2 is running. Suddenly P1's interrupt occuerred, and P1's SLIH signal is asserted for more processing. A shedule request is also triggered. Since P1 has higher priority than P2, will P2 be preemted by P1 to execute P1's SLIH immediately? If the answer is yes, the psa_call() chain will be corrupted, right? Thanks in advance. Alvin Chang

2 years, 7 months

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Platform/Application specific service extension

by Roman.Mazurak＠infineon.com

Hi, Partition is described through configuration in YAML files (manifests). This configuration includes following properties (see Adding Secure Partition - Add manifest<https://tf-m-user-guide.trustedfirmware.org/integration_guide/services/tfm_…>): * Name, type, priority, model, ... * List of services provided by partition * MMIO regions * List of IRQs * Dependencies Each platform should provide implementation of HAL which is specific to standard partitions like Crypto, ITS, etc. It's mandatory to provide proper isolation of memory/peripheral that are used by platform specific code that provides HAL implementation or add a custom dependency for standard partition. Currently platform can use following approaches to resolve the problem of extending YAML of standard TF-M partition: * Create a platform specific copy of partition YAML, see https://review.trustedfirmware.org/c/TF-M/trusted-firmware-m/+/15639 as an example of such approach. * Modify standard partition by introducing optional fields, see https://review.trustedfirmware.org/c/TF-M/trusted-firmware-m/+/17718. These both solution are not flexible enough. It requires to modify platform independent code or maintain own copy of partition YAML file with needed changes. I think it make sense to integrate partition YAML extension tool in TF-M. Platform/application should be able to provide manifest-extension file(s). Such manifest-extension file may provide additional properties which should be joined with properties provided by standard partition manifest files. For example to solve problem for https://review.trustedfirmware.org/c/TF-M/trusted-firmware-m/+/15639 ARM RSS platform may provide following manifest-extension file with structure like this: { "extensions": [ { "name": "TFM_SP_INITIAL_ATTESTATION", "dependencies": [ "TFM_MEASURED_BOOT" ] } ] } Tool which parses manifests should add a new dependency on "TFM_MEASURED_BOOT" to list of dependencies for "TFM_SP_INITIAL_ATTESTATION" partition. Please, share your opinion on this topic. Best regards, Roman.

2 years, 7 months

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Deleting last object in a data block in ITS filesystem

by Stefan Krug

Hello! Seemingly, there is an issue with file deletion in ITS. I would think it is not possible to delete the last object in a data block (so that the data block becomes empty). It's easiest to reproduce with using large objects (because then the number of involved objects is small), but would also happen with multiple smaller objects: With the following flash configuration: ITS_MAX_ASSET_SIZE=0x1000 TFM_HAL_ITS_SECTORS_PER_BLOCK=1 TFM_HAL_ITS_FLASH_AREA_SIZE=0x20000 TFM_HAL_ITS_PROGRAM_UNIT=0x100 ITS_FLASH_NAND_BUF_SIZE=1*0x1000 In a sequence of writing and deleting an object like: const uint8_t big_file[ITS_MAX_ASSET_SIZE] = {0}; status = psa_its_set(uid, sizeof(big_file), big_file, flags); status = psa_its_remove(uid); deleting the file fails with the status of PSA_ERROR_GENERIC_ERROR. What I think happens is: Due to the size of the file, it does not fit in the metadata block, and is put a second (data only) block. The object is written there as expected. When the data block is deleted later, an attempt is being made to compact it with its_flash_fs_dblock_compact_block(). However, there is no data to keep before the object to be deleted and also no data to keep after it, this block will become empty, so no call to its_flash_fs_block_to_block_move() happens, which causes no call to fs_ctx->ops->write() happens. Now the flash driver in my case is a buffering its_flash_nand.c. In the write() call it would associate a buffer for the physical sector to write. But since there is no write() call the subsequent fs_ctx->ops->flush() fails as it has no buffer to flush out. I believe no compaction of the block should even be attempted - it is known that the block will be empty beforehand. Perhaps similar to https://review.trustedfirmware.org/c/TF-M/trusted-firmware-m/+/17578, this is yet another reason to skip compacting of the block? It would be very much appreciated if one of the experts could confirm this suspicious behavior or point out a mistake I am making. Thank you very much, best regards Stefan Krug

2 years, 7 months

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Announcing TF-Mv1.6.1 fix

by Anton Komlev

Hello, This is an announcement of TF-M v1.6.1 hotfix preparation. The reason for the hot fix is the recently found incorrect stack sealing in Library model. The library mode is deprecated already but is available in v1.6.0 and the intention is to leave it in the best shape to our knowledge. Security analysis shows no vulnerability was brought by this defect, so it is not a security fix. The plan is to issue the fix by Nov 17. TF-M release cadence and process is here: https://tf-m-user-guide.trustedfirmware.org/releases/release_process.htmlte… Thanks, Anton

2 years, 7 months

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TF-M Profile Medium-ARoT-less

by David Hu

Hi all, TF-M Profile Medium-ARoT-less is proposed to align with PSA Certified ARoT-less Level 2 protection profile [1]. May I ask for your review and comment please? Please check following patches: https://review.trustedfirmware.org/q/topic:%22arot-less%22+(status:open%20O… Any feedback is welcome. [1] https://www.psacertified.org/app/uploads/2022/10/JSADEN019-PSA_Certified_Le… Best regards, Hu Ziji

2 years, 7 months

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Lost data when overwriting object using its_set?

by Stefan Krug

Hello! While playing around with TF-M I have stumbled upon unexpected behavior: In a sequence of ITS api calls like: a.) psa_its_set(TEST_UID_1, sizeof(write_data_1), write_data_1, PSA_STORAGE_FLAG_NONE); b.) psa_its_set(TEST_UID_2, 0, NULL, PSA_STORAGE_FLAG_NONE); c.) psa_its_remove(TEST_UID_1); d.) psa_its_set(TEST_UID_2, sizeof(write_data_2), write_data_2, PSA_STORAGE_FLAG_NONE); e.) psa_its_get(TEST_UID_2, 0, sizeof(read_data_2), read_data_2, &read_data_length); with #define TEST_UID_1 2U #define TEST_UID_2 3U const uint8_t write_data_1[] = "ONE"; const uint8_t write_data_2[] = "TWO"; It seems that step e) does not return the data written in step d). I believe I have root-caused it to an issue in its_flash_delete_idx() (see below), but since this is a rather straightforward API call sequence, I wonder whether this is not rather an issue in my environment and would be glad if someone could confirm it or point me to a direction of a potential different cause? I am using TF-M version 1.6, a nor flash with (erase) block size 0x1000 bytes and a program unit size (page size) of 0x100 bytes. Thank you, best regards Stefan Krug More analysis details: After step c) there will be the following relevant metadata blocks in the filesystem: 1.) unused metadata block (used to have the metadata of TEST_UID_1) 2.) metadata block of TEST_UID_2 During step d) the update of TEST_UID_2 is done in two steps - first step is to write metadata + content of TEST_UID_2. After this step, the metadata blocks look like: 1.) NEW metadata block of TEST_UID_2 2.) old metadata block of TEST_UID_2 (indicating TEST_UID_2 to be erased) The second step is to delete the outdated file, and compact/defragment the data in the file system. This is done in its_flash_fs_delete_idx(). its_flash_fs_delete_idx will collect the amount of data bytes to preserve. There are two parts of data to be preserved, a chunk of data before the deleted file (of size del_file_data_idx) and a chunk of data after the deleted file. Calculation of del_file_data_idx is done by taking the start offset of the to-be-deleted file. In this particular situation the start of the old TEST_UID_2 is the same as the start of the new TEST_UID_2. The subsequent its_flash_fs_dblock_compact_block will only keep data up to del_file_data_idx - in this case it will NOT keep the data of the new TEST_UID_2 - this data is lost.

2 years, 7 months

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Latest status of S/NS build split PoC

by David Hu

Hi all, I rebase and update the S/NS build split PoC as requests. Could you please take a look at the latest patch set if you are interested? Trusted-firmware-m part: https://review.trustedfirmware.org/q/project:TF-M%252Ftrusted-firmware-m+br… Tf-m-tests part: https://review.trustedfirmware.org/q/project:TF-M%252Ftf-m-tests+branch:mas… The general idea was presented in https://www.trustedfirmware.org/docs/tf-m_forum_20220120_Restructure_TF-M_b… while some details are improved in code. Any comment and feedback is welcome! Best regards, Hu Ziji

2 years, 8 months

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TFM_PARTITION_AUDIT_LOG references in the code after Lib Model deprecation

by Bohdan.Hunko＠infineon.com

Hi all, TFM Library model has been deprecated, thus AUDIT logging partition has been deleted, but I still see a reference to that partition in config/check_config.cmake lines 102-103: #Audit log is not supported in IPC model, disable it by default tfm_invalid_config(TFM_PARTITION_AUDIT_LOG) Looks like this should be removed or comment fixed. An I missing something or this is a mistake that should be fixed? 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>

2 years, 8 months

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an521 L3 protection setting questions

by Bohdan.Hunko＠infineon.com

Hi all, I have a few questions regarding an521 platform protection settings for Level 3 isolation. In platform/ext/target/arm/mps2/an521/tfm_hal_isolation.c there is an const static struct mpu_armv8m_region_cfg_t region_cfg[] - for L3 it specifies to protect: * Code (from Image$$PT_RO_START$$Base to Image$$PT_RO_END$$Base) to be accessible in both PRIV and UNPRIV states. * PSA RoT partitions data in RAM (from Image$$PT_PRIV_RWZI_START$$Base to Image$$PT_PRIV_RWZI_END$$Base)to be accessible only in UNPRIV state. * TFM_SP_META_PTR to be accessible in both PRIV and UNPRIV states. Also in this file mpu_armv8m_enable() function call specifies PRIVILEGED_DEFAULT_ENABLE for MPU. I have following question to this configuration * Does this configuration mean that in L3 PSA RoT code is not isolated from APP RoT (APP RoT can read/execute PSA RoT domain code)? * How SPM data (TFM_BSS and TFM_DATA sections from scatter file) is protected? I cant see it being protected by MPU. * Is it skipped because PRIVILEGED_DEFAULT_ENABLE is set which means that SPM will be able to access this data and this allows to save one MPU region? * If so then why MPU region is used for PSA RoT partitions data? 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>

2 years, 8 months

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[RFC]Library Model deprecation

by Summer Qin

Hi, We plan to merge Library Model deprecation patches<https://review.trustedfirmware.org/q/topic:%22library-model-deprecation%22+…> this Friday since some other development work depends on this. May I ask for a review on these patches? Best Regards, Summer

2 years, 8 months

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