steve
76ada04442
Resolve final-review findings: commandRole is now the single source of truth (Run resolves role once and threads it to handlers, replacing hardcoded openStore roles). Tighten crypto/SKILL/SPEC/USER-MANUAL wording and document init's agent-key-on-first-init-only semantics. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
79 lines
2.1 KiB
Go
79 lines
2.1 KiB
Go
// Package crypto provides AES-256-GCM field encryption; keys are loaded from EMCLI_KEY (agent) or EMCLI_ADMIN_KEY (admin).
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package crypto
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import (
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"crypto/aes"
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"crypto/cipher"
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"crypto/rand"
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"encoding/base64"
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"errors"
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"fmt"
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"io"
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"os"
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)
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// keyFromEnv reads and validates a base64-encoded 32-byte AES key from the
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// named environment variable. Errors name the variable so callers get a
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// role-appropriate message.
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func keyFromEnv(varName string) ([]byte, error) {
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raw := os.Getenv(varName)
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if raw == "" {
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return nil, fmt.Errorf("%s is not set", varName)
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}
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key, err := base64.StdEncoding.DecodeString(raw)
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if err != nil || len(key) != 32 {
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return nil, fmt.Errorf("%s must be base64 of exactly 32 bytes", varName)
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}
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return key, nil
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}
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// AgentKeyFromEnv reads the agent KEK from EMCLI_KEY (agent commands only).
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func AgentKeyFromEnv() ([]byte, error) { return keyFromEnv("EMCLI_KEY") }
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// AdminKeyFromEnv reads the admin KEK from EMCLI_ADMIN_KEY (all commands).
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func AdminKeyFromEnv() ([]byte, error) { return keyFromEnv("EMCLI_ADMIN_KEY") }
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// NewDEK returns a fresh random 32-byte data-encryption key.
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func NewDEK() ([]byte, error) {
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dek := make([]byte, 32)
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if _, err := io.ReadFull(rand.Reader, dek); err != nil {
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return nil, err
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}
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return dek, nil
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}
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func newGCM(key []byte) (cipher.AEAD, error) {
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block, err := aes.NewCipher(key)
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if err != nil {
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return nil, err
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}
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return cipher.NewGCM(block)
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}
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// Seal encrypts plaintext, returning nonce||ciphertext.
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func Seal(key, plaintext []byte) ([]byte, error) {
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gcm, err := newGCM(key)
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if err != nil {
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return nil, err
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}
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nonce := make([]byte, gcm.NonceSize())
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if _, err := io.ReadFull(rand.Reader, nonce); err != nil {
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return nil, err
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}
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return gcm.Seal(nonce, nonce, plaintext, nil), nil
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}
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// Open reverses Seal. A wrong key or tampered blob returns an error.
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func Open(key, blob []byte) ([]byte, error) {
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gcm, err := newGCM(key)
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if err != nil {
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return nil, err
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}
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ns := gcm.NonceSize()
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if len(blob) < ns {
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return nil, errors.New("ciphertext too short")
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}
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nonce, ct := blob[:ns], blob[ns:]
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return gcm.Open(nil, nonce, ct, nil)
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}
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