Sub2API v1.0 - AI API 网关（二开初始版本，基于上游 Wei-Shaw/sub2api）

backend/internal/service/openai_live_attestation.go

@@ -0,0 +1,110 @@
+package service
+
+import (
+	"context"
+	"crypto/aes"
+	"crypto/cipher"
+	"crypto/rand"
+	"crypto/sha256"
+	"encoding/base64"
+	"errors"
+	"fmt"
+	"io"
+	"strings"
+
+	"github.com/Wei-Shaw/sub2api/internal/config"
+)
+
+const liveAttestationHeader = "x-oai-attestation"
+
+type liveAttestationAES struct {
+	key [32]byte
+}
+
+func newLiveAttestationCipher(cfg *config.Config) SecretEncryptor {
+	if cfg == nil || strings.TrimSpace(cfg.JWT.Secret) == "" {
+		return nil
+	}
+	return &liveAttestationAES{
+		key: sha256.Sum256([]byte("sub2api/live-attestation/v1\x00" + cfg.JWT.Secret)),
+	}
+}
+
+func (c *liveAttestationAES) Encrypt(plaintext string) (string, error) {
+	block, err := aes.NewCipher(c.key[:])
+	if err != nil {
+		return "", err
+	}
+	gcm, err := cipher.NewGCM(block)
+	if err != nil {
+		return "", err
+	}
+	nonce := make([]byte, gcm.NonceSize())
+	if _, err := io.ReadFull(rand.Reader, nonce); err != nil {
+		return "", fmt.Errorf("generate Live attestation nonce: %w", err)
+	}
+	encrypted := gcm.Seal(nonce, nonce, []byte(plaintext), nil)
+	return base64.RawStdEncoding.EncodeToString(encrypted), nil
+}
+
+func (c *liveAttestationAES) Decrypt(ciphertext string) (string, error) {
+	encrypted, err := base64.RawStdEncoding.DecodeString(ciphertext)
+	if err != nil {
+		return "", fmt.Errorf("decode Live attestation: %w", err)
+	}
+	block, err := aes.NewCipher(c.key[:])
+	if err != nil {
+		return "", err
+	}
+	gcm, err := cipher.NewGCM(block)
+	if err != nil {
+		return "", err
+	}
+	if len(encrypted) < gcm.NonceSize() {
+		return "", errors.New("encrypted Live attestation is too short")
+	}
+	plaintext, err := gcm.Open(nil, encrypted[:gcm.NonceSize()], encrypted[gcm.NonceSize():], nil)
+	if err != nil {
+		return "", fmt.Errorf("decrypt Live attestation: %w", err)
+	}
+	return string(plaintext), nil
+}
+
+func (s *OpenAIGatewayService) prepareLiveAttestation(ctx context.Context) (string, string, error) {
+	if s == nil || s.liveAttestation == nil {
+		return "", "", &LiveAttestationUnavailableError{
+			Reason: "Sub2API has no platform DeviceCheck provider",
+		}
+	}
+	if s.liveAttestationCipher == nil {
+		return "", "", &LiveAttestationUnavailableError{
+			Reason: "JWT secret is required to protect the Sideband attestation",
+		}
+	}
+	header, err := s.liveAttestation.Generate(ctx)
+	if err != nil {
+		return "", "", &LiveAttestationUnavailableError{Reason: err.Error()}
+	}
+	ciphertext, err := s.liveAttestationCipher.Encrypt(header)
+	if err != nil {
+		return "", "", &LiveAttestationUnavailableError{
+			Reason: "failed to protect the generated DeviceCheck attestation",
+		}
+	}
+	return header, ciphertext, nil
+}
+
+func (s *OpenAIGatewayService) decryptLiveAttestation(record *LiveCallRecord) (string, error) {
+	if record == nil || strings.TrimSpace(record.AttestationCiphertext) == "" || s.liveAttestationCipher == nil {
+		return "", &LiveAttestationUnavailableError{
+			Reason: "the Live call has no reusable DeviceCheck attestation",
+		}
+	}
+	header, err := s.liveAttestationCipher.Decrypt(record.AttestationCiphertext)
+	if err != nil {
+		return "", &LiveAttestationUnavailableError{
+			Reason: "the Live call DeviceCheck attestation cannot be decrypted on this instance",
+		}
+	}
+	return header, nil
+}