Add recover_key & assert_recover_key to rodeos

libraries/rodeos/include/b1/rodeos/callbacks/crypto.hpp

@@ -1,10 +1,14 @@
 #pragma once
 
 #include <b1/rodeos/callbacks/vm_types.hpp>
+#include <eosio/chain/config.hpp>
+#include <fc/crypto/public_key.hpp>
 #include <fc/crypto/ripemd160.hpp>
 #include <fc/crypto/sha1.hpp>
 #include <fc/crypto/sha256.hpp>
 #include <fc/crypto/sha512.hpp>
+#include <fc/crypto/signature.hpp>
+#include <fc/io/datastream.hpp>
 
 namespace b1::rodeos {
 
@@ -15,8 +19,70 @@ struct crypto_callbacks {
       throw std::runtime_error("wasm called " + std::string(name) + ", which is unimplemented");
    }
 
-   void assert_recover_key(int, int, int, int, int) { return unimplemented<void>("assert_recover_key"); }
-   int  recover_key(int, int, int, int, int) { return unimplemented<int>("recover_key"); }
+   void assert_recover_key( legacy_ptr<const fc::sha256> digest,
+                            legacy_span<const char> sig,
+                            legacy_span<const char> pub ) const {
+      fc::crypto::signature s;
+      fc::crypto::public_key p;
+      fc::datastream<const char*> ds( sig.data(), sig.size() );
+      fc::datastream<const char*> pubds ( pub.data(), pub.size() );
+
+      fc::raw::unpack( ds, s );
+      fc::raw::unpack( pubds, p );
+
+      // TODO: enforce supported key types
+      // EOS_ASSERT(static_cast<unsigned>(s.which()) < db.get<protocol_state_object>().num_supported_key_types,
+      //            eosio::chain::unactivated_signature_type,
+      //            "Unactivated signature type used during assert_recover_key");
+      // EOS_ASSERT(static_cast<unsigned>(p.which()) < db.get<protocol_state_object>().num_supported_key_types,
+      //            eosio::chain::unactivated_key_type,
+      //            "Unactivated key type used during assert_recover_key");
+
+      // TODO: enforce subjective signature length limit maximum-variable-signature-length in queries. Filters don't need this protection.
+      //   EOS_ASSERT(s.variable_size() <= configured_subjective_signature_length_limit(),
+      //              eosio::chain::sig_variable_size_limit_exception, "signature variable length component size greater than subjective maximum");
+
+      auto check = fc::crypto::public_key( s, *digest, false );
+      EOS_ASSERT( check == p, eosio::chain::crypto_api_exception, "Error expected key different than recovered key" );
+   }
+
+   int32_t recover_key( legacy_ptr<const fc::sha256> digest,
+                                   legacy_span<const char> sig,
+                                   legacy_span<char> pub ) const {
+      fc::crypto::signature s;
+      fc::datastream<const char*> ds( sig.data(), sig.size() );
+      fc::raw::unpack(ds, s);
+
+      // TODO: enforce supported key types
+      // EOS_ASSERT(static_cast<unsigned>(s.which()) < db.get<protocol_state_object>().num_supported_key_types,
+      //            eosio::chain::unactivated_signature_type,
+      //            "Unactivated signature type used during assert_recover_key");
+
+      // TODO: enforce subjective signature length limit maximum-variable-signature-length in queries. Filters don't need this protection.
+      //   EOS_ASSERT(s.variable_size() <= configured_subjective_signature_length_limit(),
+      //              eosio::chain::sig_variable_size_limit_exception, "signature variable length component size greater than subjective maximum");
+
+      auto recovered = fc::crypto::public_key(s, *digest, false);
+
+      // the key types newer than the first 2 may be varible in length
+      if (static_cast<unsigned>(s.which()) >= eosio::chain::config::genesis_num_supported_key_types ) {
+         EOS_ASSERT(pub.size() >= 33, eosio::chain::wasm_execution_error,
+                    "destination buffer must at least be able to hold an ECC public key");
+         auto packed_pubkey = fc::raw::pack(recovered);
+         auto copy_size = std::min<size_t>(pub.size(), packed_pubkey.size());
+         std::memcpy(pub.data(), packed_pubkey.data(), copy_size);
+         return packed_pubkey.size();
+      } else {
+         // legacy behavior, key types 0 and 1 always pack to 33 bytes.
+         // this will do one less copy for those keys while maintaining the rules of
+         //    [0..33) dest sizes: assert (asserts in fc::raw::pack)
+         //    [33..inf) dest sizes: return packed size (always 33)
+         fc::datastream<char*> out_ds( pub.data(), pub.size() );
+         fc::raw::pack(out_ds, recovered);
+         return out_ds.tellp();
+      }
+   }
+
    void assert_sha256(int, int, int) { return unimplemented<void>("assert_sha256"); }
    void assert_sha1(int, int, int) { return unimplemented<void>("assert_sha1"); }
    void assert_sha512(int, int, int) { return unimplemented<void>("assert_sha512"); }