6823e5a30d
- PKCE (S256) in OAuth flow: code_verifier in oauth_states, code_challenge in auth URL - CryptoService: AES-256-GCM encryption for OAuth provider tokens at rest - OAuth redirect URL validated against OAUTH_ALLOWED_REDIRECT_DOMAINS - CHAT_JWT_SECRET must differ from JWT_SECRET in production - Migration script: cmd/tools/encrypt_oauth_tokens for existing tokens - Fixes: VEZA-SEC-003, VEZA-SEC-004, VEZA-SEC-009, VEZA-SEC-010
128 lines
3.7 KiB
Go
128 lines
3.7 KiB
Go
package services
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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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)
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const (
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// NonceSize for AES-GCM (12 bytes recommended by NIST)
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gcmNonceSize = 12
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// Prefix for encrypted tokens stored in DB (detect already-encrypted)
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encryptedTokenPrefix = "veza_enc_v1:"
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)
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// CryptoService provides AES-256-GCM encryption for sensitive data (e.g. OAuth tokens at rest)
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type CryptoService struct {
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aead cipher.AEAD
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}
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// NewCryptoService creates a CryptoService with the given key (32 bytes for AES-256)
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func NewCryptoService(key []byte) (*CryptoService, error) {
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if len(key) < 32 {
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return nil, errors.New("encryption key must be at least 32 bytes for AES-256")
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}
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// Use first 32 bytes
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key32 := key
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if len(key) > 32 {
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key32 = key[:32]
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}
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block, err := aes.NewCipher(key32)
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if err != nil {
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return nil, fmt.Errorf("aes new cipher: %w", err)
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}
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aead, err := cipher.NewGCM(block)
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if err != nil {
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return nil, fmt.Errorf("gcm: %w", err)
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}
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return &CryptoService{aead: aead}, nil
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}
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// NewCryptoServiceFromBase64 creates a CryptoService from a base64-encoded key
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func NewCryptoServiceFromBase64(keyBase64 string) (*CryptoService, error) {
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if keyBase64 == "" {
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return nil, errors.New("encryption key must not be empty")
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}
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key, err := base64.RawStdEncoding.DecodeString(keyBase64)
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if err != nil {
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// Try standard base64
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key, err = base64.StdEncoding.DecodeString(keyBase64)
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if err != nil {
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return nil, fmt.Errorf("decode key: %w", err)
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}
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}
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return NewCryptoService(key)
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}
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// NewCryptoServiceFromHex creates a CryptoService from a hex-encoded key (optional, for future)
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// For now we use base64. Key can also be raw bytes if passed as string - we'll decode.
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// Encrypt encrypts plaintext with AES-256-GCM. Returns base64-encoded result.
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func (c *CryptoService) Encrypt(plaintext []byte) ([]byte, error) {
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nonce := make([]byte, gcmNonceSize)
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if _, err := io.ReadFull(rand.Reader, nonce); err != nil {
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return nil, fmt.Errorf("rand nonce: %w", err)
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}
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ciphertext := c.aead.Seal(nil, nonce, plaintext, nil)
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// Prepend nonce: nonce || ciphertext (ciphertext includes tag)
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out := make([]byte, 0, len(nonce)+len(ciphertext))
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out = append(out, nonce...)
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out = append(out, ciphertext...)
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return out, nil
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}
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// Decrypt decrypts ciphertext (format: nonce || sealed). Returns plaintext.
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func (c *CryptoService) Decrypt(ciphertext []byte) ([]byte, error) {
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if len(ciphertext) < gcmNonceSize {
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return nil, errors.New("ciphertext too short")
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}
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nonce := ciphertext[:gcmNonceSize]
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sealed := ciphertext[gcmNonceSize:]
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return c.aead.Open(nil, nonce, sealed, nil)
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}
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// EncryptString encrypts a string and returns the prefixed base64 result for DB storage
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func (c *CryptoService) EncryptString(plaintext string) (string, error) {
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if plaintext == "" {
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return "", nil
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}
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enc, err := c.Encrypt([]byte(plaintext))
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if err != nil {
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return "", err
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}
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return encryptedTokenPrefix + base64.RawStdEncoding.EncodeToString(enc), nil
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}
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// DecryptString decrypts a string stored with EncryptString (checks prefix)
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func (c *CryptoService) DecryptString(stored string) (string, error) {
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if stored == "" {
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return "", nil
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}
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if len(stored) < len(encryptedTokenPrefix) || stored[:len(encryptedTokenPrefix)] != encryptedTokenPrefix {
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// Not encrypted (legacy plaintext)
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return stored, nil
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}
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b64 := stored[len(encryptedTokenPrefix):]
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enc, err := base64.RawStdEncoding.DecodeString(b64)
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if err != nil {
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enc, err = base64.StdEncoding.DecodeString(b64)
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if err != nil {
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return "", fmt.Errorf("decode stored: %w", err)
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}
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}
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dec, err := c.Decrypt(enc)
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if err != nil {
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return "", err
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}
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return string(dec), nil
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}
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// EncryptedTokenPrefix returns the prefix used for encrypted tokens
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func EncryptedTokenPrefix() string {
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return encryptedTokenPrefix
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}
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