According to the review by Bill Cox [1], the Atmel SHA204A random number generator produces random numbers with very low entropy. Set the lowest possible entropy for this chip just to be safe. [1] https://www.metzdowd.com/pipermail/cryptography/2014-December/023858.html Fixes: da001fb651b00e1d ("crypto: atmel-i2c - add support for SHA204A random number generator") Signed-off-by: Marek Behún <kabel@xxxxxxxxxx> --- drivers/crypto/atmel-sha204a.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/crypto/atmel-sha204a.c b/drivers/crypto/atmel-sha204a.c index 75bebec2c757..0fcf4a39de27 100644 --- a/drivers/crypto/atmel-sha204a.c +++ b/drivers/crypto/atmel-sha204a.c @@ -163,6 +163,12 @@ static int atmel_sha204a_probe(struct i2c_client *client) i2c_priv->hwrng.name = dev_name(&client->dev); i2c_priv->hwrng.read = atmel_sha204a_rng_read; + /* + * According to review by Bill Cox [1], this HWRNG has very low entropy. + * [1] https://www.metzdowd.com/pipermail/cryptography/2014-December/023858.html + */ + i2c_priv->hwrng.quality = 1; + ret = devm_hwrng_register(&client->dev, &i2c_priv->hwrng); if (ret) dev_warn(&client->dev, "failed to register RNG (%d)\n", ret); -- 2.49.0
