Stephan,
On Sun, Jan 06, 2019 at 07:11:50PM +0100, Stephan Müller wrote:
> Am Sonntag, 6. Januar 2019, 14:36:08 CET schrieb Vitaly Chikunov:
>
> > Add Elliptic Curve Russian Digital Signature Algorithm (GOST R
> > 34.10-2012, RFC 7091, ISO/IEC 14888-3) is one of the Russian (and since
> > 2018 the CIS countries) cryptographic standard algorithms (called GOST
> > algorithms). Only signature verification is supported, with intent to be
> > used in the IMA.
>
> Do you happen to have test vectors for the testmgr?
Yes, I will add this.
> > +/* Parse DER encoded subjectPublicKey. */
> > +static int ecrdsa_set_pub_key(struct crypto_akcipher *tfm, const void *ber,
> > + unsigned int len)
> > +{
> > + struct ecrdsa_ctx *ctx = akcipher_tfm_ctx(tfm);
> > + unsigned int ndigits;
> > + const u8 *k = ber;
> > + unsigned int offset;
> > +
> > + /* First chance to zero ctx */
> > + memset(ctx, 0, sizeof(*ctx));
> > +
> > + if (len < 3 ||
> > + k[0] != 0x04 || /* OCTET STRING */
> > + (k[1] < 0x80 && len != k[1] + 2) ||
> > + (k[1] == 0x81 && len != k[2] + 3) ||
> > + k[1] > 0x81)
> > + return -EBADMSG;
> > + offset = (k[1] < 0x80)? 2 : 3;
> > + k += offset;
> > + len -= offset;
>
> Why do you manually parse the ASN.1 structure instead of using the ASN.1
> parser?
I am not sure this worth effort and will not be most degenerate use of
asn1_ber_decoder, since 1) I only need to parse one type in each case:
OCTET STRING string above code, and OIDs in below code; 2) this data is
said to be in DER format, which asn1_ber_decoder can not enforce. Surely
this will also produce more code and files.
> > +/* Parse DER encoded SubjectPublicKeyInfo.AlgorithmIdentifier.parameters.
> > */ +static int ecrdsa_set_params(struct crypto_akcipher *tfm, enum OID
> > algo, + const void *params, unsigned int paramlen)
> > +{
> > + struct ecrdsa_ctx *ctx = akcipher_tfm_ctx(tfm);
> > + const u8 *p = params;
> > + int i;
> > +
> > + if (algo == OID_gost2012PublicKey256) {
> > + ctx->digest = "streebog256";
> > + ctx->digest_oid = OID_gost2012Digest256;
> > + ctx->digest_len = 256 / 8;
> > + } else if (algo == OID_gost2012PublicKey512) {
> > + ctx->digest = "streebog512";
> > + ctx->digest_oid = OID_gost2012Digest512;
> > + ctx->digest_len = 512 / 8;
> > + } else
> > + return -ENOPKG;
> > + ctx->curve = NULL;
> > + ctx->curve_oid = 0;
> > + ctx->algo_oid = algo;
> > +
> > + for (i = 0; i < paramlen; i += p[i + 1] + 2) {
> > + const struct ecc_curve *curve;
> > + enum OID oid;
> > +
> > + if (paramlen - i < 2 ||
> > + p[i] != 0x06 || /* OBJECT IDENTIFIER */
>
> Same here and in the following
>
> > + p[i + 1] > paramlen - i - 2)
> > + return -EBADMSG;
> > + oid = look_up_OID(p + i + 2, p[i + 1]);
> > +MODULE_ALIAS_CRYPTO("ecrdsa");
>
> I do not think you need that alias as the module name already will be named
> this way. I guess you rather should add ecrdsa-generic as module alias.
Thanks!
