From 6ff6304497c900a0284e3aa89ad86f0ed01f86d8 Mon Sep 17 00:00:00 2001 From: Dominik Brodowski Date: Mon, 24 Jan 2022 21:29:47 +0100 Subject: [PATCH] hwrng: core - read() callback must be called for size of 32 or more bytes According to , the @max parameter of the ->read callback "is a multiple of 4 and >= 32 bytes". That promise was not kept by add_early_randomness(), which only asked for 16 bytes. As rng_buffer_size() is at least 32, we can simply ask for 32 bytes. Cc: Matt Mackall Cc: Herbert Xu Cc: Jason A. Donenfeld Signed-off-by: Dominik Brodowski Signed-off-by: Herbert Xu --- drivers/char/hw_random/core.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/drivers/char/hw_random/core.c b/drivers/char/hw_random/core.c index e860e044b19e..c2d260b5dd92 100644 --- a/drivers/char/hw_random/core.c +++ b/drivers/char/hw_random/core.c @@ -64,10 +64,9 @@ static size_t rng_buffer_size(void) static void add_early_randomness(struct hwrng *rng) { int bytes_read; - size_t size = min_t(size_t, 16, rng_buffer_size()); mutex_lock(&reading_mutex); - bytes_read = rng_get_data(rng, rng_buffer, size, 0); + bytes_read = rng_get_data(rng, rng_buffer, 32, 0); mutex_unlock(&reading_mutex); if (bytes_read > 0) add_device_randomness(rng_buffer, bytes_read); -- 2.11.0