- BIGNUM *kinv=NULL,*r=NULL;
- BIGNUM *m=NULL;
- BIGNUM *xr=NULL,*s=NULL;
- BN_CTX *ctx=NULL;
- unsigned char *p;
- int i,len=0,ret=0,reason=ERR_R_BN_LIB;
- ASN1_INTEGER rbs,sbs;
- MS_STATIC unsigned char rbuf[50]; /* assuming r is 20 bytes +extra */
- MS_STATIC unsigned char sbuf[50]; /* assuming s is 20 bytes +extra */
-
- i=BN_num_bytes(dsa->q); /* should be 20 */
- if ((dlen > i) || (dlen > 50))
- {
- reason=DSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE;
- goto err;
- }
-
- ctx=BN_CTX_new();
- if (ctx == NULL) goto err;
-
- if ((dsa->kinv == NULL) || (dsa->r == NULL))
- {
- if (!DSA_sign_setup(dsa,ctx,&kinv,&r)) goto err;
- }
- else
- {
- kinv=dsa->kinv;
- dsa->kinv=NULL;
- r=dsa->r;
- dsa->r=NULL;
- }
-
- m=BN_new();
- xr=BN_new();
- s=BN_new();
- if (m == NULL || xr == NULL || s == NULL) goto err;
-
- if (BN_bin2bn(dgst,dlen,m) == NULL) goto err;
-
- /* Compute s = inv(k) (m + xr) mod q */
- if (!BN_mul(xr, dsa->priv_key, r)) goto err; /* s = xr */
- if (!BN_add(s, xr, m)) goto err; /* s = m + xr */
- if (!BN_mod_mul(s,s,kinv,dsa->q,ctx)) goto err;
-
- /*
- * Now create a ASN.1 sequence of the integers R and S.
- */
- rbs.data=rbuf;
- sbs.data=sbuf;
- rbs.type = V_ASN1_INTEGER;
- sbs.type = V_ASN1_INTEGER;
- rbs.length=BN_bn2bin(r,rbs.data);
- sbs.length=BN_bn2bin(s,sbs.data);
-
- len =i2d_ASN1_INTEGER(&rbs,NULL);
- len+=i2d_ASN1_INTEGER(&sbs,NULL);
-
- p=sig;
- ASN1_put_object(&p,1,len,V_ASN1_SEQUENCE,V_ASN1_UNIVERSAL);
- i2d_ASN1_INTEGER(&rbs,&p);
- i2d_ASN1_INTEGER(&sbs,&p);
- *siglen=(p-sig);
- ret=1;
-err:
- if (!ret) DSAerr(DSA_F_DSA_SIGN,reason);
-
-#if 1 /* do the right thing :-) */
- if (kinv != NULL) BN_clear_free(kinv);
- if (r != NULL) BN_clear_free(r);
-#endif
- if (ctx != NULL) BN_CTX_free(ctx);
- if (m != NULL) BN_clear_free(m);
- if (xr != NULL) BN_clear_free(xr);
- if (s != NULL) BN_clear_free(s);
- return(ret);