Re: [PATCH 04/14] crypto: jitterentropy - Add library API

[Thomas Huth <thuth@redhat.com>]

Am 18.10.26 um 22:46 schrieb Eric Biggers:
> Make the jitterentropy RNG accessible using a regular set of functions.
> 
> This will allow drbg.c to just access it directly, instead of going
> through the overly-general crypto_rng abstraction.
> 
> Later commits will remove crypto_rng.
> 
> Note that the library API should also continue to meet all the same
> certification requirements, including the health check which occurs on
> the first call to crypto_jent_alloc().
> 
> Signed-off-by: Eric Biggers <ebiggers@kernel.org>
> ---
...
> +int crypto_jent_get_bytes(struct jitterentropy *rng, u8 *out,
> +			  unsigned int out_len)
> +{
> +	int ret;
> +
> +	guard(mutex)(&rng->jent_lock);
> +
> +	ret = jent_read_entropy(rng->entropy_collector, out, out_len);
> +
> +	if (ret == -3) {
> +		/* Handle permanent health test error */
> +		/*
> +		 * If the kernel was booted with fips=1, it implies that
> +		 * the entire kernel acts as a FIPS 140 module. In this case
> +		 * an SP800-90B permanent health test error is treated as
> +		 * a FIPS module error.
> +		 */
> +		if (fips_enabled)
> +			panic("Jitter RNG permanent health test failure\n");
> +
> +		pr_err("Jitter RNG permanent health test failure\n");
> +		return -EFAULT;
EFAULT means "bad address" in the sense of a page fault ... not sure whether 
this is the appropriate error code here? Maybe -EIO would be a better fit?

  Thomas