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
This commit introduces a new SSL error code
`MBEDTLS_ERR_SSL_VERSION_MISMATCH`
which can be used to indicate operation failure due to a
mismatch of version or configuration.
It is put to use in the implementation of `mbedtls_ssl_session_load()`
to signal the attempt to de-serialize a session which has been serialized
in a build of Mbed TLS using a different version or configuration.
This commit improves the test exercising the behaviour of
session deserialization when facing an unexpected version
or config, by testing ver/cfg corruption at any bit in the
ver/cfg header of the serialized data; previously, it had
only tested the first bit of each byte.
The size of the ticket used in this test dropped from 192 to 143 bytes, so
move all sizes used in this test down 50 bytes. Also, we now need to adapt the
server response size as the default size would otherwise collide with the new
mtu value.
The chosen fix matches what's currently done in the baremetal branch - except
the `#ifdef` have been adapted because now in baremetal the digest is not kept
if renegotiation is disabled.
We have explicit recommendations to use US spelling for technical writing, so
let's apply this to code as well for uniformity. (My fingers tend to prefer UK
spelling, so this needs to be fixed in many places.)
sed -i 's/\([Ss]eriali\)s/\1z/g' **/*.[ch] **/*.function **/*.data ChangeLog
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 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.
While 'session hash' is currently unique, so suitable to prove that the
intended code path has been taken, it's a generic enough phrase that in the
future we might add other debug messages containing it in completely unrelated
code paths. In order to future-proof the accuracy of the test, let's use a
more specific string.
* origin/pr/2790: (40 commits)
Fix possibly-lossy conversion warning from MSVC
Reintroduce length 0 check for records
Don't use memcpy() for 2-byte copy operation
Remove integer parsing macro
Fix alignment in record header parsing routine
Don't disallow 'record from another epoch' log msg in proxy ref test
Make sure 'record from another epoch' is displayed for next epoch
Implement record checking API
Mark ssl_parse_record_header() as `const` in SSL context
Make mbedtls_ssl_in_hdr_len() CID-unaware
Remove duplicate setting of ssl->in_msgtype and ssl->in_msglen
Move update of in_xxx fields in ssl_get_next_record()
Move update of in_xxx fields outside of ssl_prepare_record_content()
Reduce dependency of ssl_prepare_record_content() on in_xxx fields
Move ssl_update_in_pointers() to after record hdr parsing
Mark DTLS replay check as `const` on the SSL context
Move updating the internal rec ptrs to outside of rec hdr parsing
Mark ssl_decrypt_buf() as `const in the input SSL context
Adapt ssl_prepare_record_content() to use SSL record structure
Use record length from record structure when fetching content in TLS
...
It happens regularly in test runs that the server example application
shuts down a connection, goes into waiting mode for a new connection,
and then receives the encrypted ClosureAlert from the client. The only
reason why this does currently not trigger the 'record from another epoch'
message is that we handle ClientHello parsing outside of the main record
stack because we want to be able to detect SSLv2 ClientHellos. However,
this is likely to go away, and once it happens, we'll see the log message.
Further, when record checking is used, every record, including the mentioned
closure alert, is passed to the record checking API before being passed to
the rest of the stack, which leads to the log message being printed.
In summary, grepping for 'record from another epoch' is a fragile way
of checking whether a reordered message has arrived. A more reliable
way is to grep for 'Buffer record from epoch' which is printed when
a record from a future epoch is actually buffered, and 'ssl_buffer_message'
which is the function buffering a future handshake message.
compat.sh used to skip OpenSSL altogether for DTLS 1.2, because older
versions of OpenSSL didn't support it. But these days it is supported.
We don't want to use DTLS 1.2 with OpenSSL unconditionally, because we
still use legacy versions of OpenSSL to test with legacy ciphers. So
check whether the version we're using supports it.
Without any -O option, the default is -O0, and then the assembly code
is not used, so this would not be a non-regression test for the
assembly code that doesn't build.
