Validating sha3 of a dapp bundle (#1993)

* Validating sha3 of a file

* sha3 in utils

* Removing devtools

dapps/src/apps/fetcher.rs

@@ -30,7 +30,8 @@ use hyper::Control;
 use hyper::status::StatusCode;
 
 use random_filename;
-use util::Mutex;
+use util::{Mutex, H256};
+use util::sha3::sha3;
 use page::LocalPageEndpoint;
 use handlers::{ContentHandler, AppFetcherHandler, DappHandler};
 use endpoint::{Endpoint, EndpointPath, Handler};
@@ -137,10 +138,12 @@ impl<R: URLHint> AppFetcher<R> {
 
 #[derive(Debug)]
 pub enum ValidationError {
-	ManifestNotFound,
-	ManifestSerialization(String),
 	Io(io::Error),
 	Zip(zip::result::ZipError),
+	InvalidDappId,
+	ManifestNotFound,
+	ManifestSerialization(String),
+	HashMismatch { expected: H256, got: H256, },
 }
 
 impl From<io::Error> for ValidationError {
@@ -198,8 +201,15 @@ impl DappHandler for DappInstaller {
 
 	fn validate_and_install(&self, app_path: PathBuf) -> Result<Manifest, ValidationError> {
 		trace!(target: "dapps", "Opening dapp bundle at {:?}", app_path);
-		// TODO [ToDr] Validate file hash
-		let file = try!(fs::File::open(app_path));
+		let mut file = try!(fs::File::open(app_path));
+		let hash = try!(sha3(&mut file));
+		let dapp_id = try!(self.dapp_id.as_str().parse().map_err(|_| ValidationError::InvalidDappId));
+		if dapp_id != hash {
+			return Err(ValidationError::HashMismatch {
+				expected: dapp_id,
+				got: hash,
+			});
+		}
 		// Unpack archive
 		let mut zip = try!(zip::ZipArchive::new(file));
 		// First find manifest file

dapps/src/lib.rs

@@ -55,11 +55,11 @@ extern crate rand;
 extern crate ethabi;
 extern crate jsonrpc_core;
 extern crate jsonrpc_http_server;
+extern crate mime_guess;
+extern crate rustc_serialize;
 extern crate parity_dapps;
 extern crate ethcore_rpc;
 extern crate ethcore_util as util;
-extern crate mime_guess;
-extern crate rustc_serialize;
 
 mod endpoint;
 mod apps;

devtools/src/random_path.rs

@@ -67,10 +67,18 @@ impl RandomTempPath {
 	}
 }
 
+impl AsRef<Path> for RandomTempPath {
+	fn as_ref(&self) -> &Path {
+		self.as_path()
+	}
+}
+
 impl Drop for RandomTempPath {
 	fn drop(&mut self) {
-		if let Err(e) = fs::remove_dir_all(self.as_path()) {
-			panic!("Failed to remove temp directory. Here's what prevented this from happening:  ({})", e);
+		if let Err(_) = fs::remove_dir_all(&self) {
+			if let Err(e) = fs::remove_file(&self) {
+				panic!("Failed to remove temp directory. Here's what prevented this from happening:  ({})", e);
+			}
 		}
 	}
 }

util/Cargo.toml

@@ -32,6 +32,7 @@ parking_lot = "0.2.6"
 using_queue = { path = "using_queue" }
 table = { path = "table" }
 ansi_term = "0.7"
+tiny-keccak= "1.0"
 
 [features]
 default = []

util/src/lib.rs

@@ -112,6 +112,7 @@ extern crate parking_lot;
 pub extern crate using_queue;
 pub extern crate table;
 extern crate ansi_term;
+extern crate tiny_keccak;
 
 pub mod bloom;
 pub mod standard;

util/src/sha3.rs

@@ -17,7 +17,9 @@
 //! Wrapper around tiny-keccak crate.
 extern crate sha3 as sha3_ext;
 
+use std::io;
 use std::mem::uninitialized;
+use tiny_keccak::Keccak;
 use bytes::{BytesConvertable, Populatable};
 use hash::{H256, FixedHash};
 use self::sha3_ext::*;
@@ -64,12 +66,56 @@ impl<T> Hashable for T where T: BytesConvertable {
 	}
 }
 
-#[test]
-fn sha3_empty() {
-	assert_eq!([0u8; 0].sha3(), SHA3_EMPTY);
-}
-#[test]
-fn sha3_as() {
-	assert_eq!([0x41u8; 32].sha3(), From::from("59cad5948673622c1d64e2322488bf01619f7ff45789741b15a9f782ce9290a8"));
+/// Calculate SHA3 of given stream.
+pub fn sha3<R: io::Read>(r: &mut R) -> Result<H256, io::Error> {
+	let mut output = [0u8; 32];
+	let mut input = [0u8; 1024];
+	let mut sha3 = Keccak::new_keccak256();
+
+	// read file
+	loop {
+		let some = try!(r.read(&mut input));
+		if some == 0 {
+			break;
+		}
+		sha3.update(&input[0..some]);
+	}
+
+	sha3.finalize(&mut output);
+	Ok(output.into())
 }
 
+#[cfg(test)]
+mod tests {
+	use std::fs;
+	use std::io::Write;
+	use super::*;
+
+	#[test]
+	fn sha3_empty() {
+		assert_eq!([0u8; 0].sha3(), SHA3_EMPTY);
+	}
+	#[test]
+	fn sha3_as() {
+		assert_eq!([0x41u8; 32].sha3(), From::from("59cad5948673622c1d64e2322488bf01619f7ff45789741b15a9f782ce9290a8"));
+	}
+
+	#[test]
+	fn should_sha3_a_file() {
+		// given
+		use devtools::RandomTempPath;
+		let path = RandomTempPath::new();
+		// Prepare file
+		{
+			let mut file = fs::File::create(&path).unwrap();
+			file.write_all(b"something").unwrap();
+		}
+
+		let mut file = fs::File::open(&path).unwrap();
+		// when
+		let hash = sha3(&mut file).unwrap();
+
+		// then
+		assert_eq!(format!("{:?}", hash), "68371d7e884c168ae2022c82bd837d51837718a7f7dfb7aa3f753074a35e1d87");
+	}
+}