In mpi_montmul, an auxiliary function for modular
exponentiation (mbedtls_mpi_mod_exp) that performs Montgomery
multiplication, the last step is a conditional subtraction to force
the result into the correct range. The current implementation uses a
branch and therefore may leak information about secret data to an
adversary who can observe what branch is taken through a side channel.
Avoid this potential leak by always doing the same subtraction and
doing a contant-trace conditional assignment to set the result.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Separate out a version of mpi_safe_cond_assign that works on
equal-sized limb arrays, without worrying about allocation sizes or
signs.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
This reverts commit 2cc69fffcf.
A check was added in mpi_montmul because clang-analyzer warned about a
possibly null pointer. However this was a false positive. Recent
versions of clang-analyzer no longer emit a warning (3.6 does, 6
doesn't).
Incidentally, the size check was wrong: mpi_montmul needs
T->n >= 2 * (N->n + 1), not just T->n >= N->n + 1.
Given that this is an internal function which is only used from one
public function and in a tightly controlled way, remove both the null
check (which is of low value to begin with) and the size check (which
would be slightly more valuable, but was wrong anyway). This allows
the function not to need to return an error, which makes the source
code a little easier to read and makes the object code a little
smaller.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Invasive testing strategy
Create a new header `common.h`.
Introduce a configuration option `MBEDTLS_TEST_HOOKS` for test-specific code, to be used in accordance with the invasive testing strategy.
People who prefer to rely on HMAC_DRBG (for example because they use it for
deterministic ECDSA and don't want a second DRBG for code size reasons) should
be able to build and run the tests suites without CTR_DRBG.
Ideally we should make sure the level of testing (SSL) is the same regardless
of which DRBG modules is enabled, but that's a more significant piece of work.
For now, just ensure everything builds and `make test` passes.
Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
While at it, fix a few other obvious ones such as ENTROPY and TIMING_C when
applicable.
A non-regression test for CTR_DRBG will be added in a follow-up commit.
Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
While at it, declare deps on ENTROPY as well.
A non-regression test will be added in a follow-up commit.
Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
This commit modifies the generate_psa_constants.py script to take as
input argument the location of where to write the
psa_constant_names_generated.c file.
For make-based build system, this commit does not change anything.
For CMake build system, this commit modifies the generation location of
that file to be inside the build directory and include it from there in
psa_constant_names.c
Fix#3365
Signed-off-by: Hugues de Valon <hugues.devalon@arm.com>
Convert all text files to Unix line endings unless they're Windows
stuff.
Make sure that all text files have a trailing newline.
Remove whitespace at the end of lines.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
We're only interested in files that are committed and pushed to be
included in Mbed TLS, not in any other files that may be lying around.
So ask git for the list of file names.
This script is primarily intended to run on the CI, and there it runs
on a fresh Git checkout plus potentially some other checkouts or
leftovers from a previous part of the CI job. It should also run
reasonably well on developer machines, where there may be various
additional files. In both cases, git is available.
Ad hoc directory exclusions are no longer needed.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Have an explicit list of exemptions for specific checks rather than
whitelisting files to check. Some checks, such as permissions, should
apply to all files.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Add output of python3 version to output_env.sh.
Added in addition to the version of `python` as some
project's scripts try both executable names.
Signed-off-by: Ronald Cron <ronald.cron@arm.com>
When generate_errors.pl was first written, there was no asn1.h. But
now there is one and it does not need any special treatment.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Make the contributing document link to how to create a changelog rather
than just linking to the Changelog itself.
Signed-off-by: Paul Elliott <paul.elliott@arm.com>
