pki: Add ssh_pki_publickey_to_base64().

include/libssh/libssh.h

@@ -444,6 +444,9 @@ LIBSSH_API int ssh_pki_import_pubkey_file(ssh_session session,
                                           const char *filename,
                                           ssh_key *pkey);
 LIBSSH_API ssh_string ssh_pki_publickey_to_blob(const ssh_key key);
+LIBSSH_API int ssh_pki_publickey_to_base64(const ssh_key key,
+                                           unsigned char **b64_key,
+                                           enum ssh_keytypes_e *ptype);
 
 LIBSSH_API int ssh_userauth_pki_pubkey(ssh_session session, const char *username,
                             ssh_string publickey, ssh_key privatekey);

src/pki.c

@@ -714,6 +714,48 @@ ssh_string ssh_pki_publickey_to_blob(const ssh_key key)
     return pki_publickey_to_string(key);
 }
 
+/**
+ * @brief Convert a public key to a base64 hased key.
+ *
+ * @param[in] key       The key to hash
+ *
+ * @param[out] b64_key  A pointer to store the base64 hased key.
+ *
+ * @param[out] ptype    The type of the key.
+ *
+ * @return              SSH_OK on success, SSH_ERROR on error.
+ *
+ * @see ssh_string_free_char()
+ */
+int ssh_pki_publickey_to_base64(const ssh_key key, unsigned char **b64_key,
+        enum ssh_keytypes_e *ptype)
+{
+    enum ssh_keytypes_e type;
+    ssh_string key_str;
+    ssh_buffer key_buf;
+    char *type_c;
+    unsigned char *b64;
+    int rc;
+
+    if (key == NULL || b64_key == NULL || ptype == NULL) {
+        return SSH_ERROR;
+    }
+
+    key_str = pki_publickey_to_string(key);
+    if (key_str == NULL) {
+        return SSH_ERROR;
+    }
+
+
+    b64 = bin_to_base64(ssh_string_data(key_str), ssh_string_len(key_str));
+    ssh_string_free(key_str);
+
+    *ptype = type;
+    *b64_key = b64;
+
+    return SSH_OK;
+}
+
 /*
  * This function signs the session id (known as H) as a string then
  * the content of sigbuf */

tests/unittests/torture_pki.c

@@ -306,6 +306,11 @@ static void torture_pki_publickey_rsa_base64(void **state)
     rc = ssh_pki_import_pubkey_base64(session, q, type, &key);
     assert_true(rc == 0);
 
+    rc = ssh_pki_publickey_to_base64(key, &b64_key, &type);
+    assert_true(rc == 0);
+
+    assert_string_equal(q, b64_key);
+
     free(key_buf);
     ssh_key_free(key);
 }