The mitigation for vulnerabilities discovered in
OCB2 (https://eprint.iacr.org/2019/311, called XEX* attack, or XEXStarAttack, in code)
introduced in be97594 (#4227) willingly allowed for some packets with specific
characteristics to be dropped during encryption to prevent the vulnerability
from being exploited.
It was assumed that the chance of such packets was sufficiently small (given
we are dealing with compressed audio) that such loss was acceptable.
It was however discovered that digital silence (as produced by e.g. a noise
gate) will cause Opus to emit almost exclusively such packets, leading to strong
artifacts on the receiving end. See #4385.
This commit tries to work around the issue by modifying such packets in a way
which will no longer require them to be dropped, and yet produce the expected
output on the receiver side.
As far as I understand [Opus] (specifically section 4.1, 4.3.0 and 4.3.3), the
0s are simply unused bits and are only there because we running Opus in constant
bitrate mode. So, flipping one of them should have no effect on the resulting
audio.
[Opus]: https://tools.ietf.org/html/rfc6716Fixes#4719
As some tests only make sense to be run if a given component is included
in the build (client/server), this commit makes sure no unnecessary
tests are built (and run).
Furthermore it removed the dependency of some tests on a certain target
having a source-dir property.
And finally it also removed the references to "NO_USE_SRV" from
TestServerResolver as this macro is never defined anywhere (it's
probably a remnant of the old qmake system).
Co-Authored-By: Sebastian Parborg <darkdefende@gmail.com>
This commit removes all qmake-related build-files from the system. We
have now migrated to cmake and are no longer maintaining qmake anyways
and therefore there is no reason to keep it.
Removing it also clearly states to any potential user/programmer that
this project is no longer intended to be compiled with qmake.
Given that the .pri files no longer exist, the mumble-version.py script
had to be adapted to read the version from the CMakeLists.txt file
instead.
Furthermore a few of the submodules support cmake natively and therefore
we no longer need the src/buid-directory approach in order to build
them. The respective build dirs have been removed and the src-dirs have
been renamed.
OCB2 is known to be broken under certain conditions:
https://eprint.iacr.org/2019/311
To execute the universal attacks described in the paper, an attacker needs
access to an encryption oracle that allows it to perform encryption queries with
attacker-chosen nonce. Luckily in Mumble the encryption nonce is a fixed counter
which is far too restrictive for the universal attacks to be feasible against
Mumble.
The basic attacks do not require an attacker-chosen nonce and as such are more
applicable to Mumble. They are however of limited use and do require an en- and
a decryption oracle which Mumble seemingly does not provide at the same time.
To be on the safe side, this commit implements the counter-cryptanalysis
measure described in the paper in section 9 for the sender and receiver side.
This way if either server of client are patched, their communication is almost
certainly (merely lacking formal proof) not susceptible to the attacks described
in the paper.
This commit adds all the missing includes when the PCH header is not used.
Also, some includes are reordered and/or made consistent (e.g. "#include <QtEndian>" -> "#include <QtCore/QtEndian>").
According to Qt's documentation the PCH header doesn't need to be included.
From https://doc.qt.io/qt-5/qmake-precompiledheaders.html:
"To make your project use precompiled headers, you only need to define the PRECOMPILED_HEADER variable in your project file."
"qmake will handle the rest, to ensure the creation and use of the precompiled header file. You do not need to include the precompiled header file in HEADERS, as qmake will do this if the configuration supports precompiled headers."
Now that test.pri adds source files and headers by default, the .pro files
of our tests need to append to SOURCES and HEADERS to ensure everything
test.pri adds to SOURCES and HEADERS are kept around.
The murmur_pch.h file which most tests use -- either directly,
or indrectly -- depends on being able to include OpenSSL headers.
Some of our tests did not include(qmake/openssl.pri), which meant that
those tests would fail to build in CONFIG(no-pch), such as on macOS.
This commit works around that issue by depending on OpenSSL for all tests.
