Wrong extension node case - constraints that don't apply ignored

privacy-scaling-explorations · Apr 9, 2024 · 133d8b2 · 133d8b2
1 parent 91325b9
commit 133d8b2
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Showing 4 changed files with 20 additions and 12 deletions.
diff --git a/zkevm-circuits/src/mpt_circuit/account_leaf.rs b/zkevm-circuits/src/mpt_circuit/account_leaf.rs
@@ -205,6 +205,8 @@ impl<F: Field> AccountLeafConfig<F> {
                 MPTProofType::CodeHashChanged.expr(),
             );
 
+            let is_wrong_ext_case = parent_data[1].is_last_level_and_wrong_ext_case.expr();
+
             for is_s in [true, false] {
                 ifx! {not!(config.is_mod_extension[is_s.idx()].expr()) => {
                     // Placeholder leaf checks
@@ -273,7 +275,9 @@ impl<F: Field> AccountLeafConfig<F> {
                     // Total number of nibbles needs to be KEY_LEN_IN_NIBBLES.
                     let num_nibbles =
                         num_nibbles::expr(rlp_key.key_value.len(), key_data[is_s.idx()].is_odd.expr());
-                    require!(key_data[is_s.idx()].num_nibbles.expr() + num_nibbles.expr() => KEY_LEN_IN_NIBBLES);
+                    ifx! {not!(is_wrong_ext_case) => {
+                        require!(key_data[is_s.idx()].num_nibbles.expr() + num_nibbles.expr() => KEY_LEN_IN_NIBBLES);
+                    }}
 
                     // Check if the leaf is in its parent.
                     // Check is skipped for placeholder leaves which are dummy leaves.
@@ -282,7 +286,8 @@ impl<F: Field> AccountLeafConfig<F> {
                     // Note that the constraint works for the case when there is the placeholder branch above
                     // the leaf too - in this case `parent_data.hash` contains the hash of the node above the placeholder
                     // branch.
-                    ifx! {not!(config.is_placeholder_leaf[is_s.idx()]) => {
+                    ifx! {not!(or::expr(&[config.is_placeholder_leaf[is_s.idx()].expr(), is_wrong_ext_case.clone()])) => {
+                    // ifx! {not!(config.is_placeholder_leaf[is_s.idx()]) => {
                         let hash = parent_data[is_s.idx()].hash.expr();
                         require!((1.expr(), leaf_rlc, rlp_key.rlp_list.num_bytes(), hash.lo(), hash.hi()) =>> @KECCAK);
                     } elsex {
@@ -305,7 +310,9 @@ impl<F: Field> AccountLeafConfig<F> {
                                 // Note that this does not hold when there is NonExistingAccountProof wrong leaf scenario,
                                 // in this case there is a non-nil leaf. However, in this case the leaf is not a placeholder,
                                 // so the check below is not triggered.
-                                require!(parent_data[is_s.idx()].rlc.expr() => 128.expr());
+                                ifx! {not!(is_wrong_ext_case) => {
+                                    require!(parent_data[is_s.idx()].rlc.expr() => 128.expr());
+                                }}
                             }}
                         }}
                     }}
@@ -407,18 +414,20 @@ impl<F: Field> AccountLeafConfig<F> {
             // To check whether it's wrong extension node - is_last_level_and_wrong_ext_case = 1, parent is extension
             // To check whether it's the nil leaf - use IsPlaceholderLeafGadget
 
+            // TODO: when is_last_level_and_wrong_ext_case, the proof type needs to be non-existing
+            // config.is_non_existing_account_proof.expr(),
+            // config.parent_data[true.idx()].is_extension.expr(),
+
             config.wrong_ext_node = WrongExtNodeGadget::construct(
                 cb,
                 key_item.hash_rlc(),
-                config.is_non_existing_account_proof.expr(),
+                is_wrong_ext_case,
                 &wrong_ext_middle,
                 &wrong_ext_middle_nibbles,
                 &wrong_ext_after,
                 &wrong_ext_after_nibbles,
-                config.parent_data[true.idx()].is_extension.expr(),
                 config.key_data[true.idx()].clone(),
                 config.key_data_prev.clone(),
-                &cb.key_r.expr(),
             ); 
 
             // Anything following this node is below the account

diff --git a/zkevm-circuits/src/mpt_circuit/branch.rs b/zkevm-circuits/src/mpt_circuit/branch.rs
@@ -64,6 +64,7 @@ impl<F: Field> BranchGadget<F> {
         key_mult: Expression<F>,
         num_nibbles: Expression<F>,
         is_key_odd: Expression<F>,
+        is_last_level_and_wrong_ext_case: Expression<F>,
     ) -> Self {
         let mut config = BranchGadget::default();
 
@@ -193,7 +194,7 @@ impl<F: Field> BranchGadget<F> {
                     )
                 };
 
-                ifx! {not!(is_placeholder[is_s.idx()]) => {
+                ifx! {not!(or::expr(&[is_placeholder[is_s.idx()].expr(), is_last_level_and_wrong_ext_case.clone()])) => {
                     ifx!{or::expr(&[is_root[is_s.idx()].expr(), not!(is_not_hashed)]) => {
                         // Hashed branch hash in parent branch
                         let hash = &parent_hash[is_s.idx()];

diff --git a/zkevm-circuits/src/mpt_circuit/extension_branch.rs b/zkevm-circuits/src/mpt_circuit/extension_branch.rs
@@ -135,6 +135,7 @@ impl<F: Field> ExtensionBranchConfig<F> {
                 key_mult_post_ext.expr(),
                 num_nibbles.expr(),
                 is_key_odd.expr(),
+                config.is_last_level_and_wrong_ext_case.expr(),
             );
             let branch = config.branch.get_post_state();
 

diff --git a/zkevm-circuits/src/mpt_circuit/helpers.rs b/zkevm-circuits/src/mpt_circuit/helpers.rs
@@ -1329,20 +1329,17 @@ impl<F: Field> WrongExtNodeGadget<F> {
     pub(crate) fn construct(
         cb: &mut MPTConstraintBuilder<F>,
         expected_key: Expression<F>,
-        is_non_existing: Expression<F>,
+        is_wrong_ext_case: Expression<F>,
         wrong_ext_middle: &RLPItemView<F>,
         wrong_ext_middle_nibbles: &RLPItemView<F>,
         wrong_ext_after: &RLPItemView<F>,
         wrong_ext_after_nibbles: &RLPItemView<F>,
-        is_parent_extension: Expression<F>,
         key_data: KeyData<F>,
         key_data_prev: KeyData<F>,
-        r: &Expression<F>,
     ) -> Self {
         let mut config = WrongExtNodeGadget::default();
         circuit!([meta, cb.base], {
-            // TODO: distinguish between wrong extension node / wrong leaf / nil leaf
-            ifx! {and::expr(&[is_non_existing, is_parent_extension]) => { 
+            ifx! {is_wrong_ext_case => { 
                 // We have a key split into three parts,
                 // meaning that there the first part parity doesn't
                 // tell us about the parity of the second part (depends on the third part as well).