diff options
| author | Kees Cook | 2017-07-12 14:34:04 -0700 |
|---|---|---|
| committer | Linus Torvalds | 2017-07-12 16:26:00 -0700 |
| commit | ee7998c50c2697737c6530431709f77c852bf0d6 (patch) | |
| tree | ad6f1c9946eae9286b3e5495cef00e3791256920 | |
| parent | 9380fa60b10ebd6ee7c3fcdb2cf162f4d7cf9fc5 (diff) | |
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>
| -rw-r--r-- | drivers/char/random.c | 5 | ||||
| -rw-r--r-- | init/main.c | 1 |
2 files changed, 6 insertions, 0 deletions
diff --git a/drivers/char/random.c b/drivers/char/random.c index 01a260f67437..23cab7a8c1c1 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -987,6 +987,11 @@ void add_device_randomness(const void *buf, unsigned int size) unsigned long time = random_get_entropy() ^ jiffies; unsigned long flags; + if (!crng_ready()) { + crng_fast_load(buf, size); + return; + } + trace_add_device_randomness(size, _RET_IP_); spin_lock_irqsave(&input_pool.lock, flags); _mix_pool_bytes(&input_pool, buf, size); diff --git a/init/main.c b/init/main.c index df58a416dd1d..052481fbe363 100644 --- a/init/main.c +++ b/init/main.c @@ -518,6 +518,7 @@ asmlinkage __visible void __init start_kernel(void) /* * Set up the initial canary ASAP: */ + add_latent_entropy(); boot_init_stack_canary(); cgroup_init_early(); |