Add PK_Signer::signature_length

2 files changed, 10 insertions, 6 deletions

diff --git a/src/lib/prov/openssl/openssl_ec.cpp b/src/lib/prov/openssl/openssl_ec.cpp
index b9e53b6fd..33f277d5a 100644
--- a/src/lib/prov/openssl/openssl_ec.cpp
+++ b/src/lib/prov/openssl/openssl_ec.cpp
@@ -229,8 +229,11 @@ class OpenSSL_ECDSA_Signing_Operation final : public PK_Ops::Signature_with_EMSA
 
          const EC_GROUP* group = ::EC_KEY_get0_group(m_ossl_ec.get());
          m_order_bits = ::EC_GROUP_get_degree(group);
+         m_order_bytes = (m_order_bits + 7) / 8;
          }
 
+      size_t signature_length() const { return 2*m_order_bytes; }
+
       secure_vector<uint8_t> raw_sign(const uint8_t msg[], size_t msg_len,
                                    RandomNumberGenerator&) override
          {
@@ -240,8 +243,6 @@ class OpenSSL_ECDSA_Signing_Operation final : public PK_Ops::Signature_with_EMSA
          if(!sig)
             throw OpenSSL_Error("ECDSA_do_sign");
 
-         const size_t order_bytes = (m_order_bits + 7) / 8;
-
 #if OPENSSL_VERSION_NUMBER < 0x10100000L || defined(LIBRESSL_VERSION_NUMBER)
          const BIGNUM* r = sig->r;
          const BIGNUM* s = sig->s;
@@ -253,9 +254,9 @@ class OpenSSL_ECDSA_Signing_Operation final : public PK_Ops::Signature_with_EMSA
 
          const size_t r_bytes = BN_num_bytes(r);
          const size_t s_bytes = BN_num_bytes(s);
-         secure_vector<uint8_t> sigval(2*order_bytes);
-         BN_bn2bin(r, &sigval[order_bytes - r_bytes]);
-         BN_bn2bin(s, &sigval[2*order_bytes - s_bytes]);
+         secure_vector<uint8_t> sigval(2*m_order_bytes);
+         BN_bn2bin(r, &sigval[m_order_bytes - r_bytes]);
+         BN_bn2bin(s, &sigval[2*m_order_bytes - s_bytes]);
          return sigval;
          }
 
@@ -263,7 +264,8 @@ class OpenSSL_ECDSA_Signing_Operation final : public PK_Ops::Signature_with_EMSA
 
    private:
       std::unique_ptr<EC_KEY, std::function<void (EC_KEY*)>> m_ossl_ec;
-      size_t m_order_bits = 0;
+      size_t m_order_bits;
+      size_t m_order_bytes;
    };
 
 }
diff --git a/src/lib/prov/openssl/openssl_rsa.cpp b/src/lib/prov/openssl/openssl_rsa.cpp
index 6385bcbb3..cf9c2b52b 100644
--- a/src/lib/prov/openssl/openssl_rsa.cpp
+++ b/src/lib/prov/openssl/openssl_rsa.cpp
@@ -205,6 +205,8 @@ class OpenSSL_RSA_Signing_Operation final : public PK_Ops::Signature_with_EMSA
             throw OpenSSL_Error("d2i_RSAPrivateKey");
          }
 
+      size_t signature_length() const override { return ::RSA_size(m_openssl_rsa.get()); }
+
       secure_vector<uint8_t> raw_sign(const uint8_t msg[], size_t msg_len,
                                    RandomNumberGenerator&) override
          {