The loop ends when there are no more bits to process, with one twist: when
that happens, we need to clear the window one last time. Since the window
does not start empty (E_limbs==0 is not supported), the loop always starts
with a non-empty window and some bits to process. So it's correct to move
the window clearing logic to the end of the loop. This lets us exit the loop
when the end of the exponent is reached.
It would be clearer not to do the final window clearing inside the loop, so
we wouldn't need to repeat the loop termination condition (end of exponent
reached) inside the loop. However, this requires duplicating the code to
clear the window. Empirically, this causes a significant code size increase,
even if the window clearing code is placed into a function.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
We are looking at the exponent at limb granularity and therefore
exponent bits can't go below 32.
The `mpi_` prefix is also removed as it is better not to have prefix at
all than to have just a partial. (Full prefix would be overly long and
would hurt readability.)
Signed-off-by: Janos Follath <janos.follath@arm.com>
The test cases aim to mirror the legacy function, but needed the some
cases to be removed because:
- Null representation is not valid in core
- There are no negative numbers in core
- Bignum core doesn't do parameter checking and there are no promises for
even N
The _size variant of the test has been removed as bignum core doesn't do
parameter checking and there is no promises for inputs that are larger
than MBEDTLS_MPI_MAX_SIZE.
Signed-off-by: Janos Follath <janos.follath@arm.com>
Now that we have a function that calls
mbedtls_mpi_core_ct_uint_table_lookup(), the compiler won't complain if
we make it static.
Signed-off-by: Janos Follath <janos.follath@arm.com>
On platforms with size_t different from int, mismatch between size_t and
mpi_uint can cause incorrect results or complaints from the compiler.
Signed-off-by: Janos Follath <janos.follath@arm.com>
mpi_core_exp_mod: Cast local variable explicitly
Signed-off-by: Janos Follath <janos.follath@arm.com>
- external errors are now checked in the specified point. If the
same error happens in another line, then this is not valid and
the test fails
- fixed some inconsistency in which injected error codes were not
taken from the data file. Now all the expected error code are
read from the data file
- added a couple of defines to shrink the code
Signed-off-by: Valerio Setti <vsetti@baylibre.com>
As for ecjpake_setup(), now the test function can handle:
- "external" errors, through parameters set by the data file
- "internal" ones, through enums which inject ad-hoc failures
Similarly also ecjpake_rounds() can handle both type of errors,
but right now there's no erroneous case in the associated ".data"
file.
In both cases, after an error the current test is terminated.
Signed-off-by: Valerio Setti <vsetti@baylibre.com>
In this way, in case of error, it is not possible to continue using
the same psa_pake_operation_t without reinitializing it.
This should make the PSA pake's behavior closer to what expected by
the specification
Signed-off-by: Valerio Setti <vsetti@baylibre.com>
