Now that the script might additionally run mypy, it's more
user-friendly to indicate what's going on at the beginning as well.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
`test_fail` automatically sets `test_info.result`. This commit removes a case
where `test_info.result` was being manually set after `test_fail` was called.
Signed-off-by: Chris Jones <christopher.jones@arm.com>
In component_test_no_hmac_drbg, the fact that HMAC_DRBG is disabled
doesn't affect the SSL code, but the fact that deterministic ECDSA is
disabled does. So run some ECDSA-related SSL tests.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Support HMAC_DRBG in ssl_client2 and ssl_server2, in addition to
CTR_DRBG. CTR_DRBG is still used if present, but it's now possible to
run the SSL test programs with CTR_DRBG disabled.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
TEST_ASSERT jumps to the exit label, so it must not be called from
cleanup code executed after the exit label. It's legitimate (and
indeed very common) to call PSA_DONE in cleanup code, so PSA_DONE must
not jump to exit.
Define an auxiliary function test_fail_if_psa_leaking() that calls
test_fail() with the error message provided by
mbedtls_test_helper_is_psa_leaking(). This function currently needs to
be in helpers.function rather than in a PSA-specific helper file
because it calls test_fail which is defined in helpers.function.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Don't microoptimize memory usage in tests: use separate buffers for
the input and the output. Allocate the input buffer dynamically
because the size is a parameter of the test case. Allocate the output
buffer dynamically because it's generally good practice in tests so
that a memory sanitizer can detect a buffer overflow.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
When verifying the impact of a forced RNG failure, depend on the built-in
implementation of the algorithm that uses randomization, whether it's
because the algorithm is randomized or because our implementation uses
randomization for (e.g.) blinding. An external implementation could use
its own randomness source which is not affected by the forced failure of
the RNG driver.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Under MBEDTLS_ERR_RSA_RNG_FAILED, add tests where the random generator
failed. This commit tests the following operations:
* psa_generate_random()
* psa_generate_key() for a symmetric key
* Deterministic signatures that use blinding (RSA PKCS#1v1.5,
deterministic ECDSA).
* Randomized signatures (RSA PSS, randomized ECDSA).
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
To reduce the risk of people accidentally using the test
implementation of mbedtls_psa_external_get_random(), which is
insecure, require the user to explicitly call
mbedtls_test_enable_insecure_external_rng() first.
Disabling the test implementation of mbedtls_psa_external_get_random()
will also allow negative testing for MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG,
which will be added in a subsequent commit.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Include psa_crypto_helpers.h automatically if MBEDTLS_PSA_CRYPTO_C is
enabled, like helpers.h is included automatically.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
psa_crypto_helpers.h no longer defines static functions, so it can be
included anywhere without worrying about unused functions.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
`tests/scripts/all.sh test_psa_collect_statuses` calls
`tests/scripts/psa_collect_statuses.py` which calls
`make -DRECORD_PSA_STATUS_COVERAGE_LOG` which must generate
`include/test/instrument_record_status.h`.
With the refactoring of `psa_crypto_helpers.{h,c}`, this now
needs to be done before building `psa_crypto_helpers.c`.
Also, remove `include/test/instrument_record_status.h` unconditionally
in `make clean`, which helps keep the build tree clean.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Move function definitions from psa_crypto_helpers.h to
psa_crypto_helpers.c.
No behavior change.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Refactor some PSA test helper functions and macros to avoid depending
on test_info and test_fail inside functions. These identifiers are
only defined in helpers.function, so they're only available in test
suites, and not in test helper modules (tests/src/*.c) which are also
linked into example programs.
This is in preparation for moving function definitions from
psa_crypto_helpers.h to psa_crypto_helpers.c.
No behavior change.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Since 349eadc58f, test_fail() reports
the first failure. So it's safe to call test_fail() again to report a
cleanup failure when we don't want to potentially erase information
about an earlier failure.
The behavior of mbedtls_test_helper_is_psa_pristine() changes if
test_info.result was neither TEST_RESULT_SUCCESS nor
TEST_RESULT_FAILED, but this should not matter since a skipped test
should not cause mbedtls_test_helper_is_psa_pristine() to fail.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
With just the option --can-pylint or --can-mypy, check whether the
requisite tool is available with an acceptable version and exit.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
mypy automatically checks the modules when it encounters them as
imports. Don't make it check them twice, because it would complain
about encountering them through different paths (via the command line
as scripts/mbedtls_dev/*.py and via imports as just mbedtls_dev/*.py).
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
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>
Create a directory mbedtls_dev intended to contain various Python
module for use by Python scripts located anywhere in the Mbed TLS
source tree.
Move get_c_expression_values and its auxiliary functions into a new
Python module mbedtls_dev.c_build_helper.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Generalize the very ad hoc run_c function into a function to generate
a C program to print the value of a list of expressions. Refactor the
code into several functions to make it more manageable.
No intended behavior change.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Allow Python scripts in tests/scripts to import modules located in the
scripts directory. To do this, use
```
import scripts_path # pylint: disable=unused-import
```
Declare the scripts directory to pylint and to mypy.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Since no typing stubs are available for mbed_host_tests.py, mypy
errors out on mbedtls_test.py with
error: Skipping analyzing 'mbed_host_tests': found module but no type hints or library stubs
Ignore this import to get at least some benefit from mypy without
spending significant effort to write stubs.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Add enough type annotations to pass mypy 0.782 with Python 3.5. The
source code will still run normally under older Python versions.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Executable scripts must have shebang (#!) line to be effectively
executable on most Unix-like systems. Enforce this, and conversely
enforce that files with a shebang line are executable.
Check that the specified interperter is consistent with the file
extension.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Executed ./scripts/bump_version.sh --version 2.25.0 --so-crypto 6
Increasing the SO version of the crypto library, because the openless
API improvement came with API/ABI incompatibilities. For example
- the size of psa_key_handle_t changed
- the type of a parameter in 18 public functions has changed from
psa_key_handle_t to mbedtls_svc_key_id_t
Signed-off-by: Janos Follath <janos.follath@arm.com>
In order to remove large buffers from the stack, the der data is written
into the same buffer that the pem is eventually written into, however
although the pem data is zero terminated, there is now data left in the
buffer after the zero termination, which can cause
mbedtls_x509_crt_parse to fail to parse the same buffer if passed back
in. Patches also applied to mbedtls_pk_write_pubkey_pem, and
mbedtls_pk_write_key_pem, which use similar methods of writing der data
to the same buffer, and tests modified to hopefully catch any future
regression on this.
Signed-off-by: Paul Elliott <paul.elliott@arm.com>
Make sure that if a buffer is allowed to be empty, a null pointer is
accepted if the buffer length is 0. This was already the case for most
but not all arguments to mbedtls_cipher_auth_{en,de}crypt{,_ext}.
Make sure to pass NULL for an empty buffer in the tests.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Run all the addition and subtraction tests with the result aliased to
the first operand and with the result aliased to the second operand.
Before, only some of the aliasing possibilities were tested, for only
some of the functions, with only some inputs.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Fixes an issue where configs that had `MBEDTLS_MPI_MAX_BITS` greater than 256
but smaller than the test that was running (792 bits) the test would fail
incorrectly.
Signed-off-by: Chris Jones <christopher.jones@arm.com>
Move dependancy on `MBEDTLS_MPI_MAX_BITS` to apply to the specific test cases
which will break when `MBEDTLS_MPI_MAX_BITS` is too small. This re-enables
previous tests that were turned off accidentally.
Signed-off-by: Chris Jones <christopher.jones@arm.com>
Previously `mbedtls_mpi_exp_mod` was tested with values that were over
`MBEDTLS_MPI_MAX_SIZE` in size. This is useful to do as some paths are only
taken when the exponent is large enough however, on builds where
`MBEDTLS_MPI_MAX_SIZE` is under the size of these test values.
This fix turns off these tests when `MBEDTLS_MPI_MAX_SIZE` is too small to
safely test (notably this is the case in config-thread.h).
Signed-off-by: Chris Jones <christopher.jones@arm.com>
In two test cases, the exponentiation computation was not being fully tested
as when A_bytes (the base) == N_bytes (the modulus) -> A = N. When this is the
case A is reduced to 0 and therefore the result of the computation will always
be 0.
This fixes that issue and therefore increases the test coverage to ensure
different computations are actually being run.
Signed-off-by: Chris Jones <christopher.jones@arm.com>
Reword test cases to be easier to read and understand.
Adds comments to better explain what the test is doing.
Signed-off-by: Chris Jones <christopher.jones@arm.com>
This temporarily breaks all.sh '*deprecated*' (deprecated functions still used
in the library), which will be fix in the next commit.
Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
We want to test both sets of functions (ext and non-ext) in turn, so goto exit
is not really and option.
Also, separate setting up the context (which is going to be the same for both
ext and non-ext functions) from setting up the buffers (which will vary).
Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
Add two further boundary tests for cases where both the exponent and modulus to
`mbedtls_mpi_exp_mod()` are `MBEDTLS_MPI_MAX_SIZE`, or longer, bytes long.
Signed-off-by: Chris Jones <christopher.jones@arm.com>
* development: (488 commits)
Fix removal of deprecated PSA constants
Use GitHub-compatible table formatting
Remove psa header files in uninstall part
Change function casting in `ssl_calc_finished_tls_sha384`
Fix GCC warning in `ssl_calc_finished_tls_sha384`
Add changelog entry file to `ChangeLog.d`
Fix GCC warning in `ssl_calc_finished_tls_sha384`
Fix GCC warning about `test_snprintf`
Fix mismatched function parameters (prototype/definition)
Fix build failure on gcc-11
Copyediting
Clarifications around key import
Fix copypasta
A variable is unused in some configurations
Rename test_driver_keygen to test_driver_key_management
Move "internal use" sentence attached to the wrong function
Added changelog
Plug in the entry point for public key export through driver
tests: psa: Reset key attributes where needed
Improve/fix documentation
...
Adds test cases to ensure that `mbedtls_mpi_exp_mod` will return an error with
an exponent or modulus that is greater than `MBEDTLS_MPI_MAX_SIZE` in size.
Adds test cases to ensure that Diffie-Hellman will fail to make a key pair
(using `mbedtls_dhm_make_public`) when the prime modulus is greater than
`MBEDTLS_MPI_MAX_SIZE` in size.
Signed-off-by: Chris Jones <christopher.jones@arm.com>
Add a test case to ensure `mbedtls_mpi_exp_mod` fails when using a key size
larger than MBEDTLS_MPI_MAX_SIZE.
Add a test case to ensure that Diffie-Hellman operations fail when using a key
size larger than MBEDTLS_MPI_MAX_SIZE.
Signed-off-by: Chris Jones <christopher.jones@arm.com>
New tests have been added for all the hash algorithms to
confirm they compile correctly when using PSA_WANT and
accelerator guards.
Signed-off-by: John Durkop <john.durkop@fermatsoftware.com>
Add missing tag check for algorithm parameters when comparing the
signature in the description part of the cert against the actual
signature whilst loading a certificate. This was found by a
certificate (created by fuzzing) that openssl would not verify, but
mbedtls would.
Regression test added (one of the client certs modified accordingly)
Signed-off-by: Paul Elliott <paul.elliott@arm.com>
mbedtls_ctr_drbg_set_reseed_interval() and
mbedtls_hmac_drbg_set_reseed_interval() can now be called before
their seed functions and the reseed_interval value will persist.
Previously it would be overwritten with the default value.
*_drbg_reseed_interval is now set in init() and free().
mbedtls_ctr_drbg_free() and mbedtls_hmac_drbg_free() now
reset the drbg context to the state immediately after init().
Tests:
- Added test to check that DRBG reseeds when reseed_counter
reaches reseed_interval, if reseed_interval set before seed
and reseed_interval is less than MBEDTLS_CTR_DRBG_RESEED_INTERVAL.
Signed-off-by: gacquroff <gavina352@gmail.com>
Positive tests: test that the RNG has the expected size, given that we
know how many leading zeros it has because we know how the function
consumes bytes and when the test RNG produces null bytes.
Negative tests: test that if the RNG is willing to emit less than the
number of wanted bytes, the function fails.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
GCC 11 generated the warnings because the parameter `ret_buf`
was declared as `const char[10]`, but some of the arguments
provided in `run_test_snprintf` are shorter literals, like "".
Now the type of `ret_buf` is `const char *`.
Both implementations of `test_snprintf` were fixed.
Signed-off-by: Rodrigo Dias Correa <rodrigo@correas.us>
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>
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>
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>
Moved new check_crypto_config.h file from include/psa to library
directory and the file is now included from *.c instead of the
crypto_config.h file. Fixed guards in PSA crypto library based
on review comments for new PSA crypto config features.
Signed-off-by: John Durkop <john.durkop@fermatsoftware.com>
Revised the placement of various new MBEDTLS_PSA_BUILTIN_xxx
guards based on review comments. Corrected guards in psa
test driver to use _ACCEL version instead of _BUILTIN version.
Updated check_config_psa.h to include additional dependency checks
for more algorithms. Renamed some of the new tests to be a little
more clear on the purpose.
Signed-off-by: John Durkop <john.durkop@fermatsoftware.com>
For consistency across the code base, prefer
persistent over permanent to qualify a key
stored in persistent storage.
Signed-off-by: Ronald Cron <ronald.cron@arm.com>
When looking for an empty key slot to store
the description of a key, if all key slots
are in use, reuse the first encountered
and unaccessed key slot containing the
description of a permanent key.
Signed-off-by: Ronald Cron <ronald.cron@arm.com>
Add a counter of unaccessed slots and use it
in tests to check that at the end of PSA tests
all key slot are unaccessed.
Signed-off-by: Ronald Cron <ronald.cron@arm.com>
The identifier of keys created/registred should be in
the application range.
This is by spec for key creation.
This may change for registered key.
Signed-off-by: Ronald Cron <ronald.cron@arm.com>
The lifetime of key attributes now encodes whether a key is
volatile/persistent or not AND its location.
Fix PSA code where the fact that the lifetime encodes
the key location was not taken into account properly.
Fix the impacted tests and add two non regression tests.
Signed-off-by: Ronald Cron <ronald.cron@arm.com>
When key identifiers encode key owner, add tests
checking that:
. the key owner of an imported volatile key is
the one specified.
. a key identifier of a volatile key with a valid
PSA key identifier but the wrong owner is
rejected.
Signed-off-by: Ronald Cron <ronald.cron@arm.com>
Volatile key identifiers in the vendor range are
reserved to volatile keys thus don't allow them
for persistent keys when creating a key.
Signed-off-by: Ronald Cron <ronald.cron@arm.com>
For persistent keys there were two successive
INVALIDATE_BY_(CLOSING/DESTROYING) identical tests
where the comments of the second test rather
indicated that it should had been an
INVALIDATE_BY_(CLOSING/DESTROYING)_WITH_SHUTDOWN test.
Signed-off-by: Ronald Cron <ronald.cron@arm.com>
Rename ways of invalidating keys before introducing
key purging tests because the "CLOSE_BY" prefix doesn't
get on well with the purge operation.
Signed-off-by: Ronald Cron <ronald.cron@arm.com>
Code under MBEDTLS_USE_PSA_CRYPTO define is PSA client
code intended to use key identifiers of type psa_key_id_t.
Thus the MBEDTLS_PSA_CRYPTO_KEY_ID_ENCODES_OWNER
configuration option is incompatible with
MBEDTLS_USE_PSA_CRYPTO.
State this in config.h and check_config.h.
As a consequence:
. remove MBEDTLS_PSA_CRYPTO_KEY_ID_ENCODES_OWNER from
the full configuration, as MBEDTLS_USE_PSA_CRYPTO is
part of it.
. add a new component in all.sh to keep testing the
library when MBEDTLS_PSA_CRYPTO_KEY_ID_ENCODES_OWNER
is set.
Signed-off-by: Ronald Cron <ronald.cron@arm.com>
As handles are now key identifiers, a handle may be
valid now even if it does not refer to any key
known to the library.
Signed-off-by: Ronald Cron <ronald.cron@arm.com>
Define psa_key_handle_t to be equal to
mbedtls_svc_key_id_t. Make the handle of a persistent
key be equal to its key identifier. For volatile keys,
make the key handle equal to the volatile key
identifier of the created volatile key.
The unit tests are modified just to make them compile
not to make them run successfully. They are fixed in
the subsequent commits.
Signed-off-by: Ronald Cron <ronald.cron@arm.com>
Updated macros in config_psa.h that used ECC_xxx to use KEY_TYPE_ECC_xxx
per comments from review. Implemented a check_config_psa.h to help with
dependency checking of features enabled in config_psa.h. Added
check_config_psa.h to visual studio project.
Signed-off-by: John Durkop <john.durkop@fermatsoftware.com>
In order to pass existing tests like test_psa_crypto_config_basic
and test_psa_crypto_config_no_driver, all the new features need
to be enabled in the default crypto_config.h file. This change
enables those features by default and updates the other new
tests to compensate for everything being enabled by disabling
some features for some of the tests as needed.
Signed-off-by: John Durkop <john.durkop@fermatsoftware.com>
Updated some of the test names to better reflect what they are testing.
Expanded the testing around RSA feature for PSA crypto config. Updated
the test script to support backing up and restoring the
include/psa/crypto_config.h file so that features can be individually
setup for each unique feature test.
Signed-off-by: John Durkop <john.durkop@fermatsoftware.com>
In the original attempt to add RSA support to PSA crypto config was too
generic. This set of changes adds support for the following RSA features:
PSA_WANT_ALG_RSA_PKCS1V15_CRYPT, PSA_WANT_ALG_RSA_PKCS1V15_SIGN,
PSA_WANT_ALG_RSA_OAEP, PSA_WANT_ALG_RSA_PSS, PSA_WANT_KEY_TYPE_RSA_KEY_PAIR,
and PSA_WANT_KEY_TYPE_RSA_PUBLIC_KEY.
There were also some updates to ensure the proper inclusion of PSA crypto
library code when certain features are enabled. These updates were made to
address warnings and errors in builds from the new tests for these
features being added for PSA crypto configuration.
Signed-off-by: John Durkop <john.durkop@fermatsoftware.com>
The KEY_TYPE_ECC_KEY_PAIR and KEY_TYPE_ECC_PUBLIC_KEY were previously
being guarded by MBEDTLS_ECP_C in the PSA crypto library code. This change
moves it to the new MBEDTLS_PSA_BUILTIN_xxx and separates KEY_PAIR
and PUBLIC_KEY as needed. Tests have also been added to validate the new
settings.
Signed-off-by: John Durkop <john.durkop@fermatsoftware.com>
This phase adds in support for the following features being
added to the list of features that can be configured in the
include/psa/crypto_config.h header file using the PSA_WANT_ALG_xxx
macros: ECDH, HMAC, HKDF, and RSA. These changes include changes to
the PSA crypto library to use the appropriate new guards that
will allow the feature to be compiled in or out either using
new PSA_WANT_ALG_xxx or the previous MBEDTLS_xxx macros.
For HKDF and HMAC, most of the PSA library code did not have a
specific matching MBEDTLS_xxx macro for that feature, but was instead
using the generic dependent MBEDTLS_MD_C macro. The ECDH and RSA
features more closely aligned with a direct replacement with a similar
macro.
The new tests for RSA, HMAC, and HKDF would normally unset additional
dependent macros, but when attempting to implement that level of
testing it required removal of too many core features like MD_C, PK_C,
ECP_C and other low level features. This may point to additional phases of
work to complete the transition of these features to the new model.
Signed-off-by: John Durkop <john.durkop@fermatsoftware.com>
Add a build with MBEDTLS_ERROR_STRERROR_DUMMY but not MBEDTLS_ERROR_C.
Previously, both options were enabled by default, but
MBEDTLS_ERROR_STRERROR_DUMMY only matters when MBEDTLS_ERROR_C is
enabled, so its effect was not tested.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Two sample configuration file were not being tested:
config-no-entropy.h and config-psa-crypto.h. Add them.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
* zero key buffer on failure
* readability improvements
* psa_finish_key_creation adjustment after removing import_key_into_slot
Signed-off-by: Steven Cooreman <steven.cooreman@silabs.com>
Force using IPv4 in the GNU_CLI SRTP tests, as introduced for
other tests in #1918.
Signed-off-by: Johan Pascal <johan.pascal@belledonne-communications.com>
Since `gnutls-cli` resolves `localhost` as an IPv6 address, and the server
is bound to IPv4 address, gnutl-cli fails to negotiate DTLS sessions.
Force the server to bind to IPv6 address, as a workaround.
Signed-off-by: Johan Pascal <johan.pascal@belledonne-communications.com>
