From 7191c628fe07b70d3f37de736d173d1b115396ed Mon Sep 17 00:00:00 2001 From: Dominik Brodowski Date: Wed, 9 Feb 2022 19:57:06 +0100 Subject: [PATCH] random: fix locking for crng_init in crng_reseed() crng_init is protected by primary_crng->lock. Therefore, we need to hold this lock when increasing crng_init to 2. As we shouldn't hold this lock for too long, only hold it for those parts which require protection. Signed-off-by: Dominik Brodowski Reviewed-by: Eric Biggers Signed-off-by: Jason A. Donenfeld --- drivers/char/random.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/drivers/char/random.c b/drivers/char/random.c index 8ae7d0b30280c1..1ccd92efa8f41e 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -502,6 +502,7 @@ static void crng_reseed(void) int entropy_count; unsigned long next_gen; u8 key[CHACHA_KEY_SIZE]; + bool finalize_init = false; /* * First we make sure we have POOL_MIN_BITS of entropy in the pool, @@ -529,12 +530,14 @@ static void crng_reseed(void) ++next_gen; WRITE_ONCE(base_crng.generation, next_gen); WRITE_ONCE(base_crng.birth, jiffies); - spin_unlock_irqrestore(&base_crng.lock, flags); - memzero_explicit(key, sizeof(key)); - if (crng_init < 2) { invalidate_batched_entropy(); crng_init = 2; + finalize_init = true; + } + spin_unlock_irqrestore(&base_crng.lock, flags); + memzero_explicit(key, sizeof(key)); + if (finalize_init) { process_random_ready_list(); wake_up_interruptible(&crng_init_wait); kill_fasync(&fasync, SIGIO, POLL_IN);