Both the Wifi driver and the WireGuard port used local implementations for
their source of randomness. Wifi used a Xoroshiro128+ PRNG for rapid generation
of random values but initialized this PRNG always with the same static seed
value. WireGuard, in contrast, requested each random byte directly from the
jitterentropy lib, which is considered to be very time intensive.
This commit removes the local variants of random.cc and introduces a new
centralized lx_emul/random.cc . The new variant combines the former approaches,
so, that jitterentropy is accessed only in order to generate a random seed for
a Xoroshiro128+ PRNG. Front-end requests for random values are then fulfilled
efficiently via the PRNG.
:Warning:
The output of the Xoroshiro128+ PRNG that is used in the new implementation of
the lx_emul randomness functions has known statistical problems (see
https://en.wikipedia.org/wiki/Xoroshiro128%2B#Statistical_Quality).
Furthermore, the integration of Xoroshir128+ with the lx_emul code was not
reviewed/audited for its security-related properties, so far, and has the
known deficiency of seeding the PRNG only once during initialization. Thus,
we strongly advise against the use of the lx_emul randomness functions for
security-critical purposes.
Ref #4397
This commit de-duplicates the redundant dummy implementations and
to some degree also the 'lx_emul.c' implementations while also
decluttering the various 'dep.list' files.
The code is moved into 'src/lib/pc/lx_emul' where it becomes part
of the 'pc_lx_emul' library.
Fixes#4500.
The driver falls in line with the previous 'legacy_wifi_drv' component
where the ported wireless LAN stack and device driver is encapsulated
in a library. This library in return is used by the 'Libc::Component'
providing the necessary environment for the 'wpa_supplicant'.
In constrast to the old driver a 'wifi' VFS plugin is in charge of
initalizing the 'Lx_kit::Env' prior to executing any static
constructors.
Fixes#4455.
This commit contains:
* Minimal Linux kernel target: pc_linux
* Library to generate a Linux build directory, config, generated headers
* API depot package
The actual work was provided by Josef Soentgen.
Ref genodelabs/genode#4416
