Verify signed skill bundles before extraction (#734)

* Verify signed skill bundles before extraction

Sign release ZIPs locally with an Ed25519 key from 1Password and pin the public trust root in the Rust installer. Reject unauthenticated downloads before extraction and preserve existing installs on failure. Document the signature-first rollout and explicit local trust paths.

AI-assisted implementation prepared by Codex at Paul Bakaus’s request.

* Fix signed-bundle review guardrails

Make keyring loading failures fatal before any download, accept standard release redirect statuses while retaining URL pinning, and require the signature sidecar before tagging. Add regressions for all three review findings.

AI-assisted changes prepared and tested by Codex at Paul Bakaus’s request.
This commit is contained in:
Paul Bakaus
2026-09-04 18:21:01 -07:00
committed by GitHub
parent 46ffe5caa2
commit 8dac6ae7e0
16 changed files with 800 additions and 6 deletions
Generated
+2
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@@ -698,6 +698,8 @@ dependencies = [
"libc",
"once_cell",
"regex",
"ring",
"serde",
"serde_json",
"sha2",
"ureq",
+2
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@@ -10,9 +10,11 @@ impeccable-common = { path = "../common" }
impeccable-context = { path = "../context" }
impeccable-detect = { path = "../detect" }
serde_json = { workspace = true }
serde = { workspace = true }
regex = { workspace = true }
once_cell = { workspace = true }
sha2 = "0.10"
ring = "0.17.14"
ureq = { version = "2", default-features = false, features = ["tls", "json"] }
url = "2"
zip = { version = "2", default-features = false, features = ["deflate"] }
+144 -2
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@@ -17,6 +17,7 @@ use crate::providers::{
opencode_global_config_dir, provider_display_name, Scope, Sys, API_BASE, PROVIDER_DIRS,
};
use crate::util::{self, jsp};
use crate::bundle_signature::{self, TrustedKeys, MAX_SIGNATURE_BYTES};
/// Ceiling on any single download this crate performs (triage C4). The
/// launcher-only universal bundle is under 25 MB (the Cloudflare Pages file
@@ -80,6 +81,7 @@ pub struct FetchResponse {
fn ureq_fetch(url: &str) -> Result<FetchResponse, String> {
let agent = ureq::AgentBuilder::new()
.timeout_connect(std::time::Duration::from_secs(30))
.timeout(std::time::Duration::from_secs(120))
.redirects(0)
.build();
match agent.get(url).call() {
@@ -293,13 +295,48 @@ pub fn download_and_extract_bundle(sys: &Sys) -> Result<String, String> {
if let Some(local) = sys.env.get("IMPECCABLE_BUNDLE_PATH").filter(|v| !v.is_empty()) {
return copy_or_extract_local_bundle(sys, local);
}
download_remote_bundle(sys, &mut ureq_fetch, bundle_signature::trusted_keys())
}
fn download_remote_bundle(
sys: &Sys,
fetch: &mut dyn FnMut(&str) -> Result<FetchResponse, String>,
keys: Result<TrustedKeys, String>,
) -> Result<String, String> {
keys.and_then(|keys| download_and_extract_signed_bundle(sys, fetch, &keys))
.map_err(|e| format!("{}{e}. Nothing was installed; retry or update the CLI. If this persists, report it at https://github.com/pbakaus/impeccable/issues/479", bundle_signature::ERROR_PREFIX))
}
fn download_and_extract_signed_bundle(
sys: &Sys,
fetch: &mut dyn FnMut(&str) -> Result<FetchResponse, String>,
keys: &TrustedKeys,
) -> Result<String, String> {
let tmp = util::tmpdir(&sys.env);
let staging = util::mkdtemp(&jsp::join(&[&tmp, "impeccable-update-"]))?;
let tmp_zip = jsp::join(&[&staging, "bundle.zip"]);
let tmp_signature = jsp::join(&[&staging, "bundle.sig.json"]);
let result = (|| -> Result<(), String> {
download_file(&format!("{API_BASE}/api/download/bundle/universal"), &tmp_zip)?;
extract_zip_file(&tmp_zip, &staging, &sys.cwd)?;
// Resolve once, then request both assets from that exact release. Never
// pair a latest-version lookup with a independently changing ZIP URL.
let response = fetch(&format!("{API_BASE}/api/download/bundle/universal"))?;
if !matches!(response.status, 301 | 302 | 303 | 307 | 308) {
return Err(format!("Expected a signed bundle release redirect (HTTP {})", response.status));
}
let location = response.location.ok_or("Missing bundle release redirect")?;
let version = bundle_signature::release_version(&location)?;
download_file_capped(&format!("{location}.sig.json"), &tmp_signature, fetch, MAX_SIGNATURE_BYTES)?;
download_file_with(&location, &tmp_zip, fetch)?;
let signature = std::fs::read(&tmp_signature).map_err(|e| e.to_string())?;
let file = std::fs::File::open(&tmp_zip).map_err(|e| e.to_string())?;
let mut reader = std::io::BufReader::new(file);
bundle_signature::verify_reader(&mut reader, &signature, &version, keys)?;
// Reuse the verified file handle rather than reopening by pathname.
use std::io::Seek;
reader.rewind().map_err(|e| e.to_string())?;
extract_zip_from(reader, &staging, &sys.cwd)?;
util::rm_rf(&tmp_zip);
util::rm_rf(&tmp_signature);
Ok(())
})();
match result {
@@ -931,4 +968,109 @@ mod tests {
assert_eq!(normalize_for_hash("x .claude/skills/y .trae-cn/skills/z .agent/skills/"), "x .PROVIDER/skills/y .PROVIDER/skills/z .PROVIDER/skills/");
assert_eq!(normalize_for_hash(".other/skills/"), ".other/skills/");
}
#[test]
fn keyring_load_failure_is_fatal_before_any_download() {
let sys = Sys::new(Default::default(), "/".into());
let mut fetch = |_: &str| -> Result<FetchResponse, String> {
panic!("A failed keyring must never reach the network");
};
let error = download_remote_bundle(&sys, &mut fetch, Err("Invalid compiled bundle signing keyring".into())).unwrap_err();
assert!(error.starts_with(bundle_signature::ERROR_PREFIX), "{error}");
assert!(error.contains("Invalid compiled bundle signing keyring"), "{error}");
}
#[test]
fn release_resolution_accepts_standard_redirects_only() {
for status in [200, 300, 301, 302, 303, 304, 305, 306, 307, 308, 404] {
let root = tmp_dir(&format!("redirect-{status}"));
let sys = Sys::new([("TMPDIR".into(), root.clone()), ("TEMP".into(), root.clone())].into(), root.clone());
let mut requests = 0;
let mut fetch = |_: &str| -> Result<FetchResponse, String> {
requests += 1;
if requests > 1 { return Err("reached signature download".into()); }
Ok(FetchResponse {
status,
location: Some("https://github.com/pbakaus/impeccable/releases/download/skill-v4.2.0/universal.zip".into()),
body: Box::new(std::io::empty()),
})
};
let error = download_and_extract_signed_bundle(&sys, &mut fetch, &Default::default()).unwrap_err();
if matches!(status, 301 | 302 | 303 | 307 | 308) {
assert_eq!(error, "reached signature download", "HTTP {status}");
assert_eq!(requests, 2);
} else {
assert!(error.contains("Expected a signed bundle release redirect"), "{error}");
assert_eq!(requests, 1);
}
assert_eq!(std::fs::read_dir(&root).unwrap().count(), 0);
util::rm_rf(&root);
}
}
#[test]
fn signed_download_verifies_before_extraction_and_cleans_all_failures() {
use ring::signature::{Ed25519KeyPair, KeyPair};
let key = Ed25519KeyPair::from_seed_unchecked(&[7; 32]).unwrap();
let hex = |bytes: &[u8]| bytes.iter().map(|b| format!("{b:02x}")).collect::<String>();
let keys = [("test-only".into(), hex(key.public_key().as_ref()))].into();
let zip = zip_bytes(&[(".claude/skills/impeccable/SKILL.md", b"verified skill")]);
let digest = format!("{:x}", Sha256::digest(&zip));
let payload = format!("impeccable-skill-bundle-v1\ntest-only\nskill-v4.2.0\nuniversal.zip\n{}\n{digest}\n", zip.len());
let signature = serde_json::to_vec(&serde_json::json!({
"schema": 1, "keyId": "test-only", "version": "4.2.0", "artifact": "universal.zip",
"size": zip.len(), "sha256": digest, "signature": hex(key.sign(payload.as_bytes()).as_ref()),
})).unwrap();
let release = "https://github.com/pbakaus/impeccable/releases/download/skill-v4.2.0/universal.zip";
for case in ["valid", "tampered", "missing", "oversized", "downgrade", "malformed-zip", "invalid-signature"] {
let root = tmp_dir(case);
let temp = format!("{root}/temp");
std::fs::create_dir(&temp).unwrap();
let installed = format!("{root}/existing-skill.md");
std::fs::write(&installed, "user's existing skill").unwrap();
let sys = Sys::new([("TMPDIR".into(), temp.clone()), ("TEMP".into(), temp.clone())].into(), root.clone());
let mut requested = Vec::new();
let mut fetch = |url: &str| -> Result<FetchResponse, String> {
requested.push(url.to_string());
let mut res = FetchResponse { status: 200, location: None, body: Box::new(std::io::Cursor::new(Vec::new())) };
if url.ends_with("/api/download/bundle/universal") {
res.status = 302;
res.location = Some(release.into());
} else if url == format!("{release}.sig.json") {
res.body = Box::new(std::io::Cursor::new(signature.clone()));
match case {
"missing" => res.status = 404,
"oversized" => res.body = Box::new(std::io::repeat(b' ')),
"downgrade" => { res.status = 302; res.location = Some("http://unsafe.test/sig".into()); }
"invalid-signature" => res.body = Box::new(std::io::Cursor::new(b"{}".to_vec())),
_ => {}
}
} else if url == release {
let mut bytes = zip.clone();
if case == "tampered" { bytes[0] ^= 1; }
if case == "malformed-zip" { bytes = b"not even a ZIP".to_vec(); }
res.body = Box::new(std::io::Cursor::new(bytes));
} else { panic!("Unexpected URL: {url}"); }
Ok(res)
};
let result = download_and_extract_signed_bundle(&sys, &mut fetch, &keys);
if case == "valid" {
let staging = result.unwrap();
assert_eq!(std::fs::read_to_string(format!("{staging}/.claude/skills/impeccable/SKILL.md")).unwrap(), "verified skill");
assert!(!util::exists(&format!("{staging}/bundle.zip")));
assert!(!util::exists(&format!("{staging}/bundle.sig.json")));
util::rm_rf(&staging);
} else {
let error = result.unwrap_err();
if case == "malformed-zip" {
assert!(error.contains("size"), "must reject before ZIP parsing: {error}");
}
}
assert_eq!(std::fs::read_to_string(&installed).unwrap(), "user's existing skill");
assert_eq!(std::fs::read_dir(&temp).unwrap().count(), 0, "staging leak in {case}");
assert_eq!(requested[0], format!("{API_BASE}/api/download/bundle/universal"));
assert_eq!(requested[1], format!("{release}.sig.json"));
util::rm_rf(&root);
}
}
}
+232
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@@ -0,0 +1,232 @@
//! Authenticity gate for remote skill bundles. The only trust roots are the
//! public keys compiled into this binary, never anything in a download.
use once_cell::sync::Lazy;
use regex::Regex;
use ring::signature::{UnparsedPublicKey, ED25519};
use serde::Deserialize;
use sha2::{Digest, Sha256};
use std::{collections::BTreeMap, io::Read};
pub(crate) const MAX_SIGNATURE_BYTES: u64 = 16 * 1024;
pub(crate) const ERROR_PREFIX: &str = "Could not verify skill bundle: ";
pub(crate) type TrustedKeys = BTreeMap<String, String>;
static VERSION: Lazy<Regex> = Lazy::new(|| {
Regex::new(
r"^(0|[1-9]\d*)\.(0|[1-9]\d*)\.(0|[1-9]\d*)(?:-[0-9A-Za-z-]+(?:\.[0-9A-Za-z-]+)*)?(?:\+[0-9A-Za-z-]+(?:\.[0-9A-Za-z-]+)*)?$"
).unwrap()
});
pub(crate) fn trusted_keys() -> Result<TrustedKeys, String> {
serde_json::from_str(include_str!("../../../scripts/bundle-signing-keys.json"))
.map_err(|_| "Invalid compiled bundle signing keyring".into())
}
pub(crate) fn release_version(location: &str) -> Result<String, String> {
let version = location
.strip_prefix("https://github.com/pbakaus/impeccable/releases/download/skill-v")
.and_then(|s| s.strip_suffix("/universal.zip"))
.filter(|v| v.len() <= 128 && VERSION.is_match(v));
version.map(str::to_string).ok_or_else(|| {
"Bundle download must redirect to a versioned Impeccable GitHub release".into()
})
}
#[derive(Deserialize)]
#[serde(rename_all = "camelCase", deny_unknown_fields)]
struct Envelope {
schema: u32,
key_id: String,
version: String,
artifact: String,
size: u64,
sha256: String,
signature: String,
}
fn decode_hex(value: &str, size: usize) -> Result<Vec<u8>, String> {
if value.len() != size * 2
|| !value
.bytes()
.all(|b| b.is_ascii_digit() || (b'a'..=b'f').contains(&b))
{
return Err("Invalid bundle signature encoding".into());
}
(0..value.len())
.step_by(2)
.map(|i| u8::from_str_radix(&value[i..i + 2], 16).map_err(|_| "Invalid hex".into()))
.collect()
}
pub(crate) fn verify_reader(
reader: &mut dyn Read,
signature: &[u8],
version: &str,
keys: &TrustedKeys,
) -> Result<(), String> {
if signature.len() as u64 > MAX_SIGNATURE_BYTES {
return Err("Bundle signature is too large".into());
}
let envelope: Envelope = serde_json::from_slice(signature)
.map_err(|_| "Missing or malformed bundle signature".to_string())?;
if envelope.schema != 1
|| envelope.version != version
|| !VERSION.is_match(version)
|| envelope.artifact != "universal.zip"
|| envelope.size == 0
|| envelope.size > crate::bundle::MAX_DOWNLOAD_BYTES
{
return Err("Bundle signature metadata does not match the requested release".into());
}
let public_key = keys
.get(&envelope.key_id)
.ok_or("Unknown bundle signing key; update the Impeccable CLI and retry")?;
let public_key = decode_hex(public_key, 32)?;
let signature = decode_hex(&envelope.signature, 64)?;
decode_hex(&envelope.sha256, 32)?;
let payload = format!(
"impeccable-skill-bundle-v1\n{}\nskill-v{}\n{}\n{}\n{}\n",
envelope.key_id, envelope.version, envelope.artifact, envelope.size, envelope.sha256
);
UnparsedPublicKey::new(&ED25519, public_key)
.verify(payload.as_bytes(), &signature)
.map_err(|_| "Bundle signature verification failed".to_string())?;
let mut hash = Sha256::new();
let mut size = 0u64;
let mut buffer = [0u8; 64 * 1024];
loop {
let count = reader.read(&mut buffer).map_err(|e| e.to_string())?;
if count == 0 {
break;
}
size += count as u64;
if size > envelope.size {
return Err("Bundle size does not match its signature".into());
}
hash.update(&buffer[..count]);
}
if size != envelope.size || format!("{:x}", hash.finalize()) != envelope.sha256 {
return Err("Bundle digest or size does not match its signature".into());
}
Ok(())
}
#[cfg(test)]
mod tests {
use super::*;
use ring::signature::{Ed25519KeyPair, KeyPair};
#[test]
#[ignore = "Set IMPECCABLE_VERIFY_BUNDLE and IMPECCABLE_VERIFY_BUNDLE_VERSION to a reviewed release ZIP"]
fn verifies_reviewed_release_with_production_keyring() {
let path = std::env::var("IMPECCABLE_VERIFY_BUNDLE").unwrap();
let version = std::env::var("IMPECCABLE_VERIFY_BUNDLE_VERSION").unwrap();
let signature = std::fs::read(format!("{path}.sig.json")).unwrap();
let mut file = std::fs::File::open(path).unwrap();
verify_reader(&mut file, &signature, &version, &trusted_keys().unwrap()).unwrap();
}
#[test]
fn verifies_node_interoperability_vector() {
let fixture: serde_json::Value = serde_json::from_str(include_str!(
"../../../tests/fixtures/bundle-signature.json"
))
.unwrap();
let bundle = fixture["bundle"].as_str().unwrap().as_bytes();
let envelope = serde_json::to_vec(&fixture["envelope"]).unwrap();
let keys = serde_json::from_value(fixture["keys"].clone()).unwrap();
verify_reader(&mut &bundle[..], &envelope, "4.2.0", &keys).unwrap();
}
fn fixture() -> (Vec<u8>, Vec<u8>, std::collections::BTreeMap<String, String>) {
// A public, deterministic TEST key. Never present in the production keyring.
let key = Ed25519KeyPair::from_seed_unchecked(&[7; 32]).unwrap();
let bundle = b"test bundle".to_vec();
let digest = format!("{:x}", Sha256::digest(&bundle));
let payload = format!(
"impeccable-skill-bundle-v1\ntest-only\nskill-v4.2.0\nuniversal.zip\n11\n{digest}\n"
);
let hex = |bytes: &[u8]| bytes.iter().map(|b| format!("{b:02x}")).collect::<String>();
let envelope = serde_json::json!({
"schema": 1, "keyId": "test-only", "version": "4.2.0",
"artifact": "universal.zip", "size": 11, "sha256": digest,
"signature": hex(key.sign(payload.as_bytes()).as_ref()),
});
(
bundle,
serde_json::to_vec(&envelope).unwrap(),
[("test-only".into(), hex(key.public_key().as_ref()))].into(),
)
}
#[test]
fn accepts_signed_bytes_and_rejects_tampering() {
let (bundle, envelope, keys) = fixture();
verify_reader(&mut &bundle[..], &envelope, "4.2.0", &keys).unwrap();
for tampered in [b"Test bundle".as_slice(), b"test bundle extra", b"test"] {
assert!(verify_reader(&mut &tampered[..], &envelope, "4.2.0", &keys).is_err());
}
assert!(verify_reader(&mut &bundle[..], &envelope, "4.2.1", &keys).is_err());
assert!(verify_reader(&mut &bundle[..], &envelope, "4.2.0", &Default::default()).is_err());
}
#[test]
fn rejects_changed_metadata_bad_encodings_and_unsigned_bundles() {
let (bundle, envelope, keys) = fixture();
for (field, value) in [
("schema", serde_json::json!(2)),
("keyId", serde_json::json!("attacker")),
("version", serde_json::json!("4.2.1")),
("artifact", serde_json::json!("other.zip")),
("size", serde_json::json!(10)),
("sha256", serde_json::json!("0".repeat(64))),
("signature", serde_json::json!("0".repeat(128))),
("signature", serde_json::json!("ff")),
("sha256", serde_json::json!("g".repeat(64))),
(
"publicKey",
serde_json::json!("never trust an embedded key"),
),
] {
let mut bad: serde_json::Value = serde_json::from_slice(&envelope).unwrap();
bad[field] = value;
assert!(
verify_reader(
&mut &bundle[..],
&serde_json::to_vec(&bad).unwrap(),
"4.2.0",
&keys
)
.is_err(),
"{field}"
);
}
for malformed in [b"".as_slice(), b"{}", b"not json"] {
assert!(verify_reader(&mut &bundle[..], malformed, "4.2.0", &keys).is_err());
}
let duplicate = String::from_utf8(envelope)
.unwrap()
.replacen('{', "{\"schema\":1,", 1);
assert!(verify_reader(&mut &bundle[..], duplicate.as_bytes(), "4.2.0", &keys).is_err());
}
#[test]
fn release_location_is_exact_and_versioned() {
let prefix = "https://github.com/pbakaus/impeccable/releases/download/";
assert_eq!(
release_version(&format!("{prefix}skill-v4.2.0/universal.zip")).unwrap(),
"4.2.0"
);
for bad in [
format!("{prefix}skill-v4.2.0/other.zip"),
format!("{prefix}skill-v4.2.0/universal.zip?key=x"),
format!("{prefix}skill-v4.2.0/universal.zip#x"),
format!("{prefix}skill-v04.2.0/universal.zip"),
"http://github.com/pbakaus/impeccable/releases/download/skill-v4.2.0/universal.zip".into(),
"https://github.com/attacker/impeccable/releases/download/skill-v4.2.0/universal.zip".into(),
"https://github.com.evil.test/pbakaus/impeccable/releases/download/skill-v4.2.0/universal.zip".into(),
] {
assert!(release_version(&bad).is_err(), "{bad}");
}
}
}
+2 -1
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@@ -588,7 +588,8 @@ fn install(flags: &[String], io: &mut Io) -> R<()> {
match bundle::download_and_extract_bundle(&sys) {
Ok(dir) => bundle_dir = Some(dir),
Err(e) => {
if !missing_hook_targets.is_empty() || !missing_selected_targets.is_empty() {
if e.starts_with(crate::bundle_signature::ERROR_PREFIX)
|| !missing_hook_targets.is_empty() || !missing_selected_targets.is_empty() {
return Err(e);
}
update_check_skipped = true;
+6 -2
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@@ -3,8 +3,7 @@
//! `cli/bin/commands/skills.mjs` (plus the slice of `cli/lib/impeccable-config.mjs`
//! it imports).
//!
//! Two deliberate departures from the JS, both part of the release that
//! replaces the Node scripts with the binary:
//! Deliberate departures from the original JS behavior:
//!
//! 1. After a skill directory is written (fresh install, refresh, update), if
//! its `scripts/VERSION` exists and `scripts/bin/<os>-<arch>/impeccable`
@@ -19,11 +18,16 @@
//! (`impeccable_hook::admin`) writes, and both paths recognize a manifest
//! entry as ours through `impeccable_context::hook_markers`, so the two
//! never drift on detection. See `hook_manifest`.
//! 3. Remote skill ZIPs require an Ed25519 signature from a compiled-in key
//! before extraction. Failure is fatal even when an existing install is
//! present. Explicit local bundle overrides remain unsigned development
//! inputs. See `bundle_signature` and docs/BUNDLE-SIGNING.md.
//!
//! Everything else (messages, exit codes, endpoints, flags, prompts, file
//! layout) follows the JS byte for byte.
pub mod bundle;
mod bundle_signature;
pub mod commands;
pub mod engine_binary;
pub mod hook_manifest;
+117
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@@ -0,0 +1,117 @@
# Skill bundle signatures
`impeccable install`, `update`, and `check` authenticate a remote skill ZIP
before extracting it. `universal.zip.sig.json` is an Ed25519 signature over
the ZIP's SHA-256 digest, byte length, release version, artifact name, and key
ID. The engine trusts only `scripts/bundle-signing-keys.json`, compiled into
the binary. A signature cannot introduce a new trusted key.
The download endpoint on impeccable.style redirects to a versioned GitHub
release. The installer resolves that redirect once and downloads the ZIP and
its signature from that same release. Every subsequent redirect must use
HTTPS. Missing signatures, unknown keys, changed metadata, and changed ZIP
bytes stop the operation before extraction or writes to installed skills.
The temporary download directory is removed on failure.
## Sign a release
Install the 1Password CLI and enable its desktop app integration. The signing
item holds the PKCS#8 Ed25519 private key in a concealed `private-key` field.
Set references, not key material, in your shell:
```sh
export OP_ACCOUNT='<account ID or sign-in address>'
export IMPECCABLE_SIGNING_KEY_REF='op://<vault ID>/<item ID>/private-key'
bun run release:skill
```
For a persistent setup on your machine, use local Git settings instead:
```sh
git config --local impeccable.signingAccount '<account ID or sign-in address>'
git config --local impeccable.signingKeyRef 'op://<vault ID>/<item ID>/private-key'
```
Those values stay in `.git/config`, outside version control. Environment
variables take precedence. Neither setting contains the private key.
The release command rebuilds the ZIP, reads the key through `op read`, checks
that its public key is trusted, and writes the sidecar before creating any
tag or release. The ZIP and sidecar are uploaded together. The key is never
passed as a command argument, written to a temporary file, or printed. It
does exist briefly in the local signing process's memory. 1Password failures
are reported without forwarding child-process output.
`--dry-run` does not access 1Password or create a signature. It checks the
usual release prerequisites and shows both assets in the upload plan; it
does not prove that signing credentials work.
To sign an already-published release for the initial rollout, download and
review the exact released `universal.zip`, then run:
```sh
node scripts/sign-bundle.mjs 4.2.0 /path/to/universal.zip
```
Check the resulting sidecar against the Rust verifier and compiled public key:
```sh
IMPECCABLE_VERIFY_BUNDLE=/path/to/universal.zip \
IMPECCABLE_VERIFY_BUNDLE_VERSION=4.2.0 \
cargo test -p impeccable-skills verifies_reviewed_release_with_production_keyring -- --ignored
```
This creates only the local sidecar. It neither uploads it nor replaces the
ZIP. Never regenerate an old ZIP and sign those different bytes as the old
release. Uploading the sidecar is a separate maintainer approval step.
## Rollout and rotation
Before shipping the enforcing engine, publish a valid signature beside the
exact ZIP currently served by impeccable.style. Verify the pair using a
locally built engine, then release the engine, its npm platform packages, and
the CLI/skill pins. Keep the existing release available throughout. Do not
release an enforcing engine with an empty keyring or an unsigned served ZIP.
For planned rotation, ship an engine trusting both the old and new public
keys before signing with the new key. Older engines that do not know the new
key will refuse the download and ask for a CLI update. A compromised key
requires an engine update removing that public key; removing it from a
website does not revoke trust in already-installed binaries. Keep the
dedicated signing item separate from GitHub and deployment credentials.
## Scope
This protects against bundle substitution when an attacker can change the
download endpoint, release asset, or both, but cannot use the signing key or
replace the trusted engine. It is not a freshness protocol: a previously
signed release can still be replayed. Signed timestamp metadata and rollback
state are separate work. Signatures do not establish that authored skill
content is safe, and do not authenticate separately downloaded engine
binaries (those currently use their existing SHA-256 sidecars).
`IMPECCABLE_BUNDLE_PATH` and `impeccable link` are explicit local-development
trust paths. They continue to accept unsigned local files/directories. Do not
use those overrides to get around a failed remote verification. There is no
unsigned-network fallback or skip-signature flag.
## Wire format
JSON sidecar fields: `schema` (1), `keyId`, `version`, `artifact`
(`universal.zip`), `size`, `sha256`, `signature`. Hex strings are lowercase;
the public key is 32 bytes and the signature is 64 bytes. Unknown or repeated
fields are rejected. The signature payload is UTF-8 with LF line endings
and a final LF:
```text
impeccable-skill-bundle-v1
<keyId>
skill-v<version>
universal.zip
<size as decimal>
<sha256 as lowercase hex>
```
The Node signer and Rust verifier share a fixed test vector under
`tests/fixtures/bundle-signature.json`. Its deterministic test key must never
be added to the production keyring.
+10
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@@ -342,6 +342,16 @@ Optional keys added later by engines (appended after the above): `ignoreValue` (
#### `impeccable help|install|link|update|check` and `impeccable skills <verb>` (`cli/bin/commands/skills.mjs`)
**Rust authenticity addition (#479):** the historical JS bundle flow below
is superseded for remote downloads. The Rust installer resolves the site's
redirect (301/302/303/307/308) to a versioned Impeccable GitHub release and verifies
`universal.zip.sig.json` against a compiled-in Ed25519 public key before ZIP
extraction. Missing/invalid signatures, unknown keys, mismatched metadata or
content, and failures fetching either asset exit nonzero, including when
`install` finds an existing installation. No downloaded content reaches the
installed skill or hook files. Explicit `IMPECCABLE_BUNDLE_PATH` and `link`
retain their local-development trust behavior. See [bundle signing](BUNDLE-SIGNING.md).
- **Invoked from**: README.md ("npx impeccable install / update"), README.npm.md Quick Start (`npx impeccable skills install`, `... install -y --providers=claude,codex --scope=project`, `... update`, `... install --no-hooks`, `... link --source=.impeccable --providers=claude,cursor`, `... skills help`), `README.md:360` (hook consent explanation).
- `run(args)`: `args[0]``undefined|help|--help|-h``showHelp()`; `install``install(rest)`; `link`; `update`; `check` (ignores flags); else `stderr> Unknown skills command: ${sub}` + `Run 'impeccable --help' for available commands.`, `exit 1`.
- Constants: `API_BASE = 'https://impeccable.style'`; `PROVIDER_DIRS = ['.claude','.cursor','.gemini','.agents','.agent','.github','.grok','.hermes','.kiro','.opencode','.pi','.qoder','.trae','.trae-cn','.rovodev','.vibe']`; aliases (`agent``.agent`, `agents`/`codex``.agents`, `antigravity``.agent`, `claude`/`claude-code``.claude`, `copilot`/`github``.github`, `cursor`, `gemini`, `grok`/`grok-build`/`xai``.grok`, `hermes`, `kiro`, `opencode`, `pi`, `qoder`, `rovo-dev`/`rovodev``.rovodev`, `trae`, `trae-cn`, `vibe`); leading `.` stripped and lowercased before alias lookup; a literal PROVIDER_DIR value is accepted as-is. `DEFAULT_TARGETS = ['.claude','.agents']`. User-scope skill dir overrides: `.agent``~/.gemini/config/skills`, `.hermes``$HERMES_HOME/skills` (only when HERMES_HOME under home) else `~/.hermes/skills`, `.pi``~/.pi/agent/skills`, `.opencode``$OPENCODE_CONFIG_DIR|$XDG_CONFIG_HOME/opencode|~/.config/opencode` + `/skills`; others `~/<provider>/skills`. Project scope: `<root>/<provider>/skills`.
+4
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@@ -232,6 +232,10 @@ this feature, replacing the `detectText` call it makes into the npm
## Releases
Remote skill ZIPs require a pinned-key signature before extraction. See
[bundle signing](BUNDLE-SIGNING.md) for the 1Password setup and the required
signature-first rollout order.
Two release kinds touch the runtime, in this order:
1. **Engine** (`engine-v<ENGINE_VERSION>`): `bun run release:engine` verifies
+3
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@@ -0,0 +1,3 @@
{
"release-2026-09": "7433133bb92da2c0da4186925f36dbd36219c11192451df56f25fd6a23dd7db9"
}
+20
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@@ -19,6 +19,7 @@ import path from 'node:path';
import { fileURLToPath } from 'node:url';
import { checkEngineRelease } from './check-engine-release.mjs';
import { readEngineVersion } from './fetch-engine.mjs';
import { signReleaseBundle } from './sign-bundle.mjs';
const repoRoot = path.resolve(path.dirname(fileURLToPath(import.meta.url)), '..');
@@ -255,6 +256,25 @@ for (const artifact of cfg.artifacts) {
ok(artifact);
}
// Sign the final rebuilt bytes before any tag or upload. Dry runs do not
// unlock 1Password or write a signature; they only show the publishing plan.
if (component === 'skill') {
const signatureArtifact = 'dist/universal.zip.sig.json';
step('Signing universal.zip with the trusted 1Password release key');
if (dryRun) {
console.log(' [dry-run] Sign dist/universal.zip (1Password is not accessed)');
} else {
try {
signReleaseBundle({ zipPath: path.join(repoRoot, 'dist/universal.zip'), version });
} catch (error) {
fail(error.message);
}
if (!existsSync(path.join(repoRoot, signatureArtifact))) fail(`Missing artifact: ${signatureArtifact}`);
ok('signature verified locally');
}
cfg.artifacts.push(signatureArtifact);
}
console.log('\n--- Release notes preview ---');
console.log(notes);
console.log('--- end preview ---\n');
+105
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@@ -0,0 +1,105 @@
#!/usr/bin/env node
// Local release signing. Private key material travels from op through a pipe
// into crypto, never through argv, environment values, logs or temporary files.
import { createHash, createPrivateKey, createPublicKey, sign, verify } from 'node:crypto';
import { execFileSync } from 'node:child_process';
import { readFileSync, writeFileSync, statSync } from 'node:fs';
import { fileURLToPath } from 'node:url';
import path from 'node:path';
export const VERSION_PATTERN = /^(0|[1-9]\d*)\.(0|[1-9]\d*)\.(0|[1-9]\d*)(?:-[0-9A-Za-z-]+(?:\.[0-9A-Za-z-]+)*)?(?:\+[0-9A-Za-z-]+(?:\.[0-9A-Za-z-]+)*)?$/;
const MAX_BUNDLE_BYTES = 256 * 1024 * 1024;
const repoRoot = fileURLToPath(new URL('../', import.meta.url));
function localSetting(name) {
try {
return execFileSync('git', ['config', '--local', '--get', name], {
cwd: repoRoot, encoding: 'utf8', stdio: ['ignore', 'pipe', 'pipe'],
}).trim();
} catch { return undefined; }
}
export function publicKeyHex(key) {
if (key.asymmetricKeyType !== 'ed25519') throw new Error('Signing requires an Ed25519 key.');
const jwk = key.export({ format: 'jwk' });
return Buffer.from(jwk.x, 'base64url').toString('hex');
}
// Shared wire format with crates/skills/src/bundle_signature.rs. UTF-8, LF,
// trailing LF. Sign fields explicitly so JSON whitespace/order is irrelevant.
export function signaturePayload({ keyId, version, artifact, size, sha256 }) {
return Buffer.from(`impeccable-skill-bundle-v1\n${keyId}\nskill-v${version}\n${artifact}\n${size}\n${sha256}\n`);
}
export function readTrustedKeys() {
return JSON.parse(readFileSync(new URL('./bundle-signing-keys.json', import.meta.url), 'utf8'));
}
export function signBundle(bytes, version, privateKey, trustedKeys) {
if (typeof version !== 'string' || version.length > 128 || !VERSION_PATTERN.test(version)) throw new Error('Invalid skill version for signing.');
if (!bytes.length || bytes.length > MAX_BUNDLE_BYTES) throw new Error('Invalid bundle size for signing.');
const publicKey = createPublicKey(privateKey);
const publicHex = publicKeyHex(publicKey);
const keyId = Object.keys(trustedKeys).find(id => trustedKeys[id] === publicHex);
if (!keyId || !/^[a-z0-9-]{1,64}$/.test(keyId)) {
throw new Error('The signing key is not in the trusted bundle keyring.');
}
const envelope = {
schema: 1, keyId, version, artifact: 'universal.zip', size: bytes.length,
sha256: createHash('sha256').update(bytes).digest('hex'),
};
const payload = signaturePayload(envelope);
const signature = sign(null, payload, privateKey);
if (!verify(null, payload, publicKey, signature)) throw new Error('Signature self-check failed.');
return { ...envelope, signature: signature.toString('hex') };
}
function readFrom1Password(reference, account) {
return execFileSync('op', ['read', reference, '--no-newline', ...(account ? ['--account', account] : [])], {
stdio: ['ignore', 'pipe', 'pipe'], timeout: 120000, maxBuffer: 16384,
});
}
export function signReleaseBundle({ zipPath, version, trustedKeys = readTrustedKeys(),
secretReference = process.env.IMPECCABLE_SIGNING_KEY_REF ?? localSetting('impeccable.signingKeyRef'),
account = process.env.OP_ACCOUNT ?? localSetting('impeccable.signingAccount'), readSecret = readFrom1Password }) {
if (!secretReference?.startsWith('op://')) {
throw new Error('Set IMPECCABLE_SIGNING_KEY_REF to the 1Password private-key reference (op://vault/item/field).');
}
if (typeof version !== 'string' || version.length > 128 || !VERSION_PATTERN.test(version)) throw new Error('Invalid skill version for signing.');
if (statSync(zipPath).size > MAX_BUNDLE_BYTES) throw new Error('Invalid bundle size for signing.');
const bytes = readFileSync(zipPath);
let pem;
try {
const secret = readSecret(secretReference, account);
pem = Buffer.isBuffer(secret) ? secret : Buffer.from(secret);
} catch {
// Child-process exceptions can contain stdout/stderr. Never propagate them.
throw new Error('Could not read the signing key from 1Password. Check CLI integration and unlock the vault.');
}
let privateKey;
try {
privateKey = createPrivateKey(pem);
} catch {
throw new Error('The 1Password field is not a valid PKCS#8 private key.');
} finally {
pem.fill(0);
}
const envelope = signBundle(bytes, version, privateKey, trustedKeys);
const output = `${zipPath}.sig.json`;
writeFileSync(output, `${JSON.stringify(envelope, null, 2)}\n`);
return output;
}
if (process.argv[1] && path.resolve(process.argv[1]) === fileURLToPath(import.meta.url)) {
try {
const [version, zipPath, ...extra] = process.argv.slice(2);
if (!zipPath || extra.length || path.basename(zipPath) !== 'universal.zip') {
throw new Error('Usage: node scripts/sign-bundle.mjs <skill-version> <path/to/universal.zip>');
}
console.log(`Signed ${signReleaseBundle({ zipPath, version })}`);
} catch (error) {
console.error(error.message);
process.exitCode = 1;
}
}
+1
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@@ -70,6 +70,7 @@ export const SUITES = {
'tests/openai-plugin.test.mjs',
'tests/process-group.test.mjs',
'tests/release.test.mjs',
'tests/bundle-signing.test.mjs',
'tests/skill-reference.test.mjs',
'tests/readme-gitignore.test.mjs',
'tests/test-suites.test.mjs',
+85
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@@ -0,0 +1,85 @@
import { test } from 'node:test';
import assert from 'node:assert/strict';
import { generateKeyPairSync, createPrivateKey, createPublicKey, verify } from 'node:crypto';
import { mkdtempSync, writeFileSync, readFileSync, rmSync } from 'node:fs';
import { tmpdir } from 'node:os';
import path from 'node:path';
import { signBundle, signaturePayload, publicKeyHex, signReleaseBundle, readTrustedKeys } from '../scripts/sign-bundle.mjs';
const { privateKey, publicKey } = generateKeyPairSync('ed25519');
const trustedKeys = { 'test-only': publicKeyHex(publicKey) };
test('production keyring is populated and excludes the public test key', () => {
const keys = readTrustedKeys();
const fixture = JSON.parse(readFileSync(new URL('./fixtures/bundle-signature.json', import.meta.url)));
assert.ok(Object.keys(keys).length > 0);
for (const [id, key] of Object.entries(keys)) {
assert.match(id, /^[a-z0-9-]{1,64}$/);
assert.match(key, /^[0-9a-f]{64}$/);
assert.notEqual(key, fixture.keys['test-only']);
}
});
test('matches the shared Node/Rust interoperability vector (public test seed)', () => {
const fixture = JSON.parse(readFileSync(new URL('./fixtures/bundle-signature.json', import.meta.url)));
const key = createPrivateKey({
key: Buffer.concat([Buffer.from('302e020100300506032b657004220420', 'hex'), Buffer.alloc(32, 7)]),
format: 'der', type: 'pkcs8',
});
assert.deepEqual(signBundle(Buffer.from(fixture.bundle), '4.2.0', key, fixture.keys), fixture.envelope);
});
test('signs the exact bundle with version, size, digest, artifact and domain bound', () => {
const bundle = Buffer.from('test bundle');
const envelope = signBundle(bundle, '4.2.0', privateKey, trustedKeys);
assert.equal(envelope.keyId, 'test-only');
assert.equal(envelope.version, '4.2.0');
assert.equal(envelope.size, bundle.length);
assert.equal(envelope.artifact, 'universal.zip');
assert.equal(envelope.schema, 1);
assert.match(signaturePayload(envelope).toString(), /^impeccable-skill-bundle-v1\n/);
assert.ok(verify(null, signaturePayload(envelope), publicKey, Buffer.from(envelope.signature, 'hex')));
for (const changed of [
{ version: '4.2.1' }, { size: 1 }, { sha256: '0'.repeat(64) },
{ artifact: 'other.zip' }, { keyId: 'other-key' },
]) {
assert.equal(verify(null, signaturePayload({ ...envelope, ...changed }), publicKey,
Buffer.from(envelope.signature, 'hex')), false);
}
});
test('rejects unknown or non-Ed25519 keys and invalid versions', () => {
assert.throws(() => signBundle(Buffer.from('zip'), '4.2.0', privateKey, {}), /trusted/);
for (const version of ['4.2.0\nother', '../4.2.0', '', '04.2.0', '4.2']) {
assert.throws(() => signBundle(Buffer.from('zip'), version, privateKey, trustedKeys), /version/);
}
const rsa = generateKeyPairSync('rsa', { modulusLength: 2048 });
assert.throws(() => publicKeyHex(rsa.publicKey), /Ed25519/);
});
test('1Password read uses a pipe, checks the pinned key, writes only a public signature', () => {
const root = mkdtempSync(path.join(tmpdir(), 'impeccable-sign-test-'));
try {
const zipPath = path.join(root, 'universal.zip');
writeFileSync(zipPath, 'test bundle');
const secretReference = 'op://test-vault/test-item/private-key';
let called = false;
signReleaseBundle({ zipPath, version: '4.2.0', trustedKeys, secretReference,
readSecret(reference) {
called = true;
assert.equal(reference, secretReference);
return privateKey.export({ type: 'pkcs8', format: 'pem' });
},
});
assert.ok(called);
const envelope = JSON.parse(readFileSync(`${zipPath}.sig.json`, 'utf8'));
assert.ok(verify(null, signaturePayload(envelope), createPublicKey(privateKey),
Buffer.from(envelope.signature, 'hex')));
assert.doesNotMatch(readFileSync(`${zipPath}.sig.json`, 'utf8'), /PRIVATE KEY/);
assert.throws(() => signReleaseBundle({ zipPath, version: '4.2.0', trustedKeys,
secretReference, readSecret() { throw new Error('SECRET that must not leak'); },
}), /Could not read.*1Password/);
} finally {
rmSync(root, { recursive: true, force: true });
}
});
+15
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@@ -0,0 +1,15 @@
{
"bundle": "test bundle",
"keys": {
"test-only": "ea4a6c63e29c520abef5507b132ec5f9954776aebebe7b92421eea691446d22c"
},
"envelope": {
"schema": 1,
"keyId": "test-only",
"version": "4.2.0",
"artifact": "universal.zip",
"size": 11,
"sha256": "9df2a47bee5f48b9752b2cbd2d6075076556ee293adc97f66f0e0a916e4f6471",
"signature": "35dfe147573341b1fdcb4bc4054b0e96c5d07b9069bd1257f745d6ad6c3eca72f52876e7d0403cffeac2e60ef2dea41879ca4cb9cecaebb463332aaf9d15620b"
}
}
+52 -1
View File
@@ -88,7 +88,7 @@ describe('release.mjs guards', () => {
// (and check-engine-release.mjs imports fetch-engine.mjs), so stage them
// too or the dry runs fail to resolve the modules instead of exercising
// the guard.
for (const dep of ['check-engine-release.mjs', 'fetch-engine.mjs']) {
for (const dep of ['check-engine-release.mjs', 'fetch-engine.mjs', 'sign-bundle.mjs', 'bundle-signing-keys.json']) {
fs.copyFileSync(path.join(REPO_ROOT, 'scripts', dep), path.join(workDir, 'scripts', dep));
}
write('.claude-plugin/plugin.json', JSON.stringify({ name: 'impeccable', version: '1.2.3' }));
@@ -171,6 +171,57 @@ describe('release.mjs guards', () => {
assert.match(stdout, /tag is free/);
assert.match(stdout, /\[dry-run\] git tag -a skill-v1\.2\.3/);
assert.match(stdout, /\[dry-run\] gh release create skill-v1\.2\.3/);
assert.match(stdout, /1Password is not accessed/);
assert.match(stdout, /gh release create[^\n]+universal\.zip\.sig\.json/);
assert.equal(fs.existsSync(path.join(workDir, 'dist/universal.zip.sig.json')), false);
});
it('refuses a real release before tagging when signing is not configured', () => {
const pkg = JSON.parse(fs.readFileSync(path.join(workDir, 'package.json'), 'utf8'));
pkg.scripts = { 'build:release': 'node -e "process.exit(0)"' };
write('package.json', JSON.stringify(pkg));
git(workDir, 'add', 'package.json');
git(workDir, 'commit', '-m', 'fixture build command');
git(workDir, 'push', 'origin', 'main');
assert.throws(() => execFileSync(process.execPath, ['scripts/release.mjs', 'skill'], {
cwd: workDir, encoding: 'utf8', stdio: 'pipe',
env: { ...process.env, IMPECCABLE_SKIP_ENGINE_CHECK: '1', IMPECCABLE_SIGNING_KEY_REF: '' },
}), error => {
assert.match(error.stderr, /Set IMPECCABLE_SIGNING_KEY_REF/);
assert.doesNotMatch(error.stdout, /Creating annotated tag|Creating GitHub release/);
return true;
});
assert.equal(git(workDir, 'tag'), '');
assert.equal(git(workDir, 'ls-remote', '--tags', 'origin'), '');
});
it('refuses before tagging when the signer returns without creating the sidecar', () => {
const pkg = JSON.parse(fs.readFileSync(path.join(workDir, 'package.json'), 'utf8'));
pkg.scripts = { 'build:release': 'node -e "process.exit(0)"' };
write('package.json', JSON.stringify(pkg));
// Stub only inside this disposable repository. No 1Password access, tags,
// or real GitHub publication can occur even if the assertion regresses.
write('scripts/sign-bundle.mjs', 'export function signReleaseBundle() {}\n');
const releaseSource = fs.readFileSync(RELEASE_SCRIPT, 'utf8');
const tagStep = 'step(`Creating annotated tag ${tag}`);';
assert.ok(releaseSource.includes(tagStep), 'fixture must intercept the tag step');
write('scripts/release.mjs', releaseSource.replace(
tagStep,
'throw new Error("UNEXPECTED_TAG_STEP");'
));
git(workDir, 'add', 'package.json', 'scripts/sign-bundle.mjs', 'scripts/release.mjs');
git(workDir, 'commit', '-m', 'fixture signer with missing output');
git(workDir, 'push', 'origin', 'main');
assert.throws(() => execFileSync(process.execPath, ['scripts/release.mjs', 'skill'], {
cwd: workDir, encoding: 'utf8', stdio: 'pipe',
env: { ...process.env, IMPECCABLE_SKIP_ENGINE_CHECK: '1' },
}), error => {
assert.match(error.stderr, /Missing artifact: dist\/universal\.zip\.sig\.json/);
assert.doesNotMatch(error.stderr, /UNEXPECTED_TAG_STEP/);
return true;
});
assert.equal(git(workDir, 'tag'), '');
assert.equal(git(workDir, 'ls-remote', '--tags', 'origin'), '');
});
it('converts the changelog entry to markdown release notes', () => {