From 4d1f1a0d96869df9df821a5270ba52e05bbeacda Mon Sep 17 00:00:00 2001 From: "Jason A. Donenfeld" Date: Fri, 23 Sep 2022 02:42:51 +0200 Subject: [PATCH] random: clamp credited irq bits to maximum mixed commit e78a802a7b4febf53f2a92842f494b01062d85a8 upstream. Since the most that's mixed into the pool is sizeof(long)*2, don't credit more than that many bytes of entropy. Fixes: e3e33fc2ea7f ("random: do not use input pool from hard IRQs") Cc: stable@vger.kernel.org Signed-off-by: Jason A. Donenfeld Signed-off-by: Greg Kroah-Hartman --- drivers/char/random.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/char/random.c b/drivers/char/random.c index 1cbc33ee5a5f..1c9cb58dcce7 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -977,7 +977,7 @@ static void mix_interrupt_randomness(struct work_struct *work) local_irq_enable(); mix_pool_bytes(pool, sizeof(pool)); - credit_init_bits(max(1u, (count & U16_MAX) / 64)); + credit_init_bits(clamp_t(unsigned int, (count & U16_MAX) / 64, 1, sizeof(pool) * 8)); memzero_explicit(pool, sizeof(pool)); }