According to SP800-90A, the DRBG seeding process should use a nonce
of length `security_strength / 2` bits as part of the DRBG seed. It
further notes that this nonce may be drawn from the same source of
entropy that is used for the first `security_strength` bits of the
DRBG seed. The present HMAC DRBG implementation does that, requesting
`security_strength * 3 / 2` bits of entropy from the configured entropy
source in total to form the initial part of the DRBG seed.
However, some entropy sources may have thresholds in terms of how much
entropy they can provide in a single call to their entropy gathering
function which may be exceeded by the present HMAC DRBG implementation
even if the threshold is not smaller than `security_strength` bits.
Specifically, this is the case for our own entropy module implementation
which only allows requesting at most 32 Bytes of entropy at a time
in configurations disabling SHA-512, and this leads to runtime failure
of HMAC DRBG when used with Mbed Crypto' own entropy callbacks in such
configurations.
This commit fixes this by splitting the seed entropy acquisition into
two calls, one requesting `security_strength` bits first, and another
one requesting `security_strength / 2` bits for the nonce.
Fixes#237.
* mbedtls-2.16: (21 commits)
Exclude DTLS 1.2 only with older OpenSSL
Document the rationale for the armel build
Switch armel build to -Os
Add a build on ARMv5TE in ARM mode
Add changelog entry for ARM assembly fix
bn_mul.h: require at least ARMv6 to enable the ARM DSP code
Changelog entry for test certificates update
Change worktree_rev to HEAD for rev-parse
Add ChangeLog entry for entropy_nv_seed test case fix
entropy_nv_seed: cope with SHA-256
entropy_nv_seed: clean up properly
Add ChangeLog entry for undefined behavior fix in test_suite_nist_kw
Don't call memset after calloc
Adapt ChangeLog
ECP restart: Don't calculate address of sub ctx if ctx is NULL
Update certificates to expire in 2029
Update soon to be expired crl
Test that a shared library build produces a dynamically linked executable
Test that the shared library build with CMake works
Add a test of MBEDTLS_CONFIG_FILE
...
The NO_INLINE annotation of tls_prf_sha256() and tls_prf_sha384() from
the last commit surprisingly had an influence on ARMC5 compilation in
that tls_prf_generic() was no longer automatically inlined into
tls_prf_sha256() if only the latter was enabled (and is the point
where tls_prf_generic() is called). This commit forces inlining
of tls_prf_generic() in this case.
Usually, compilers are clever enough to pick the best inlining
strategy, but in this instance, it appears that compiling on ARMC6,
the compilers inlines xxx_prf_yyy() and xxx_calc_finished_yyy()
even though it really shouldn't. Forbid inlining through the use
of __attribute__((noinline)).
Somehow, at least ARMC5 isn't able to recognize this automatically.
Since some of the arguments to ssl_populate_transform() are compile-
time constants in reduced configurations, inlining leads to slightly
shorter code.
This saves a few bytes in configurations where only one hash
is enabled, and configurations allowing multiple hashes probably
don't care about code-size anyway.
This function is called on client-only once the ciphersuite has
been chosen and it it is known which digest the client will need
for the handshake transcript throughout the handshake, and causes
all other unneeded handshake transcripts to be discontinued.
(On the server, we cannot call this function because we don't know
which hash the client will those in its CertificateVerify message).
However, the benefit of this call is marginal, since transcript hash
computation is negligible compared to asymmetric crypto, and moreover
the handshake transcript contexts for the unused digests are still
stored in the SSL handshake parameter structure and not freed until
the end of the handshake.
Finally, if we're running on a _really_ constrained client, there
will be only one hash function enabled anyway, and in this case
the checksum optimization has no effect.
This commit therefore removes checksum optimization altogether,
saving some code on constrained systems.
- a comment regarding the implementation of hmac_drbg_reseed_core()
was misplaced.
- add more references to the standard, and add details on how the
comments in the code refer to various parts of the standard.
Now function mbedtls_ssl_set_hostname is compile-time configurable
in config.h with define MBEDTLS_X509_REMOVE_HOSTNAME_VERIFICATION.
This affects to many x509 API's. See config.h for details.
ssl_client2 and ssl_server2 either allow loading specific CRTs
and CAs from files, or to leave them unspecified, in which case
they're automatically picked from the test certificates.
The test certificates should be chosen in a way that when
not specifying any CRT or CA parameters, the automatically
chosen ones match - but if one of them is specified but not
the other, one should not expect tests to succeed.
With the recent switch to Secp256r1-based test certificates,
the default test certificates have changed, which breaks some
ssl-opt.sh tests which specify the server CRT explicitly but
not the client trusted CAs.
This commit fixes this by specifying the client's trusted CA
explicitly in accordance with the explicitly specified server CRT.
According to SP800-90A, the DRBG seeding process should use a nonce
of length `security_strength / 2` bits as part of the DRBG seed. It
further notes that this nonce may be drawn from the same source of
entropy that is used for the first `security_strength` bits of the
DRBG seed. The present HMAC DRBG implementation does that, requesting
`security_strength * 3 / 2` bits of entropy from the configured entropy
source in total to form the initial part of the DRBG seed.
However, some entropy sources may have thresholds in terms of how much
entropy they can provide in a single call to their entropy gathering
function which may be exceeded by the present HMAC DRBG implementation
even if the threshold is not smaller than `security_strength` bits.
Specifically, this is the case for our own entropy module implementation
which only allows requesting at most 32 Bytes of entropy at a time
in configurations disabling SHA-512, and this leads to runtime failure
of HMAC DRBG when used with Mbed TLS' own entropy callbacks in such
configurations.
This commit fixes this by splitting the seed entropy acquisition into
two calls, one requesting `security_strength` bits first, and another
one requesting `security_strength / 2` bits for the nonce.
Previously, configs/baremetal_test.h added MBEDTLS_ECP_DP_SECP384R1_ENABLED
because we didn't have sufficient test certificates using Secp256r1. Now that
these test certificates have been added, we can successfully run
ssl_client2 and ssl_server2 with just Secp256r1 enabled.
This commit adds the script scripts/generate_certs.sh which
parses library/certs.c and inserts certificate and key files
for any block of the form
/* BEGIN FILE [string|binary] [variable|macro] NAME FILE */
...
/* END FILE */
Here, the first argument string / binary indicates whether the
file should be inserted as a string or as a binary array. The
second argument indicates whether the resulting object should
be registered as a C variable or a macro.
This script allows to easily update certs.c in case any of the
test certificates from tests/data_files change, or new test
certificates / keys need to be added.
One test for running with MBEDTLS_ECDH_C on and one
for running MBEDTLS_ECDH_C off. Run ssl-opt.sh with Default, DTLS
and compatibility tests with TLS-ECDHE-ECDSA-WITH-AES-256-CBC-SHA.
compat.sh used to skip OpenSSL altogether for DTLS 1.2, because older
versions of OpenSSL didn't support it. But these days it is supported.
We don't want to use DTLS 1.2 with OpenSSL unconditionally, because we
still use legacy versions of OpenSSL to test with legacy ciphers. So
check whether the version we're using supports it.
