The chosen fix matches what's currently done in the baremetal branch - except
the `#ifdef` have been adapted because now in baremetal the digest is not kept
if renegotiation is disabled.
We have explicit recommendations to use US spelling for technical writing, so
let's apply this to code as well for uniformity. (My fingers tend to prefer UK
spelling, so this needs to be fixed in many places.)
sed -i 's/\([Ss]eriali\)s/\1z/g' **/*.[ch] **/*.function **/*.data ChangeLog
This test works regardless of the serialisation format and embedded pointers
in it, contrary to the load-save test, though it requires more maintenance of
the test code (sync the member list with the struct definition).
This uncovered a bug that led to a double-free (in practice, in general could
be free() on any invalid value): initially the session structure is loaded
with `memcpy()` which copies the previous values of pointers peer_cert and
ticket to heap-allocated buffers (or any other value if the input is
attacker-controlled). Now if we exit before we got a chance to replace those
invalid values with valid ones (for example because the input buffer is too
small, or because the second malloc() failed), then the next call to
session_free() is going to call free() on invalid pointers.
This bug is fixed in this commit by always setting the pointers to NULL right
after they've been read from the serialised state, so that the invalid values
can never be used.
(An alternative would be to NULL-ify them when writing, which was rejected
mostly because we need to do it when reading anyway (as the consequences of
free(invalid) are too severe to take any risk), so doing it when writing as
well is redundant and a waste of code size.)
Also, while thinking about what happens in case of errors, it became apparent
to me that it was bad practice to leave the session structure in an
half-initialised state and rely on the caller to call session_free(), so this
commit also ensures we always clear the structure when loading failed.
This test appeared to be passing for the wrong reason, it's actually not
appropriate for the current implementation. The serialised data contains
values of pointers to heap-allocated buffers. There is no reason these should
be identical after a load-save pair. They just happened to be identical when I
first ran the test due to the place of session_free() in the test code and the
fact that the libc's malloc() reused the same buffers. The test no longer
passes if other malloc() implementations are used (for example, when compiling
with asan which avoids re-using the buffer, probably for better error
detection).
So, disable this test for now (we can re-enable it when we changed how
sessions are serialised, which will be done in a future PR, hence the name of
the dummy macro in depends_on). In the next commit we're going to add a test
that save-load is the identity instead - which will be more work in testing as
it will require checking each field manually, but at least is reliable.
This initial test ensures that a load-save function is the identity. It is so
far incomplete in that it only tests sessions without tickets or certificate.
This will be improved in the next commits.
* crypto/pr/212: (337 commits)
Make TODO comments consistent
Fix PSA tests
Fix psa_generate_random for >1024 bytes
Add tests to generate more random than MBEDTLS_CTR_DRBG_MAX_REQUEST
Fix double free in psa_generate_key when psa_generate_random fails
Fix copypasta in test data
Avoid a lowercase letter in a macro name
Correct some comments
Fix PSA init/deinit in mbedtls_xxx tests when using PSA
Make psa_calculate_key_bits return psa_key_bits_t
Adjust secure element code to the new ITS interface
More refactoring: consolidate attribute validation
Fix policy validity check on key creation.
Add test function for import with a bad policy
Test key creation with an invalid type (0 and nonzero)
Remove "allocated" flag from key slots
Take advantage of psa_core_key_attributes_t internally #2
Store the key size in the slot in memory
Take advantage of psa_core_key_attributes_t internally: key loading
Switch storage functions over to psa_core_key_attributes_t
...
Drivers that allow destroying a key must have a destroy method. This
test bug was previously not caught because of an implementation bug
that lost the error triggered by the missing destroy method.
Add a flow where the key is imported or fake-generated in the secure
element, then call psa_export_public_key and do the software
verification with the public key.
Factor common code of ram_import and ram_fake_generate into a common
auxiliary function.
Reject key types that aren't supported by this test code.
Report the bit size correctly for EC key pairs.
The methods to import and generate a key in a secure element drivers
were written for an earlier version of the application-side interface.
Now that there is a psa_key_attributes_t structure that combines all
key metadata including its lifetime (location), type, size, policy and
extra type-specific data (domain parameters), pass that to drivers
instead of separate arguments for each piece of metadata. This makes
the interface less cluttered.
Update parameter names and descriptions to follow general conventions.
Document the public-key output on key generation more precisely.
Explain that it is optional in a driver, and when a driver would
implement it. Declare that it is optional in the core, too (which
means that a crypto core might not support drivers for secure elements
that do need this feature).
Update the implementation and the tests accordingly.
Register an existing key in a secure element.
Minimal implementation that doesn't call any driver method and just
lets the application declare whatever it wants.
Pass the key creation method (import/generate/derive/copy) to the
driver methods to allocate or validate a slot number. This allows
drivers to enforce policies such as "this key slot can only be used
for keys generated inside the secure element".
Allow the application to choose the slot number in a secure element,
rather than always letting the driver choose.
With this commit, any application may request any slot. In an
implementation with isolation, it's up to the service to filter key
creation requests and apply policies to limit which applications can
request which slot.
Test the behavior of the getter/setter functions.
Test that psa_get_key_slot_number() reports a slot number for a key in
a secure element, and doesn't report a slot number for a key that is
not in a secure element.
Test that psa_get_key_slot_number() reports the correct slot number
for a key in a secure element.
Add tests that call psa_generate_random() (possibly via
psa_generate_key()) with a size that's larger than
MBEDTLS_CTR_DRBG_MAX_REQUEST. This causes psa_generate_random() to
fail because it calls mbedtls_ctr_drbg_random() without taking the
maximum request size of CTR_DRBG into account.
Non-regression test for #206
