+/*
+ * NB: this wrapper would normally be placed in rsa_lib.c and the static
+ * implementation would probably be in rsa_eay.c. Nonetheless, is kept here
+ * so that we don't introduce a new linker dependency. Eg. any application
+ * that wasn't previously linking object code related to key-generation won't
+ * have to now just because key-generation is part of RSA_METHOD.
+ */
+int RSA_generate_key_ex(RSA *rsa, int bits, BIGNUM *e_value, BN_GENCB *cb)
+{
+ if (rsa->meth->rsa_keygen)
+ return rsa->meth->rsa_keygen(rsa, bits, e_value, cb);
+ return rsa_builtin_keygen(rsa, bits, e_value, cb);
+}
+
+static int rsa_builtin_keygen(RSA *rsa, int bits, BIGNUM *e_value,
+ BN_GENCB *cb)
+{
+ BIGNUM *r0 = NULL, *r1 = NULL, *r2 = NULL, *r3 = NULL, *tmp;
+ BIGNUM *local_r0, *local_d, *local_p;
+ BIGNUM *pr0, *d, *p;
+ int bitsp, bitsq, ok = -1, n = 0;
+ BN_CTX *ctx = NULL;
+
+ local_r0 = BN_new();
+ local_d = BN_new();
+ local_p = BN_new();
+ if (!local_r0 || !local_d || !local_p)
+ goto err;
+
+ ctx = BN_CTX_new();
+ if (ctx == NULL)
+ goto err;
+ BN_CTX_start(ctx);
+ r0 = BN_CTX_get(ctx);
+ r1 = BN_CTX_get(ctx);
+ r2 = BN_CTX_get(ctx);
+ r3 = BN_CTX_get(ctx);
+ if (r3 == NULL)
+ goto err;
+
+ bitsp = (bits + 1) / 2;
+ bitsq = bits - bitsp;
+
+ /* We need the RSA components non-NULL */
+ if (!rsa->n && ((rsa->n = BN_new()) == NULL))
+ goto err;
+ if (!rsa->d && ((rsa->d = BN_new()) == NULL))
+ goto err;
+ if (!rsa->e && ((rsa->e = BN_new()) == NULL))
+ goto err;
+ if (!rsa->p && ((rsa->p = BN_new()) == NULL))
+ goto err;
+ if (!rsa->q && ((rsa->q = BN_new()) == NULL))
+ goto err;
+ if (!rsa->dmp1 && ((rsa->dmp1 = BN_new()) == NULL))
+ goto err;
+ if (!rsa->dmq1 && ((rsa->dmq1 = BN_new()) == NULL))
+ goto err;
+ if (!rsa->iqmp && ((rsa->iqmp = BN_new()) == NULL))
+ goto err;
+
+ BN_copy(rsa->e, e_value);
+
+ /* generate p and q */
+ for (;;) {
+ if (!BN_generate_prime_ex(rsa->p, bitsp, 0, NULL, NULL, cb))
+ goto err;
+ if (!BN_sub(r2, rsa->p, BN_value_one()))
+ goto err;
+ if (!BN_gcd(r1, r2, rsa->e, ctx))
+ goto err;
+ if (BN_is_one(r1))
+ break;
+ if (!BN_GENCB_call(cb, 2, n++))
+ goto err;
+ }
+ if (!BN_GENCB_call(cb, 3, 0))
+ goto err;
+ for (;;) {
+ /*
+ * When generating ridiculously small keys, we can get stuck
+ * continually regenerating the same prime values. Check for this and
+ * bail if it happens 3 times.
+ */
+ unsigned int degenerate = 0;
+ do {
+ if (!BN_generate_prime_ex(rsa->q, bitsq, 0, NULL, NULL, cb))
+ goto err;
+ } while ((BN_cmp(rsa->p, rsa->q) == 0) && (++degenerate < 3));
+ if (degenerate == 3) {
+ ok = 0; /* we set our own err */
+ RSAerr(RSA_F_RSA_BUILTIN_KEYGEN, RSA_R_KEY_SIZE_TOO_SMALL);
+ goto err;
+ }
+ if (!BN_sub(r2, rsa->q, BN_value_one()))
+ goto err;
+ if (!BN_gcd(r1, r2, rsa->e, ctx))
+ goto err;
+ if (BN_is_one(r1))
+ break;
+ if (!BN_GENCB_call(cb, 2, n++))
+ goto err;
+ }
+ if (!BN_GENCB_call(cb, 3, 1))
+ goto err;
+ if (BN_cmp(rsa->p, rsa->q) < 0) {
+ tmp = rsa->p;
+ rsa->p = rsa->q;
+ rsa->q = tmp;
+ }
+
+ /* calculate n */
+ if (!BN_mul(rsa->n, rsa->p, rsa->q, ctx))
+ goto err;
+
+ /* calculate d */
+ if (!BN_sub(r1, rsa->p, BN_value_one()))
+ goto err; /* p-1 */
+ if (!BN_sub(r2, rsa->q, BN_value_one()))
+ goto err; /* q-1 */
+ if (!BN_mul(r0, r1, r2, ctx))
+ goto err; /* (p-1)(q-1) */
+ if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) {
+ pr0 = local_r0;
+ BN_with_flags(pr0, r0, BN_FLG_CONSTTIME);
+ } else
+ pr0 = r0;
+ if (!BN_mod_inverse(rsa->d, rsa->e, pr0, ctx))
+ goto err; /* d */
+
+ /* set up d for correct BN_FLG_CONSTTIME flag */
+ if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) {
+ d = local_d;
+ BN_with_flags(d, rsa->d, BN_FLG_CONSTTIME);
+ } else
+ d = rsa->d;
+
+ /* calculate d mod (p-1) */
+ if (!BN_mod(rsa->dmp1, d, r1, ctx))
+ goto err;
+
+ /* calculate d mod (q-1) */
+ if (!BN_mod(rsa->dmq1, d, r2, ctx))
+ goto err;
+
+ /* calculate inverse of q mod p */
+ if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) {
+ p = local_p;
+ BN_with_flags(p, rsa->p, BN_FLG_CONSTTIME);
+ } else
+ p = rsa->p;
+ if (!BN_mod_inverse(rsa->iqmp, rsa->q, p, ctx))
+ goto err;
+
+ ok = 1;
+ err:
+ if (local_r0)
+ BN_free(local_r0);
+ if (local_d)
+ BN_free(local_d);
+ if (local_p)
+ BN_free(local_p);
+ if (ok == -1) {
+ RSAerr(RSA_F_RSA_BUILTIN_KEYGEN, ERR_LIB_BN);
+ ok = 0;
+ }
+ if (ctx != NULL) {
+ BN_CTX_end(ctx);
+ BN_CTX_free(ctx);
+ }
+
+ return ok;
+}