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The Jitter RNG implementation is updated to comply with upstream version
2.1.2. The change covers the following aspects:

* Time variation measurement is conducted over the LFSR operation
instead of the XOR folding

* Invcation of stuck test during initialization

* Removal of the stirring functionality and the Von-Neumann
unbiaser as the LFSR using a primitive and irreducible polynomial
generates an identical distribution of random bits

This implementation was successfully used in FIPS 140-2 validations
as well as in German BSI evaluations.

This kernel implementation was tested as follows:

* The unchanged kernel code file jitterentropy.c is compiled as part
of user space application to generate raw unconditioned noise
data. That data is processed with the NIST SP800-90B non-IID test
tool to verify that the kernel code exhibits an equal amount of noise
as the upstream Jitter RNG version 2.1.2.

* Using AF_ALG with the libkcapi tool of kcapi-rng the Jitter RNG was
output tested with dieharder to verify that the output does not
exhibit statistical weaknesses. The following command was used:
kcapi-rng -n "jitterentropy_rng" -b 100000000000 | dieharder -a -g 200

* The unchanged kernel code file jitterentropy.c is compiled as part
of user space application to test the LFSR implementation. The
LFSR is injected a monotonically increasing counter as input and
the output is fed into dieharder to verify that the LFSR operation
does not exhibit statistical weaknesses.

* The patch was tested on the Muen separation kernel which returns
a more coarse time stamp to verify that the Jitter RNG does not cause
regressions with its initialization test considering that the Jitter
RNG depends on a high-resolution timer.
Tested-by: Reto Buerki <reet@codelabs.ch>
Signed-off-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

"jitterentropy_rng" doesn't have any other implementations, nor is it
tested by the crypto self-tests.  So it was unnecessary to change it to
subsys_initcall.  Also it depends on the main clocksource being
initialized, which may happen after subsys_initcall, causing this error:

    jitterentropy: Initialization failed with host not compliant with requirements: 2

Change it back to module_init().

Fixes: c4741b23

 ("crypto: run initcalls for generic implementations earlier")
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

Use subsys_initcall for registration of all templates and generic
algorithm implementations, rather than module_init.  Then change
cryptomgr to use arch_initcall, to place it before the subsys_initcalls.

This is needed so that when both a generic and optimized implementation
of an algorithm are built into the kernel (not loadable modules), the
generic implementation is registered before the optimized one.
Otherwise, the self-tests for the optimized implementation are unable to
allocate the generic implementation for the new comparison fuzz tests.

Note that on arm, a side effect of this change is that self-tests for
generic implementations may run before the unaligned access handler has
been installed.  So, unaligned accesses will crash the kernel.  This is
arguably a good thing as it makes it easier to detect that type of bug.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

Drop duplicate header module.h from jitterentropy-kcapi.c.
Signed-off-by: Geliang Tang <geliangtang@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

As part of the Y2038 development, __getnstimeofday is not supposed to be
used any more. It is now replaced with ktime_get_ns. The Jitter RNG uses
the time stamp to measure the execution time of a given code path and
tries to detect variations in the execution time. Therefore, the only
requirement the Jitter RNG has, is a sufficient high resolution to
detect these variations.

The change was tested on x86 to show an identical behavior as RDTSC. The
used test code simply measures the execution time of the heart of the
RNG:

        jent_get_nstime(&time);
        jent_memaccess(ec, min);
        jent_fold_time(NULL, time, &folded, min);
        jent_get_nstime(&time2);
        return ((time2 - time));
Signed-off-by: Stephan Mueller <smueller@chronox.de>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

The clocksource does not provide clocksource_register() function since
f8935983

 commit (clocksource: Mostly kill clocksource_register()), so
let's remove unnecessary information about this function from a comment.
Signed-off-by: Alexander Kuleshov <kuleshovmail@gmail.com>
Suggested-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

Since the API for jent_panic() does not include format string parameters,
adjust the call to panic() to use a literal string to avoid any future
callers from leaking format strings into the panic message.
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

The core of the Jitter RNG is intended to be compiled with -O0. To
ensure that the Jitter RNG can be compiled on all architectures,
separate out the RNG core into a stand-alone C file that can be compiled
with -O0 which does not depend on any kernel include file.

As no kernel includes can be used in the C file implementing the core
RNG, any dependencies on kernel code must be extracted.

A second file provides the link to the kernel and the kernel crypto API
that can be compiled with the regular compile options of the kernel.
Signed-off-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>