This comment is about how the functions are implemented, not about their
public interface, so it doesn't belong in the header file.
It applies to everything in constant_time.c so moved there.
Signed-off-by: Gabor Mezei <gabor.mezei@arm.com>
The equality checker functions always return 0 or 1 value,
thus the type of return value can be the same dispite of the
size of the parameters.
Signed-off-by: Gabor Mezei <gabor.mezei@arm.com>
Tne unpadding part of `mbedtls_rsa_rsaes_pkcs1_v15_decrypt` function is
contant-time therefore it moved to a separate function to be prepared
for moving to the contant-time module.
Signed-off-by: Gabor Mezei <gabor.mezei@arm.com>
Add a constant-time function with size_t parameter for choosing
between two integer values, like the ?: ternary operator.
Signed-off-by: Gabor Mezei <gabor.mezei@arm.com>
All function declaration provided by ssl_invasive.h is needed only for
testing purposes and all of them are provided by constant_time.h as well.
Signed-off-by: Gabor Mezei <gabor.mezei@arm.com>
Elinimate macros defined by modules locally in the functions that are
moving to the new constant-time module.
Signed-off-by: Gabor Mezei <gabor.mezei@arm.com>
There were multiple functions called mbedtls_cf_size_bool_eq. They had exactly
the same behavior, so move the one in bignum.c and remove the other.
Signed-off-by: Gabor Mezei <gabor.mezei@arm.com>
The makefile build specifies -L. -lmbedx509 -lmbedcrypto flags first,
and only then object files referencing symbols from those libraries.
In this order the linker will not add the linked libraries to the
DT_NEEDED section because they are not referenced yet (at least that
happens for me on ubuntu 20.04 with the default gnu compiler tools).
By first specifying the object files and then the linked libraries, we
do end up with libmbedx509 and libmbedcrypto in the DT_NEEDED sections.
This way running dlopen(...) on libmedtls.so just works.
Note that the CMake build does this by default.
Signed-off-by: Harmen Stoppels <harmenstoppels@gmail.com>
At least twice, we added a classification flag but forgot to test it in the
relevant test functions. Add some protection so that this doesn't happen
again. In each classification category, put a macro xxx_FLAG_MASK_PLUS_ONE
at the end. In the corresponding test function, keep track of the flags that
are tested, and check that their mask is xxx_FLAG_MASK_PLUS_ONE - 1 which is
all the bits of the previous flags set.
Now, if we add a flag without testing it, the test
TEST_EQUAL( classification_flags_tested, xxx_FLAG_MASK_PLUS_ONE - 1 )
will fail. It will also fail if we make the set of flag numbers
non-consecutive, which is ok.
This reveals that three algorithm flags had been added but not tested (in
two separate occasions). Also, one key type flag that is no longer used by
the library was still defined but not tested, which is not a test gap but is
inconsistent. It's for DSA, which is relevant to the PSA encoding even if
Mbed TLS doesn't implement it, so keep the flag and do test it.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
The status of signature wildcards with respect to PSA_ALG_IS_HASH_AND_SIGN
is unclear in the specification. A wildcard is usually instantiated with a
specific hash, making the implementation hash-and-sign, but it could also be
instantiated with a non-hash-and-sign algorithm. For the time being, go with
what's currently implemented, which is that they are considered
hash-and-sign.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
The current definition of PSA_ALG_IS_HASH_AND_SIGN includes
PSA_ALG_RSA_PKCS1V15_SIGN_RAW and PSA_ALG_ECDSA_ANY, which don't strictly
follow the hash-and-sign paradigm: the algorithm does not encode a hash
algorithm that is applied prior to the signature step. The definition in
fact encompasses what can be used with psa_sign_hash/psa_verify_hash, so
it's the correct definition for PSA_ALG_IS_SIGN_HASH. Therefore this commit
moves definition of PSA_ALG_IS_HASH_AND_SIGN to PSA_ALG_IS_SIGN_HASH, and
replace the definition of PSA_ALG_IS_HASH_AND_SIGN by a correct one (based
on PSA_ALG_IS_SIGN_HASH, excluding the algorithms where the pre-signature
step isn't to apply the hash encoded in the algorithm).
In the definition of PSA_ALG_SIGN_GET_HASH, keep the condition for a nonzero
output to be PSA_ALG_IS_HASH_AND_SIGN.
Everywhere else in the code base (definition of PSA_ALG_IS_SIGN_MESSAGE, and
every use of PSA_ALG_IS_HASH_AND_SIGN outside of crypto_values.h), we meant
PSA_ALG_IS_SIGN_HASH where we wrote PSA_ALG_IS_HASH_AND_SIGN, so do a
global replacement.
```
git grep -l IS_HASH_AND_SIGN ':!include/psa/crypto_values.h' | xargs perl -i -pe 's/ALG_IS_HASH_AND_SIGN/ALG_IS_SIGN_HASH/g'
```
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Only tested for algorithms for which we support HMAC, since that's all we
use PSA_HASH_BLOCK_LENGTH for at the moment.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
