[Cosmos]: Add ability to sign direct with TxBody bytes only

* Generate `AuthInfo` from `SigningInput` parameters if `SignDirect.auth_info_bytes` empty

rust/tw_cosmos_sdk/src/modules/compiler/tw_compiler.rs

@@ -62,7 +62,7 @@ impl<Context: CosmosContext> TWTransactionCompiler<Context> {
         input: Proto::SigningInput<'_>,
     ) -> SigningResult<CompilerProto::PreSigningOutput<'static>> {
         let tx_hasher = TxBuilder::<Context>::tx_hasher_from_proto(&input);
-        let preimage = match TxBuilder::<Context>::try_sign_direct_args(&input) {
+        let preimage = match TxBuilder::<Context>::try_sign_direct_args(coin, &input) {
             // If there was a `SignDirect` message in the signing input, generate the tx preimage directly.
             Ok(Some(sign_direct_args)) => {
                 ProtobufPreimager::<Context>::preimage_hash_direct(&sign_direct_args, tx_hasher)?
@@ -128,7 +128,7 @@ impl<Context: CosmosContext> TWTransactionCompiler<Context> {
         let params = TxBuilder::<Context>::public_key_params_from_proto(&input);
         let public_key = Context::PublicKey::from_bytes(coin, &public_key, params)?;
 
-        let signed_tx_raw = match TxBuilder::<Context>::try_sign_direct_args(&input) {
+        let signed_tx_raw = match TxBuilder::<Context>::try_sign_direct_args(coin, &input) {
             // If there was a `SignDirect` message in the signing input, generate the `TxRaw` directly.
             Ok(Some(sign_direct_args)) => ProtobufSerializer::<Context>::build_direct_signed_tx(
                 &sign_direct_args,

rust/tw_cosmos_sdk/src/modules/tx_builder.rs

@@ -4,7 +4,7 @@
 
 use crate::address::Address;
 use crate::context::CosmosContext;
-use crate::modules::serializer::protobuf_serializer::SignDirectArgs;
+use crate::modules::serializer::protobuf_serializer::{ProtobufSerializer, SignDirectArgs};
 use crate::public_key::{CosmosPublicKey, PublicKeyParams};
 use crate::transaction::message::cosmos_generic_message::JsonRawMessage;
 use crate::transaction::message::{CosmosMessage, CosmosMessageBox};
@@ -34,16 +34,10 @@ where
         coin: &dyn CoinContext,
         input: &Proto::SigningInput<'_>,
     ) -> SigningResult<UnsignedTransaction<Context>> {
-        let fee = input
-            .fee
-            .as_ref()
-            .or_tw_err(SigningErrorType::Error_wrong_fee)
-            .context("No fee specified")?;
         let signer = Self::signer_info_from_proto(coin, input)?;
-
         Ok(UnsignedTransaction {
             signer,
-            fee: Self::fee_from_proto(fee)?,
+            fee: Self::fee_from_proto(&input.fee)?,
             chain_id: input.chain_id.to_string(),
             account_number: input.account_number,
             tx_body: Self::tx_body_from_proto(coin, input)?,
@@ -86,15 +80,20 @@ where
         }
     }
 
-    fn fee_from_proto(input: &Proto::Fee) -> SigningResult<Fee<Context::Address>> {
-        let amounts = input
+    fn fee_from_proto(input: &Option<Proto::Fee>) -> SigningResult<Fee<Context::Address>> {
+        let fee_input = input
+            .as_ref()
+            .or_tw_err(SigningErrorType::Error_wrong_fee)
+            .context("No fee specified")?;
+
+        let amounts = fee_input
             .amounts
             .iter()
             .map(Self::coin_from_proto)
             .collect::<SigningResult<_>>()?;
         Ok(Fee {
             amounts,
-            gas_limit: input.gas,
+            gas_limit: fee_input.gas,
             payer: None,
             granter: None,
         })
@@ -133,6 +132,7 @@ where
     }
 
     pub fn try_sign_direct_args(
+        context: &dyn CoinContext,
         input: &Proto::SigningInput<'_>,
     ) -> SigningResult<Option<SignDirectArgs>> {
         use Proto::mod_Message::OneOfmessage_oneof as MessageEnum;
@@ -141,15 +141,30 @@ where
             return Ok(None);
         };
 
-        match msg.message_oneof {
-            MessageEnum::sign_direct_message(ref direct) => Ok(Some(SignDirectArgs {
-                tx_body: direct.body_bytes.to_vec(),
-                auth_info: direct.auth_info_bytes.to_vec(),
-                chain_id: input.chain_id.to_string(),
-                account_number: input.account_number,
-            })),
-            _ => Ok(None),
+        let MessageEnum::sign_direct_message(ref direct) = msg.message_oneof else {
+            return Ok(None);
+        };
+
+        if direct.body_bytes.is_empty() {
+            return SigningError::err(SigningErrorType::Error_invalid_params)
+                .context("`body_bytes` must not be empty");
         }
+
+        let auth_info = if direct.auth_info_bytes.is_empty() {
+            let signer = Self::signer_info_from_proto(context, input)?;
+            let fee = Self::fee_from_proto(&input.fee)?;
+            let auth_info = ProtobufSerializer::<Context>::build_auth_info(&signer, &fee);
+            serialize(&auth_info)?
+        } else {
+            direct.auth_info_bytes.to_vec()
+        };
+
+        Ok(Some(SignDirectArgs {
+            tx_body: direct.body_bytes.to_vec(),
+            auth_info,
+            chain_id: input.chain_id.to_string(),
+            account_number: input.account_number,
+        }))
     }
 
     pub fn tx_message(

rust/tw_cosmos_sdk/tests/sign.rs

@@ -285,6 +285,45 @@ fn test_sign_direct() {
     });
 }
 
+/// Build and sign a transaction with `TxBody` bytes only,
+/// and `AuthInfo` will be generated from `SigningInput` parameters.
+#[test]
+fn test_sign_direct_with_body_bytes() {
+    use tw_cosmos_sdk::proto::cosmos::tx::v1beta1 as tx_proto;
+
+    let coin = TestCoinContext::default()
+        .with_public_key_type(PublicKeyType::Secp256k1)
+        .with_hrp("cosmos");
+
+    let body_bytes = "0a89010a1c2f636f736d6f732e62616e6b2e763162657461312e4d736753656e6412690a2d636f736d6f733168736b366a727979716a6668703564686335357463396a74636b796778306570683664643032122d636f736d6f73317a743530617a7570616e716c66616d356166687633686578777975746e756b656834633537331a090a046d756f6e120131".decode_hex().unwrap();
+
+    let sign_direct = Proto::mod_Message::SignDirect {
+        body_bytes: Cow::from(body_bytes),
+        // Do not specify the `AuthInfo` bytes.
+        auth_info_bytes: Cow::default(),
+    };
+    let mut input = Proto::SigningInput {
+        account_number: 1037,
+        chain_id: "gaia-13003".into(),
+        fee: Some(make_fee(200000, make_amount("muon", "200"))),
+        sequence: 8,
+        private_key: account_1037_private_key(),
+        messages: vec![make_message(MessageEnum::sign_direct_message(sign_direct))],
+        ..Proto::SigningInput::default()
+    };
+
+    // real-world tx: https://www.mintscan.io/cosmos/txs/817101F3D96314AD028733248B28BAFAD535024D7D2C8875D3FE31DC159F096B
+    // curl -H 'Content-Type: application/json' --data-binary '{"tx_bytes": "Cr4BCr...1yKOU=", "mode": "BROADCAST_MODE_BLOCK"}' https://api.cosmos.network/cosmos/tx/v1beta1/txs
+    // also similar TX: BCDAC36B605576C8182C2829C808B30A69CAD4959D5ED1E6FF9984ABF280D603
+    test_sign_protobuf::<StandardCosmosContext>(TestInput {
+        coin: &coin,
+        input: input.clone(),
+        tx: r#"{"mode":"BROADCAST_MODE_BLOCK","tx_bytes":"CowBCokBChwvY29zbW9zLmJhbmsudjFiZXRhMS5Nc2dTZW5kEmkKLWNvc21vczFoc2s2anJ5eXFqZmhwNWRoYzU1dGM5anRja3lneDBlcGg2ZGQwMhItY29zbW9zMXp0NTBhenVwYW5xbGZhbTVhZmh2M2hleHd5dXRudWtlaDRjNTczGgkKBG11b24SATESZQpQCkYKHy9jb3Ntb3MuY3J5cHRvLnNlY3AyNTZrMS5QdWJLZXkSIwohAlcobsPzfTNVe7uqAAsndErJAjqplnyudaGB0f+R+p3FEgQKAggBGAgSEQoLCgRtdW9uEgMyMDAQwJoMGkD54fQAFlekIAnE62hZYl0uQelh/HLv0oQpCciY5Dn8H1SZFuTsrGdu41PH1Uxa4woptCELi/8Ov9yzdeEFAC9H"}"#,
+        signature: "f9e1f4001657a42009c4eb6859625d2e41e961fc72efd2842909c898e439fc1f549916e4ecac676ee353c7d54c5ae30a29b4210b8bff0ebfdcb375e105002f47",
+        signature_json: r#"[{"pub_key":{"type":"tendermint/PubKeySecp256k1","value":"AlcobsPzfTNVe7uqAAsndErJAjqplnyudaGB0f+R+p3F"},"signature":"+eH0ABZXpCAJxOtoWWJdLkHpYfxy79KEKQnImOQ5/B9UmRbk7KxnbuNTx9VMWuMKKbQhC4v/Dr/cs3XhBQAvRw=="}]"#,
+    });
+}
+
 #[test]
 fn test_sign_direct_0a90010a() {
     let coin = TestCoinContext::default()

src/proto/Cosmos.proto

@@ -240,8 +240,10 @@ message Message {
     // For signing an already serialized transaction. Account number and chain ID must be set outside.
     message SignDirect {
         // The prepared serialized TxBody
+        // Required
         bytes body_bytes = 1;
         // The prepared serialized AuthInfo
+        // Optional. If not provided, will be generated from `SigningInput` parameters.
         bytes auth_info_bytes = 2;
     }