Make it clear that this is an abstraction of the random generator
abstraction, and not an abstraction of the PSA random generator.
mbedtls_psa_get_random and MBEDTLS_PSA_RANDOM_STATE are public-facing
definitions and will be moved in a subsequent commit.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
In the external RNG case, don't make mbedtls_psa_get_random() a
static inline function: this would likely result in identical
instances of this function in every module that uses it. Instead, make
it a single function with external linkage.
In the non-external case, instead of a trivial wrapper function, make
mbedtls_psa_get_random a constant pointer to whichever DRBG function
is being used.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Hide the obtention of the pointer to the RNG state behind a macro.
To make it possible to use this macro in a module other than
psa_crypto.c, which will happen in the future, make sure that the
definition of the macro does not reference internal variables of
psa_crypto.c. For this purpose, in the internal-DRBG case, export a
symbol containing the address of the DRBG state.
When the RNG state is a pointer a DRBG state, just keep this pointer
in a variable: there's no need to store a pointer to a larger structure.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Add two builds with MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG to all.sh:
* full minus all DRBG (validates that PSA can work without any of the
DRBG modules).
* with MBEDTLS_USE_PSA_CRYPTO and no CTR_DRBG (validates that PSA can
work without CTR_DRBG, and that it works for USE_PSA_CRYPTO).
The goal is to exercise default/full, with/out USE_PSA_CRYPTO, and
with/out deterministic ECDSA (which requires HMAC_DRBG). The choice of
pairing is rather arbitrary.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Note that the implementation here is just a sample, and integrators
are expected to replace it with whatever they need.
But do try to supply a definition that can be somewhat useful (give
room for pointer+size).
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
We generate the Doxygen documentation in a configuration where part of
config.h is excluded. See
https://github.com/ARMmbed/mbedtls/issues/520
```
/var/lib/build/include/mbedtls/config.h:3635: warning: documentation for unknown define MBEDTLS_PSA_HMAC_DRBG_MD_TYPE found.
```
This is a more general issue and fixing it is out of scope of my
current work. Therefore, just do something simple to silence Doxygen,
and never mind that this causes the documentation of
`MBEDTLS_PSA_HMAC_DRBG_MD_TYPE` to be omitted from the rendered
documentation. We'll fix that when we fix all the configuration macros
with a similar problem.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Allow the user to configure PSA to use HMAC_DRBG even if CTR_DRBG is
available, or to explicitly select the hash algorithm to use for
HMAC_DRBG, by setting MBEDTLS_PSA_HMAC_DRBG_MD_TYPE in config.h.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Support using HMAC_DRBG instead of CTR_DRBG in the PSA subsystem.
Use HMAC_DRBG if CTR_DRBG is available. Choose between SHA-256 and
SHA-512 based on availability.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Implement support for MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG.
For test purposes, write an implementation that uses libc rand().
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Define a sample type mbedtls_psa_external_random_context_t in
psa/crypto_platform.h and define the prototype of
mbedtls_psa_external_get_random() in a public header.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Create a configuration option for autonomous random drivers, i.e. PSA
crypto drivers that provide a random generator, that have their own
entropy source and do not support injecting entropy from another
source.
This commit only creates the configuration option. Subsequent commits
will add the implementation and tests.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Create wrapper functions around calls to CTR_DRBG and around calls to
entropy+DRBG. This is in preparation for allowing alternative DRBG
implementations that use the Mbed TLS entropy module, or complete RNG
implementations that bypass the entropy module as well.
This is purely a refactoring commit. No behavior change.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
After a call to psa_get_key_attributes() to retrieve
the attributes of a key into a psa_key_attributes_t
structure, a call to psa_reset_key_attributes() is
mandated to free the resources that may be
referenced by the psa_key_attributes_t structure.
Not calling psa_reset_key_attributes() may result in
a memory leak.
When a test function calls psa_get_key_parameters()
the associated key attributes are systematically
reset in the clean-up part of the function with a
comment to emphasize the need for the reset and make
it more visible.
Signed-off-by: Ronald Cron <ronald.cron@arm.com>
Rename functions to get a key slot:
. to make their naming more consistent
. to emphasize that those functions set a lock on the
key slot they return to protect it from being wiped
out and re-used while some part of the library
is accessing it.
Signed-off-by: Ronald Cron <ronald.cron@arm.com>
Move the return of the identifier of a created key from
psa_start_key_creation() to psa_finish_key_creation().
That way in case of creation error, it is less likely to
return the identifier that was temporarily assigned to
the key while trying to create it.
Signed-off-by: Ronald Cron <ronald.cron@arm.com>
Decrement the slot access count in psa_finish_key_creation()
when the finalization succeeds instead of in functions calling
psa_finish_key_creation(). That way the decrementation cannot
be forgotten and it reduces the code size.
Signed-off-by: Ronald Cron <ronald.cron@arm.com>
Special handling of volatile key identifiers is not
needed eventually, they can be handled just as
key identifier in the vendor range.
Signed-off-by: Ronald Cron <ronald.cron@arm.com>
In case of a volatile key identifier, no need to check first
the validity of the key identifier, a volatile key identifier
is valid.
Move to a forward search for non-volatile key identifiers as
now key slots with small index are allocated first by
psa_get_empty_key_slot().
Signed-off-by: Ronald Cron <ronald.cron@arm.com>
