diff options
| author | Marek Behún <kabel@kernel.org> | 2025-04-22 12:57:18 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-05-02 08:47:08 +0300 |
| commit | 4f9f61598b19d1e68ba33239199ba85f070ca00a (patch) | |
| tree | 9e18f06a9fe34927c6d75279813532202636a3f5 /drivers/crypto | |
| parent | 3a57f45b91fba0ddd5ec06e5e4fef65e7b98c696 (diff) | |
| download | linux-4f9f61598b19d1e68ba33239199ba85f070ca00a.tar.xz | |
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: 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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Marek Behún <kabel@kernel.org>
Diffstat (limited to 'drivers/crypto')
| -rw-r--r-- | drivers/crypto/atmel-sha204a.c | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/drivers/crypto/atmel-sha204a.c b/drivers/crypto/atmel-sha204a.c index a84b657598c6..51738c730717 100644 --- a/drivers/crypto/atmel-sha204a.c +++ b/drivers/crypto/atmel-sha204a.c @@ -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) |