Merge pull request #10 from monlovesmango/main

enforce vault input index of 0
taproot-wizards · Sep 27, 2024 · 48b7ee9 · 48b7ee9
2 parents a275943 + 500e8ff
commit 48b7ee9
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Showing 3 changed files with 14 additions and 4 deletions.
diff --git a/src/vault/contract.rs b/src/vault/contract.rs
@@ -203,6 +203,7 @@ impl VaultCovenant {
         let tx_commitment_spec = TxCommitmentSpec {
             prev_sciptpubkeys: false,
             prev_amounts: false,
+            input_index: false,
             outputs: false,
             ..Default::default()
         };
@@ -466,6 +467,7 @@ impl VaultCovenant {
         let tx_commitment_spec = TxCommitmentSpec {
             prev_sciptpubkeys: false,
             prev_amounts: false,
+            input_index: false,
             outputs: false,
             ..Default::default()
         };

diff --git a/src/vault/script.rs b/src/vault/script.rs
@@ -28,6 +28,8 @@ pub(crate) fn vault_trigger_withdrawal() -> ScriptBuf {
         // start with encoded leaf hash
         .push_opcode(OP_CAT) // encoded leaf hash
         .push_opcode(OP_CAT) // encoded leaf hash
+        .push_slice([0x00u8, 0x00u8, 0x00u8, 0x00u8]) // add input index of 0
+        .push_opcode(OP_SWAP) // bring working sigmsg back to top of stack
         .push_opcode(OP_CAT) // input index
         .push_opcode(OP_CAT) // spend type
         .push_slice(*DUST_AMOUNT) // push the dust amount for the target output
@@ -161,6 +163,8 @@ pub(crate) fn vault_cancel_withdrawal() -> ScriptBuf {
         // start with encoded leaf hash
         .push_opcode(OP_CAT) // encoded leaf hash
         .push_opcode(OP_CAT) // encoded leaf hash
+        .push_slice([0x00u8, 0x00u8, 0x00u8, 0x00u8]) // add input index of 0
+        .push_opcode(OP_SWAP) // bring working sigmsg back to top of stack
         .push_opcode(OP_CAT) // input index
         .push_opcode(OP_CAT) // spend type
         .push_opcode(OP_FROMALTSTACK) // get the output amount

diff --git a/src/vault/signature_building.rs b/src/vault/signature_building.rs
@@ -44,6 +44,7 @@ pub(crate) struct TxCommitmentSpec {
     pub(crate) prev_amounts: bool,
     pub(crate) prev_sciptpubkeys: bool,
     pub(crate) sequences: bool,
+    pub(crate) input_index: bool,
     pub(crate) outputs: bool,
     pub(crate) spend_type: bool,
     pub(crate) annex: bool,
@@ -62,6 +63,7 @@ impl Default for TxCommitmentSpec {
             prev_amounts: true,
             prev_sciptpubkeys: true,
             sequences: true,
+            input_index: true,
             outputs: true,
             spend_type: true,
             annex: true,
@@ -262,10 +264,12 @@ pub(crate) fn get_sigmsg_components<S: Into<TapLeafHash>>(
         debug!("input sequence: {:?}", sequence.to_hex_string(Case::Lower));
         components.push(sequence);
     } else {
-        let mut input_idx = Vec::new();
-        (input_index as u32).consensus_encode(&mut input_idx)?;
-        debug!("input index: {:?}", input_idx.to_hex_string(Case::Lower));
-        components.push(input_idx);
+        if spec.input_index {
+            let mut input_idx = Vec::new();
+            (input_index as u32).consensus_encode(&mut input_idx)?;
+            debug!("input index: {:?}", input_idx.to_hex_string(Case::Lower));
+            components.push(input_idx);
+        }
     }
 
     // If an annex is present (the lowest bit of spend_type is set):