On Tue, Jan 26, 2016 at 07:20:59AM +0100, Stephan Mueller wrote:
>
> +/*
> + * Implementation of the KDF in counter mode according to SP800-108 section
> 5.1.
> + *
> + * The caller must provide Label || 0x00 || Context in src. This src pointer
> + * may also be NULL if the caller wishes not to provide anything.
> + */
> +static int crypto_kdf_ctr_random(struct crypto_rng *rng,
> + const u8 *src, unsigned int slen,
> + u8 *dst, unsigned int dlen)
> +{
> + struct crypto_kdf_ctx *ctx = crypto_tfm_ctx(crypto_rng_tfm(rng));
> + struct shash_desc *desc = &ctx->shash;
> + unsigned int h = crypto_shash_digestsize(desc->tfm);
> + int err = 0;
> + u8 *dst_orig = dst;
> + u32 i = 1;
> + u8 iteration[sizeof(u32)];
> +
> + /* enforce the note from above */
> + if (dlen != h && src == dst)
> + return -EINVAL;
Why is this an RNG? It always produces exactly h bytes so it looks
like a hash function to me, no?
Cheers,
--
Email: Herbert Xu <[email protected]>
Home Page: http://gondor.apana.org.au/~herbert/
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