There are situations in which it is not clear what message to expect
next. For example, the message following the ServerHello might be
either a Certificate, a ServerKeyExchange or a CertificateRequest. We
deal with this situation in the following way: Initially, the message
processing function for one of the allowed message types is called,
which fetches and decodes a new message. If that message is not the
expected one, the function returns successfully (instead of throwing
an error as usual for unexpected messages), and the handshake
continues to the processing function for the next possible message. To
not have this function fetch a new message, a flag in the SSL context
structure is used to indicate that the last message was retained for
further processing, and if that's set, the following processing
function will not fetch a new record.
This commit simplifies the usage of this message-retaining parameter
by doing the check within the record-fetching routine instead of the
specific message-processing routines. The code gets cleaner this way
and allows retaining messages to be used in other situations as well
without much effort. This will be used in the next commits.
* hanno/iotssl-1341-optional-certificate-verification-needs-ca-chain-backport-2.1:
Add tests for missing CA chains and bad curves.
Fix implementation of VERIFY_OPTIONAL verification mode
In the ecdsa.c sample application we don't use hashing, we use ecdsa
directly on a buffer containing plain text. Although the text explains
that it should be the message hash it still can be confusing.
Any misunderstandings here are potentially very dangerous, because ECDSA
truncates the message hash if necessary and this can lead to trivial
signature forgeries if the API is misused and the message is passed
directly to the function without hashing.
This commit adds a hash computation step to the ecdsa.c sample
application and clarification to the doxygen documentation of the
ECDSA functions involved.
This commit adds four tests to tests/ssl-opt.sh:
(1) & (2): Check behaviour of optional/required verification when the
trusted CA chain is empty.
(3) & (4): Check behaviour of optional/required verification when the
client receives a server certificate with an unsupported curve.
This commit changes the behaviour of mbedtls_ssl_parse_certificate
to make the two authentication modes MBEDTLS_SSL_VERIFY_REQUIRED and
MBEDTLS_SSL_VERIFY_OPTIONAL be in the following relationship:
Mode == MBEDTLS_SSL_VERIFY_REQUIRED
<=> Mode == MBEDTLS_SSL_VERIFY_OPTIONAL + check verify result
Also, it changes the behaviour to perform the certificate chain
verification even if the trusted CA chain is empty. Previously, the
function failed in this case, even when using optional verification,
which was brought up in #864.
* sha1-2.1:
Cleaned up negative test predicate for test case
all.sh: test with SHA-1 enabled
SHA-1 deprecation: allow it in key exchange
Allow SHA-1 in server tests, when the signature_algorithm extension is not used
Document test data makefile
X.509 tests: obey compile-time SHA-1 support option
Allow SHA-1 in test scripts
Test that SHA-1 defaults off
Allow SHA-1 in SSL renegotiation tests
Test that X.509 verification rejects SHA-256 by default
Allow SHA-1 in X.509 and TLS tests
X.509 self-tests: replaced SHA-1 certificates by SHA-256
Added SHA256 test certificates
Remove SHA-1 in TLS by default
By default, keep allowing SHA-1 in key exchange signatures. Disabling
it causes compatibility issues, especially with clients that use
TLS1.2 but don't send the signature_algorithms extension.
SHA-1 is forbidden in certificates by default, since it's vulnerable
to offline collision-based attacks.
There is now one test case to validate that SHA-1 is rejected in
certificates by default, and one test case to validate that SHA-1 is
supported if MBEDTLS_TLS_DEFAULT_ALLOW_SHA1 is #defined.
In the TLS test client, allow SHA-1 as a signature hash algorithm.
Without this, the renegotation tests failed.
A previous commit had allowed SHA-1 via the certificate profile but
that only applied before the initial negotiation which includes the
signature_algorithms extension.
SHA-1 is now disabled by default in the X.509 layer. Explicitly enable
it in our tests for now. Updating all the test data to SHA-256 should
be done over time.
With SHA-1 deprecation, we need a few certificates using algorithms in
the default support list. Most tests still use SHA-1 though.
The generation process for the new certificates is recorded in the makefile.
Default to forbidding the use of SHA-1 in TLS where it is unsafe: for
certificate signing, and as the signature hash algorithm for the TLS
1.2 handshake signature. SHA-1 remains allowed in HMAC-SHA-1 in the
XXX_SHA ciphersuites and in the PRF for TLS <= 1.1.
For easy backward compatibility for use in controlled environments,
turn on the MBEDTLS_TLS_DEFAULT_ALLOW_SHA1 compiled-time option.
* restricted/mbedtls-2.1:
Remove obsolete macros from compat-1.3.h
Add fix for #667 to ChangeLog
Fix bug in threading sample implementation #667
Fix check-doxy-blocks.pl to run from root dir
RSA: wipe more stack buffers
RSA: wipe stack buffers
* hanno/iotssl-1241-backport-2.1:
Improve documentation
Split long lines.
Remember suitable hash function for any signature algorithm.
Introduce macros and functions to characterize certain ciphersuites.
* iotssl-1272-fix-RSA-cache-attack-2.1-restricted:
Add Changelog entry for RSA exponent blinding
Add exponent blinding to RSA with CRT
Add exponent blinding to RSA without CRT
Add missing return code checks in the functions pem_des_decrypt(),
pem_3des_decrypt() and pem_aes_decrypt() so that the calling function
mbedtls_pem_read_buffer() is notified of errors reported by the crypto
primitives AES, DES and 3DES.
This commit changes `ssl_parse_signature_algorithms_ext` to remember
one suitable ( := supported by client and by our config ) hash
algorithm per signature algorithm.
It also modifies the ciphersuite checking function
`ssl_ciphersuite_match` to refuse a suite if there
is no suitable hash algorithm.
Finally, it adds the corresponding entry to the ChangeLog.
The routine `mbedtls_ssl_write_server_key_exchange` heavily depends on
what kind of cipher suite is active: some don't need a
ServerKeyExchange at all, some need (EC)DH parameters but no server
signature, some require both. Each time we want to restrict a certain
piece of code to some class of ciphersuites, it is guarded by a
lengthy concatentation of configuration checks determining whether at
least one of the relevant cipher suites is enabled in the config; on
the code level, it is guarded by the check whether one of these
cipher suites is the active one.
To ease readability of the code, this commit introduces several helper
macros and helper functions that can be used to determine whether a
certain class of ciphersuites (a) is active in the config, and
(b) contains the currently present ciphersuite.
Fixed a bug in ssl_srv.c when parsing TLS_FALLBACK_SCSV in the
ciphersuite list that caused it to miss it sometimes. Reported by Hugo
Leisink as issue #810. Fix initially by @andreasag01; this commit
isolates the bug fix and adds a non-regression test.
Modify tests/scripts/check-doxy-blocks.pl to ensure that:
* It can only be run from the mbed TLS root directory.
* An error code is returned to the environment when a potential error
in the source code is found.
Modify tests/scripts/check-doxy-blocks.pl to ensure that:
* It can only be run from the mbed TLS root directory.
* An error code is returned to the environment when a potential error
in the source code is found.
When provided with an empty line, mpi_read_file causes a numeric
underflow resulting in a stack underflow. This commit fixes this and
adds some documentation to mpi_read_file.
The test case was generated by modifying our signature code so that it
produces a 7-byte long padding (which also means garbage at the end, so it is
essential to check that the error that is detected first is indeed the
padding rather than the final length check).
The modular inversion function hangs when provided with the modulus 1. This commit refuses this modulus with a BAD_INPUT error code. It also adds a test for this case.
The sliding window exponentiation algorithm is vulnerable to
side-channel attacks. As a countermeasure we add exponent blinding in
order to prevent combining the results of different measurements.
This commit handles the case when the Chinese Remainder Theorem is used
to accelerate the computation.
The sliding window exponentiation algorithm is vulnerable to
side-channel attacks. As a countermeasure we add exponent blinding in
order to prevent combining the results of different measurements.
This commits handles the case when the Chinese Remainder Theorem is NOT
used to accelerate computations.
