[#3193] fixed double free when using botan

Author: Razvan Becheriu

src/lib/cryptolink/botan_link.cc

@@ -70,8 +70,6 @@ CryptoLink::initialize(CryptoLink& c) {
             isc_throw(InitializationError, "Botan error: " << ex.what());
         }
     }
-    // A not yet fixed bug makes RNG to be destroyed after memory pool...
-    atexit([]{ getCryptoLink().getRNG().reset(); });
 }
 
 std::string

src/lib/cryptolink/crypto_rng.cc

@@ -23,8 +23,7 @@ RNG::~RNG() {
 }
 
 std::vector<uint8_t>
-random(size_t len)
-{
+random(size_t len) {
     RNGPtr rng(CryptoLink::getCryptoLink().getRNG());
     return (rng->random(len));
 }

src/lib/cryptolink/crypto_rng.h

@@ -42,7 +42,7 @@ class RNG : private boost::noncopyable {
     virtual std::vector<uint8_t> random(size_t len) = 0;
 
 private:
-    friend RNGPtr& CryptoLink::getRNG();
+    friend RNGPtr const& CryptoLink::getRNG() const;
 };
 
 /// \brief Generate random value. 

src/lib/cryptolink/cryptolink.cc

@@ -30,8 +30,8 @@ CryptoLink::createHMAC(const void* secret, size_t secret_len,
     return (new HMAC(secret, secret_len, hash_algorithm));
 }
 
-RNGPtr&
-CryptoLink::getRNG() {
+RNGPtr const&
+CryptoLink::getRNG() const {
     return (rng_);
 }
 

src/lib/cryptolink/cryptolink.h

@@ -211,7 +211,7 @@ class CryptoLink : private boost::noncopyable {
     ///                           in a derived class
     /// \exception LibraryError if there was any unexpected exception
     ///                         in the underlying library
-    virtual RNGPtr& getRNG();
+    virtual RNGPtr const& getRNG() const;
 
 private:
     /// \brief Initialize the library