Add files via upload

2026-08-11 13:40:23 +02:00 · 2026-06-18 12:40:54 +08:00
parent 56faefaaf9
commit d5a0f93c6c
94 changed files with 24645 additions and 0 deletions
@@ -0,0 +1,154 @@
+package c2
+
+import (
+	"crypto/aes"
+	"crypto/cipher"
+	"crypto/rand"
+	"encoding/base64"
+	"errors"
+	"io"
+)
+
+// AES-256-GCM 信封：每个 Listener 独立 32 字节密钥 + 每条消息独立 12 字节 nonce。
+// 协议格式（base64 文本，便于 HTTP body / SSE 直接传）：
+//   base64( nonce(12) || ciphertext+tag )
+// 设计要点：
+//   - GCM 自带 16 字节 AEAD tag，完整性 + 机密性一次性搞定，无需额外 HMAC；
+//   - nonce 由 crypto/rand 生成，96bit 在密钥不变期内重复概率极低（< 2^-32 / 4B 次）；
+//   - 密钥不出服务端：listener 创建时随机生成 32 字节，编译 beacon 时硬编码进去。
+
+// GenerateAESKey 生成随机 32 字节 AES-256 密钥并 base64 输出
+func GenerateAESKey() (string, error) {
+	key := make([]byte, 32)
+	if _, err := io.ReadFull(rand.Reader, key); err != nil {
+		return "", err
+	}
+	return base64.StdEncoding.EncodeToString(key), nil
+}
+
+// GenerateImplantToken 生成 32 字节 token，base64 编码（implant 携带在 HTTP header 鉴权用）
+func GenerateImplantToken() (string, error) {
+	t := make([]byte, 32)
+	if _, err := io.ReadFull(rand.Reader, t); err != nil {
+		return "", err
+	}
+	return base64.RawURLEncoding.EncodeToString(t), nil
+}
+
+// EncryptAESGCM 加密任意明文，返回 base64(nonce||ct)
+func EncryptAESGCM(keyB64 string, plaintext []byte) (string, error) {
+	key, err := decodeKey(keyB64)
+	if err != nil {
+		return "", err
+	}
+	block, err := aes.NewCipher(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 "", err
+	}
+	ct := gcm.Seal(nil, nonce, plaintext, nil)
+	out := append(nonce, ct...)
+	return base64.StdEncoding.EncodeToString(out), nil
+}
+
+// DecryptAESGCM 解密 base64(nonce||ct)，返回明文
+func DecryptAESGCM(keyB64, encB64 string) ([]byte, error) {
+	key, err := decodeKey(keyB64)
+	if err != nil {
+		return nil, err
+	}
+	raw, err := base64.StdEncoding.DecodeString(encB64)
+	if err != nil {
+		return nil, errors.New("ciphertext base64 invalid")
+	}
+	block, err := aes.NewCipher(key)
+	if err != nil {
+		return nil, err
+	}
+	gcm, err := cipher.NewGCM(block)
+	if err != nil {
+		return nil, err
+	}
+	nonceSize := gcm.NonceSize()
+	if len(raw) < nonceSize+16 { // 至少 nonce + tag
+		return nil, errors.New("ciphertext too short")
+	}
+	nonce, ct := raw[:nonceSize], raw[nonceSize:]
+	pt, err := gcm.Open(nil, nonce, ct, nil)
+	if err != nil {
+		return nil, errors.New("aead open failed (key mismatch or tampered)")
+	}
+	return pt, nil
+}
+
+// EncryptAESGCMWithAAD encrypts with additional authenticated data bound to context (e.g. session_id).
+// Prevents cross-session replay: ciphertext from session A cannot be fed to session B.
+func EncryptAESGCMWithAAD(keyB64 string, plaintext []byte, aad []byte) (string, error) {
+	key, err := decodeKey(keyB64)
+	if err != nil {
+		return "", err
+	}
+	block, err := aes.NewCipher(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 "", err
+	}
+	ct := gcm.Seal(nil, nonce, plaintext, aad)
+	out := append(nonce, ct...)
+	return base64.StdEncoding.EncodeToString(out), nil
+}
+
+// DecryptAESGCMWithAAD decrypts with AAD verification.
+func DecryptAESGCMWithAAD(keyB64, encB64 string, aad []byte) ([]byte, error) {
+	key, err := decodeKey(keyB64)
+	if err != nil {
+		return nil, err
+	}
+	raw, err := base64.StdEncoding.DecodeString(encB64)
+	if err != nil {
+		return nil, errors.New("ciphertext base64 invalid")
+	}
+	block, err := aes.NewCipher(key)
+	if err != nil {
+		return nil, err
+	}
+	gcm, err := cipher.NewGCM(block)
+	if err != nil {
+		return nil, err
+	}
+	nonceSize := gcm.NonceSize()
+	if len(raw) < nonceSize+16 {
+		return nil, errors.New("ciphertext too short")
+	}
+	nonce, ct := raw[:nonceSize], raw[nonceSize:]
+	pt, err := gcm.Open(nil, nonce, ct, aad)
+	if err != nil {
+		return nil, errors.New("aead open failed (key mismatch, tampered, or AAD mismatch)")
+	}
+	return pt, nil
+}
+
+func decodeKey(keyB64 string) ([]byte, error) {
+	key, err := base64.StdEncoding.DecodeString(keyB64)
+	if err != nil {
+		return nil, errors.New("key base64 invalid")
+	}
+	if len(key) != 32 {
+		return nil, errors.New("key must be 32 bytes (AES-256)")
+	}
+	return key, nil
+}