Skip to content

Commit

Permalink
Added the iterator and rename commands to Protected storage.
Browse files Browse the repository at this point in the history 
Signed-off-by: Marcus Streets <[email protected]>
  • Loading branch information
@MarcusJGStreets @athoelke
MarcusJGStreets authored and athoelke committed Apr 16, 2024
1 parent ef8ae85 commit 7d418ec
Show file tree
Hide file tree
Showing 2 changed files with 229 additions and 13 deletions.
6 changes: 6 additions & 0 deletions doc/storage/about.rst
View file
Original file line number Diff line number Diff line change
Expand Up @@ -41,6 +41,12 @@

Provide a Security Risk Assessment.

.. release:: 1.1.0
:date: January 2024
:confidentiality: Non-confidential

Added rename and iteration

.. release-info::
:extend:

Expand Down
236 changes: 223 additions & 13 deletions doc/storage/api/api.rst
View file
Original file line number Diff line number Diff line change
Expand Up @@ -63,7 +63,19 @@ These definitions must be defined in the header file :file:`psa/storage_common.h
.. field:: psa_storage_create_flags_t flags
The flags set when the ``uid`` was create

.. struct:: psa_storage_iterator_t

.. summary::
An implementation-defined opaque structure containing the context for an iterator.
The structure MUST contain all all the state required by the iterator.
That is, further state MUST NOT be retained by the implementation.

The structure is initilaised by the `ps_iterator_start()` function.
It is modified by the `ps_iterator_next()` function.

the caller can discard or reuse the iterator object once it has finished using it. This can be before, or after, the iterator has reached the end of the iteration.

The header file is only required to define this structure if PSA_STORAGE_SUPPORT_ITERATION is true.

.. typedef:: uint32_t psa_storage_create_flags_t

Expand Down Expand Up @@ -97,11 +109,35 @@ These definitions must be defined in the header file :file:`psa/storage_common.h

The data associated with the ``uid`` does not require replay protection. This can permit faster storage --- but it permits an attacker with physical access to revert to an earlier version of the data.

.. macro:: PSA_STORAGE_FLAG_REPLACE
(1u << 3)

Flag instructing the `psa_ps_rename()` function to replace existing stored data.

.. macro:: PSA_STORAGE_SUPPORT_SET_EXTENDED
(1u << 0)

Flag indicating that `psa_ps_create()` and `psa_ps_set_extended()` are supported.


.. macro:: PSA_STORAGE_SUPPORT_RENAME
(1u << 1)

Flag indicating that `psa_ps_rename()` is supported.

.. macro:: PSA_STORAGE_SUPPORT_ITERATION
(1u << 2)

Flag indicating that `psa_ps_iterator_start()` and `psa_ps_iterator_next()` are supported.

.. macro:: PSA_STORAGE_ITERATOR_CTX__SIZE
:definition: /* implementation-defined value */
.. summary::
A sufficient buffer size for a iterator context, in bytes.
This macro is only required if PSA_STORAGE_SUPPORT_ITERATION is true


.. _ITS-API:

Internal Trusted Storage API
Expand Down Expand Up @@ -181,7 +217,7 @@ These definitions must be defined in the header file :file:`psa/internal_trusted

* The ``uid`` value must not be zero.

* If ``uid`` exists it must not have been created as with `PSA_STORAGE_FLAG_WRITE_ONCE` --- would result in ``PSA_ERROR_NOT_PERMITTED``
* If ``uid`` exists it must not have been created as with `PSA_STORAGE_FLAG_WRITE_ONCE` --- would result in `PSA_ERROR_NOT_PERMITTED`

* The caller must have access all memory from ``p_data`` to ``p_data + data_length``.

Expand Down Expand Up @@ -235,9 +271,9 @@ These definitions must be defined in the header file :file:`psa/internal_trusted

* The value of ``data_offset`` must be less than or equal to the length of ``uid``.

* If ``data_ffset`` is greater than ``uid.size``, no data is retrieved and the functions returns PSA_INVALID_ARGUMENT.
* If ``data_offset`` is greater than ``uid.size``, no data is retrieved and the functions returns PSA_INVALID_ARGUMENT.

* If ``data_size`` is not zero, ``p_data`` must mot be ``NULL``.
* If ``data_size`` is not zero, ``p_data`` must not be ``NULL``.

* The call must have access to the memory from ``p_data`` to ``p_data + data_size - 1``.

Expand Down Expand Up @@ -353,14 +389,14 @@ These definitions must be defined in the header file :file:`psa/protected_storag
.. function:: psa_ps_set

.. summary::
Set the data associated with the specified ``uid``.
Set the data associated with the specified ``uid``, replacing any previous data.

.. param:: psa_storage_uid_t uid
The identifier for the data.
.. param:: size_t data_length
The size in bytes of the data in ``p_data``.
If ``data_length == 0`` the implementation will create a zero-length asset associated with the ``uid``.
While no data can be stored in such an asset, a call to `psa_ps_get_info()` will return ``PSA_SUCCESS``.
While no data can be stored in such an asset, a call to `psa_ps_get_info()` will return `PSA_SUCCESS`.
.. param:: const void * p_data
A buffer containing the data.
.. param:: psa_storage_create_flags_t create_flags
Expand All @@ -379,6 +415,9 @@ These definitions must be defined in the header file :file:`psa/protected_storag
* The ``uid`` is ``0``.

* The operation failed because caller cannot access some or all of the memory in the range [``p_data``, ``p_data + data_length - 1``].

* the uid exists and ``data_length`` is greater then ```capacity``

.. retval:: PSA_ERROR_NOT_SUPPORTED
The operation failed because one or more of the flags provided in ``create_flags`` is not supported or is not valid.
.. retval:: PSA_ERROR_INSUFFICIENT_STORAGE
Expand All @@ -388,8 +427,9 @@ These definitions must be defined in the header file :file:`psa/protected_storag
.. retval:: PSA_ERROR_GENERIC_ERROR
The operation failed because of an unspecified internal failure.

The newly created asset has a capacity and size that are equal to ``data_length``.
If ``uid`` does not already exist, creates a new asset, the newly created asset has a capacity and size that are equal to ``data_length``.

If ``uid`` exists and was not created with `PSA_STORAGE_FLAG_WRITE_ONCE`, replaces the existing contents with ``p_data``. ``uid.size`` is set to ``data_length``. If ``data_length`` is greater than ``uid.capcity``, ``uid.capcity`` is set to ``data_length``.

* The ``uid`` value must not be zero.

Expand Down Expand Up @@ -454,7 +494,7 @@ These definitions must be defined in the header file :file:`psa/protected_storag

* If ``data_offset`` is greater than ``uid.size`` the function retrieves no data and returns ``PSA_ERROR_INVALID_ARGUMENT``

* If ``data_size`` is not zero, ``p_data`` must mot be ``NULL``.
* If ``data_size`` is not zero, ``p_data`` must not be ``NULL``.

* The call must have access to the memory from ``p_data`` to ``p_data + data_size - 1``.

Expand Down Expand Up @@ -508,6 +548,7 @@ These definitions must be defined in the header file :file:`psa/protected_storag
* Even if all parameters are correct, the function can fail in the case of a storage failure.



.. function:: psa_ps_remove

.. summary::
Expand Down Expand Up @@ -542,6 +583,7 @@ These definitions must be defined in the header file :file:`psa/protected_storag
* Even if all parameters are correct, the function can fail in the case of a storage failure.



.. function:: psa_ps_create

.. summary::
Expand Down Expand Up @@ -594,7 +636,7 @@ These definitions must be defined in the header file :file:`psa/protected_storag
.. function:: psa_ps_set_extended

.. summary::
Overwrite part of the data of the specified ``uid``.
Overwrite part of the data of the specified ``uid``, leaving remaining data unchanged.

.. param:: psa_storage_uid_t uid
The unique identifier for the asset.
Expand Down Expand Up @@ -638,13 +680,13 @@ These definitions must be defined in the header file :file:`psa/protected_storag

Calling this function with ``data_length == 0`` is permitted. This makes no change to the stored data.

This function can overwrite existing data and/or extend it up to the capacity for the ``uid`` specified in `psa_ps_create()` but cannot create gaps.
This function can overwrite existing data and/or extend it up to the capacity for the ``uid`` specified in ``psa_ps_create()`` but cannot create gaps.

This function is optional. Consult the platform documentation to determine if it is implemented or perform a call to `psa_ps_get_support()`. This function must be implemented if `psa_ps_get_support()` returns `PSA_STORAGE_SUPPORT_SET_EXTENDED`.
This function is optional. Consult the platform documentation to determine if it is implemented or perform a call to ``psa_ps_get_support()``. This function must be implemented if ``psa_ps_get_support()`` returns ``PSA_STORAGE_SUPPORT_SET_EXTENDED``.

* The ``uid`` value must not be zero.

* If ``uid`` exists it must not have been created as with `PSA_STORAGE_FLAG_WRITE_ONCE` - would result in ``PSA_ERROR_NOT_PERMITTED``
* If ``uid`` exists it must not have been created as with ``PSA_STORAGE_FLAG_WRITE_ONCE`` - would result in ``PSA_ERROR_NOT_PERMITTED``

* ``data_offset <= size``

Expand All @@ -658,15 +700,183 @@ These definitions must be defined in the header file :file:`psa/protected_storag

* ``capacity`` unchanged.

* Data in the ranges 0 to ``data_offset`` is not modified.

* If ``data_offset + data_length < size`` then data in the range ``data_offset + data_length` to `size`` is not modified.

.. function:: psa_ps_get_support

.. return:: uint32_t

.. function:: psa_ps_rename

.. summary::
Atomically renames the storage location with the specified ``uid`` to a ``uid_new``.

.. param:: psa_storage_uid_t uid
The current identifier for the data.

.. param:: psa_storage_uid_t uid_new
The new identifier for the data.

.. param:: psa_storage_rename_flags_t rename_flags
The flags must be either ``PSA_STORAGE_FLAG_NONE`` or ``PSA_STORAGE_FLAG_REPLACE``

.. return:: psa_status_t
A status indicating the success or failure of the operation.

.. retval:: PSA_SUCCESS
The operation completed successfully.

.. retval:: PSA_ERROR_ALREADY_EXISTS
Storage with the specified ``uid_new`` already exists and ``rename_flags`` is `PSA_STORAGE_FLAG_NONE`

.. retval:: PSA_ERROR_DOES_NOT_EXIST
Storage with the specified ``uid`` does not exist.

.. retval:: PSA_ERROR_GENERIC_ERROR
The operation failed because of an unspecified internal failure.

.. retval:: PSA_ERROR_INVALID_ARGUMENT
The operation failed because either:

* ``uid`` is ``0``.
* ``uid_new`` is ``0``
* the ``psa_storage_rename_flags_t`` has a value set other than `PSA_STORAGE_FLAG_REPLACE`

.. retval:: PSA_ERROR_NOT_PERMITTED
The operation failed because ``uid_new`` exists and was created with `PSA_STORAGE_FLAG_WRITE_ONCE`.

.. retval:: PSA_ERROR_NOT_SUPPORTED
The implementation does not support the operation.

.. retval:: PSA_ERROR_STORAGE_FAILURE
The operation failed because the physical storage has failed (Fatal error).


The function renames ``uid`` to ``uid_new`` retaining the storage flags that ``uid`` was created with.

If the caller specifies `PSA_STORAGE_FLAG_REPLACE` the operation atomically replaces the exisitng contents of ```uid_new`` with those of ``uid``.

Except in the case of ``PSA_ERROR_STORAGE_FAILURE``, in which case no guarantees can be made, the operation shall either succeed or leave storage unchanged.


.. function:: psa_ps_iterator_start

.. summary::
Initialises an iterator that can be used to return a list of uids in the Protected Storage .

.. param:: psa_storage_iterator_t* context
A pointer to a context for this iterator. The pointer may be NULL. This is set to a new value on success and is undefined on error. The content of the iterator is implementation defined.

.. param:: psa_storage_uid_t filter
A value used to filter the results included in this iteration.

.. param:: int_t filter_length
A length of the filter to use, this must be a value ``0 < filter_lemngth < 63``.

.. param:: psa_storage_uid_t *result
A pointer to the location in which to store ``uid``. On success the contents of this location will be updated with the first matching ``uid``. On error, the contents are undefined.

.. return:: psa_status_t
A status indicating the success or failure of the operation.

.. retval:: PSA_SUCCESS
The operation completed successfully.

.. retval:: PSA_ERROR_DOES_NOT_EXIST
No ``uid`` matches this iteration.

.. retval:: PSA_ERROR_STORAGE_FAILURE
The operation failed because the physical storage has failed (Fatal error).

The iterator returns those values where the ``filter_length`` bits of the ``uid`` matches the left most bits in ``filter``.

The iterator will only returns those ``uid`` that were created by the caller. It MUST not return any ``uid`` created by a different user.

An iterator is not required to return uids in any specific order, but MUST return them in a consistent order each time it is called. For example, if an implementation returns entries in numerical order, it should not arbitrarily change to returning them in creation order. However, the caller should not make assumptions as to the order in which entries are returned, except that each ``uid`` will be returned only once in each iteration.

Changes to storage by other users MUST NOT affect any open iterations.

A caller may initialize multiple iteration contexts at the same time. Each iteration shall be independent. Calling ``psa_ps_iterator_next()`` on one iterator MUST not effect any other open iteration.

An iterator MUST return all data objects whose ``uid`` matches the filter that are extant when the filter was created, unless these are deleted or renamed before the iteration would return them, or the caller stops before all matching objects have been returned.

A caller may delete a ``uid`` with `psa_ps_remove(uid)` without invalidating the iteration context. the iterator MUST never return a ``uid`` that has been deleted. However, if the caller is multi-threaded it ia possible another thread may delete a ``uid``.

A caller may read the contents of any ``uid`` with `psa_ps_get()` or write with `psa_ps_set(` or `psa_ps_set_extended()` without invalidating the iteration context.

A caller may create a ``uid`` with `psa_ps_set()` or `psa_ps_create()` without invalidating the iteration context. However, the iterator is NOT guaranteed to return the new object, ``uid``, the behavior is dependent on both implementation and identity. In particular, the iterator is not expected to return ``uid`` if the iteration is already past the point at which it would naturally be returned.

A caller may call `psa_ps_rename(uid, uid_new)` without invalidating the iteration context. The iterator must not return ``uid``. The iterator is not guaranteed to return ``uid_new``, the behavior is dependent on both implementation and identity.

The following code snippet uses a linked list to store the matching files before iterating over that list and removing them.

.. code-block:: c
my_context = NULL
my_filter = 0x1111 0000 0000 0000
my_length = 0x0020
my_result = NULL
if psa_ps_iterator_start(my_context, my_filter, my-length, my_result) == PSA_SUCCESS
{
do
{
// do something with my_result
psa_ps_iterator_next(my_context, my_result)
// we will get an does not exist error when we reach the last item, any other error is a storage failure
if my_reult <> PSA_ERROR_DOES_NOT_EXIST
{
/* deal with storage failure */
}
}
while my_result == PSA_SUCCES ;
};
.. function:: psa_ps_iterator_next

.. summary::

Returns the next ``uid`` in this iteration.

.. param:: psa_storage_iterator_t* context
A pointer to a context for this iterator as returned by `psa_ps_iterator_start()` or updated by a previous call to `psa_ps_iterator_next()`. The content of the iterator will change on success and is undefined on error.

.. param:: psa_storage_uid_t *result
A pointer to the location in which to store ``uid``. On success the contents of this location will be updated with the next matching ``uid``. On error, the contents are undefined.

.. return:: psa_status_t
A status indicating the success or failure of the operation.

.. retval:: PSA_SUCCESS
The operation completed successfully.

.. retval:: PSA_ERROR_DOES_NOT_EXIST
The iterator has returned all the uids that match this iteration.

.. retval:: PSA_ERROR_STORAGE_FAILURE
The operation failed because the physical storage has failed (Fatal error).

.. retval:: PSA_ERROR_DATA_CORRUPT
The operation failed because the contents of the iteration have changed. That is a ``uid`` matching the filter has either been created or deleted.

.. retval:: PSA_ERROR_INVALID_ARGUMENT
The operation failed because either:

* The provided context is not valid.

* The caller cannot access the memory at `result`

.. function:: psa_ps_get_support

.. summary::
Returns a bitmask with flags set for the optional features supported by the implementation.

Currently defined flags are limited to:

* `PSA_STORAGE_SUPPORT_SET_EXTENDED`
* `PSA_STORAGE_SUPPORT_RENAME`
* `PSA_STORAGE_SUPPORT_ITERATION`

.. return:: uint32_t

0 comments on commit 7d418ec

Please sign in to comment.