diff mbox series

[2/6] hw_random: read() callback must be called for size of 32 or more bytes

Message ID 20220124202951.28579-2-linux@dominikbrodowski.net
State Accepted
Commit 6ff6304497c900a0284e3aa89ad86f0ed01f86d8
Headers show
Series [1/6] hw_random: explicit ordering of initcalls | expand

Commit Message

Dominik Brodowski Jan. 24, 2022, 8:29 p.m. UTC 
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: Dominik Brodowski <linux@dominikbrodowski.net>
---
 drivers/char/hw_random/core.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)
diff mbox series

Patch

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);