[PATCH 4.9 76/95] random: crng_reseed() should lock the crng instance that it is modifying

[Greg Kroah-Hartman]

4.9-stable review patch.  If anyone has any objections, please let me know.

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

From: Theodore Ts'o <ty...@mit.edu>

commit 0bb29a849a6433b72e249eea7695477b02056e94 upstream.

Reported-by: Jann Horn <ja...@google.com>
Fixes: 1e7f583af67b ("random: make /dev/urandom scalable for silly...")
Cc: sta...@kernel.org # 4.8+
Signed-off-by: Theodore Ts'o <ty...@mit.edu>
Reviewed-by: Jann Horn <ja...@google.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>

---
 drivers/char/random.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -862,7 +862,7 @@ static void crng_reseed(struct crng_stat
                _crng_backtrack_protect(&primary_crng, buf.block,
                                        CHACHA20_KEY_SIZE);
        }
-       spin_lock_irqsave(&primary_crng.lock, flags);
+       spin_lock_irqsave(&crng->lock, flags);
        for (i = 0; i < 8; i++) {
                unsigned long   rv;
                if (!arch_get_random_seed_long(&rv) &&
@@ -879,7 +879,7 @@ static void crng_reseed(struct crng_stat
                wake_up_interruptible(&crng_init_wait);
                pr_notice("random: crng init done\n");
        }
-       spin_unlock_irqrestore(&primary_crng.lock, flags);
+       spin_unlock_irqrestore(&crng->lock, flags);
 }
 
 static inline void maybe_reseed_primary_crng(void)