Squashed commit of Rust-ifying the repo:

commit e31c1965a2e6b9a21ce68be63b81915b2b090f1d Author: Hernando Castano <castano.ha@gmail.com> Date: Sun Feb 2 21:15:42 2020 -0500 Get Ethereum bridge module compiling commit a497fc1640e68682f61b39414ffb15206c6120e2 Author: Hernando Castano <castano.ha@gmail.com> Date: Thu Jan 30 12:15:43 2020 -0500 Make the toml file look a bit better commit 898fb7b06cfac7cf866e1a28fed9a4f02bd246a7 Author: Hernando Castano <castano.ha@gmail.com> Date: Thu Jan 30 12:06:27 2020 -0500 Get substrate bridge module compiling commit 81e1547e6bec9f590cad9ffba0ee5dfa82cda1c1 Author: Hernando Castano <castano.ha@gmail.com> Date: Thu Jan 30 11:40:29 2020 -0500 Create workspace and move more files around
2026-06-14 19:11:04 +00:00 · 2020-02-02 21:29:06 -05:00
parent c06777a42a
commit fbaa803034
25 changed files with 142 additions and 6355 deletions
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+// Copyright 2017-2019 Parity Technologies (UK) Ltd.
+// This file is part of Substrate.
+
+// Substrate is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Substrate is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Substrate.  If not, see <http://www.gnu.org/licenses/>.
+
+//! Logic for checking Substrate storage proofs.
+
+use hash_db::{Hasher, HashDB, EMPTY_PREFIX};
+use sp_trie::{MemoryDB, Trie, trie_types::TrieDB};
+use sp_runtime::RuntimeDebug;
+
+pub(crate) type StorageProof = Vec<Vec<u8>>;
+
+/// This struct is used to read storage values from a subset of a Merklized database. The "proof"
+/// is a subset of the nodes in the Merkle structure of the database, so that it provides
+/// authentication against a known Merkle root as well as the values in the database themselves.
+pub struct StorageProofChecker<H>
+	where H: Hasher
+{
+	root: H::Out,
+	db: MemoryDB<H>,
+}
+
+impl<H> StorageProofChecker<H>
+	where H: Hasher
+{
+	/// Constructs a new storage proof checker.
+	///
+	/// This returns an error if the given proof is invalid with respect to the given root.
+	pub fn new(root: H::Out, proof: StorageProof) -> Result<Self, Error> {
+		let mut db = MemoryDB::default();
+		for item in proof {
+			db.insert(EMPTY_PREFIX, &item);
+		}
+		let checker = StorageProofChecker {
+			root,
+			db,
+		};
+		// Return error if trie would be invalid.
+		let _ = checker.trie()?;
+		Ok(checker)
+	}
+
+	/// Reads a value from the available subset of storage. If the value cannot be read due to an
+	/// incomplete or otherwise invalid proof, this returns an error.
+	pub fn read_value(&self, key: &[u8]) -> Result<Option<Vec<u8>>, Error> {
+		self.trie()?
+			.get(key)
+			.map(|value| value.map(|value| value.to_vec()))
+			.map_err(|_| Error::StorageValueUnavailable)
+	}
+
+	fn trie(&self) -> Result<TrieDB<H>, Error> {
+		TrieDB::new(&self.db, &self.root)
+			.map_err(|_| Error::StorageRootMismatch)
+	}
+}
+
+#[derive(RuntimeDebug, PartialEq)]
+pub enum Error {
+	StorageRootMismatch,
+	StorageValueUnavailable,
+}
+
+#[cfg(test)]
+mod tests {
+	use super::*;
+
+	use sp_core::{Blake2Hasher, H256};
+	use sp_state_machine::{prove_read, backend::Backend, InMemoryBackend};
+
+	#[test]
+	fn storage_proof_check() {
+		// construct storage proof
+		let backend = <InMemoryBackend<Blake2Hasher>>::from(vec![
+			(None, vec![(b"key1".to_vec(), Some(b"value1".to_vec()))]),
+			(None, vec![(b"key2".to_vec(), Some(b"value2".to_vec()))]),
+			(None, vec![(b"key3".to_vec(), Some(b"value3".to_vec()))]),
+			// Value is too big to fit in a branch node
+			(None, vec![(b"key11".to_vec(), Some(vec![0u8; 32]))]),
+		]);
+		let root = backend.storage_root(std::iter::empty()).0;
+		let proof: StorageProof = prove_read(backend, &[&b"key1"[..], &b"key2"[..], &b"key22"[..]])
+			.unwrap()
+			.iter_nodes()
+			.collect();
+
+		// check proof in runtime
+		let checker = <StorageProofChecker<Blake2Hasher>>::new(root, proof.clone()).unwrap();
+		assert_eq!(checker.read_value(b"key1"), Ok(Some(b"value1".to_vec())));
+		assert_eq!(checker.read_value(b"key2"), Ok(Some(b"value2".to_vec())));
+		assert_eq!(checker.read_value(b"key11111"), Err(Error::StorageValueUnavailable));
+		assert_eq!(checker.read_value(b"key22"), Ok(None));
+
+		// checking proof against invalid commitment fails
+		assert_eq!(
+			<StorageProofChecker<Blake2Hasher>>::new(H256::random(), proof).err(),
+			Some(Error::StorageRootMismatch)
+		);
+	}
+}