crypto: atmel-sha204a - Set hwrng quality to lowest possible

commit 8006aff15516a170640239c5a8e6696c0ba18d8e upstream.

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: da001fb651 ("crypto: atmel-i2c - add support for SHA204A random number generator")
Cc: <[email protected]>
Signed-off-by: Marek Behún <[email protected]>
Acked-by: Ard Biesheuvel <[email protected]>
Reviewed-by: Linus Walleij <[email protected]>
Signed-off-by: Herbert Xu <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
Signed-off-by: Marek Behún <[email protected]>
This commit is contained in:
Marek Behún 2025-04-22 11:57:18 +02:00 • committed by Greg Kroah-Hartman
commit ea3ee99943

View file

@ -107,7 +107,12 @@ 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;
i2c_priv->hwrng.quality = 1024;
/*
* 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)