feat: validate asset metadata

crates/miden-protocol/asm/kernels/transaction/lib/asset.masm

@@ -1,8 +1,9 @@
 use $kernel::account_id
 use $kernel::fungible_asset
 use $kernel::non_fungible_asset
+use $kernel::util::asset->util_asset
 
-# ERRORS
+# ERRORS
 # =================================================================================================
 
 const ERR_VAULT_ASSET_KEY_ACCOUNT_ID_MUST_BE_FAUCET="account ID in asset vault key must be either of type fungible or non-fungible faucet"
@@ -65,6 +66,30 @@ pub proc validate_key
     # => [ASSET_KEY]
 end
 
+#! Validates the issuer (faucet ID) and metadata in an asset vault key.
+#!
+#! Inputs:  [ASSET_KEY]
+#! Outputs: [ASSET_KEY]
+#!
+#! Where:
+#! - ASSET_KEY is the vault key of the asset to validate.
+#!
+#! Panics if:
+#! - the asset metadata is invalid (not 0 or 1).
+#! - the faucet ID in the key is not a valid account ID.
+pub proc validate_issuer
+    # => [asset_id_suffix, asset_id_prefix, faucet_id_suffix_and_metadata, faucet_id_prefix]
+
+    dup.3 dup.3 exec.util_asset::split_suffix_and_metadata
+    # => [asset_metadata, faucet_id_suffix, faucet_id_prefix, ASSET_KEY]
+
+    exec.util_asset::validate_metadata
+    # => [faucet_id_suffix, faucet_id_prefix, ASSET_KEY]
+
+    exec.account_id::validate
+    # => [ASSET_KEY]
+end
+
 #! Returns a boolean indicating whether the asset is non-fungible.
 #!
 #! Inputs:  [ASSET_KEY]

crates/miden-protocol/asm/kernels/transaction/lib/fungible_asset.masm

@@ -148,10 +148,10 @@ end
 #!
 #! Panics if:
 #! - the asset key's account ID is not valid.
+#! - the asset key's metadata is not valid.
 #! - the asset key's faucet ID is not a fungible one.
 pub proc validate_key
-    exec.asset::key_to_faucet_id
-    exec.account_id::validate
+    exec.asset::validate_issuer
     # => [ASSET_KEY]
 
     exec.asset::is_fungible_asset_key

crates/miden-protocol/asm/kernels/transaction/lib/non_fungible_asset.masm

@@ -51,10 +51,10 @@ end
 #!
 #! Panics if:
 #! - the asset key's account ID is not valid.
+#! - the asset key's metadata is not valid.
 #! - the asset key's faucet ID is not a non-fungible one.
 pub proc validate_key
-    exec.asset::key_to_faucet_id
-    exec.account_id::validate
+    exec.asset::validate_issuer
     # => [ASSET_KEY]
 
     exec.asset::is_non_fungible_asset_key

crates/miden-protocol/asm/shared_utils/util/asset.masm

@@ -292,7 +292,7 @@ end
 #! - faucet_id_suffix_and_metadata is the faucet ID suffix merged with the asset metadata.
 #! - faucet_id_suffix is the suffix of the account ID.
 #! - asset_metadata is the asset metadata.
-proc split_suffix_and_metadata
+pub proc split_suffix_and_metadata
     u32split
     # => [suffix_metadata_lo, suffix_metadata_hi]
 
@@ -312,6 +312,20 @@ proc split_suffix_and_metadata
     # => [asset_metadata, faucet_id_suffix]
 end
 
+#! Validates that asset metadata is well formed and consumes it.
+#!
+#! Inputs:  [asset_metadata]
+#! Outputs: []
+#!
+#! Panics if:
+#! - asset_metadata is not a valid u32 or exceeds CALLBACKS_ENABLED.
+pub proc validate_metadata
+    u32assert.err=ERR_VAULT_INVALID_ENABLE_CALLBACKS
+    u32lte.CALLBACKS_ENABLED
+    assert.err=ERR_VAULT_INVALID_ENABLE_CALLBACKS
+    # => []
+end
+
 #! Creates asset metadata from the provided inputs.
 #!
 #! Inputs:  [enable_callbacks]
@@ -324,9 +338,8 @@ end
 #! Panics if:
 #! - enable_callbacks is not 0 or 1.
 proc create_metadata
-    u32assert.err=ERR_VAULT_INVALID_ENABLE_CALLBACKS
-    dup u32lte.CALLBACKS_ENABLED
-    assert.err=ERR_VAULT_INVALID_ENABLE_CALLBACKS
+    # for now, enable_callbacks is identical to asset_metadata
+    dup exec.validate_metadata
     # => [asset_metadata]
 end
 

crates/miden-protocol/build.rs

@@ -352,12 +352,21 @@ fn copy_shared_modules<T: AsRef<Path>>(source_dir: T) -> Result<()> {
 /// The generated files are written to `build_dir` (i.e. `OUT_DIR`) and included via `include!`
 /// in the source.
 fn generate_error_constants(asm_source_dir: &Path, build_dir: &str) -> Result<()> {
+    // Shared utils errors
+    // For now these are duplicated in the tx kernel and protocol error module.
+    // ------------------------------------------
+
+    let shared_utils_dir = asm_source_dir.join(SHARED_UTILS_DIR);
+    let shared_utils_errors = shared::extract_all_masm_errors(&shared_utils_dir)
+        .context("failed to extract all masm errors")?;
+
     // Transaction kernel errors
     // ------------------------------------------
 
     let tx_kernel_dir = asm_source_dir.join(ASM_TX_KERNEL_DIR);
-    let errors = shared::extract_all_masm_errors(&tx_kernel_dir)
+    let mut errors = shared::extract_all_masm_errors(&tx_kernel_dir)
         .context("failed to extract all masm errors")?;
+    errors.extend_from_slice(&shared_utils_errors);
     validate_tx_kernel_category(&errors)?;
 
     shared::generate_error_file(
@@ -373,8 +382,9 @@ fn generate_error_constants(asm_source_dir: &Path, build_dir: &str) -> Result<()
     // ------------------------------------------
 
     let protocol_dir = asm_source_dir.join(ASM_PROTOCOL_DIR);
-    let errors = shared::extract_all_masm_errors(&protocol_dir)
+    let mut errors = shared::extract_all_masm_errors(&protocol_dir)
         .context("failed to extract all masm errors")?;
+    errors.extend(shared_utils_errors);
 
     shared::generate_error_file(
         shared::ErrorModule {

crates/miden-testing/src/kernel_tests/tx/test_faucet.rs

@@ -1,5 +1,6 @@
 use alloc::sync::Arc;
 
+use miden_protocol::Felt;
 use miden_protocol::account::{Account, AccountBuilder, AccountComponent, AccountId, AccountType};
 use miden_protocol::assembly::DefaultSourceManager;
 use miden_protocol::asset::{
@@ -14,6 +15,7 @@ use miden_protocol::errors::tx_kernel::{
     ERR_FUNGIBLE_ASSET_FAUCET_IS_NOT_ORIGIN,
     ERR_NON_FUNGIBLE_ASSET_FAUCET_IS_NOT_ORIGIN,
     ERR_VAULT_FUNGIBLE_ASSET_AMOUNT_LESS_THAN_AMOUNT_TO_WITHDRAW,
+    ERR_VAULT_INVALID_ENABLE_CALLBACKS,
     ERR_VAULT_NON_FUNGIBLE_ASSET_TO_REMOVE_NOT_FOUND,
 };
 use miden_protocol::testing::account_id::{
@@ -151,6 +153,41 @@ async fn test_mint_fungible_asset_inconsistent_faucet_id() -> anyhow::Result<()>
     Ok(())
 }
 
+/// Tests that minting a fungible asset on a non-faucet account fails when the key has its asset
+/// metadata (lower 8 bits) set to u8::MAX.
+#[tokio::test]
+async fn mint_fungible_asset_fails_on_invalid_asset_metadata() -> anyhow::Result<()> {
+    let asset = FungibleAsset::mock(50);
+
+    let mut vault_key_word = asset.to_key_word();
+    vault_key_word[2] = Felt::try_from(vault_key_word[2].as_canonical_u64() | u8::MAX as u64)?;
+
+    let code = format!(
+        "
+      use $kernel::prologue
+      use mock::faucet
+
+      begin
+          exec.prologue::prepare_transaction
+          push.{ASSET_VALUE}
+          push.{ASSET_KEY}
+          call.faucet::mint
+          dropw dropw
+      end
+      ",
+        ASSET_KEY = vault_key_word,
+        ASSET_VALUE = asset.to_value_word(),
+    );
+
+    let result = TransactionContextBuilder::with_fungible_faucet(asset.faucet_id().into())
+        .build()?
+        .execute_code(&code)
+        .await;
+    assert_execution_error!(result, ERR_VAULT_INVALID_ENABLE_CALLBACKS);
+
+    Ok(())
+}
+
 /// Tests that minting a fungible asset with [`FungibleAsset::MAX_AMOUNT`] + 1 fails.
 #[tokio::test]
 async fn test_mint_fungible_asset_fails_when_amount_exceeds_max_representable_amount()