Fix #2140 - Check that producers are unique and corresponding accounts exist

libraries/chain/wasm_interface.cpp

@@ -142,6 +142,13 @@ class privileged_api : public context_aware_api {
          datastream<const char*> ds( packed_producer_schedule, datalen );
          producer_schedule_type psch;
          fc::raw::unpack(ds, psch);
+         // check that producers are unique
+         std::set<account_name> unique_producers;
+         for (const auto& p: psch.producers) {
+            EOS_ASSERT(context.is_account(p.producer_name), wasm_execution_error, "producer schedule includes a nonexisting account");
+            unique_producers.insert(p.producer_name);
+         }
+         EOS_ASSERT(psch.producers.size() == unique_producers.size(), wasm_execution_error, "duplicate producer name in producer schedule");
          context.mutable_db.modify( context.controller.get_global_properties(),
             [&]( auto& gprops ) {
                  gprops.new_active_producers = psch;

tests/chain_tests/block_tests.cpp

@@ -376,6 +376,7 @@ BOOST_AUTO_TEST_CASE(missed_blocks)
       for (char i = 'a'; i <= 'u'; i++) {
          producer_names.emplace_back(std::string("init") + i);
       }
+      chain.create_accounts(producer_names);
       chain.set_producers(producer_names);
 
       // Produce blocks until the next block production will use the new set of producers from beginning

tests/chain_tests/producer_schedule_tests.cpp

@@ -114,6 +114,31 @@ BOOST_AUTO_TEST_SUITE(producer_schedule_tests)
    } FC_LOG_AND_RETHROW()
 
 
+   BOOST_FIXTURE_TEST_CASE( verify_producers, TESTER ) try {
+      
+      vector<account_name> valid_producers = {
+         "inita", "initb", "initc", "initd", "inite", "initf", "initg",
+         "inith", "initi", "initj", "initk", "initl", "initm", "initn",
+         "inito", "initp", "initq", "initr", "inits", "initt", "initu"
+      };
+      create_accounts(valid_producers);
+      set_producers(valid_producers);
+
+      // account initz does not exist
+      vector<account_name> nonexisting_producer = { "initz" };
+      BOOST_CHECK_THROW(set_producers(nonexisting_producer), wasm_execution_error);
+      
+      // replace initg with inita, inita is now duplicate
+      vector<account_name> invalid_producers = {
+         "inita", "initb", "initc", "initd", "inite", "initf", "inita",
+         "inith", "initi", "initj", "initk", "initl", "initm", "initn",
+         "inito", "initp", "initq", "initr", "inits", "initt", "initu"
+      };
+
+      BOOST_CHECK_THROW(set_producers(invalid_producers), wasm_execution_error);
+
+   } FC_LOG_AND_RETHROW()
+
    BOOST_FIXTURE_TEST_CASE( verify_header_schedule_version, TESTER ) try {
 
       // Utility function to ensure that producer schedule version in the header is correct