hashicorp/packer · error
read verifier %q: %w
Error message
read verifier %q: %w
What it means
LoadPEMVerifier failed to read the verifier file at the given path because os.ReadFile returned an error. The library wraps the underlying OS error (e.g. *fs.PathError with ENOENT, EACCES) so the cause is preserved via errors.Unwrap. This is a file-access problem, not a key-content problem.
Source
Thrown at internal/attestation/sign_key.go:107
return nil
case ed25519.PublicKey:
if !ed25519.Verify(publicKey, pae, signature) {
return fmt.Errorf("Ed25519 verification failed")
}
return nil
default:
return fmt.Errorf("unsupported public key type %T", v.publicKey)
}
}
func (v *pemVerifier) KeyID() string {
return v.keyID
}
func LoadPEMVerifier(path string) (Verifier, error) {
contents, err := os.ReadFile(path)
if err != nil {
return nil, fmt.Errorf("read verifier %q: %w", path, err)
}
publicKey, rawVerifier, err := loadPEMPublicKey(contents)
if err != nil {
return nil, fmt.Errorf("load verifier %q: %w", path, err)
}
return &pemVerifier{
publicKey: publicKey,
keyID: sha256Hex(rawVerifier),
}, nil
}
func LoadPEMVerifierBytes(contents []byte) (*pemVerifier, error) {
publicKey, rawVerifier, err := loadPEMPublicKey(contents)
if err != nil {
return nil, err
}View on GitHub (pinned to eb36e3c3e4)
Solutions
- Verify the path exists with os.Stat / 'ls -l <path>' and fix typos in the configured path.
- Check file permissions and the effective user (chmod/chown or run as a user with read access).
- If using a relative path, switch to an absolute path or fix the process working directory.
- Inspect the wrapped error with errors.Unwrap or errors.Is(err, fs.ErrNotExist) to identify the exact OS-level cause.
Example fix
// before
v, err := attestation.LoadPEMVerifier("verifier.pem") // fails: file not found
// after
if _, err := os.Stat("/etc/packer/verifier.pem"); err != nil {
log.Fatal(err)
}
v, err := attestation.LoadPEMVerifier("/etc/packer/verifier.pem") Defensive patterns
Strategy: validation
Validate before calling
info, err := os.Stat(path)
if err != nil {
return fmt.Errorf("verifier file %q unavailable: %w", path, err)
}
if info.IsDir() {
return fmt.Errorf("verifier path %q is a directory", path)
}
f, err := os.Open(path)
if err != nil {
return fmt.Errorf("verifier file %q not readable: %w", path, err)
}
f.Close() Try / catch
v, err := attestation.LoadPEMVerifier(path)
if err != nil {
if errors.Is(err, fs.ErrNotExist) {
return fmt.Errorf("verifier file missing at %s", path)
}
if errors.Is(err, fs.ErrPermission) {
return fmt.Errorf("verifier file %s not readable by this user", path)
}
return err
} Prevention
- Resolve and validate key paths at config-load time, before signing/verification runs.
- Use absolute paths and embed them from a single config source to avoid typos.
- In containers, verify secret mounts exist in the entrypoint before starting the app.
- Check errors with errors.Is(err, fs.ErrNotExist) / fs.ErrPermission to branch precisely.
When it happens
Trigger: Calling LoadPEMVerifier(path) or any caller (NewVerifier, verifierForEnvelope) with a path that does not exist, is a directory, has too-restrictive permissions, or sits on an unavailable mount.
Common situations: Typo in the verifier path in config; file deleted or never provisioned; running the binary as a different user than the key owner; container image missing the mounted key; relative path resolved against an unexpected working directory.
Understand the failure class
Background: "File not found" and ENOENT errors: why libraries can't find a file that should exist — this error's family across 50 libraries.
Related errors
- load verifier %q: %w
- read signer %q: %w
- no PEM block found
- decode keyless certificate: no PEM block found
- parse keyless certificate: %w
AI-assisted analysis of hashicorp/packer@eb36e3c3e4 (2026-09-05).
Data as JSON: /api/errors/f297af9736c1a531.
Report an issue: GitHub.