diff mbox series

[5.15,07/27] random: clamp credited irq bits to maximum mixed

Message ID 20221013175143.791866092@linuxfoundation.org
State New
Headers
Series None |

Commit Message

Greg KH Oct. 13, 2022, 5:52 p.m. UTC 
  From: Jason A. Donenfeld <Jason@zx2c4.com>

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 <Jason@zx2c4.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/char/random.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff mbox series

Patch

--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -980,7 +980,7 @@  static void mix_interrupt_randomness(str
 	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));
 }