crypto: add Certificate::getId(), Certificate::getUID()

include/opendht/crypto.h

@@ -122,13 +122,19 @@ struct Certificate : public Serializable {
     Certificate(const Blob& crt);
     Certificate(Certificate&& o) noexcept : cert(o.cert) { o.cert = nullptr; };
     Certificate& operator=(Certificate&& o) noexcept;
-
     ~Certificate();
-    operator bool() const { return cert; }
-    PublicKey getPublicKey() const;
+
     void pack(Blob& b) const override;
     void unpack(Blob::const_iterator& begin, Blob::const_iterator& end) override;
 
+    operator bool() const { return cert; }
+    PublicKey getPublicKey() const;
+
+    /** Same as getPublicKey().getId() */
+    InfoHash getId() const;
+
+    std::string getUID() const;
+
     gnutls_x509_crt_t cert {};
 private:
     Certificate(const Certificate&) = delete;

src/crypto.cpp

@@ -312,7 +312,8 @@ PublicKey::getId() const
 {
     InfoHash id;
     size_t sz = id.size();
-    gnutls_pubkey_get_key_id(pk, 0, id.data(), &sz);
+    if (gnutls_pubkey_get_key_id(pk, 0, id.data(), &sz) != GNUTLS_E_SUCCESS || sz != id.size())
+        return {};
     return id;
 }
 
@@ -380,6 +381,31 @@ Certificate::getPublicKey() const
     return pk_ret;
 }
 
+InfoHash
+Certificate::getId() const
+{
+    if (not cert)
+        return {};
+    InfoHash id;
+    size_t sz = id.size();
+    if (gnutls_x509_crt_get_key_id(cert, 0, id.data(), &sz) != GNUTLS_E_SUCCESS || sz != id.size())
+        throw std::runtime_error("Can't get certificate public key ID.");
+    return id;
+}
+
+std::string
+Certificate::getUID() const
+{
+    std::string uid;
+    uid.resize(512);
+    size_t uid_sz = uid.size();
+    int ret = gnutls_x509_crt_get_dn_by_oid(cert, GNUTLS_OID_LDAP_UID, 0, 0, &(*uid.begin()), &uid_sz);
+    if (ret != GNUTLS_E_SUCCESS)
+        return {};
+    uid.resize(uid_sz);
+    return uid;
+}
+
 PrivateKey
 PrivateKey::generate(unsigned key_length)
 {