random: treat bootloader trust toggle the same way as cpu trust toggle

stable inclusion
from stable-v5.10.119
commit f3bc5eca83d37a1a723d4c378a167a83d1b9c771
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I5L6BB

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=f3bc5eca83d37a1a723d4c378a167a83d1b9c771



--------------------------------

commit d97c68d1 upstream.

If CONFIG_RANDOM_TRUST_CPU is set, the RNG initializes using RDRAND.
But, the user can disable (or enable) this behavior by setting
`random.trust_cpu=0/1` on the kernel command line. This allows system
builders to do reasonable things while avoiding howls from tinfoil
hatters. (Or vice versa.)

CONFIG_RANDOM_TRUST_BOOTLOADER is basically the same thing, but regards
the seed passed via EFI or device tree, which might come from RDRAND or
a TPM or somewhere else. In order to allow distros to more easily enable
this while avoiding those same howls (or vice versa), this commit adds
the corresponding `random.trust_bootloader=0/1` toggle.

Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Graham Christensen <graham@grahamc.com>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Link: https://github.com/NixOS/nixpkgs/pull/165355


Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>
Acked-by: Xie XiuQi <xiexiuqi@huawei.com>