72 lines
2.8 KiB
ReStructuredText
72 lines
2.8 KiB
ReStructuredText
.. psa_protected_storage:
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PSA Protected Storage
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#####################
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Overview
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********
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This sample demonstrates how the Protected Storage (PS) API can be used for storing data.
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Protected storage provides a key/value storage interface where data is (by default) encrypted, with
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optional authentication and rollback protection. The default crypto algorithm is ``AES-128-GCM``.
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The encryption key is derived from the Hardware Unique Key (HUK), which is often set via device
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fuses, etc.
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Using the PS API, this sample stores data to non-volatile storage. The sample shows how data can
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be stored to and read from UIDs, and how overwrite protection can be enabled using flags.
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TF-M includes a maximum number of PS records, set via ``PS_NUM_ASSETS`` (default 10 as of
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TF-M 1.3), and a maximum record size, set via ``PS_MAX_ASSET_SIZE`` (default of 2048 as of
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TF-M 1.3.0). These defaults may be different depending on the platform being used, the current
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value will be printed by the build system during the TF-M compilation step.
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More information about Protected Storage can be found in the Platform Security Architecture (PSA)
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Secure Storage API: https://developer.arm.com/architectures/architecture-security-features/platform-security
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This sample is available for platforms that are supported in the trusted-firmware-m repo:
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https://git.trustedfirmware.org/TF-M/trusted-firmware-m.git/
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See sample.yaml for a list of supported platforms.
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Building and Running
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********************
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On Target
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=========
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Refer to :ref:`tfm_psa_crypto` for detailed instructions.
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Note that the board needs to be completely erased before programming the sample, as the flash area
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used might contain data from before. The board must also be erased between each time the sample is
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run as the overwrite protection will not be removed with a power reset.
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On QEMU
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========
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Refer to :ref:`tfm_ipc` for detailed instructions.
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Following is an example based on ``west build``
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.. code-block:: bash
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$ west build samples/tfm_integration/psa_protected_storage/ -p -b mps2_an521_ns -t run
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Sample Output
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=============
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.. code-block:: console
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*** Booting Zephyr OS build zephyr-v2.5.0-2791-g5585355dde0c ***
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TF-M Protected Storage sample started. PSA Protected Storage API Version 1.0
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Writing data to UID1: The quick brown fox jumps over the lazy dog
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Info on data stored in UID1:
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- Size: 16
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- Capacity: 0x42
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- Flags: 0x 0
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Read and compare data stored in UID1
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Data stored in UID1: The quick brown fox jumps over the lazy dog
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Overwriting data stored in UID1 with: Lorem ipsum dolor sit amet
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Writing data to UID2 with overwrite protection: The quick brown fox jumps over the lazy dog
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Attempting to write 'The quick brown fox jumps over the lazy dog' to UID2
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Got expected error (PSA_ERROR_NOT_PERMITTED) when writing to protected UID
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Removing UID1
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