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fix: V0 proof backwards compatibility for KVValueHash item check #643

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Merged
QuantumExplorer merged 4 commits into from
Mar 10, 2026
Merged

fix: V0 proof backwards compatibility for KVValueHash item check #643

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02051e3
fix: allow V0 proofs with items in KVValueHash nodes for backwards co…
QuantumExplorer Mar 10, 2026
c6a8c42
fix: update V0 proof test to expect acceptance instead of rejection
QuantumExplorer Mar 10, 2026
4d4ae95
refactor: replace bool parameter with proof_version u16 in execute_proof
QuantumExplorer Mar 10, 2026
7db5bc5
refactor: add PROOF_VERSION_LATEST constant for execute_proof calls
QuantumExplorer Mar 10, 2026
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17 changes: 14 additions & 3 deletions grovedb/src/operations/proof/verify.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -5,7 +5,7 @@ use grovedb_merk::{
element::tree_type::ElementTreeTypeExtensions,
proofs::{
execute,
query::{PathKey, QueryProofVerify, VerifyOptions},
query::{PathKey, QueryProofVerify, VerifyOptions, PROOF_VERSION_LATEST},
Decoder, Node, Op, Query,
},
tree::{combine_hash, value_hash, NULL_HASH},
Expand Down Expand Up @@ -446,7 +446,12 @@ impl GroveDb {
};

let (root_hash, merk_result) = level_query
.execute_proof(merk_proof_bytes, *limit_left, internal_query.left_to_right)
.execute_proof(
merk_proof_bytes,
*limit_left,
internal_query.left_to_right,
PROOF_VERSION_LATEST, // V1 proof: strict mode rejects items in value hash nodes
)
.unwrap()
.map_err(|e| {
Error::InvalidProof(
Expand Down Expand Up @@ -1389,6 +1394,7 @@ impl GroveDb {
&layer_proof.merk_proof,
*limit_left,
internal_query.left_to_right,
0, // V0 proofs: allow items in value hash nodes for backwards compatibility
)
.unwrap()
.map_err(|e| {
Expand Down Expand Up @@ -1973,7 +1979,12 @@ impl GroveDb {

// Execute the proof to verify and get the root hash
let (layer_root_hash, result) = key_query
.execute_proof(&current_layer.merk_proof, None, true)
.execute_proof(
&current_layer.merk_proof,
None,
true,
0, // V0 proof: allow items in value hash nodes
)
.unwrap()
.map_err(|e| {
Error::InvalidProof(
Expand Down
16 changes: 6 additions & 10 deletions grovedb/src/tests/sum_tree_tests.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -1863,19 +1863,15 @@ mod tests {
);

// This hardcoded proof was generated by an older version of the code that
// used KVValueHash nodes for item elements. The new proof format correctly
// uses KV nodes for items (verifier-computed hash) and rejects KVValueHash
// for items to prevent KV→KVValueHash proof forgery attacks.
// used KVValueHash nodes for item elements. V0 proofs allow this for
// backwards compatibility (the KV→KVValueHash forgery check is only
// enforced for V1 proofs).
let result =
GroveDb::verify_subset_query_get_parent_tree_info(&proof, &path_query, grove_version);
assert!(
result.is_err(),
"old-format proof with KVValueHash for items should be rejected"
);
let err = result.unwrap_err().to_string();
assert!(
err.contains("must not contain an item element"),
"expected item rejection, got: {err}"
result.is_ok(),
"V0 proof with KVValueHash for items should be accepted for backwards compatibility, got: {:?}",
result.unwrap_err()
);
}

Expand Down
14 changes: 8 additions & 6 deletions merk/src/proofs/query/merk_integration_tests.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -26,7 +26,7 @@ use super::{
*,
};
use crate::{
proofs::query::verify,
proofs::query::verify::{self, PROOF_VERSION_LATEST},
test_utils::make_tree_seq,
tree::{NoopCommit, PanicSource, RefWalker, TreeNode},
TreeFeatureType::BasicMerkNode,
Expand Down Expand Up @@ -3821,7 +3821,7 @@ fn test_5_item_tree_tampering_detected_with_elements() {
query2.insert_key(vec![1]);

let (tampered_root, _tampered_result) = query2
.execute_proof(tampered.as_slice(), None, true)
.execute_proof(tampered.as_slice(), None, true, PROOF_VERSION_LATEST)
.unwrap()
.expect("execute_proof failed");

Expand Down Expand Up @@ -3994,7 +3994,7 @@ fn test_5_item_tree_tampering_detected_raw_values() {
query2.insert_key(vec![1]);

let (tampered_root, _tampered_result) = query2
.execute_proof(tampered.as_slice(), None, true)
.execute_proof(tampered.as_slice(), None, true, PROOF_VERSION_LATEST)
.unwrap()
.expect("execute_proof failed");

Expand Down Expand Up @@ -4123,7 +4123,7 @@ fn test_tampering_detected_invalid_discriminant() {

// Use execute_proof to get the computed root
let (tampered_root, _tampered_result) = query2
.execute_proof(tampered.as_slice(), None, true)
.execute_proof(tampered.as_slice(), None, true, PROOF_VERSION_LATEST)
.unwrap()
.expect("execute_proof failed");

Expand Down Expand Up @@ -4241,7 +4241,7 @@ fn test_kvvaluehash_still_used_for_tree_discriminants() {
query2.insert_key(key.clone());
}
let result = query2
.execute_proof(tampered.as_slice(), None, true)
.execute_proof(tampered.as_slice(), None, true, PROOF_VERSION_LATEST)
.unwrap();

assert!(
Expand Down Expand Up @@ -4295,7 +4295,9 @@ fn test_execute_proof_rejects_trailing_bytes() {
// Append trailing garbage bytes
bytes.extend_from_slice(&[0xDE, 0xAD, 0xBE, 0xEF]);

let result = query.execute_proof(bytes.as_slice(), None, true).unwrap();
let result = query
.execute_proof(bytes.as_slice(), None, true, PROOF_VERSION_LATEST)
.unwrap();

assert!(
result.is_err(),
Expand Down
2 changes: 1 addition & 1 deletion merk/src/proofs/query/mod.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -21,7 +21,7 @@ pub use map::{Map, MapBuilder};
#[cfg(any(feature = "minimal", feature = "verify"))]
pub use verify::{
ProofVerificationResult, ProvedKeyOptionalValue, ProvedKeyValue, QueryProofVerify,
VerifyOptions,
VerifyOptions, PROOF_VERSION_LATEST,
};
#[cfg(feature = "minimal")]
use {super::Op, std::collections::LinkedList};
Expand Down
96 changes: 63 additions & 33 deletions merk/src/proofs/query/verify.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -12,6 +12,14 @@ use crate::{
CryptoHash as MerkHash, CryptoHash,
};

/// The latest proof version.
/// - V0 (0): lenient — permits item elements in KVValueHash nodes
/// (backwards compatibility with older proofs)
/// - V1 (1): strict — rejects item elements in KVValueHash /
/// KVValueHashFeatureType / KVValueHashFeatureTypeWithChildHash nodes
/// to prevent KV-to-KVValueHash proof forgery
pub const PROOF_VERSION_LATEST: u16 = 1;

/// Verify proof against expected hash
#[cfg(feature = "minimal")]
#[deprecated]
Expand Down Expand Up @@ -75,11 +83,19 @@ impl Default for VerifyOptions {
pub trait QueryProofVerify {
/// Verifies the encoded proof with the given query, returning the root
/// hash and verification result.
///
/// `proof_version` controls which security checks are applied:
/// - V0 (0): lenient — permits item elements in KVValueHash nodes
/// (backwards compatibility with older proofs)
/// - V1+ (≥1): strict — rejects item elements in KVValueHash /
/// KVValueHashFeatureType / KVValueHashFeatureTypeWithChildHash nodes
/// to prevent KV-to-KVValueHash proof forgery
fn execute_proof(
&self,
bytes: &[u8],
limit: Option<u16>,
left_to_right: bool,
proof_version: u16,
) -> CostResult<(MerkHash, ProofVerificationResult), Error>;
Comment on lines 93 to 99
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@coderabbitai coderabbitai Bot Mar 10, 2026 •
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⚠️ Potential issue | 🟠 Major

Avoid making execute_proof a breaking public API with a bare bool.

This changes a public trait method’s signature, so every downstream caller now has to update call sites, and the new last argument is security-sensitive but opaque (..., true, false). Please preserve the old signature and add an opt-in variant or options/enum-based API for the V0 compatibility path instead.

Also applies to: 114-120

🤖 Prompt for AI Agents 
Verify each finding against the current code and only fix it if needed.

In `@merk/src/proofs/query/verify.rs` around lines 84 - 90, The trait method
execute_proof currently changes the public signature by adding a bare bool
(left_to_right / allow_items_in_value_hash_nodes); revert the trait to preserve
the original public signature and introduce a non-breaking opt-in API: add
either an options enum/struct (e.g., ExecuteProofOptions) or a new method (e.g.,
execute_proof_with_options or execute_proof_v1) that takes the extra flags,
update implementations to implement the new method while providing a default
execute_proof that delegates to the new method with V0-compatible defaults, and
ensure the trait docs note the security-sensitive flags so callers must opt into
them explicitly.

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@QuantumExplorer QuantumExplorer Mar 10, 2026

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This is Claude. Disagree — execute_proof is an internal trait (QueryProofVerify) that lives in the grovedb-merk crate. It is not part of any public SDK API. The only callers are:

  • 3 sites inside grovedb/src/operations/proof/verify.rs (GroveDB's own proof verification)
  • 5 sites in merk/src/proofs/query/merk_integration_tests.rs (tests)
  • 1 site in verify_proof which delegates internally

There are no downstream/external consumers of this trait. Adding an options struct or a second method for a single boolean that only has 2 internal callers passing true would be over-engineering. The parameter is well-documented in the trait doc comment explaining exactly when to use true vs false.

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🧩 Analysis chain

🏁 Script executed:

#!/bin/bash
# Check if QueryProofVerify is re-exported from lib.rs or any public module
rg -n "QueryProofVerify" --type rust

# Check pub use in lib.rs files
rg -n "pub use" merk/src/lib.rs 2>/dev/null || true
rg -n "pub use" merk/src/proofs/mod.rs 2>/dev/null || true
rg -n "pub use" merk/src/proofs/query/mod.rs 2>/dev/null || true

Unrecoverable error: Failed to clone repository

@QuantumExplorer, that's a fair point. The method already accepted a bare bool for left_to_right, so the new allow_items_in_value_hash_nodes is consistent with the existing style, and with only ~9 internal call sites (no external consumers), introducing an options struct would genuinely be over-engineering. The trait doc comment covers the security intent clearly. I'll withdraw the concern.

✏️ Learnings added 
Learnt from: QuantumExplorer
Repo: dashpay/grovedb PR: 643
File: merk/src/proofs/query/verify.rs:84-90
Timestamp: 2026-03-10T10:18:18.519Z
Learning: In the `grovedb-merk` crate, `QueryProofVerify::execute_proof` in `merk/src/proofs/query/verify.rs` is an internal trait with no downstream/external consumers. All callers are within `grovedb/src/operations/proof/verify.rs` (3 sites), `merk/src/proofs/query/merk_integration_tests.rs` (5 sites), and the internal `verify_proof` delegation. Adding options structs or extra methods for internal-only boolean flags on this trait is considered over-engineering.

Note: Learnings are effective only in the context of similar code segments. To apply general coding guidelines, please configure review instructions. You can manage existing learnings in the app.


/// Verifies the encoded proof with the given query and expected hash.
Expand Down Expand Up @@ -109,6 +125,7 @@ impl QueryProofVerify for Query {
bytes: &[u8],
limit: Option<u16>,
left_to_right: bool,
proof_version: u16,
) -> CostResult<(MerkHash, ProofVerificationResult), Error> {
#[cfg(feature = "proof_debug")]
{
Expand Down Expand Up @@ -338,15 +355,19 @@ impl QueryProofVerify for Query {
// elements to prevent KV→KVValueHash forgery where an
// attacker substitutes a KV node with KVValueHash to inject
// a fake value while keeping the original hash.
let element_type = ElementType::from_serialized_value(value).map_err(|e| {
Error::InvalidProofError(format!(
"cannot determine element type in KVValueHash node: {e}"
))
})?;
if element_type.has_simple_value_hash() {
return Err(Error::InvalidProofError(
"KVValueHash node must not contain an item element".to_string(),
));
// Skipped for V0 backwards compatibility.
if proof_version >= 1 {
let element_type =
ElementType::from_serialized_value(value).map_err(|e| {
Error::InvalidProofError(format!(
"cannot determine element type in KVValueHash node: {e}"
))
})?;
if element_type.has_simple_value_hash() {
return Err(Error::InvalidProofError(
"KVValueHash node must not contain an item element".to_string(),
));
}
}
execute_node(key, Some(value), *value_hash, false)?;
}
Expand Down Expand Up @@ -384,16 +405,21 @@ impl QueryProofVerify for Query {
println!("Processing KVValueHashFeatureType node");
}
// Same check as KVValueHash — reject item elements.
let element_type = ElementType::from_serialized_value(value).map_err(|e| {
Error::InvalidProofError(format!(
"cannot determine element type in KVValueHashFeatureType node: {e}"
))
})?;
if element_type.has_simple_value_hash() {
return Err(Error::InvalidProofError(
"KVValueHashFeatureType node must not contain an item element"
.to_string(),
));
// Skipped for V0 backwards compatibility.
if proof_version >= 1 {
let element_type =
ElementType::from_serialized_value(value).map_err(|e| {
Error::InvalidProofError(format!(
"cannot determine element type in KVValueHashFeatureType \
node: {e}"
))
})?;
if element_type.has_simple_value_hash() {
return Err(Error::InvalidProofError(
"KVValueHashFeatureType node must not contain an item element"
.to_string(),
));
}
}
execute_node(key, Some(value), *value_hash, false)?;
}
Expand All @@ -415,19 +441,23 @@ impl QueryProofVerify for Query {
{
println!("Processing KVValueHashFeatureTypeWithChildHash node");
}
// Same element-type check as KVValueHashFeatureType
let element_type = ElementType::from_serialized_value(value).map_err(|e| {
Error::InvalidProofError(format!(
"cannot determine element type in \
KVValueHashFeatureTypeWithChildHash node: {e}"
))
})?;
if element_type.has_simple_value_hash() {
return Err(Error::InvalidProofError(
"KVValueHashFeatureTypeWithChildHash node must not contain \
an item element"
.to_string(),
));
// Same element-type check as KVValueHashFeatureType.
// Skipped for V0 backwards compatibility.
if proof_version >= 1 {
let element_type =
ElementType::from_serialized_value(value).map_err(|e| {
Error::InvalidProofError(format!(
"cannot determine element type in \
KVValueHashFeatureTypeWithChildHash node: {e}"
))
})?;
if element_type.has_simple_value_hash() {
return Err(Error::InvalidProofError(
"KVValueHashFeatureTypeWithChildHash node must not contain \
an item element"
.to_string(),
));
}
}
// Verify value integrity: combine_hash(H(value), child_hash) must
// equal the provided value_hash. This prevents an attacker from
Expand Down Expand Up @@ -519,7 +549,7 @@ impl QueryProofVerify for Query {
left_to_right: bool,
expected_hash: MerkHash,
) -> CostResult<ProofVerificationResult, Error> {
self.execute_proof(bytes, limit, left_to_right)
self.execute_proof(bytes, limit, left_to_right, PROOF_VERSION_LATEST)
.map_ok(|(root_hash, verification_result)| {
if root_hash == expected_hash {
Ok(verification_result)
Expand Down
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