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.
Instead of each driver providing its own header file use a central
header as the initcall order header should cover _all_ provided
initcalls resulting from the used 'pc_linux' kernel config.
Note that the 'pc_linux' configuration was extended with the
'USB_USBNET' option because the module's initcall is needed for the
Genode C API for USB glue-code and the 'PACKET' option needed by
the wireless lan driver.
The lack of theses options was not noticed as each driver used its
own initcall header so far that stemmed from the initial porting
effort.
Issue #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.
.SHELLFLAGS is extended by option pipefail to make pipes fail if any pipe
element fails. As .SHELLFLAGS is exported into sub-make instances it
must be unexported before calling third-party build systems recursively.
* Drivers have to use lx_kit/memory_dma.cc
* Protocol-stacks use lx_kit/memory_non_dma.cc
* Moreover the device-dependent lx_emul parts get removed
from the common lx_emul import rules
Fix#4443
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
