Rely on Asan to detect a potential buffer overflow, instead of doing a
manual check. This makes the code simpler and Asan can detect
underflows as well as overflows.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
In the cleanup code for persistent_key_load_key_from_storage(), we
only attempt to reopen the key so that it will be deleted if it exists
at that point. It's intentional that we do nothing if psa_open_key()
fails here.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
If any of the TEST_ASSERT()s that are before the call to
mbedtls_pk_warp_as_opaque() failed, when reaching the exit label
psa_destroy_key() would be called with an uninitialized argument.
Found by Clang.
Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
* development:
Update copyright notices to use Linux Foundation guidance
Undef ASSERT before defining it to ensure that no previous definition has sneaked in through included files.
Add ChangeLog entry for X.509 CN-type vulnerability
Improve documentation of cn in x509_crt_verify()
Fix comparison between different name types
Add test: DNS names should not match IP addresses
Remove obsolete buildbot reference in compat.sh
Fix misuse of printf in shell script
Fix added proxy command when IPv6 is used
Simplify test syntax
Fix logic error in setting client port
ssl-opt.sh: include test name in log files
ssl-opt.sh: remove old buildbot-specific condition
ssl-opt.sh: add proxy to all DTLS tests
Signed-off-by: Dan Handley <dan.handley@arm.com>
The documentation of mbedtls_pk_wrap_as_opaque is quite clear:
* \param handle Output: a PSA key handle.
* It's the caller's responsibility to call
* psa_destroy_key() on that handle after calling
* mbedtls_pk_free() on the PK context.
But the test failed to call psa_destroy_key().
While at it, also use PSA_DONE(): it ensures that if we fail to destroy the
key, we'll get an explicit error message about it without the need for
valgrind.
This is a preliminary to adding a valgrind-based test for constant-flow code:
we need to make sure the rest of the tests are fully valgrind-clean, which
they weren't.
Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
The tests are supposed to be failing now (in all.sh component
test_memsan_constant_flow), but they don't as apparently MemSan doesn't
complain when the src argument of memcpy() is uninitialized, see
https://github.com/google/sanitizers/issues/1296
The next commit will add an option to test constant flow with valgrind, which
will hopefully correctly flag the current non-constant-flow implementation.
Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@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>
RFC5280 does not state that the `revocationDate` should be checked.
In addition, when no time source is available (i.e., when MBEDTLS_HAVE_TIME_DATE is not defined), `mbedtls_x509_time_is_past` always returns 0. This results in the CRL not being checked at all.
https://tools.ietf.org/html/rfc5280
Signed-off-by: Raoul Strackx <raoul.strackx@fortanix.com>
* development: (55 commits)
Log change as bugfix
Add changelog entry
Clarify updates to the persistent state in storage
With multiple applicable transparent drivers, the order is unspecified
Minor clarifications
Give some examples of purpsoses of pure-software transparent driver
Fix typos
Add a link to the PSA API specification
Explain locations vs lifetimes
Initialize key pointer in ecdh to NULL
Add buffer zeroization when ecp_write_key fails
Simplified key slot deletion
Style fixes
Use arc4random_buf instead of rand on NetBSD
Apply review feedback
Update open question section about public key storage
Remove the paragraph about declaring application needs
Change driver persistent data to a callback interface
Rework and expand key management in opaque drivers
Fix typos and copypasta
...
Since it is being dereferenced by free on exit it should be inited to NULL.
Also added a small test that would trigger the issue.
Signed-off-by: Steven Cooreman <steven.cooreman@silabs.com>
PSA Crypto was checking the byte length of a to-be-imported public ECP key
against the expected length for Weierstrass keys, forgetting that
Curve25519/Curve448 exists.
Signed-off-by: Steven Cooreman <steven.cooreman@silabs.com>
The usage of "!memcmp()" is at least not recommended
and better to use the macro dedicated for buffer
comparisons.
Signed-off-by: Ronald Cron <ronald.cron@arm.com>
The convention from the TLS RFC is a bit unusual, so even if the test
function's introductory comment mentions that we're taking the RFC's
definition, it doesn't hurt to repeat it in crucial places.
Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
Passing a length of 0 to it is perfectly acceptable, the macro was designed to
handle it correctly.
Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
We only have a single integer available for two nested loops, but the loop
sizes are small enough compared to the integer's range that we can encode both
indexes. Since the integer is displayed in decimal in case of errors, use a
power of 10 to pack the two indexes together.
Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
Currently this breaks all.sh component test_memsan_constant_flow, just as
expected, as the current implementation is not constant flow.
This will be fixed in the next commit.
Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
Everything works at the byte level, not bit level. Flipping the lsb is just
one convenient way to corrupt a byte, but don't really care about individual
bits.
Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
Add a few more negative test cases for mbedtls_x509_crl_parse.
The test data is manually adapted from the existing positive test case
"X509 CRL ASN1 (TBSCertList, sig present)" which decomposes as
305c
3047 tbsCertList TBSCertList
020100 version INTEGER OPTIONAL
300d signatureAlgorithm AlgorithmIdentifier
06092a864886f70d01010e
0500
300f issuer Name
310d300b0603550403130441424344
170c303930313031303030303030 thisUpdate Time
3014 revokedCertificates
3012 entry 1
8202abcd userCertificate CertificateSerialNumber
170c303831323331323335393539 revocationDate Time
300d signatureAlgorithm AlgorithmIdentifier
06092a864886f70d01010e
0500
03020001 signatureValue BIT STRING
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
The test function now depends on MBEDTLS_TEST_HOOKS, which is enabled by
config.py full, and since there are already components in all.sh exercising
the full config, this test function is sill exercised even with this new
dependency.
Since this is the first time a test function depends on MBEDTLS_TEST_HOOKS,
fix a bug in check-names.sh that wasn't apparent so far: headers from
library/*.h were not considered when looking for macro definitions. This
became apparent because MBEDTLS_STATIC_TESTABLE is defined in library/common.h
and started being used in library/ssl_msg.c, so was flagged as a likely typo.
Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
The dummy implementation is not constant-flow at all for now, it's just
here as a starting point and a support for developing the tests and putting
the infrastructure in place.
Depending on the implementation strategy, there might be various corner cases
depending on where the lengths fall relative to block boundaries. So it seems
safer to just test all possible lengths in a given range than to use only a
few randomly-chosen values.
Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
The ssl_tranform structure lacks some members accessed by this function when
CBC is not enabled.
This was found by test-ref-configs.pl and all.sh
test_when_no_ciphersuites_have_mac, so no need to add a new test.
Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
Started as copies of the AES block, then:
- for ARIA, just s/AES/ARIA/
- for Camellia, just s/AES/Camellia/
- for 3DES, s/AES/3DES/ then s/3DES_128_CBC/DES_EDE3_CBC/ then manually
subtract 8 to all plaintext lengths that were > 8. This accounts for the
fact that the block size of DES is 8 not 16.
Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
All started from a copy of the SHA256 block and modified as follows:
- for MD5, just s/SHA256/MD5/
- for SHA384, adapt the dependency line then s/SHA256/SHA384
- for SHA1, s/SHA256/SHA1/ then manually adapt the plaintext length for the
cases with "!trunc, B-1" and "!trunc, B", as the MAC length (20) is not a
multiple of the block size (16) for this hash
Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
- plaintext length = 0 or 1
- plaintext length + MAC length = -1 or 0 mod block_size
(using the minimum plaintext length that works)
Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
Compared to the previous approach of having the bad padding provided as input
to the testing function, this allows to test more kinds of incorrect data,
with less test cases in the .data file and more important no manually-generated
non-trivial data in the test case parameters, making it much easier to
complete the testing matrix.
Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
PSA_ALG_ECB_NO_PADDING came in to the PSA Crypto API spec v1.0.0, but
was not implemented yet in the mbed TLS implementation.
Signed-off-by: Steven Cooreman <steven.cooreman@silabs.com>
They did not match their description, probably due to a botched manual
endianness conversion where the nibbles also got swapped.
Signed-off-by: Steven Cooreman <steven.cooreman@silabs.com>
Follow the PSA Crypto specification which was updated between 1.0 beta3
and 1.0.0.
Add corresponding test cases.
Signed-off-by: Steven Cooreman <steven.cooreman@silabs.com>
mbedtls_ecp_write_key is a mirror function to mbedtls_ecp_read_key, which
writes a private key back into a byte buffer in the correct format.
This is a helpful convenience function, since the byte order is defined
differently between Montgomery and Weierstrass curves. Since this difference
is accounted for in mbedtls_ecp_read_key, it made sense to add
mbedtls_ecp_write_key for the purpose of abstracting this away such that
psa_export_key doesn't need to take byte order into account.
Signed-off-by: Steven Cooreman <steven.cooreman@silabs.com>
Rename PSA_DH_GROUP_xxx to PSA_DH_FAMILY_xxx, also rename
PSA_KEY_TYPE_GET_GROUP to PSA_KEY_TYPE_DH_GET_FAMILY and rename
psa_dh_group_t to psa_dh_family_t. Old defines are provided in
include/crypto_compat.h for backward compatibility.
Signed-off-by: Paul Elliott <paul.elliott@arm.com>
Rename PSA_ECC_CURVE_xxx to PSA_ECC_FAMILY_xxx, also rename
PSA_KEY_TYPE_GET_CURVE to PSA_KEY_TYPE_ECC_GET_FAMILY and rename
psa_ecc_curve_t to psa_ecc_family_t. Old defines are provided in
include/crypto_compat.h for backward compatibility.
Signed-off-by: Paul Elliott <paul.elliott@arm.com>
This makes the implementation of mbedtls_param_failed()
for testing purpose available to programs. Thus removing
the ad-hoc implementations in programs.
Signed-off-by: Ronald Cron <ronald.cron@arm.com>
In preparation of moving mbedtls_param_failed() to test
common code, isolate mbedtls_param_failed() long
jump data and set up from unit test data and code.
Signed-off-by: Ronald Cron <ronald.cron@arm.com>
In preparation of moving mbedtls_param_failed() to test
common code, isolate mbedtls_param_failed() call check
from unit test data.
Signed-off-by: Ronald Cron <ronald.cron@arm.com>
In preparation of moving mbedtls_param_failed() to test
common code, move mbedtls_param_failed() call location
record into a context dedicated to mbedtls_param_failed().
Signed-off-by: Ronald Cron <ronald.cron@arm.com>
Do not hexify binary data to compare them, do compare
them directly. That simplifies the check code and save
memory.
Signed-off-by: Ronald Cron <ronald.cron@arm.com>
Remove `hex` in name of variables of type data_t to reserve it
for variables of type char* that are the hexadecimal
representation of a data buffer.
Signed-off-by: Ronald Cron <ronald.cron@arm.com>
Executed "./scripts/bump_version.sh --version 2.23.0 --so-crypto 5"
A symbol has been removed from the mbedcrypto library since the last
release:
mbedtls_ecc_group_to_psa ( enum mbedtls_ecp_group_id grpid,
size_t* bits )
This is an ABI break and we need to increase the SO version.
Signed-off-by: Janos Follath <janos.follath@arm.com>
The metadata tests depend on the corresponding feature because there
is no guarantee that the metadata is correct if the feature is
disabled. There are metadata test cases for some algorithms and key
types that are declared but not supported. These test cases are
present but can never run.
It is debatable whether having these test cases is a good thing in
case they become runnable in the future, or a bad thing because
they're dead code. We're working on detecting test cases that are
never executed for accidental reasons (e.g. typo in a dependency or
missing configuration on the CI), and having test cases that are
deliberately never executed messes this up. So remove these test
cases. If we do implement the corresponding feature, it'll be easy to
add the corresponding metadata test cases.
The features that had metadata tests but no implementations were:
* SHA-512/256 and SHA-512/224 (hypothetical dependency: MBEDTLS_SHA512_256)
* DSA (hypothetical dependency: MBEDTLS_DSA_C)
* SHA-3 and HMAC-SHA-3 (hypothetical dependency: MBEDTLS_SHA3_C)
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Rework mbedtls_test_unhexify to extend its scope of usage.
Return in error when the function detects an error instead
of calling mbedtls_exit().
Improve safety by checking the output buffer is not overrun.
Signed-off-by: Ronald Cron <ronald.cron@arm.com>
In test functions calling mbedtls_test_unhexify(), change the
type of the associated parameters from `char*` to `data_t`.
That way the `unhexify` operation is done by the test
framework and not by the unit test code.
Use for the new parameters of type data_t the name of the
local variable that use to store the `unhexify` version of
the `char*` parameter.
Signed-off-by: Ronald Cron <ronald.cron@arm.com>
In preparation of changing the type of some parameters
of mbedtls_ccm_star_encrypt_and_tag/auth_decrypt from
`char *` to `data_t` to get rid of the calls to
mbedtls_test_unhexify():
- Change the name of parameters and local variables to
clarify which ones are related to the outputs of the
library functions under test and which ones are
related to the expected values of those outputs.
- Use two different buffers to store the plain and cipher
text as expected by the library functions.
Signed-off-by: Ronald Cron <ronald.cron@arm.com>
In preparation of changing the type of some parameters
of aes_encrypt_ofb() from `char *` to `data_t` to get rid
of the calls to mbedtls_test_unhexify():
- Change the name of parameters and local variables to
clarify which ones are related to the outputs of the
library functions under test and which ones are
related to the expected values of those outputs.
- Add assertion on fragment_size parameter
Signed-off-by: Ronald Cron <ronald.cron@arm.com>
In preparation of changing the type of some parameters
of mbedtls_nist_kw_wrap/unwrap() from `char *` to `data_t`
to get rid of the calls to mbedtls_test_unhexify():
- Change the name of parameters and local variables to
clarify which ones are related to the outputs of the
library functions under test and which ones are
related to the expected values of those outputs.
Signed-off-by: Ronald Cron <ronald.cron@arm.com>
In preparation of changing the type of some parameters of
test_chacha20() from `char *` to `data_t` to get rid of the
calls to mbedtls_test_unhexify():
- Reduce the size of output[] buffer to 375 as its content
is "ASCII expended" into a buffer of 751 bytes.
- Align naming of variables to store and check the
output of mbedtls_chacha20_crypt(). No *dst* variables
anynore, only *output* variables.
- Use two different buffers to store the expected output
of mbedtls_chacha20_crypt() (expected_output_str[]) and
the ASCII string representation of the output of
mbedtls_chacha20_crypt() (output_string[]). Both were
stored in dst_str[] before.
Signed-off-by: Ronald Cron <ronald.cron@arm.com>
In preparation of changing the type of some parameters
of test_hkdf() from `char *` to `data_t` to get rid of the
calls to mbedtls_test_unhexify():
- Align naming of variables related to the expected okm
- Rename `okm_hex[]` to `okm_string[]`
- Added TEST_ASSERT( expected_okm_len <= sizeof( okm ) ) to check
that the okm[] buffer is large enough for the okm output.
Signed-off-by: Ronald Cron <ronald.cron@arm.com>
In preparation of changing the type of some parameters
of some test functions from `char *` to `data_t` to get
rid of the calls to mbedtls_test_unhexify():
- Align the name of source data length local variable
with the name of the local variable containing the
source data, respectively src_str and src_str_len.
- Change the type of length, index local variables
from int to size_t.
Signed-off-by: Ronald Cron <ronald.cron@arm.com>
Pass the "certificate policies" extension to the callback supplied to
mbedtls_x509_crt_parse_der_with_ext_cb() if it contains unsupported
policies. This allows the callback to fully replicate the behaviour
of the deprecated MBEDTLS_X509_ALLOW_UNSUPPORTED_CRITICAL_EXTENSION
configuration.
Signed-off-by: Nicola Di Lieto <nicola.dilieto@gmail.com>
Another coverity bug - #350039
When this test discovers a key of the wrong type, it still throws it
through the export function in order to check that it too will detect
this as a not permitted action. For the buffer and buffer length
arguments it passes in a local pointer (which will most likely be NULL),
and the sizeof that pointer, as it knows that they will never be used.
Coverity rightly (imho) flagged this as suspicious - if we are going to
pass in incorrect parameters, at least make them obviously incorrect, and
ones that will not potentially cause errors if the code later changes.
There is, for example safety checks for zero length buffer, but less
protection for an insufficiently sized one.
Signed-off-by: Paul Elliott <paul.elliott@arm.com>
Command to find the files in which lines have gone
larger than 79 characters due to the renaming:
grep '.\{80\}' \
`git diff-tree --no-commit-id --name-only -r HEAD` \
| grep "\<mbedtls_test_rnd_"
Signed-off-by: Ronald Cron <ronald.cron@arm.com>
Command to find the files in which lines have gone
larger than 79 characters due to the renaming:
grep '.\{80\}' \
`git diff-tree --no-commit-id --name-only -r HEAD` \
| grep hexcmp
Signed-off-by: Ronald Cron <ronald.cron@arm.com>
Command to find the files in which lines have gone
larger than 79 characters due to the renaming:
grep '.\{80\}' \
`git diff-tree --no-commit-id --name-only -r HEAD` \
| grep unhexify_alloc
Signed-off-by: Ronald Cron <ronald.cron@arm.com>
Command to find the files in which lines have gone
larger than 79 characters due to the renaming:
grep '.\{80\}' \
`git diff-tree --no-commit-id --name-only -r HEAD` \
| grep hexify
Signed-off-by: Ronald Cron <ronald.cron@arm.com>
The purpose of random.c file is to contain the helper
functions to generate random numbers that have been
in helpers.function so far.
The purpose of random.h is to contain the interface
exposed by random.c thus helper function prototypes.
Signed-off-by: Ronald Cron <ronald.cron@arm.com>
The purpose of helpers.c file is to contain the helper
functions that have been in helpers.function so far and
that are not related to the mechanism of unit test
execution and not related to random number generation
(will be moved in a dedicated file).
The purpose of helpers.h is to contain the interface
exposed by helpers.c thus helper function prototypes.
Make the changes in the build systems (make and cmake)
to build helpers.c and link it to test executables
along with mbedtls library.
Signed-off-by: Ronald Cron <ronald.cron@arm.com>
Fix for coverity bugs 349041, 349052
Allocated pointers could potentially be leaked in the case of errors.
Signed-off-by: Paul Elliott <paul.elliott@arm.com>
Strict platforms cannot be expected to accept C99 code as valid
when earlier standards versions are selected.
This helps the programs build on Solaris-like platforms (e.g.
illumos).
Fixes#3420
Signed-off-by: nia <nia@netbsd.org>
Just adding an empty file. The purpose of this header
file is to contain the definition of generic macros
used for the purpose of testing.
Signed-off-by: Ronald Cron <ronald.cron@arm.com>
In preparation of moving the content of helpers.function
to its own compilation unit, remove/add static qualifiers
where appropriate.
Signed-off-by: Ronald Cron <ronald.cron@arm.com>
Create an include folder dedicated to include files for
tests. With the upcoming work on tests for PSA crypto
drivers the number of includes specific to tests is going
to increase significantly thus create a dedicated folder.
Don't put the include files in the include folder but in
include/test folder. This way test headers can be included
using a test/* path pattern as mbedtls and psa headers
are included using an mbedtls/* and psa/* path pattern.
This makes explicit the scope of the test headers.
Move the existing includes for tests into include/test and
update the code and build systems (make and cmake)
accordingly.
Signed-off-by: Ronald Cron <ronald.cron@arm.com>
Add the min/max version negotiation tests from ssl-opt.sh as unit
tests for the sake of utility and easier running of tests during
development
Signed-off-by: Paul Elliott <paul.elliott@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.
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>
TLS 1.3 and DTLS 1.2 + CID hide the real content type of a record
within the record's inner plaintext, while always using the same
content type for the protected record:
- TLS 1.3 always uses ApplicationData
- DTLS 1.2 + CID always uses a special CID content type.
This commit enhances the record encryption unit test to check
that the record content type is indeed correctly hidden.
Signed-off-by: Hanno Becker <hanno.becker@arm.com>
Now that lifetimes have structures and secure element drivers handle
all the lifetimes with a certain location, update driver registration
to take a location as argument rather than a lifetime.
This commit updates the tests.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
<stdio.h> only declares the non-ISO-C function fileno() if an
appropriate POSIX symbol is defined or if using a compiler such as GCC
in non-pedantic mode. Define the appropriate POSIX symbol.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
When parsing a certificate with the basic constraints extension
the max_pathlen that was read from it was incremented regardless
of its value. However, if the max_pathlen is equal to INT_MAX (which
is highly unlikely), an undefined behaviour would occur.
This commit adds a check to ensure that such value is not accepted
as valid. Relevant tests for INT_MAX and INT_MAX-1 are also introduced.
Certificates added in this commit were generated using the
test_suite_x509write, function test_x509_crt_check. Input data taken
from the "Certificate write check Server1 SHA1" test case, so the generated
files are like the "server1.crt", but with the "is_ca" field set to 1 and
max_pathlen as described by the file name.
Signed-off-by: Andrzej Kurek <andrzej.kurek@arm.com>
Enable MBEDTLS_X509_ALLOW_EXTENSIONS_NON_V3 in the full config. There's
no reason to keep it out. We weren't testing it at all on the CI.
Add a missing dependency on !MBEDTLS_X509_ALLOW_EXTENSIONS_NON_V3 to
some test cases that either were testing that v3 extensions are only
accepted in v3 certificates, or where parsing returns a different
error when MBEDTLS_X509_ALLOW_EXTENSIONS_NON_V3 is enabled.
Add a few positive and negative test cases with
MBEDTLS_X509_ALLOW_EXTENSIONS_NON_V3 enabled.
Fix one test case with MBEDTLS_X509_ALLOW_EXTENSIONS_NON_V3 where the
intended output of mbedtls_x509_crt_info had changed in
890819a597 but the test case was missed
because it was never executed.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
This commit introduces two changes:
- Add in_msg and out_msg calculations for buffer upsizing. This was previously
considered as unnecessary, but renegotiation using certain ciphersuites needs
this.
- Improving the way out_msg and in_msg pointers are calculated, so that even
if no resizing is introduced, the pointers remain the same;
New tests added:
- various renegotiation schemes with a range of MFL's and ciphersuites;
- an ssl-opt.sh test exercising two things that were problematic: renegotiation
with TLS-ECDHE-ECDSA-WITH-AES-128-CCM-8 and a server MFL that's smaller
than the one negotiated by the client.
Signed-off-by: Andrzej Kurek <andrzej.kurek@arm.com>
The identifiers of the unmet dependencies of a test case are
stored in a buffer of fixed size that can be potentially to
small to store all the unmet dependencies. Indicate in test
reports if some unmet dependencies are missing.
Signed-off-by: Ronald Cron <ronald.cron@arm.com>
Fix potential buffer overflow when tracking the unmet dependencies
of a test case. The identifiers of unmet dependencies are stored
in an array of fixed size. Ensure that we don't overrun the array.
Signed-off-by: Ronald Cron <ronald.cron@arm.com>
Fix an intermittent crash when running test suites in non-verbose
mode (i.e. with -v off) and with the outcome file enabled. The
array unmet_dependencies was only filled in verbose mode, but was used
in write_outcome_result regardless.
Since unmet_dependencies only ever contains strings that are integers
written out in decimal, store the integer instead. Do this
unconditionally since it doesn't cost any extra memory.
It would be better to record the dependency names, both in the verbose
output and in the outcome file. But the dependency names are not
currently available at runtime.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Conflicts:
* .github/issue_template.md, .github/pull_request_template.md:
The changes in Mbed Crypto are not relevant to Mbed TLS. Keep the
mbedtls versions.
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.
Add dependencies on !MBEDTLS_SHA512_NO_SHA384 to X.509 and SSL unit
tests that use SHA-384 (identified based on having a description that
contains "SHA384" or "SHA-384").
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}${2}/g' include/mbedtls/*.h library/*.c programs/*/*.c scripts/data_files/rename-1.3-2.0.txt tests/suites/*.function
```
Merge `unremove-non-crypto` into `mbedtls/development`. The branch
`unremove-non-crypto` was obtained by starting from `mbed-crypto/development`,
then reverting many commits that removed X.509 and TLS functionality when Mbed
Crypto forked from Mbed TLS (the “unremoval”), then make a few tweaks to
facilitate the merge.
The unremoval step restored old versions of some tls files. If a file doesn't
exist in mbed-crypto, check out the mbedtls version, regardless of what
happened during the unremoval of tls files in the crypto tree. Also
unconditionally take the mbedtls version of a few files where the
modifications are completely project-specific and are not relevant in
mbed-crypto:
* `.github/issue_template.md`: completely different. We may want to reconcile
them independently as a follow-up.
* `.travis.yml`: would only be reverted to an earlier tls version.
* `README.md`: completely different. We may want to reconcile them
independently as a follow-up.
* `doxygen/input/doc_mainpage.h`: the changes in crypto were minimal and not
relevant except as a stopgap as mbed-crypto did not have its own product
versioning in the Doxygen documentation.
* `tests/.jenkins/Jenkinsfile`: completely different.
* `tests/data_files/Makefile`: there were no changes in mbed-crypto,
but the unremoval step restored an old version.
Shell script for everything to do after the merge apart from the conflict
resolution:
```
tls_files=($(comm -23 <(git ls-tree -r --name-only HEAD) <(git ls-tree -r --name-only $(git merge-base upstream-crypto/development MERGE_HEAD))))
tls_files+=($tls_files .github/issue_template.md .travis.yml README.md doxygen/input/doc_mainpage.h tests/.jenkins/Jenkinsfile tests/data_files/Makefile)
git checkout --theirs HEAD -- $tls_files
git add -- $tls_files
```
Resolve the remaining conflicts:
* `library/CMakeLists.txt`:
* Keep the TLS definition of `src_crypto`
* `USE_SHARED_MBEDTLS_LIBRARY`: keep all three libraries, with both
`include` and `crypto/include` in `target_include_directories`, all with
version `2.21.0`.
* `programs/Makefile`:
* Reconcile the APPS lists (add/add from a differently-formatted common
ancestor): insert the `psa/*` from crypto into the tls list.
* Keep the `fuzz` target defined only in tls version.
* Keep the recipe (only in tls version) cleaning `ssl_pthread_server`
stuff for the `clean` target.
* `scripts/config.py`:
* `include_in_full`: add/add conflict. Keep both.
* `tests/scripts/all.sh`:
* `component_test_no_use_psa_crypto_full_cmake_asan`: partially old
version in crypto. Take the tls version.
* `component_test_malloc_0_null` and more: take
`component_test_malloc_0_null` from crypto (with `config.py` rather than
`config.pl`, and with `$ASAN_FLAGS` rather than an explicit list), but
add the call to `ssl-opt.sh` from tls. Take the other components from
crypto.
With this commit, building and running the unit tests with both `make ` and
`cmake` work in the default configuration on Linux. Other platforms, build
systems and configurations are likely not to work, and there is some
regression in test coverage.
There is some loss of functionality because the unremoval step restored older
versions of tls content. This commit contains the latest tls version of
tls-only files, but some changes from the tls side in files that existed on
both sides have regressed. Most problematic changes are hunks that remove some
tls-specific feature and contain either a C preprocessor symbol identifying a
tls-specific module or option, or the name of a tls-specific file. Hunks
that remove a tls-specific preprocessor symbol can be identified with the
regular expression `^-.*MBEDTLS_(ERR_)?(PKCS11|X509|NET|SSL)_`.
Subsequent commits will revert a few parts of the patch from this merge commit
in order to restore the tls functionality that it removes, ensure that the
test coverage includes what was covered in either branch, and fix test
failures.
This reverts commit 9afb2e9921.
Conflicts:
* include/CMakeLists.txt
* "Make config.h available" comment: there has been a change
adjacent to where it was removed. Just re-add what was removed.
* tests/CMakeLists.txt:
* compat.sh: there has been a change immediately before where it was
removed. Just re-add what was removed.
Counting of the fragments has been shifted from the writing section to
the reading. This is more reliable because one reading is made for one
fragment and during one write the library can internally divide data
into two fragments
Signed-off-by: Piotr Nowicki <piotr.nowicki@arm.com>
Initialize variables to NULL before doing any operations that might fail.
This fixes a case where the allocation fails on the first context, which
previously made the code free the second, uninitialized context.
Signed-off-by: Andrzej Kurek <andrzej.kurek@arm.com>
Add a conditional buffer resizing feature. Introduce tests exercising
it in various setups (serialization, renegotiation, mfl manipulations).
Signed-off-by: Andrzej Kurek <andrzej.kurek@arm.com>
Adds an additional boundary check to the test parameter bytes_arg in
generate_random() in test_suite_psa_crypto.function.
This is to check against a possible underflow, and to avoid a warning,
"argument ... exceeds maximum object size", (-Werror=alloc-size-larger-than)
that GCC 7 generates.
Signed-off-by: Simon Butcher <simon.butcher@arm.com>
Exercise the feature alone, with record splitting and DTLS connection ID.
Signed-off-by: Andrzej Kurek <andrzej.kurek@arm.com>
Signed-off-by: Darryl Green <darryl.green@arm.com>
For this test it is good to have a handshake messages length as big as
possible, so for the server the certificate verification mode is
changed from default NONE to REQUIRED. It requires the client to send
certificate date to the server during handshake
Signed-off-by: Piotr Nowicki <piotr.nowicki@arm.com>
Create and provide a structure with default options so that the caller won't have
to pass all of the parameters each time the handshake is called. In the future
this can be improved so that the options are passed as a string, just like in
ssl-opt.sh.
Signed-off-by: Andrzej Kurek <andrzej.kurek@arm.com>
(Only the top-level ones, ie, for each call to eg asn1_get_mpi(), ensure
there's at least one test case that makes this call fail in one way, but don't
test the various ways to make asn1_get_mpi fail - that should be covered
elsewhere.)
- the new checks added by the previous commits needed exercising
- existing tests sometimes had wrong descriptions or where passing for the
wrong reason (eg with the "length mismatch" test, the function actually
failed before reaching the length check)
- while at it, add tests for the rest as well
The valid minimal-size key was generated with:
openssl genrsa 128 2>/dev/null | openssl rsa -outform der 2>/dev/null | xxd -p
Files deleted by us: keep them deleted.
```
git rm $(git status -s | sed -n 's/^DU //p')
```
Individual files with conflicts:
* `README.md`: keep the crypto version.
* `doxygen/input/doc_mainpage.h`: keep the crypto version (with an obsolete Mbed Crypto version number).
* `include/mbedtls/error.h`:
* `ERROR`: similar additions made through parallel commits, with only whitespace differences. Align with the tls version.
* `library/CMakeLists.txt`: keep the crypto version.
* `library/Makefile`: keep the crypto version.
* `scripts/generate_errors.pl`: keep the crypto version (the relevant changes were made through parallel commits).
* `tests/scripts/check-test-cases.py`:
* `Results`: keep the crypto version, which has both the new argument to the constructor (added in crypto only) and the class docstring (added through parallel commits).
* `tests/suites/helpers.function`:
* `ARRAY_LENGTH`, `ASSERT_ALLOC`: additions in the same location. Keep both, in indifferent order.
* `tests/suites/target_test.function`:
* `receive_uint32`: keep the crypto version which has an additional bug fix. The tls changes made in tls are irrelevant after this bug fix.
* `visualc/VS2010/mbedTLS.vcxproj`: run `scripts/generate_visualc_files.pl`.
Review of non-conflicting changes:
* `all.sh`: 1 change.
* zlib test components: don't add them.
* `include/CMakeLists.txt`: 1 change.
* `target_include_directories`: doesn't work as is (different target name). Don't take the change.
* All other non-conflicting changes: take them.
Let the caller decide what certificates and keys are loaded (EC/RSA)
instead of loading both for the server, and an unspecified one
for the client. Use only DER encoding.
Change the encoding of key types, EC curve families and DH group
families to make the low-order bit a parity bit (with even parity).
This ensures that distinct key type values always have a Hamming
distance of at least 2, which makes it easier for implementations to
resist single bit flips.
All key types now have an encoding on 32 bits where the bottom 16 bits
are zero. Change to using 16 bits only.
Keep 32 bits for key types in storage, but move the significant
half-word from the top to the bottom.
Likewise, change EC curve and DH group families from 32 bits out of
which the top 8 and bottom 16 bits are zero, to 8 bits only.
Reorder psa_core_key_attributes_t to avoid padding.
Remove the values of curve encodings that are based on the TLS registry
and include the curve size, keeping only the new encoding that merely
encodes a curve family in 8 bits.
Keep the old constant names as aliases for the new values and
deprecate the old names.
Define constants for ECC curve families and DH group families. These
constants have 0x0000 in the lower 16 bits of the key type.
Support these constants in the implementation and in the PSA metadata
tests.
Switch the slot management and secure element driver HAL tests to the
new curve encodings. This requires SE driver code to become slightly
more clever when figuring out the bit-size of an imported EC key since
it now needs to take the data size into account.
Switch some documentation to the new encodings.
Remove the macro PSA_ECC_CURVE_BITS which can no longer be implemented.
Change the representation of psa_ecc_curve_t and psa_dh_group_t from
the IETF 16-bit encoding to a custom 24-bit encoding where the upper 8
bits represent a curve family and the lower 16 bits are the key size
in bits. Families are based on naming and mathematical similarity,
with sufficiently precise families that no two curves in a family have
the same bit size (for example SECP-R1 and SECP-R2 are two different
families).
As a consequence, the lower 16 bits of a key type value are always
either the key size or 0.
Don't rely on the bit size encoded in the PSA curve identifier, in
preparation for removing that.
For some inputs, the error code on EC key creation changes from
PSA_ERROR_INVALID_ARGUMENT to PSA_ERROR_NOT_SUPPORTED or vice versa.
There will be further such changes in subsequent commits.
Key types are now encoded through a category in the upper 4 bits (bits
28-31) and a type-within-category in the next 11 bits (bits 17-27),
with bit 16 unused and bits 0-15 only used for the EC curve or DH
group.
For symmetric keys, bits 20-22 encode the block size (0x0=stream,
0x3=8B, 0x4=16B).
psa_hash_compare is tested for good cases and invalid-signature cases
in hash_compute_compare. Also test invalid-argument cases. Also run a
few autonomous test cases with valid arguments.
Because two buffers were aliased too early in the code, it was possible that
after an allocation failure, free() would be called twice for the same pointer.
Previously mocked non-blocking read/write was returning 0 when buffer was empty/full. That was causing ERR_SSL_CONN_EOF error in tests which was using these mocked callbacks. Beside that non-blocking read/write was returning ERR_SSL_WANT_READ/_WRITE depending on block pattern set by test design. Such behavior forced to redesign of these functions so that they could be used in other tests
This error occurs when free space in the buffer is in the middle (the buffer has come full circle) and function mbedtls_test_buffer_put is called. Then the arguments for memcpy are calculated incorrectly and program ends with segmentation fault
Before, the string to parse may contain trailing garbage (there was
never more than one byte), and there was a separate argument
indicating the length of the content. Now, the string to parse is the
exact content, and the test code runs an extra test step with a
trailing byte added.
If there was a fatal error (bizarre behavior from the standard
library, or missing test data file), execute_tests did not close the
outcome file. Fix this.
Fix get_len_step when buffer_size==0. The intent of this test is to
ensure (via static or runtime buffer overflow analysis) that
mbedtls_asn1_get_len does not attempt to access beyond the end of the
buffer. When buffer_size is 0 (reached from get_len when parsing a
1-byte buffer), the buffer is buf[1..1] because allocating a 0-byte
buffer might yield a null pointer rather than a valid pointer. In this
case the end of the buffer is p==buf+1, not buf+buffer_size which is
buf+0.
The test passed because calling mbedtls_asn1_get_len(&p,end,...) with
end < p happens to work, but this is not guaranteed.
In a unit test we want to avoid accessing the network. To test the
handshake in the unit test suite we need to implement a connection
between the server and the client. This socket implementation uses
two ring buffers to mock the transport layer.
In a unit test we want to avoid accessing the network. To test the
handshake in the unit test suite we need to implement a connection
between the server and the client. This ring buffer implementation will
serve as the said connection.
The new macro ASSERT_ALLOC allocates memory with mbedtls_calloc and
fails the test if the allocation fails. It outputs a null pointer if
the requested size is 0. It is meant to replace existing calls to
mbedtls_calloc.
We're going to create some edge cases where the attributes of a key
are not bitwise identical to the attributes passed during creation.
Have a test function ready for that.
When MBEDTLS_TEST_DEPRECATED is defined, run some additional tests to
validate deprecated PSA macros. We don't need to test deprecated
features extensively, but we should at least ensure that they don't
break the build.
Add some code to component_build_deprecated in all.sh to run these
tests with MBEDTLS_DEPRECATED_WARNING enabled. The tests are also
executed when MBEDTLS_DEPRECATED_WARNING and
MBEDTLS_DEPRECATED_REMOVED are both disabled.
Rename some macros and functions related to signature which are
changing as part of the addition of psa_sign_message and
psa_verify_message.
perl -i -pe '%t = (
PSA_KEY_USAGE_SIGN => PSA_KEY_USAGE_SIGN_HASH,
PSA_KEY_USAGE_VERIFY => PSA_KEY_USAGE_VERIFY_HASH,
PSA_ASYMMETRIC_SIGNATURE_MAX_SIZE => PSA_SIGNATURE_MAX_SIZE,
PSA_ASYMMETRIC_SIGN_OUTPUT_SIZE => PSA_SIGN_OUTPUT_SIZE,
psa_asymmetric_sign => psa_sign_hash,
psa_asymmetric_verify => psa_verify_hash,
); s/\b(@{[join("|", keys %t)]})\b/$t{$1}/ge' $(git ls-files . ':!:**/crypto_compat.h')
The test suites should always run self-tests for all enabled features.
Otherwise we miss failing self-tests in CI runs, because we don't
always run the selftest program independently.
There was one spurious dependency to remove:
MBEDTLS_CTR_DRBG_USE_128_BIT_KEY for ctr_drbg, which was broken but
has now been fixed.
First deal with deleted files.
* Files deleted by us: keep them deleted.
* Files deleted by them, whether modified by us or not: keep our version.
```
git rm $(git status -s | sed -n 's/^DU //p')
git reset -- $(git status -s | sed -n 's/^D //p')
git checkout -- $(git status -s | sed -n 's/^ D //p')
git add -- $(git status -s | sed -n 's/^UD //p')
```
Individual files with conflicts:
* `3rdparty/everest/library/Hacl_Curve25519_joined.c`: spurious conflict because git mistakenly identified this file as a rename. Keep our version.
* `README.md`: conflict due to their change in a paragraph that doesn't exist in our version. Keep our version of this paragraph.
* `docs/architecture/Makefile`: near-identical additions. Adapt the definition of `all_markdown` and include the clean target.
* `doxygen/input/docs_mainpage.h`: conflict in the version number. Keep our version number.
* `include/mbedtls/config.h`: two delete/modify conflicts. Keep the removed chunks out.
* `library/CMakeLists.txt`: discard all their changes as they are not relevant.
* `library/Makefile`:
* Discard the added chunk about the crypto submodule starting with `INCLUDING_FROM_MBEDTLS:=1`.
* delete/modify: keep the removed chunk out.
* library build: This is almost delete/modify. Their changes are mostly not applicable. Do keep the `libmbedcrypto.$(DLEXT): | libmbedcrypto.a` order dependency.
* `.c.o`: `-o` was added on both sides but in a different place. Change to their place.
* `library/error.c`: to be regenerated.
* `library/version_features.c`: to be regenerated.
* `programs/Makefile`: Most of the changes are not relevant. The one relevant change is in the `clean` target for Windows; adapt it by removing `/S` from our version.
* `programs/test/query_config.c`: to be regenerated.
* `scripts/config.py`: added in parallel on both sides. Keep our version.
* `scripts/footprint.sh`: parallel changes. Keep our version.
* `scripts/generate_visualc_files.pl`: one delete/modify conflict. Keep the removed chunks out.
* `tests/Makefile`: discard all of their changes.
* `tests/scripts/all.sh`:
* `pre_initialize_variables` add `append_outcome`: add it.
* `pre_initialize_variables` add `ASAN_CFLAGS`: already there, keep our version.
* `pre_parse_command_line` add `--no-append-outcome`: add it.
* `pre_parse_command_line` add `--outcome-file`: add it.
* `pre_print_configuration`: add `MBEDTLS_TEST_OUTCOME_FILE`.
* Several changes in SSL-specific components: keep our version without them.
* Several changes where `config.pl` was changed to `config.py` and there was an adjacent difference: keep our version.
* Changes regarding the inclusion of `MBEDTLS_MEMORY_xxx`: ignore them here, they will be normalized in a subsequent commit.
* `component_test_full_cmake_gcc_asan`: add it without the TLS tests.
* `component_test_no_use_psa_crypto_full_cmake_asan`: keep the fixed `msg`, discard other changes.
* `component_test_memory_buffer_allocator_backtrace`, `component_test_memory_buffer_allocator`: add them without the TLS tests.
* `component_test_m32_everest`: added in parallel on both sides. Keep our version.
* `tests/scripts/check-names.sh`, `tests/scripts/list-enum-consts.pl`, `tests/scripts/list-identifiers.sh`, ``tests/scripts/list-macros.sh`: discard all of their changes.
* `tests/scripts/test-ref-configs.pl`: the change in the conflict is not relevant, so keep our version there.
* `visualc/VS2010/*.vcxproj`: to be regenerated.
Regenerate files:
```
scripts/generate_visualc_files.pl
git add visualc/VS2010/*.vcxproj
scripts/generate_errors.pl
git add library/error.c
scripts/generate_features.pl
git add library/version_features.c
scripts/generate_query_config.pl
git add programs/test/query_config.c
```
Rejected changes in non-conflicting files:
* `CMakeLists.txt`: discard their addition which has already been side-ported.
* `doxygen/mbedtls.doxyfile`: keep the version number change. Discard the changes related to `../crypto` paths.
Keep the following changes after examination:
* `.travis.yml`: all of their changes are relevant.
* `include/mbedtls/error.h`: do keep their changes. Even though Crypto doesn't use TLS errors, it must not encroach on TLS's allocated numbers.
* `tests/scripts/check-test-cases.py`: keep the code dealing with `ssl-opt.sh`. It works correctly when the file is not present.
In pk_sign_verify, if mbedtls_pk_sign() failed, sig_len was passed to
mbedtls_pk_verify_restartable() without having been initialized. This
worked only because in the only test case that expects signature to
fail, the verify implementation doesn't look at sig_len before failing
for the expected reason.
The value of sig_len if sign() fails is undefined, so set sig_len to
something sensible.
Add pk_write test cases where the ASN.1 INTEGER encoding of the
private value would not have the mandatory size for the OCTET STRING
that contains the value.
ec_256_long_prv.pem is a random secp256r1 private key, selected so
that the private value is >= 2^255, i.e. the top bit of the first byte
is set (which would cause the INTEGER encoding to have an extra
leading 0 byte).
ec_521_short_prv.pem is a random secp521r1 private key, selected so
that the private value is < 2^519, i.e. the first byte is 0 and the
top bit of the second byte is 0 (which would cause the INTEGER
encoding to have one less 0 byte at the start).
The corner case tests were designed for 32 and 64 bit limbs
independently and performed only on the target platform. On the other
platform they are not corner cases anymore, but we can still exercise
them.
The corner case tests were designed for 64 bit limbs and failed on 32
bit platforms because the numbers in the test ended up being stored in a
different number of limbs and the function (correctly) returnd an error
upon receiving them.
The signature of mbedtls_mpi_cmp_mpi_ct() meant to support using it in
place of mbedtls_mpi_cmp_mpi(). This meant full comparison functionality
and a signed result.
To make the function more universal and friendly to constant time
coding, we change the result type to unsigned. Theoretically, we could
encode the comparison result in an unsigned value, but it would be less
intuitive.
Therefore we won't be able to represent the result as unsigned anymore
and the functionality will be constrained to checking if the first
operand is less than the second. This is sufficient to support the
current use case and to check any relationship between MPIs.
The only drawback is that we need to call the function twice when
checking for equality, but this can be optimised later if an when it is
needed.
None of the test cases in tests_suite_memory_buffer_alloc actually
need MBEDTLS_MEMORY_DEBUG. Some have additional checks when
MBEDTLS_MEMORY_DEBUG but all are useful even without it. So enable
them all and #ifdef out the parts that require DEBUG.
The test case "Memory buffer small buffer" emits a message
"FATAL: verification of first header failed". In this test case, it's
actually expected, but it looks weird to see this message from a
passing test. Add a comment that states this explicitly, and modify
the test description to indicate that the failure is expected, and
change the test function name to be more accurate.
Fix#309
The default entropy nonce length is either zero or nonzero depending
on the desired security strength and the entropy length.
The implementation calculates the actual entropy nonce length from the
actual entropy length, and therefore it doesn't need a constant that
indicates the default entropy nonce length. A portable application may
be interested in this constant, however. And our test code could
definitely use it.
Define a constant MBEDTLS_CTR_DRBG_ENTROPY_NONCE_LEN and use it in
test code. Previously, test_suite_ctr_drbg had knowledge about the
default entropy nonce length built in and test_suite_psa_crypto_init
failed. Now both use MBEDTLS_CTR_DRBG_ENTROPY_NONCE_LEN.
This change means that the test ctr_drbg_entropy_usage no longer
validates that the default entropy nonce length is sensible. So add a
new test that checks that the default entropy length and the default
entropy nonce length are sufficient to ensure the expected security
strength.
Change the default entropy nonce length to be nonzero in some cases.
Specifically, the default nonce length is now set in such a way that
the entropy input during the initial seeding always contains enough
entropy to achieve the maximum possible security strength per
NIST SP 800-90A given the key size and entropy length.
If MBEDTLS_CTR_DRBG_ENTROPY_LEN is kept to its default value,
mbedtls_ctr_drbg_seed() now grabs extra entropy for a nonce if
MBEDTLS_CTR_DRBG_USE_128_BIT_KEY is disabled and either
MBEDTLS_ENTROPY_FORCE_SHA256 is enabled or MBEDTLS_SHA512_C is
disabled. If MBEDTLS_CTR_DRBG_USE_128_BIT_KEY is enabled, or if
the entropy module uses SHA-512, then the default value of
MBEDTLS_CTR_DRBG_ENTROPY_LEN does not require a second call to the
entropy function to achieve the maximum security strength.
This choice of default nonce size guarantees NIST compliance with the
maximum security strength while keeping backward compatibility and
performance high: in configurations that do not require grabbing more
entropy, the code will not grab more entropy than before.
