[openssl-dev] [openssl.org #4280] OpenSSL 1.1.0 pre 2: feature request: ECDSA_SIG_set0(const ECDSA_SIG*, BIGNUM *, BIGNUM *) is needed

[Douglas E Engert]

I agree.

Until OpenSSL adds a ECDSA_SIG_set0 there is a way, for example:

         rv = PKCS11_ecdsa_sign(dgst, dlen, sigret, &siglen, key);
         nLen = siglen / 2;
         if (rv > 0) {
                 sig = ECDSA_SIG_new();
                 if (sig) {
#if OPENSSL_VERSION_NUMBER >= 0x10100000L
                 /*
                  * OpenSSL 1.1 does not have a way to allocate r and s
                  * in ECDSA_SIG as it is now hidden.
                  * Will us dummy ASN1 so r and s are allocated then
                  * use ECDSA_SIG_get0 to get access to r and s
                  * can then update r annd s
                  */
                         const unsigned char *a;
                         unsigned char dasn1[8] =
                                 {0x30, 0x06, 0x02, 0x01, 0x00, 0x02, 0x01, 0x00};
                         BIGNUM *r;
                         BIGNUM *s;
                         a = dasn1;
                         d2i_ECDSA_SIG(&sig, &a, 8);
                         ECDSA_SIG_get0(&r, &s, sig);
                         BN_bin2bn(&sigret[0], nLen, r);
                         BN_bin2bn(&sigret[nLen], nLen, s);
#else
                         BN_bin2bn(&sigret[0], nLen, sig->r);
                         BN_bin2bn(&sigret[nLen], nLen, sig->s);
#endif
                 }
         }
         return sig;

On 1/29/2016 3:59 AM, Aleksey Sanin via RT wrote:
> Hello,
>
> At the moment, there is no way to set r/s in the ECDSA_SIG structure
> manually to verify the signature encoded into a different format.
> Would be great to add a simple function:
>
> void ECDSA_SIG_set0(const ECDSA_SIG*, BIGNUM *, BIGNUM *)
>
> to set these values similar to other XXX_set0() functions.
>
> Thanks,
>

-- 

  Douglas E. Engert  <DEEngert at gmail.com>