crypto: drbg - fix maximum value checks on 32 bit systems

The maximum values for additional input string or generated blocks is
larger than 1<<32. To ensure a sensible value on 32 bit systems, return
SIZE_MAX on 32 bit systems. This value is lower than the maximum
allowed values defined in SP800-90A. The standard allow lower maximum
values, but not larger values.

SIZE_MAX - 1 is used for drbg_max_addtl to allow
drbg_healthcheck_sanity to check the enforcement of the variable
without wrapping.

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
1 file changed