+static BN_BLINDING *rsa_get_blinding(RSA *rsa, int *local, BN_CTX *ctx)
+{
+ BN_BLINDING *ret;
+ int got_write_lock = 0;
+ CRYPTO_THREADID cur;
+
+ CRYPTO_r_lock(CRYPTO_LOCK_RSA);
+
+ if (rsa->blinding == NULL)
+ {
+ CRYPTO_r_unlock(CRYPTO_LOCK_RSA);
+ CRYPTO_w_lock(CRYPTO_LOCK_RSA);
+ got_write_lock = 1;
+
+ if (rsa->blinding == NULL)
+ rsa->blinding = RSA_setup_blinding(rsa, ctx);
+ }
+
+ ret = rsa->blinding;
+ if (ret == NULL)
+ goto err;
+
+ CRYPTO_THREADID_current(&cur);
+ if (!CRYPTO_THREADID_cmp(&cur, BN_BLINDING_thread_id(ret)))
+ {
+ /* rsa->blinding is ours! */
+
+ *local = 1;
+ }
+ else
+ {
+ /* resort to rsa->mt_blinding instead */
+
+ *local = 0; /* instructs rsa_blinding_convert(), rsa_blinding_invert()
+ * that the BN_BLINDING is shared, meaning that accesses
+ * require locks, and that the blinding factor must be
+ * stored outside the BN_BLINDING
+ */
+
+ if (rsa->mt_blinding == NULL)
+ {
+ if (!got_write_lock)
+ {
+ CRYPTO_r_unlock(CRYPTO_LOCK_RSA);
+ CRYPTO_w_lock(CRYPTO_LOCK_RSA);
+ got_write_lock = 1;
+ }
+
+ if (rsa->mt_blinding == NULL)
+ rsa->mt_blinding = RSA_setup_blinding(rsa, ctx);
+ }
+ ret = rsa->mt_blinding;
+ }
+
+ err:
+ if (got_write_lock)
+ CRYPTO_w_unlock(CRYPTO_LOCK_RSA);
+ else
+ CRYPTO_r_unlock(CRYPTO_LOCK_RSA);
+ return ret;
+}
+
+static int rsa_blinding_convert(BN_BLINDING *b, BIGNUM *f, BIGNUM *unblind,
+ BN_CTX *ctx)
+ {
+ if (unblind == NULL)
+ /* Local blinding: store the unblinding factor
+ * in BN_BLINDING. */
+ return BN_BLINDING_convert_ex(f, NULL, b, ctx);
+ else
+ {
+ /* Shared blinding: store the unblinding factor
+ * outside BN_BLINDING. */
+ int ret;
+ CRYPTO_w_lock(CRYPTO_LOCK_RSA_BLINDING);
+ ret = BN_BLINDING_convert_ex(f, unblind, b, ctx);
+ CRYPTO_w_unlock(CRYPTO_LOCK_RSA_BLINDING);
+ return ret;
+ }
+ }
+
+static int rsa_blinding_invert(BN_BLINDING *b, BIGNUM *f, BIGNUM *unblind,
+ BN_CTX *ctx)
+ {
+ /* For local blinding, unblind is set to NULL, and BN_BLINDING_invert_ex
+ * will use the unblinding factor stored in BN_BLINDING.
+ * If BN_BLINDING is shared between threads, unblind must be non-null:
+ * BN_BLINDING_invert_ex will then use the local unblinding factor,
+ * and will only read the modulus from BN_BLINDING.
+ * In both cases it's safe to access the blinding without a lock.
+ */
+ return BN_BLINDING_invert_ex(f, unblind, b, ctx);
+ }
+
+/* signing */