Handle missing runtimes and add runtime sanity checking

src/build_upgrade.rs

@@ -19,6 +19,10 @@ pub(crate) struct UpgradeArgs {
 	#[clap(long = "local")]
 	pub(crate) local: bool,
 
+	/// Skip sanity checks on the downloaded runtime blobs (e.g. their file size).
+	#[clap(long = "no-runtime-checks")]
+	pub(crate) no_runtime_checks: bool,
+
 	/// The Fellowship release version. Should be semver and correspond to the release published.
 	#[clap(long = "relay-version")]
 	pub(crate) relay_version: Option<String>,
@@ -184,6 +188,8 @@ pub(crate) fn parse_inputs(prefs: UpgradeArgs) -> UpgradeDetails {
 		None => None,
 	};
 
+	let no_runtime_checks = prefs.no_runtime_checks;
+
 	// Get a version from one of the args. (This still feels dirty.)
 	let version = relay_version.clone().unwrap_or(asset_hub_version.unwrap_or(
 		bridge_hub_version.unwrap_or(encointer_version.unwrap_or(collectives_version.unwrap_or(
@@ -202,7 +208,7 @@ pub(crate) fn parse_inputs(prefs: UpgradeArgs) -> UpgradeDetails {
 
 	make_version_directory(directory.as_str());
 
-	UpgradeDetails { relay, networks, directory, output_file, additional }
+	UpgradeDetails { relay, networks, directory, output_file, additional, no_runtime_checks }
 }
 
 // Create a directory into which to place runtime blobs and the final call data.
@@ -264,7 +270,32 @@ async fn download_runtimes(upgrade_details: &UpgradeDetails) {
 		let path_name = format!("{directory}{fname}");
 		println!("Downloading... {fname}");
 		let response = reqwest::get(download_url).await.expect("we need files to work");
+
+		let status = response.status();
+		assert!(status.is_success(), "Failed to download {}: HTTP {}", fname, status);
+
 		let runtime = response.bytes().await.expect("need bytes");
+
+		if !upgrade_details.no_runtime_checks {
+			// Substrate zstd-compressed blob magic (`sp_maybe_compressed_blob::ZSTD_PREFIX`).
+			const ZSTD_PREFIX: [u8; 8] = [82, 188, 83, 118, 70, 219, 142, 5];
+			assert!(
+				runtime.starts_with(&ZSTD_PREFIX),
+				"Downloaded {} is not a zstd-compressed Substrate runtime blob. \
+				 Pass --no-runtime-checks to skip.",
+				fname,
+			);
+
+			let size = runtime.len();
+			assert!(
+				(100 * 1024..=10 * 1024 * 1024).contains(&size),
+				"Downloaded {} is {} bytes; expected between 100 KiB and 10 MiB. \
+				 Pass --no-runtime-checks to skip.",
+				fname,
+				size,
+			);
+		}
+
 		// todo: we could actually just hash the file, mutate UpgradeDetails, and not write it.
 		// saving it may be more convenient anyway though, since someone needs to upload it after
 		// the referendum enacts.

src/functions.rs

@@ -10,6 +10,6 @@ pub(crate) fn get_proposal_bytes(proposal: String) -> Vec<u8> {
 	} else {
 		// This is a file path
 		let contents = fs::read_to_string(proposal).expect("Should give a valid file path");
-		hex::decode(contents.as_str().trim_start_matches("0x")).expect("Valid proposal")
+		hex::decode(contents.as_str().trim_start_matches("0x").trim()).expect("Valid proposal")
 	}
 }

src/submit_referendum.rs

@@ -391,6 +391,7 @@ async fn polkadot_fellowship_for_kusama_referenda(
 		pallet_referenda::pallet::Call as ReferendaCall,
 		pallet_whitelist::pallet::Call as WhitelistCall,
 	};
+	use polkadot_collectives::runtime_types::staging_xcm::v5::junction::NetworkId;
 	use polkadot_collectives::runtime_types::{
 		bounded_collections::bounded_vec::BoundedVec as CollectivesBoundedVec,
 		collectives_polkadot_runtime::OriginCaller as CollectivesOriginCaller,
@@ -408,15 +409,10 @@ async fn polkadot_fellowship_for_kusama_referenda(
 			Instruction, Xcm,
 		},
 		xcm::{
-			double_encoded::DoubleEncoded,
-			v3::MaybeErrorCode,
-			v3::OriginKind,
-			v3::WeightLimit,
-			VersionedLocation,
-			VersionedXcm::V5,
+			double_encoded::DoubleEncoded, v3::MaybeErrorCode, v3::OriginKind, v3::WeightLimit,
+			VersionedLocation, VersionedXcm::V5,
 		},
 	};
-	use polkadot_collectives::runtime_types::staging_xcm::v5::junction::NetworkId;
 	// Fellowship is on the Polkadot Collectives chain.
 	//
 	// 1. Create a whitelist call on Kusama Asset Hub.

src/types.rs

@@ -152,6 +152,8 @@ pub(super) struct UpgradeDetails {
 	pub(super) output_file: String,
 	// An additional call to be enacted in the same batch as the system upgrade.
 	pub(super) additional: Option<CallInfo>,
+	// Skip sanity checks on the downloaded runtime blobs.
+	pub(super) no_runtime_checks: bool,
 }
 
 // A network and the version to which it will upgrade.