1 files changed, 103 insertions, 0 deletions
diff --git a/credentials.hh b/credentials.hh
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+++ b/credentials.hh
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+/*
+ * This file is part of PowerDNS or dnsdist.
+ * Copyright -- PowerDNS.COM B.V. and its contributors
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * In addition, for the avoidance of any doubt, permission is granted to
+ * link this program with OpenSSL and to (re)distribute the binaries
+ * produced as the result of such linking.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+#pragma once
+
+#include <memory>
+#include <string>
+
+class SensitiveData
+{
+public:
+  SensitiveData(size_t bytes);
+  SensitiveData(std::string&& data);
+  SensitiveData& operator=(SensitiveData&&);
+
+  ~SensitiveData();
+  void clear();
+  const std::string& getString() const
+  {
+    return d_data;
+  }
+  std::string& getString()
+  {
+    return d_data;
+  }
+
+private:
+  std::string d_data;
+};
+
+std::string hashPassword(const std::string& password);
+std::string hashPassword(const std::string& password, uint64_t workFactor, uint64_t parallelFactor, uint64_t blockSize);
+bool verifyPassword(const std::string& hash, const std::string& password);
+bool verifyPassword(const std::string& binaryHash, const std::string& salt, uint64_t workFactor, uint64_t parallelFactor, uint64_t blockSize, const std::string& binaryPassword);
+bool isPasswordHashed(const std::string& password);
+
+class CredentialsHolder
+{
+public:
+  /* if hashPlaintext is true, the password is in cleartext and hashing is available,
+     the hashed form will be kept in memory.
+     Note that accepting hashed password from an untrusted source might open
+     us to a denial of service, since we currently don't cap the the parameters,
+     including the work factor */
+  CredentialsHolder(std::string&& password, bool hashPlaintext);
+  ~CredentialsHolder();
+
+  CredentialsHolder(const CredentialsHolder&) = delete;
+  CredentialsHolder& operator=(const CredentialsHolder&) = delete;
+
+  bool matches(const std::string& password) const;
+  /* whether it was constructed from a hashed and salted string */
+  bool wasHashed() const
+  {
+    return d_wasHashed;
+  }
+  /* whether it is hashed in memory */
+  bool isHashed() const
+  {
+    return d_isHashed;
+  }
+
+  static bool isHashingAvailable();
+  static SensitiveData readFromTerminal();
+
+  static uint64_t const s_defaultWorkFactor;
+  static uint64_t const s_defaultParallelFactor;
+  static uint64_t const s_defaultBlockSize;
+
+private:
+  SensitiveData d_credentials;
+  /* if the password is hashed, we only extract
+     the salt and parameters once */
+  std::string d_salt;
+  uint64_t d_workFactor{0};
+  uint64_t d_parallelFactor{0};
+  uint64_t d_blockSize{0};
+  /* seed our hash so it's not predictable */
+  uint32_t d_fallbackHashPerturb{0};
+  uint32_t d_fallbackHash{0};
+  /* whether it was constructed from a hashed and salted string */
+  bool d_wasHashed{false};
+  /* whether it is hashed in memory */
+  bool d_isHashed{false};
+};