random: do not ignore early device randomness
authorKees Cook <keescook@chromium.org>
Wed, 12 Jul 2017 21:34:04 +0000 (14:34 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Wed, 12 Jul 2017 23:26:00 +0000 (16:26 -0700)
commitee7998c50c2697737c6530431709f77c852bf0d6
treead6f1c9946eae9286b3e5495cef00e3791256920
parent9380fa60b10ebd6ee7c3fcdb2cf162f4d7cf9fc5
random: do not ignore early device randomness

The add_device_randomness() function would ignore incoming bytes if the
crng wasn't ready.  This additionally makes sure to make an early enough
call to add_latent_entropy() to influence the initial stack canary,
which is especially important on non-x86 systems where it stays the same
through the life of the boot.

Link: http://lkml.kernel.org/r/20170626233038.GA48751@beast
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jessica Yu <jeyu@redhat.com>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Lokesh Vutla <lokeshvutla@ti.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: AKASHI Takahiro <takahiro.akashi@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
drivers/char/random.c
init/main.c