Commit 6ff63044 authored by Dominik Brodowski's avatar Dominik Brodowski Committed by Herbert Xu
Browse files

hwrng: core - read() callback must be called for size of 32 or more bytes 



According to <linux/hw_random.h>, 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 <mpm@selenic.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: default avatarDominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent 26a03981

drivers/char/hw_random/core.c

+1 −2
Original line number Diff line number Diff line
@@ -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);