diff options
| author | Marek Behún <kabel@kernel.org> | 2025-04-22 11:57:18 +0200 |
|---|---|---|
| committer | Herbert Xu <herbert@gondor.apana.org.au> | 2025-04-23 09:32:57 +0800 |
| commit | 8006aff15516a170640239c5a8e6696c0ba18d8e (patch) | |
| tree | 7e1100d6083bf63f2e831422746e2f1d0bfc4e4c /drivers | |
| parent | 002ba346e3d76bb2b09448beed06c5ea1b0e06b8 (diff) | |
crypto: atmel-sha204a - Set hwrng quality to lowest possible
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")
Cc: <stable@vger.kernel.org>
Signed-off-by: Marek Behún <kabel@kernel.org>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/crypto/atmel-sha204a.c | 6 |
1 files changed, 6 insertions, 0 deletions
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); |