Multisig made robust to replay attack

src/main/run/of_michelson.ml

@@ -83,13 +83,11 @@ let evaluate_michelson ?options program =
   let%bind etv = evaluate ?options program in
   ex_value_ty_to_michelson etv
 
-let pack_message_lambda (lambda:Michelson.t) =
-  let open Memory_proto_alpha.Protocol.Script_typed_ir in
-  let input_ty = Lambda_t (Unit_t None , List_t ((Operation_t None),None,false) , None) in
-  let%bind lambda =
+let pack_payload (payload:Michelson.t) ty =
+  let%bind payload =
     Trace.trace_tzresult_lwt (simple_error "error parsing message") @@
-    Memory_proto_alpha.parse_michelson_data lambda input_ty in
+    Memory_proto_alpha.parse_michelson_data payload ty in
   let%bind data =
     Trace.trace_tzresult_lwt (simple_error "error packing message") @@
-    Memory_proto_alpha.pack input_ty lambda in
+    Memory_proto_alpha.pack ty payload in
   ok @@ data

src/test/contracts/multisig.ligo

@@ -2,8 +2,10 @@
 type counter_t is nat
 type threshold_t is nat
 type authorized_keys_t is list(key)
+type id_t is string
 
 type storage_t is record
+  id : id_t ;
   counter : counter_t ;
   threshold : threshold_t ;
   auth : authorized_keys_t ;
@@ -28,14 +30,15 @@ function check_message (const param : check_message_pt;
   if param.counter =/= s.counter then
     failwith ("Counters does not match")
   else block {
-    var packed_msg : bytes := bytes_pack(message) ;
+    const packed_payload : bytes =
+      bytes_pack((message , param.counter , s.id , get_chain_id));
     var valid : nat := 0n ;
 
     for sig in list param.signatures block {
       var is_valid : bool := False ;
 
       for pk in list s.auth block {
-        if crypto_check(pk,sig,packed_msg) then is_valid := True
+        if crypto_check(pk,sig,packed_payload) then is_valid := True
         else skip;
       };
 

src/test/multisig_tests.ml

@@ -33,22 +33,26 @@ let str_keys (raw_pk, raw_sk) =
   let (sk_str:string) = Base58.simple_encode (Ed25519.Secret_key.b58check_encoding) raw_sk in
   (pk_str,sk_str)
 
-let sign_message (msg : expression) raw_sk : string result =
+let sign_message (payload : expression) raw_sk : string result =
   let open Tezos_crypto in
   let (sk : Signature.secret_key) = Signature.Ed25519 raw_sk in
   let%bind program,_ = get_program () in
-  let%bind (msg : Tezos_utils.Michelson.michelson) =
+  let%bind code =
     let env = Ast_typed.program_environment program in
-    Ligo.Run.Of_simplified.compile_expression ~env ~state:(Typer.Solver.initial_state) msg
-  in
-  let%bind msg' = Ligo.Run.Of_michelson.pack_message_lambda msg in
-  let (signed_data:Signature.t) = Signature.sign sk msg' in
+    Compile.Of_simplified.compile_expression_as_function
+      ~env ~state:(Typer.Solver.initial_state) payload in
+  let Compiler.Program.{input=_;output=(Ex_ty payload_ty);body=_} = code in
+  let%bind (payload: Tezos_utils.Michelson.michelson) =
+    Ligo.Run.Of_michelson.evaluate_michelson code in
+  let%bind packed_payload = Ligo.Run.Of_michelson.pack_payload payload payload_ty in
+  let (signed_data:Signature.t) = Signature.sign sk packed_payload in
   let signature_str = Signature.to_b58check signed_data in
   ok signature_str
 
 let init_storage threshold counter pkeys =
   let keys = List.map (fun el -> e_key @@ fst @@ str_keys el) pkeys in
   ez_e_record [
+    ("id" , e_string "MULTISIG" ) ;
     ("counter" , e_nat counter ) ;
     ("threshold" , e_nat threshold) ;
     ("auth" , e_typed_list keys t_key ) ;
@@ -59,11 +63,19 @@ let empty_op_list =
 let empty_message = e_lambda "arguments"
   (Some t_unit) (Some (t_list t_operation))
   empty_op_list
+let chain_id_zero = e_chain_id @@ Tezos_crypto.Base58.simple_encode
+  Tezos_base__TzPervasives.Chain_id.b58check_encoding
+  Tezos_base__TzPervasives.Chain_id.zero
 
 (* sign the same message 'msg' with the secret keys of 'keys' *)
 let params counter msg keys = 
   let aux = fun acc sk ->
-    let%bind signature = sign_message msg (snd sk) in
+    let payload = e_tuple
+      [ msg ; 
+        e_nat counter ; 
+        e_string "MULTISIG" ; 
+        chain_id_zero ] in
+    let%bind signature = sign_message payload (snd sk) in
     ok @@ (e_signature signature)::acc in
   let%bind signed_msgs = Trace.bind_fold_list aux [] keys in
   ok @@ e_constructor