static VALUE
kdf_hkdf(int argc, VALUE *argv, VALUE self)
{
VALUE ikm, salt, info, opts, kwargs[4], str;
static ID kwargs_ids[4];
int saltlen, ikmlen, infolen;
size_t len;
const EVP_MD *md;
EVP_PKEY_CTX *pctx;
if (!kwargs_ids[0]) {
kwargs_ids[0] = rb_intern_const("salt");
kwargs_ids[1] = rb_intern_const("info");
kwargs_ids[2] = rb_intern_const("length");
kwargs_ids[3] = rb_intern_const("hash");
}
rb_scan_args(argc, argv, "1:", &ikm, &opts);
rb_get_kwargs(opts, kwargs_ids, 4, 0, kwargs);
StringValue(ikm);
ikmlen = RSTRING_LENINT(ikm);
salt = StringValue(kwargs[0]);
saltlen = RSTRING_LENINT(salt);
info = StringValue(kwargs[1]);
infolen = RSTRING_LENINT(info);
len = (size_t)NUM2LONG(kwargs[2]);
if (len > LONG_MAX)
rb_raise(rb_eArgError, "length must be non-negative");
md = ossl_evp_get_digestbyname(kwargs[3]);
str = rb_str_new(NULL, (long)len);
pctx = EVP_PKEY_CTX_new_id(EVP_PKEY_HKDF, NULL);
if (!pctx)
ossl_raise(eKDF, "EVP_PKEY_CTX_new_id");
if (EVP_PKEY_derive_init(pctx) <= 0) {
EVP_PKEY_CTX_free(pctx);
ossl_raise(eKDF, "EVP_PKEY_derive_init");
}
if (EVP_PKEY_CTX_set_hkdf_md(pctx, md) <= 0) {
EVP_PKEY_CTX_free(pctx);
ossl_raise(eKDF, "EVP_PKEY_CTX_set_hkdf_md");
}
if (EVP_PKEY_CTX_set1_hkdf_salt(pctx, (unsigned char *)RSTRING_PTR(salt),
saltlen) <= 0) {
EVP_PKEY_CTX_free(pctx);
ossl_raise(eKDF, "EVP_PKEY_CTX_set_hkdf_salt");
}
if (EVP_PKEY_CTX_set1_hkdf_key(pctx, (unsigned char *)RSTRING_PTR(ikm),
ikmlen) <= 0) {
EVP_PKEY_CTX_free(pctx);
ossl_raise(eKDF, "EVP_PKEY_CTX_set_hkdf_key");
}
if (EVP_PKEY_CTX_add1_hkdf_info(pctx, (unsigned char *)RSTRING_PTR(info),
infolen) <= 0) {
EVP_PKEY_CTX_free(pctx);
ossl_raise(eKDF, "EVP_PKEY_CTX_set_hkdf_info");
}
if (EVP_PKEY_derive(pctx, (unsigned char *)RSTRING_PTR(str), &len) <= 0) {
EVP_PKEY_CTX_free(pctx);
ossl_raise(eKDF, "EVP_PKEY_derive");
}
rb_str_set_len(str, (long)len);
EVP_PKEY_CTX_free(pctx);
return str;
}