The extra code running after the removed return instruction should not generate any output. Only the read config value must be printed.
Signed-off-by: gabor-mezei-arm <gabor.mezei@arm.com>
As a result, the copyright of contributors other than Arm is now
acknowledged, and the years of publishing are no longer tracked in the
source files.
Also remove the now-redundant lines declaring that the files are part of
MbedTLS.
This commit was generated using the following script:
# ========================
#!/bin/sh
# Find files
find '(' -path './.git' -o -path './3rdparty' ')' -prune -o -type f -print | xargs sed -bi '
# Replace copyright attribution line
s/Copyright.*Arm.*/Copyright The Mbed TLS Contributors/I
# Remove redundant declaration and the preceding line
$!N
/This file is part of Mbed TLS/Id
P
D
'
# ========================
Signed-off-by: Bence Szépkúti <bence.szepkuti@arm.com>
The example application programs/ssl/ssl_client2 allows the
configuration of a client CRT through the parameters
- crt_file, key_file
However, password protected key files are not supported.
This commit adds a new command line option
- key_pwd
which allow to specify a password for the key file specified
in the key_file parameter.
The example application programs/ssl/ssl_server2 allows the
configuration of up to two CRTs through the command line
parameters
- crt_file, key_file
- crt_file2, key_file2.
However, password protected key files are not supported.
This commit adds command line options
- key_pwd
- key_pwd2
which allow to specify passwords for the key files specified
in key_file and key_file2, respectively.
Use list of executables to:
- factorize the code to define executables
- highlight the similarities and differences of the executable definitions
- avoid list duplication
Use alphabetic order for executables in lists.
Signed-off-by: Ronald Cron <ronald.cron@arm.com>
The path to source files were relative which triggered
warnings when generating the build system.
Move to absolute paths based on CMAKE_CURRENT_SOURCE_DIR.
Signed-off-by: Ronald Cron <ronald.cron@arm.com>
1. When `ssl_server2` export key functionality fails,
don't exit the server, but reset it, to have the
server recover for next connection.
2. Add text filters for `export keys functionality` test in ssl-opt.sh
to check for additional output, to verify if the export suceeded.
This was discovered in the `ssl-opt.sh` script, where the server exited,
before the test tried to kill the server priocess, resulting in a
`kill: No such process` message.
Fixes#2662
Signed-off-by: Ron Eldor <Ron.Eldor@arm.com>
Don't use string literals that are longer than 4095 bytes, which is
the minimum that C99 compilers are required to support. Compilers are
extremely likely to support longer literals, but `gcc -std=c99 -pedantic`
complains.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Since the server might want to have a different maximum fragment length
for the outgoing messages than the negotiated one - introduce a new way of
computing it. This commit also adds additional ssl-opt.sh tests ensuring
that the maximum fragment lengths are set as expected.
mbedtls_ssl_get_max_frag_len() is now a deprecated function,
being an alias to mbedtls_ssl_get_output_max_frag_len(). The behaviour
of this function is the same as before.
Signed-off-by: Andrzej Kurek <andrzej.kurek@arm.com>
Merge the latest state of the target branch (mbedtls/development) into the
pull request to merge mbed-crypto into mbedtls.
Conflicts:
* ChangeLog: add/add conflict. Resolve by using the usual section order.
Rename identifiers containing double-underscore (`__`) to avoid `__`.
The reason to avoid double-underscore is that all identifiers
containing double-underscore are reserved in C++. Rename all such
identifiers that appear in any public header, including ssl_internal.h
which is in principle private but in practice is installed with the
public headers.
This commit makes check-names.sh pass.
```
perl -i -pe 's/\bMBEDTLS_SSL__ECP_RESTARTABLE\b/MBEDTLS_SSL_ECP_RESTARTABLE_ENABLED/g; s/\bMBEDTLS_KEY_EXCHANGE_(_\w+)_(_\w+)\b/MBEDTLS_KEY_EXCHANGE${1}${2}/g' include/mbedtls/*.h library/*.c programs/*/*.c scripts/data_files/rename-1.3-2.0.txt tests/suites/*.function
```
The ssl-opt.sh test cases using session resumption tend to fail occasionally
on the CI due to a race condition in how ssl_server2 and ssl_client2 handle
the reconnection cycle.
The server does the following in order:
- S1 send application data
- S2 send a close_notify alert
- S3 close the client socket
- S4 wait for a "new connection" (actually a new datagram)
- S5 start a handshake
The client does the following in order:
- C1 wait for and read application data from the server
- C2 send a close_notify alert
- C3 close the server socket
- C4 reset session data and re-open a server socket
- C5 start a handshake
If the client has been able to send the close_notify (C2) and if has been
delivered to the server before if closes the client socket (S3), when the
server reaches S4, the datagram that we start the new connection will be the
ClientHello and everything will be fine.
However if S3 wins the race and happens before the close_notify is delivered,
in S4 the close_notify is what will be seen as the first datagram in a new
connection, and then in S5 this will rightfully be rejected as not being a
valid ClientHello and the server will close the connection (and go wait for
another one). The client will then fail to read from the socket and exit
non-zero and the ssl-opt.sh harness will correctly report this as a failure.
In order to avoid this race condition in test using ssl_client2 and
ssl_server2, this commits introduces a new command-line option
skip_close_notify to ssl_client2 and uses it in all ssl-opt.sh tests that use
session resumption with DTLS and ssl_server2.
This works because ssl_server2 knows how many messages it expects in each
direction and in what order, and closes the connection after that rather than
relying on close_notify (which is also why there was a race in the first
place).
Tests that use another server (in practice there are two of them, using
OpenSSL as a server) wouldn't work with skip_close_notify, as the server won't
close the connection until the client sends a close_notify, but for the same
reason they don't need it (there is no race between receiving close_notify and
closing as the former is the cause of the later).
An alternative approach would be to make ssl_server2 keep the connection open
until it receives a close_notify. Unfortunately it creates problems for tests
where we simulate a lossy network, as the close_notify could be lost (and the
client can't retransmit it). We could modify udp_proxy with an option to never
drop alert messages, but when TLS 1.3 comes that would no longer work as the
type of messages will be encrypted.
Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
As the SSL programs, like ssl_client2 and ssl_server2, are dependent on
SSL and therefore about to be removed, the only consumer of query_config
is the query_compile_time_config test. As such, it makes sense to move
query_config to be next to what uses it.
If `context_buf = mbedtls_calloc( 1, buf_len )` failed,
`context_buf_len` was not initialized. Noticed by
`gcc -Os -Werror=maybe-uninitialized`.
This was only a problem in ssl_server2 (a test program), only with
MBEDTLS_SSL_CONTEXT_SERIALIZATION enabled.
Make client_random and server_random const in
mbedtls_ssl_export_keys_ext_t, so that the key exporter is discouraged
from modifying the client/server hello.
Update examples and tests use const for hello.random as well, to ensure
that the export callbacks are of the proper type.
Fixes#2759
This commit adds command line options
- nss_keylog=0/1
- nss_keylog_file=FILENAME
to the example programs ssl/ssl_client2 and ssl/ssl_server2 which
allow to print and export the session keys in the NSS keylog
for debugging purposes.
* origin/pr/2803:
Add a ChangeLog entry for mbedtls_net_close()
Added mbedtls_net_close and use it in ssl_fork_server to correctly disassociate the client socket from the parent process and the server socket from the child process.
The code wants timer callbacks to be set (checked in fetch_input()), and can't
easily check whether we're using nbio, so it seems easier to require the
callbacks to be always set rather than only with nbio as was previously done.
context_buf was never free()d. Moreover, since we want to free it on error
paths as well, and even properly zeroize it in order to demonstrate good
memory hygiene, we need to make it and its length main()-scoped.
Previously it was missing reset in case 1, and in case 2 the code was never
executed as the option value was reset to 0.
Tighten checking of return values of save(NULL, 0) now that it works.
Also, improve the printed output as well as the comments.
I checked manually that everything now works and fail in the expected way:
save, reset-or-reinit and load all succeed, but the subsequent read or write
fails.
This is enabled by default as we generally enable things by default unless
there's a reason not to (experimental, deprecated, security risk).
We need a compile-time option because, even though the functions themselves
can be easily garbage-collected by the linker, implementing them will require
saving 64 bytes of Client/ServerHello.random values after the handshake, that
would otherwise not be needed, and people who don't need this feature
shouldn't have to pay the price of increased RAM usage.
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 allows callers to discover what an appropriate size is. Otherwise they'd
have to either try repeatedly, or allocate an overly large buffer (or some
combination of those).
Adapt documentation an example usage in ssl_client2.
Avoid useless copy with mbedtls_ssl_get_session() before serialising.
Used in ssl_client2 for testing and demonstrating usage, but unfortunately
that means mbedtls_ssl_get_session() is no longer tested, which will be fixed
in the next commit.
This provides basic testing for the session (de)serialisation functions, as
well as an example of how to use them.
Tested locally with tests/ssl-opt.sh -f '^Session resume'.
* origin/pr/2781:
Documentation fixes according to review
Remove unused label in ssl_client2/ssl_server2
Add missing word in documentation of mbedtls_ssl_check_record()
cli/srv ex: Add dbg msg if record checking gives inconsistent result
Fix minor issues in documentation of mbedtls_ssl_check_record()
State that record checking is DTLS only and doesn't check content type
Update version_features.c
Pass dgrams to mbedtls_ssl_check_record in ssl_client2/server2
Add IO wrappers to ssl_server2 as interm's between NET and SSL layer
Add IO wrappers to ssl_client2 as interm's between NET and SSL layer
Introduce configuration option and API for SSL record checking
This is done to account for platforms, for which we want custom behavior
upon the program termination, hence we call `mbedtls_exit()` instead of
returning from `main()`.
* origin/pr/2697:
Update crypto submodule
Add all.sh component that exercises invalid_param checks
Remove mbedtls_param_failed from programs
Make it easier to define MBEDTLS_PARAM_FAILED as assert
Make test suites compatible with #include <assert.h>
Pass -m32 to the linker as well
Don't systematically rebuild programs
* origin/pr/2681:
unconditional mbedtls_ssl_conf_rng
Adding usage and removing dummy random
comment alignment
Commit to C90 style
Adds missing ret definition
More clarity for ifdef orders
Only warns if MBEDTLS_HAVE_TIME
Option used added in string
Code review
Style fixes
SSL reproducible test mode
* origin/pr/2260:
Update crypto submodule
Remove heading spaces in tests/data_files/Makefile
Re-generate library/certs.c from script
Add new line at the end of test-ca2.key.enc
Use strict syntax to annotate origin of test data in certs.c
Add run to all.sh exercising !MBEDTLS_PEM_PARSE_C + !MBEDTLS_FS_IO
Allow DHM self test to run without MBEDTLS_PEM_PARSE_C
ssl-opt.sh: Auto-skip tests that use files if MBEDTLS_FS_IO unset
Document origin of hardcoded certificates in library/certs.c
Adapt ChangeLog
Rename server1.der to server1.crt.der
Add DER encoded files to git tree
Add build instructions to generate DER versions of CRTs and keys
Document "none" value for ca_path/ca_file in ssl_client2/ssl_server2
ssl_server2: Skip CA setup if `ca_path` or `ca_file` argument "none"
ssl_client2: Skip CA setup if `ca_path` or `ca_file` argument "none"
Correct white spaces in ssl_server2 and ssl_client2
Adapt ssl_client2 to parse DER encoded test CRTs if PEM is disabled
Adapt ssl_server2 to parse DER encoded test CRTs if PEM is disabled
All sample and test programs had a definition of mbedtls_param_failed.
This was necessary because we wanted to be able to build them in a
configuration with MBEDTLS_CHECK_PARAMS set but without a definition
of MBEDTLS_PARAM_FAILED. Now that we activate the sample definition of
MBEDTLS_PARAM_FAILED in config.h when testing with
MBEDTLS_CHECK_PARAMS set, this boilerplate code is no longer needed.
Introduce a new configuration option MBEDTLS_CHECK_PARAMS_ASSERT,
which is disabled by default. When this option is enabled,
MBEDTLS_PARAM_FAILED defaults to assert rather than to a call to
mbedtls_param_failed, and <assert.h> is included.
This fixes#2671 (no easy way to make MBEDTLS_PARAM_FAILED assert)
without breaking backward compatibility. With this change,
`config.pl full` runs tests with MBEDTLS_PARAM_FAILED set to assert,
so the tests will fail if a validation check fails, and programs don't
need to provide their own definition of mbedtls_param_failed().
This allows to test PSK-based ciphersuites via ssl_server2 in builds
which have MBEDTLS_X509_CRT_PARSE_C enabled but both MBEDTLS_FS_IO and
MBEDTLS_CERTS_C disabled.
This allows to test PSK-based ciphersuites via ssl_client2 in builds
which have MBEDTLS_X509_CRT_PARSE_C enabled but both MBEDTLS_FS_IO and
MBEDTLS_CERTS_C disabled.
A similar change is applied to the `crt_file` and `key_file` arguments.
This commit modifies the CID configuration API mbedtls_ssl_conf_cid_len()
to allow the configuration of the stack's behaviour when receiving an
encrypted DTLS record with unexpected CID.
Context:
The CID draft does not require that the length of CIDs used for incoming
records must not change in the course of a connection. Since the record
header does not contain a length field for the CID, this means that if
CIDs of varying lengths are used, the CID length must be inferred from
other aspects of the record header (such as the epoch) and/or by means
outside of the protocol, e.g. by coding its length in the CID itself.
Inferring the CID length from the record's epoch is theoretically possible
in DTLS 1.2, but it requires the information about the epoch to be present
even if the epoch is no longer used: That's because one should silently drop
records from old epochs, but not the entire datagrams to which they belong
(there might be entire flights in a single datagram, including a change of
epoch); however, in order to do so, one needs to parse the record's content
length, the position of which is only known once the CID length for the epoch
is known. In conclusion, it puts a significant burden on the implementation
to infer the CID length from the record epoch, which moreover mangles record
processing with the high-level logic of the protocol (determining which epochs
are in use in which flights, when they are changed, etc. -- this would normally
determine when we drop epochs).
Moreover, with DTLS 1.3, CIDs are no longer uniquely associated to epochs,
but every epoch may use a set of CIDs of varying lengths -- in that case,
it's even theoretically impossible to do record header parsing based on
the epoch configuration only.
We must therefore seek a way for standalone record header parsing, which
means that we must either (a) fix the CID lengths for incoming records,
or (b) allow the application-code to configure a callback to implement
an application-specific CID parsing which would somehow infer the length
of the CID from the CID itself.
Supporting multiple lengths for incoming CIDs significantly increases
complexity while, on the other hand, the restriction to a fixed CID length
for incoming CIDs (which the application controls - in contrast to the
lengths of the CIDs used when writing messages to the peer) doesn't
appear to severely limit the usefulness of the CID extension.
Therefore, the initial implementation of the CID feature will require
a fixed length for incoming CIDs, which is what this commit enforces,
in the following way:
In order to avoid a change of API in case support for variable lengths
CIDs shall be added at some point, we keep mbedtls_ssl_set_cid(), which
includes a CID length parameter, but add a new API mbedtls_ssl_conf_cid_len()
which applies to an SSL configuration, and which fixes the CID length that
any call to mbetls_ssl_set_cid() which applies to an SSL context that is bound
to the given SSL configuration must use.
While this creates a slight redundancy of parameters, it allows to
potentially add an API like mbedtls_ssl_conf_cid_len_cb() later which
could allow users to register a callback which dynamically infers the
length of a CID at record header parsing time, without changing the
rest of the API.
Resolve conflicts by performing the following:
- Ensure calls to mbedtls_x509_crt_verify_* are made with callbacks
* origin/pr/2539:
Make CRT callback tests more robust
Rename constant in client2.c
Fix typo
Add test for configuration specific CRT callback
Fix doxygen documentation of mbedtls_ssl_set_verify()
Add test exercising context-specific CRT callback to ssl-opt.sh
Add cmd to use context-specific CRT callback in ssl_client2
Implement context-specific verification callbacks
Add context-specific CRT verification callbacks
Improve documentation of mbedtls_ssl_conf_verify()
* origin/pr/2532: (29 commits)
Document and test flags in x509_verify
Fix style issues and a typo
Fix name to function call
Address comments for x509 tests
Address review comments regarding ssl_client2 and ssl tests
Remove mbedtls_ from the static function name
Change docs according to review comments
Change the verify function naming
Fix ssl_client2 and ssl_server2 if !PLATFORM_C
Correct placement of usage macro in ssl_client2
Update version_features.c
Remove trailing whitespace in test_suite_x509parse.function
Update query_config.c
Add ssl-opt.sh tests for trusted CA callbacks
Only run X.509 CRT verification tests with CA callback tests if !CRL
Minor fixes to CA callback tests
Declare CA callback type even if feature is disabled
Implement X.509 CRT verification using CA callback
Add prototype for CRT verification with static and dynamic CA list
Make use of CA callback if present when verifying peer CRT chain
...
The CA callback changes introduce mbedtls_calloc() and
mbedtls_free() to ssl_client2 and ssl_server2, which
wasn't defined unless MBEDTLS_PLATFORM_C was set.
Ensure this merge passes tests by auto-generating query_config.c, adding
MBEDTLS_ECDH_LEGACY_CONTEXT to it.
* restricted/pr/552:
Fix mbedtls_ecdh_get_params with new ECDH context
Test undefining MBEDTLS_ECDH_LEGACY_CONTEXT in all.sh
Define MBEDTLS_ECDH_LEGACY_CONTEXT in config.h
Add changelog entry for mbedtls_ecdh_get_params robustness
Fix ecdh_get_params with mismatching group
Add test case for ecdh_get_params with mismatching group
Add test case for ecdh_calc_secret
Fix typo in documentation
Update the crypto submodule to the top of the Mbed Crypto development
branch. This brings in a version of Mbed Crypto that enables building
Mbed Crypto tests that depend on private headers, like
'psa_crypto_invasive.h'.
This also requires updating our config.h to include new configuration
options added to Mbed Crypto. MBEDTLS_PSA_ITS_FILE_C replaces
MBEDTLS_PSA_CRYPTO_STORAGE_FILE_C and MBEDTLS_PSA_CRYPTO_STORAGE_ITS_C.
MBEDTLS_PSA_INJECT_ENTROPY replaces MBEDTLS_PSA_HAS_ITS_IO.
* public/pr/2421: (68 commits)
Fix unused variable warning in ssl_parse_certificate_coordinate()
Add missing compile time guard in ssl_client2
Update programs/ssl/query_config.c
ssl_client2: Reset peer CRT info string on reconnect
Add further debug statements on assertion failures
Fix typo in documentation of ssl_parse_certificate_chain()
Add debug output in case of assertion failure
Fix typo in SSL ticket documentation
Add config sanity check for !MBEDTLS_SSL_KEEP_PEER_CERTIFICATE
ssl_client2: Zeroize peer CRT info buffer when reconnecting
Reintroduce numerous ssl-opt.sh tests if !MBEDTLS_SSL_KEEP_PEER_CERT
ssl_client2: Extract peer CRT info from verification callback
Improve documentation of mbedtls_ssl_get_peer_cert()
Improve documentation of MBEDTLS_SSL_KEEP_PEER_CERTIFICATE
Fix indentation of Doxygen comment in ssl_internal.h
Set peer CRT length only after successful allocation
Remove question in comment about verify flags on cli vs. server
Remove misleading and redundant guard around restartable ECC field
Add test for !MBEDTLS_SSL_KEEP_PEER_CERTIFICATE to all.sh
Free peer CRT chain immediately after verifying it
...
So far, `ssl_client2` printed the CRT info for the peer's CRT
by requesting the latter through `mbedtls_ssl_get_peer_cert()`
at the end of the handshake, and printing it via
`mbedtls_x509_crt_info()`. When `MBEDTLS_SSL_KEEP_PEER_CERTIFICATE`
is disabled, this does no longer work because the peer's CRT
isn't stored beyond the handshake.
This makes some tests in `ssl-opt.sh` fail which rely on the CRT
info output for the peer certificate.
This commit modifies `ssl_client2` to extract the peer CRT info
from the verification callback, which is always called at a time
when the peer's CRT is available. This way, the peer's CRT info
is still printed if `MBEDTLS_SSL_KEEP_PEER_CERTIFICATE` is disabled.
Additional work done as part of merge:
- Run ./tests/scripts/check-generated-files.sh and check in the
resulting changes to programs/ssl/query_config.c
This commit improves hygiene and formatting of macro definitions
throughout the library. Specifically:
- It adds brackets around parameters to avoid unintended
interpretation of arguments, e.g. due to operator precedence.
- It adds uses of the `do { ... } while( 0 )` idiom for macros that
can be used as commands.
Additional changes to temporarily enable running tests:
ssl_srv.c and test_suite_ecdh use mbedtls_ecp_group_load instead of
mbedtls_ecdh_setup
test_suite_ctr_drbg uses mbedtls_ctr_drbg_update instead of
mbedtls_ctr_drbg_update_ret
The previous prototype gave warnings are the strings produced by #cond and
__FILE__ are const, so we shouldn't implicitly cast them to non-const.
While at it modifying most example programs:
- include the header that has the function declaration, so that the definition
can be checked to match by the compiler
- fix whitespace
- make it work even if PLATFORM_C is not defined:
- CHECK_PARAMS is not documented as depending on PLATFORM_C and there is
no reason why it should
- so, remove the corresponding #if defined in each program...
- and add missing #defines for mbedtls_exit when needed
The result has been tested (make all test with -Werror) with the following
configurations:
- full with CHECK_PARAMS with PLATFORM_C
- full with CHECK_PARAMS without PLATFORM_C
- full without CHECK_PARAMS without PLATFORM_C
- full without CHECK_PARAMS with PLATFORM_C
Additionally, it has been manually tested that adding
mbedtls_aes_init( NULL );
near the normal call to mbedtls_aes_init() in programs/aes/aescrypt2.c has the
expected effect when running the program.
The sample programs require an additional handler function of
mbedtls_param_failed() to handle any failed parameter validation checks enabled
by the MBEDTLS_CHECK_PARAMS config.h option.
Otherwise, if `mbedtls_psa_get_free_key_slot()` fails to find a fresh
key slot, the slot value will be undefined, and the call to
`psa_destroy_key()` at the end of `main()` is undefined behavior.
Previously, command line arguments `psk_slot` and `psk_list_slot`
could be used to indicate the PSA key slots that the example
applications should use to store the PSK(s) provided.
This commit changes this approach to use the utility function
`mbedtls_psa_get_free_key_slot()` to obtain free key slots from
the PSA Crypto implementation automatically, so that users only
need to pass boolean flags `psk_opaque` and `psk_list_opaque`
on the command line to enable / disable PSA-based opaque PSKs.
This commit adds command line parameters `psk_slot` and `psk_list_slot`
to the example application `programs/ssl/ssl_server2`. These have the
following semantics:
- `psk_slot`: The same semantics as for the `ssl_client2` example
application. That is, if a PSK is configured through the use
of the command line parameters `psk` and `psk_identity`, then
`psk_slot=X` can be used to import the PSK into PSA key slot X
and registering it statically with the SSL configuration through
the new API call mbedtls_ssl_conf_hs_opaque().
- `psk_list_slot`: In addition to the static PSK registered in the
the SSL configuration, servers can register a callback for picking
the PSK corresponding to the PSK identity that the client chose.
The `ssl_server2` example application uses such a callback to select
the PSK from a list of PSKs + Identities provided through the
command line parameter `psk_list`, and to register the selected
PSK via `mbedtls_ssl_set_hs_psk()`. In this case, the new parameter
`psk_list_slot=X` has the effect of registering all PSKs provided in
in `psk_list` as PSA keys in the key slots starting from slot `X`,
and having the PSK selection callback register the chosen PSK
through the new API function `mbedtls_ssl_set_hs_psk_opaque()`.
This commit adds support for the use of PSA-based opaque PSKs
in the TLS client example application programs/ssl/ssl_client2.
Specifically, a numerical command line option `psk_slot` with
the following constraints and semantics is added:
- It can only be used alongside the provisioning of a raw PSK
through the preexisting `psk` command line option.
- It can only be used if both TLS 1.2 and a PSK-only ciphersuite
are enforced through the appropriate use of the `min_version`
and `force_ciphersuite` command line options.
- If the previous conditions are met, setting `psk_slot=d` will
result in the PSA key slot with identifier `d` being populated
with the raw PSK data specified through the `psk` parameter
and passed to Mbed TLS via `mbedtls_ssl_conf_psk_opaque()`
prior to the handshake.
Enforcing the TLS version and ciphersuite is necessary to determine
the exact KDF algorithm the PSK will be used for. This is required
as it is currently not possible to set up a key without specifying
exactly one algorithm the key may be used with.
