change SSL certificate fingerprint whitelisting from SHA1 to SHA-256

SHA1 is too close to bruteforceable

contrib/epee/include/net/net_ssl.h

@@ -37,6 +37,8 @@
 #include <boost/asio/ssl.hpp>
 #include <boost/system/error_code.hpp>
 
+#define SSL_FINGERPRINT_SIZE 32
+
 namespace epee
 {
 namespace net_utils

contrib/epee/src/net_ssl.cpp

@@ -321,7 +321,7 @@ bool ssl_options_t::has_fingerprint(boost::asio::ssl::verify_context &ctx) const
     unsigned int size{ 0 };
 
     // create the digest from the certificate
-    if (!X509_digest(cert, EVP_sha1(), digest.data(), &size)) {
+    if (!X509_digest(cert, EVP_sha256(), digest.data(), &size)) {
       MERROR("Failed to create certificate fingerprint");
       return false;
     }

src/rpc/core_rpc_server.cpp

@@ -28,6 +28,7 @@
 // 
 // Parts of this file are originally copyright (c) 2012-2013 The Cryptonote developers
 
+#include <boost/preprocessor/stringize.hpp>
 #include "include_base_utils.h"
 #include "string_tools.h"
 using namespace epee;
@@ -159,6 +160,14 @@ namespace cryptonote
       const std::vector<std::string> ssl_allowed_fingerprint_strings = command_line::get_arg(vm, arg_rpc_ssl_allowed_fingerprints);
       std::vector<std::vector<uint8_t>> ssl_allowed_fingerprints{ ssl_allowed_fingerprint_strings.size() };
       std::transform(ssl_allowed_fingerprint_strings.begin(), ssl_allowed_fingerprint_strings.end(), ssl_allowed_fingerprints.begin(), epee::from_hex::vector);
+      for (const auto &fpr: ssl_allowed_fingerprints)
+      {
+        if (fpr.size() != SSL_FINGERPRINT_SIZE)
+        {
+          MERROR("SHA-256 fingerprint should be " BOOST_PP_STRINGIZE(SSL_FINGERPRINT_SIZE) " bytes long.");
+          return false;
+        }
+      }
 
       if (!ssl_ca_path.empty() || !ssl_allowed_fingerprints.empty())
         ssl_options = epee::net_utils::ssl_options_t{std::move(ssl_allowed_fingerprints), std::move(ssl_ca_path)};

src/wallet/wallet2.cpp

@@ -39,6 +39,7 @@
 #include <boost/algorithm/string/join.hpp>
 #include <boost/asio/ip/address.hpp>
 #include <boost/range/adaptor/transformed.hpp>
+#include <boost/preprocessor/stringize.hpp>
 #include "include_base_utils.h"
 using namespace epee;
 
@@ -340,6 +341,11 @@ std::unique_ptr<tools::wallet2> make_basic(const boost::program_options::variabl
   {
     std::vector<std::vector<uint8_t>> ssl_allowed_fingerprints{ daemon_ssl_allowed_fingerprints.size() };
     std::transform(daemon_ssl_allowed_fingerprints.begin(), daemon_ssl_allowed_fingerprints.end(), ssl_allowed_fingerprints.begin(), epee::from_hex::vector);
+    for (const auto &fpr: daemon_ssl_allowed_fingerprints)
+    {
+      THROW_WALLET_EXCEPTION_IF(fpr.size() != SSL_FINGERPRINT_SIZE, tools::error::wallet_internal_error,
+          "SHA-256 fingerprint should be " BOOST_PP_STRINGIZE(SSL_FINGERPRINT_SIZE) " bytes long.");
+    }
 
     ssl_options = epee::net_utils::ssl_options_t{
       std::move(ssl_allowed_fingerprints), std::move(daemon_ssl_ca_file)

src/wallet/wallet_rpc_server.cpp

@@ -31,6 +31,7 @@
 #include <boost/asio/ip/address.hpp>
 #include <boost/filesystem/operations.hpp>
 #include <boost/algorithm/string.hpp>
+#include <boost/preprocessor/stringize.hpp>
 #include <cstdint>
 #include "include_base_utils.h"
 using namespace epee;
@@ -254,6 +255,14 @@ namespace tools
     {
       std::vector<std::vector<uint8_t>> allowed_fingerprints{ rpc_ssl_allowed_fingerprints.size() };
       std::transform(rpc_ssl_allowed_fingerprints.begin(), rpc_ssl_allowed_fingerprints.end(), allowed_fingerprints.begin(), epee::from_hex::vector);
+      for (const auto &fpr: rpc_ssl_allowed_fingerprints)
+      {
+        if (fpr.size() != SSL_FINGERPRINT_SIZE)
+        {
+          MERROR("SHA-256 fingerprint should be " BOOST_PP_STRINGIZE(SSL_FINGERPRINT_SIZE) " bytes long.");
+          return false;
+        }
+      }
 
       rpc_ssl_options = epee::net_utils::ssl_options_t{
         std::move(allowed_fingerprints), std::move(rpc_ssl_ca_file)