The documentation of CTR_DRBG erroneously claimed that
mbedtls_ctr_drbg_set_entropy_len() had an impact on the initial
seeding. This is in fact not the case: mbedtls_ctr_drbg_seed() forces
the initial seeding to grab MBEDTLS_CTR_DRBG_ENTROPY_LEN bytes of
entropy. Fix the documentation and rewrite the discussion of the
entropy length and the security strength accordingly.
Explain how MBEDTLS_CTR_DRBG_ENTROPY_LEN is set next to the security
strength statement, rather than giving a partial explanation (current
setting only) in the documentation of MBEDTLS_CTR_DRBG_ENTROPY_LEN.
NIST and many other sources call it a "personalization string", and
certainly not "device-specific identifiers" which is actually somewhat
misleading since this is just one of many things that might go into a
personalization string.
Improve the formatting and writing of the documentation based on what
had been done for CTR_DRBG.
Document the maximum size and nullability of some buffer parameters.
Document that a derivation function is used.
Document the security strength of the DRBG depending on the
compile-time configuration and how it is set up. In particular,
document how the nonce specified in SP 800-90A is set.
Mention how to link the ctr_drbg module with the entropy module.
* State explicit whether several numbers are in bits or bytes.
* Clarify whether buffer pointer parameters can be NULL.
* Explain the value of constants that are dependent on the configuration.
Alternative implementations are often hardware accelerators and might
not need an RNG for blinding. But if they do, then we make them misuse
the RNG in the deterministic case.
There are several way around this:
- Exposing a lower level function for replacement. This would be the
optimal solution, but litters the API and is not backward compatible.
- Introducing a new compile time option for replacing the deterministic
function. This would mostly cover the same code as
MBEDTLS_ECDSA_DETERMINISTIC and would be yet another compile time flag.
- Reusing the existing MBEDTLS_ECDSA_DETERMINISTIC macro. This changes
the algorithm used by the PK layer from deterministic to randomised if
the alternative implementation is present.
This commit implements the third option. This is a temporary solution
and should be fixed at the next device driver API change.
The current interface does not allow passing an RNG, which is needed for
blinding. Using the scheme's internal HMAC-DRBG results the same
blinding values for the same key and message, diminishing the
effectiveness of the countermeasure. A new function
`mbedtls_ecdsa_det_ext` is available to address this problem.
`mbedtls_ecdsa_sign_det` reuses the internal HMAC-DRBG instance to
implement blinding. The advantage of this is that the algorithm is
deterministic too, not just the resulting signature. The drawback is
that the blinding is always the same for the same key and message.
This diminishes the efficiency of blinding and leaks information about
the private key.
A function that takes external randomness fixes this weakness.
x0-x3 are skipped such that function parameters to not have to be moved.
MULADDC_INIT and MULADDC_STOP are mostly empty because it is more
efficient to keep everything in registers (and that should easily be
possible). I considered a MULADDC_HUIT implementation, but could not
think of something that would be more efficient than basically 8
consecutive MULADDC_CORE. You could combine the loads and stores, but
it's probably more efficient to interleave them with arithmetic,
depending on the specific microarchitecture. NEON allows to do a
64x64->128 bit multiplication (and optional accumulation) in one
instruction, but is not great at handling carries.
Document that a curve returned by mbedtls_ecp_curve_list() or
mbedtls_ecp_grp_id_list() may lack support for ECDH or ECDSA.
Add a corresponding changelog entry, under "API Changes" because we
have changed the behavior: formerly, these functions skipped ECDH-only
curves, although this was not documented.
* crypto/pr/212: (337 commits)
Make TODO comments consistent
Fix PSA tests
Fix psa_generate_random for >1024 bytes
Add tests to generate more random than MBEDTLS_CTR_DRBG_MAX_REQUEST
Fix double free in psa_generate_key when psa_generate_random fails
Fix copypasta in test data
Avoid a lowercase letter in a macro name
Correct some comments
Fix PSA init/deinit in mbedtls_xxx tests when using PSA
Make psa_calculate_key_bits return psa_key_bits_t
Adjust secure element code to the new ITS interface
More refactoring: consolidate attribute validation
Fix policy validity check on key creation.
Add test function for import with a bad policy
Test key creation with an invalid type (0 and nonzero)
Remove "allocated" flag from key slots
Take advantage of psa_core_key_attributes_t internally #2
Store the key size in the slot in memory
Take advantage of psa_core_key_attributes_t internally: key loading
Switch storage functions over to psa_core_key_attributes_t
...
Resolve conflicts by performing the following actions:
- Reject changes to ChangeLog, as Mbed Crypto doesn't have one
- Reject changes to tests/compat.sh, as Mbed Crypto doesn't have it
- Reject changes to programs/fuzz/onefile.c, as Mbed Crypto doesn't have
it
- Resolve minor whitespace differences in library/ecdsa.c by taking the
version from Mbed TLS upstream.
* origin/development:
Honor MBEDTLS_CONFIG_FILE in fuzz tests
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
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
Adapt ChangeLog
ECP restart: Don't calculate address of sub ctx if ctx is NULL
Commit 16b1bd89326e "bn_mul.h: add ARM DSP optimized MULADDC code"
added some ARM DSP instructions that was assumed to always be available
when __ARM_FEATURE_DSP is defined to 1. Unfortunately it appears that
the ARMv5TE architecture (GCC flag -march=armv5te) supports the DSP
instructions, but only in Thumb mode and not in ARM mode, despite
defining __ARM_FEATURE_DSP in both cases.
This patch fixes the build issue by requiring at least ARMv6 in addition
to the DSP feature.
Conflict resolution:
* `scripts/config.pl`:
Take the exclusion of `MBEDTLS_PSA_CRYPTO_SE_C` from the API branch.
Take the removal of `MBEDTLS_PSA_CRYPTO_STORAGE_ITS_C` (obsolete) from
the development branch.
* `tests/scripts/all.sh`:
Multiple instances of factoring a sequence of `config.pl` calls into
a mere `config.pl baremetal` in the development branch, and a change in
the composition of `baremetal` in the API branch. In each case, take the
version from development.
* `tests/suites/test_suite_psa_crypto_slot_management.function`:
A function became non-static in development and disappeared in the API
branch. Keep the version from the API branch. Functions need to be
non-static if they're defined but unused in some configurations,
which is not the case for any function in this file at the moment.
* `tests/suites/test_suite_psa_crypto.function`:
Consecutive changes in the two branches, reconciled.
Resolve conflicts by performing the following operations:
- Reject changes related to building a crypto submodule, since Mbed
Crypto is the crypto submodule.
- Reject X.509, NET, and SSL changes.
- Reject changes to README, as Mbed Crypto is a different project from
Mbed TLS, with a different README.
- Avoid adding mention of ssl-opt.sh in a comment near some modified
code in include/CMakeLists.txt (around where ENABLE_TESTING as added).
- Align config.pl in Mbed TLS with config.pl in Mbed Crypto where PSA
options are concerned, to make future merging easier. There is no
reason for the two to be different in this regard, now that Mbed TLS
always depends on Mbed Crypto. Remaining differences are only the
PSA_CRYPTO_KEY_FILE_ID_ENCODES_OWNER option and the absence of X.509,
NET, and SSL related options in Mbed Crypto's config.pl.
- Align config.h in Mbed Crypto with Mbed TLS's copy, with a few notable
exceptions:
- Leave CMAC on by default.
- Leave storage on by default (including ITS emulation).
- Avoid documenting the PSA Crypto API as is in beta stage in
documentation for MBEDTLS_PSA_CRYPTO_C.
The only remaining differences are a lack of X.509, NET, and SSL
options in Mbed Crypto's config.h, as well as an additional
Mbed-Crypto-specific PSA_CRYPTO_KEY_FILE_ID_ENCODES_OWNER option.
Documentation for the check params feature and related macros is also
updated to match Mbed TLS's description.
- Reject tests/data_files/Makefile changes to generate DER versions of
CRTs and keys, as none of those are used by Mbed Crypto tests.
- Add the "no PEM and no filesystem" test to all.sh, without ssl-opt.sh
run, as Mbed Crypto doesn't have ssl-opt.sh. Also remove use of PSA
Crypto storage and ITS emulation, since those depend on filesystem
support.
- Reject addition of test when no ciphersuites have MAC to all.sh, as
the option being tested, MBEDTLS_SSL_SOME_MODES_USE_MAC, is not
present in Mbed Crypto.
- Use baremetal config in all.sh, as Mbed Crypto's baremetal
configuration does exclude the net module (as it doesn't exist in Mbed
Crypto)
- Reject cmake_subproject_build changes, continuing to link only
libmbedcrypto.
- Reject changes to visualc and associated templates. Mbed Crypto
doesn't need additional logic to handle submodule-sourced headers.
- Avoid adding fuzzers from Mbed TLS. The only relevant fuzzers are the
privkey and pubkey fuzzers, but non-trivial work would be required to
integrate those into Mbed Crypto (more than is comfortable in a merge
commit).
- Reject addition of Docker wrappers for compat.sh and ssl-opt.sh, as
those are not present in Mbed Crypto.
- Remove calls to SSL-related scripts from basic-in-docker.sh
Fix test errors by performing the following:
- Avoid using a link that Doxygen can't seem to resolve in Mbed Crypto,
but can resolve in Mbed TLS. In documentation for
MBEDTLS_CHECK_PARAMS, don't attempt to link to MBEDTLS_PARAM_FAILED.
* origin/development: (339 commits)
Do not build fuzz on windows
No booleans and import config
Removing space before opening parenthesis
Style corrections
Syntax fix
Fixes warnings from MSVC
Add a linker flag to enable gcov in basic-build-test.sh
Update crypto submodule to a revision with the HAVEGE header changes
Test with MBEDTLS_ECP_RESTARTABLE
Allow TODO in code
Use the docstring in the command line help
Split _abi_compliance_command into smaller functions
Record the commits that were compared
Document how to build the typical argument for -s
Allow running /somewhere/else/path/to/abi_check.py
tests: Limit each log to 10 GiB
Warn if VLAs are used
Remove redundant compiler flag
Consistently spell -Wextra
Fix parsing issue when int parameter is in base 16
...
Secure element support is not yet usable in the real world. Only part
of the feature is implemented and the part that's implemented is not
sufficient for real-world uses. A lot of error handling is missing,
and there are no tests.
This commit should be reverted once the feature has stabilized.
