We were still reusing the internal HMAC-DRBG of the deterministic ECDSA
for blinding. This meant that with cryptographically low likelyhood the
result was not the same signature as the one the deterministic ECDSA
algorithm has to produce (however it is still a valid ECDSA signature).
To correct this we seed a second HMAC-DRBG with the same seed to restore
correct behavior. We also apply a label to avoid reusing the bits of the
ephemeral key for a different purpose and reduce the chance that they
leak.
This workaround can't be implemented in the restartable case without
penalising the case where external RNG is available or completely
defeating the purpose of the restartable feature, therefore in this case
the small chance of incorrect behavior remains.
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.
* crypto/development: (863 commits)
crypto_platform: Fix typo
des: Reduce number of self-test iterations
Fix -O0 build for Aarch64 bignum multiplication.
Make GNUC-compatible compilers use the right mbedtls_t_udbl again on Aarch64 builds.
Add optimized bignum multiplication for Aarch64.
Enable 64-bit limbs for all Aarch64 builds.
HMAC DRBG: Split entropy-gathering requests to reduce request sizes
psa: Use application key ID where necessary
psa: Adapt set_key_id() for when owner is included
psa: Add PSA_KEY_ID_INIT
psa: Don't duplicate policy initializer
crypto_extra: Use const seed for entropy injection
getting_started: Update for PSA Crypto API 1.0b3
Editorial fixes.
Cross reference 'key handles' from INVALID_HANDLE
Update documentation for psa_destroy_key
Update documentation for psa_close_key
Update psa_open_key documentation
Remove duplicated information in psa_open_key
Initialize key bits to max size + 1 in psa_import_key
...
* origin/development:
Fix uninitialized variable in x509_crt
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.
Add ChangeLog entry
fix memory leak in mpi_miller_rabin()
* 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.
* origin/development: (42 commits)
Handle deleting non-existant files on Windows
Update submodule
Use 3rdparty headers from the submodule
Add Everest components to all.sh
3rdparty: Add config checks for Everest
Fix macros in benchmark.c
Update generated files
3rdparty: Fix inclusion order of CMakeLists.txt
Fix trailing whitespace
ECDH: Fix inclusion of platform.h for proper use of MBEDTLS_ERR_PLATFORM_FEATURE_UNSUPPORTED
ECDH: Fix use of ECDH API in full handshake benchmark
ECDH: Removed unnecessary calls to mbedtls_ecp_group_load in ECDH benchmark
ECDH: Fix Everest x25519 make_public
Fix file permissions
3rdparty: Rename THIRDPARTY_OBJECTS
3rdparty: Update description of MBEDTLS_ECDH_VARIANT_EVEREST_ENABLED
3rdparty: Fix Makefile coding conventions
ECDSA: Refactor return value checks for mbedtls_ecdsa_can_do
Add a changelog entry for Everest ECDH (X25519)
Document that curve lists can include partially-supported curves
...
Manually edit ChangeLog to ensure correct placement of ChangeLog notes.
* origin/pr/2799: (42 commits)
Handle deleting non-existant files on Windows
Update submodule
Use 3rdparty headers from the submodule
Add Everest components to all.sh
3rdparty: Add config checks for Everest
Fix macros in benchmark.c
Update generated files
3rdparty: Fix inclusion order of CMakeLists.txt
Fix trailing whitespace
ECDH: Fix inclusion of platform.h for proper use of MBEDTLS_ERR_PLATFORM_FEATURE_UNSUPPORTED
ECDH: Fix use of ECDH API in full handshake benchmark
ECDH: Removed unnecessary calls to mbedtls_ecp_group_load in ECDH benchmark
ECDH: Fix Everest x25519 make_public
Fix file permissions
3rdparty: Rename THIRDPARTY_OBJECTS
3rdparty: Update description of MBEDTLS_ECDH_VARIANT_EVEREST_ENABLED
3rdparty: Fix Makefile coding conventions
ECDSA: Refactor return value checks for mbedtls_ecdsa_can_do
Add a changelog entry for Everest ECDH (X25519)
Document that curve lists can include partially-supported curves
...
If we try to delete a non-existant file using del on Windows, as
can happen when running make clean, del will throw an error. Make
the Makefiles more robust by only deleting files if they exist.
This patch fixes an issue we encountered with more stringent compiler
warnings. The signature_is_good variable has a possibility of being
used uninitialized. This patch moves the use of the variable to a
place where it cannot be used while uninitialized.
Signed-off-by: Andy Gross <andy.gross@linaro.org>
The SSL context maintains a set of 'out pointers' indicating the
address at which to write the header fields of the next outgoing
record. Some of these addresses have a static offset from the
beginning of the record header, while other offsets can vary
depending on the active record encryption mechanism: For example,
if an explicit IV is in use, there's an offset between the end
of the record header and the beginning of the encrypted data to
allow the explicit IV to be placed in between; also, if the DTLS
Connection ID (CID) feature is in use, the CID is part of the
record header, shifting all subsequent information (length, IV, data)
to the back.
When setting up an SSL context, the out pointers are initialized
according to the identity transform + no CID, and it is important
to keep them up to date whenever the record encryption mechanism
changes, which is done by the helper function ssl_update_out_pointers().
During context deserialization, updating the out pointers according
to the deserialized record transform went missing, leaving the out
pointers the initial state. When attemping to encrypt a record in
this state, this lead to failure if either a CID or an explicit IV
was in use. This wasn't caught in the tests by the bad luck that
they didn't use CID, _and_ used the default ciphersuite based on
ChaChaPoly, which doesn't have an explicit IV. Changing either of
this would have made the existing tests fail.
This commit fixes the bug by adding a call to ssl_update_out_pointers()
to ssl_context_load() implementing context deserialization.
Extending test coverage is left for a separate commit.
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.
* origin/development:
Update the crypto submodule
Use multipart PSA key derivation API
platform: Include stdarg.h where needed
Update Mbed Crypto to contain mbed-crypto#152
CMake: Add a subdirectory build regression test
README: Enable builds as a CMake subproject
ChangeLog: Enable builds as a CMake subproject
Remove use of CMAKE_SOURCE_DIR
Update library version to 2.18.0
* origin/pr/2807:
platform: Include stdarg.h where needed
Update Mbed Crypto to contain mbed-crypto#152
CMake: Add a subdirectory build regression test
README: Enable builds as a CMake subproject
ChangeLog: Enable builds as a CMake subproject
Remove use of CMAKE_SOURCE_DIR
Update library version to 2.18.0
Avoid compiler errors when MBEDTLS_PSA_CRYPTO_KEY_FILE_ID_ENCODES_OWNER
is set by using the application ID type.
[Error] psa_crypto_slot_management.c@175,9: used type 'psa_key_id_t' (aka 'psa_key_file_id_t') where arithmetic or pointer type is required
Bring Mbed TLS 2.18.0 and 2.18.1 release changes back into the
development branch. We had branched to release 2.18.0 and 2.18.1 in
order to allow those releases to go out without having to block work on
the `development` branch.
Manually resolve conflicts in the Changelog by moving all freshly addded
changes to a new, unreleased version entry.
Reject changes to include/mbedtls/platform.h made in the mbedtls-2.18
branch, as that file is now sourced from Mbed Crypto.
* mbedtls-2.18:
platform: Include stdarg.h where needed
Update Mbed Crypto to contain mbed-crypto#152
CMake: Add a subdirectory build regression test
README: Enable builds as a CMake subproject
ChangeLog: Enable builds as a CMake subproject
Remove use of CMAKE_SOURCE_DIR
Update library version to 2.18.0
* origin/development: (114 commits)
Don't redefine calloc and free
Add changelog entry to record checking
Fix compiler warning
Add debug messages
Remove duplicate entries from ChangeLog
Fix parameter name in doxygen
Add missing guards for mac usage
Improve reability and debugability of large if
Fix a typo in a comment
Fix MSVC warning
Fix compile error in reduced configurations
Avoid duplication of session format header
Implement config-checking header to context s11n
Provide serialisation API only if it's enabled
Fix compiler warning: comparing signed to unsigned
Actually reset the context on save as advertised
Re-use buffer allocated by handshake_init()
Enable serialisation tests in ssl-opt.sh
Change requirements for setting timer callback
Add setting of forced fields when deserializing
...
Breaking into a series of statements makes things easier when stepping through
the code in a debugger.
Previous comments we stating the opposite or what the code tested for (what we
want vs what we're erroring out on) which was confusing.
Also expand a bit on the reasons for these restrictions.
Modelled after the config-checking header from session s11n.
The list of relevant config flags was established by manually checking the
fields serialized in the format, and which config.h flags they depend on.
This probably deserves double-checking by reviewers.
