This test works regardless of the serialisation format and embedded pointers
in it, contrary to the load-save test, though it requires more maintenance of
the test code (sync the member list with the struct definition).
This uncovered a bug that led to a double-free (in practice, in general could
be free() on any invalid value): initially the session structure is loaded
with `memcpy()` which copies the previous values of pointers peer_cert and
ticket to heap-allocated buffers (or any other value if the input is
attacker-controlled). Now if we exit before we got a chance to replace those
invalid values with valid ones (for example because the input buffer is too
small, or because the second malloc() failed), then the next call to
session_free() is going to call free() on invalid pointers.
This bug is fixed in this commit by always setting the pointers to NULL right
after they've been read from the serialised state, so that the invalid values
can never be used.
(An alternative would be to NULL-ify them when writing, which was rejected
mostly because we need to do it when reading anyway (as the consequences of
free(invalid) are too severe to take any risk), so doing it when writing as
well is redundant and a waste of code size.)
Also, while thinking about what happens in case of errors, it became apparent
to me that it was bad practice to leave the session structure in an
half-initialised state and rely on the caller to call session_free(), so this
commit also ensures we always clear the structure when loading failed.
This test appeared to be passing for the wrong reason, it's not actually not
appropriate for the current implementation. The serialised data contains
values of pointers to heap-allocated buffers. There is no reason these should
be identical after a load-save pair. They just happened to be identical when I
first ran the test due to the place of session_free() in the test code and the
fact that the libc's malloc() reused the same buffers. The test no longer
passes if other malloc() implementations are used (for example, when compiling
with asan which avoids re-using the buffer, probably for better error
detection).
So, disable this test for now (we can re-enable it when we changed how
sessions are serialised, which will be done in a future PR, hence the name of
the dummy macro in depends_on). In the next commit we're going to add a test
that save-load is the identity instead - which will be more work in testing as
it will require checking each field manually, but at least is reliable.
This initial test ensures that a load-save function is the identity. It is so
far incomplete in that it only tests sessions without tickets or certificate.
This will be improved in the next commits.
Part of the record encryption/decryption tests is to gradually
increase the space available at the front and/or at the back of
a record and observe when encryption starts to succeed. If exactly
one of the two parameters is varied at a time, the expectation is
that encryption will continue to succeed once it has started
succeeding (that's not true if both pre- and post-space are varied
at the same time).
Moreover, previously the test would take turns when choosing which
transform should be used for encryption, and which for decryption.
With the introduction of the CID feaature, this switching of transforms
doesn't align with the expectation of eventual success of the encryption,
since the overhead of encryption might be different for the parties,
because both parties may use different CIDs for their outgoing records.
This commit modifies the tests to not take turns between transforms,
but to always use the same transforms for encryption and decryption
during a single round of the test.
This commit adds tests to check the behavior of the record encryption
routine `ssl_encrypt_buf` when the buffer surrounding the plaintext is
too small to hold the expansion in the beginning and end (due to IV's,
padding, and MAC).
Each test starts successively increases the space available at the
beginning, end, or both, of the record buffer, and checks that the
record encryption either fails with a BUFFER_TOO_SMALL error, or
that it succeeds. Moreover, if it succeeds, it is checked that
decryption succeeds, too, and results in the original record.
This commit adds tests exercising mutually inverse pairs of
record encryption and decryption transformations for the various
transformation types allowed in TLS: Stream, CBC, and AEAD.
* origin/pr/2364:
Increase okm_hex buffer to contain null character
Minor modifications to hkdf test
Add explanation for okm_string size
Update ChangeLog
Reduce buffer size of okm
Reduce Stack usage of hkdf test function
* restricted/pr/553:
Fix mbedtls_ecdh_get_params with new ECDH context
Add changelog entry for mbedtls_ecdh_get_params robustness
Fix ecdh_get_params with mismatching group
Add test case for ecdh_get_params with mismatching group
Add test case for ecdh_calc_secret
Fix typo in documentation
It was failing to set the key in the ENCRYPT direction before encrypting.
This just happened to work for GCM and CCM.
After re-encrypting, compare the length to the expected ciphertext
length not the plaintext length. Again this just happens to work for
GCM and CCM since they do not perform any kind of padding.
* public/pr/2429:
Add ChangeLog entry for unused bits in bitstrings
Improve docs for ASN.1 bitstrings and their usage
Add tests for (named) bitstring to suite_asn1write
Fix ASN1 bitstring writing
Add a test case for doing an ECDH calculation by calling
mbedtls_ecdh_get_params on both keys, with keys belonging to
different groups. This should fail, but currently passes.
`test_hkdf` in the hkdf test suites consumed stack of ~6KB with
6 buffers of ~1KB each. This causes stack overflow on some platforms
with smaller stack. The buffer sizes were reduced. By testing, the sizes
can be reduced even further, as the largest seen size is 82 bytes(for okm).
