113 lines
3.0 KiB
Go
113 lines
3.0 KiB
Go
package middleware
|
||
|
||
import (
|
||
"crypto/rand"
|
||
"encoding/hex"
|
||
"net/http"
|
||
|
||
"metazone.cc/metalab/internal/config"
|
||
|
||
"github.com/gin-gonic/gin"
|
||
)
|
||
|
||
const (
|
||
csrfCookieName = "mlb_csrf"
|
||
csrfHeaderName = "X-CSRF-Token"
|
||
csrfMetaName = "csrf_token"
|
||
csrfTokenLen = 32 // 字节
|
||
)
|
||
|
||
// CSRF 中间件：Double Submit Cookie 模式
|
||
// 前端 JS 从 Cookie 中读取 token 并放入 X-CSRF-Token 请求头，后端验证两者一致
|
||
// GET / HEAD / OPTIONS 请求自动放行
|
||
func CSRF(cfg *config.Config) gin.HandlerFunc {
|
||
return func(c *gin.Context) {
|
||
// 安全读取豁免
|
||
if c.Request.Method == http.MethodGet ||
|
||
c.Request.Method == http.MethodHead ||
|
||
c.Request.Method == http.MethodOptions {
|
||
c.Next()
|
||
return
|
||
}
|
||
|
||
cookieToken, err := c.Cookie(csrfCookieName)
|
||
if err != nil || cookieToken == "" {
|
||
c.AbortWithStatusJSON(http.StatusForbidden, gin.H{
|
||
"success": false, "message": "CSRF 验证失败",
|
||
})
|
||
return
|
||
}
|
||
|
||
headerToken := c.GetHeader(csrfHeaderName)
|
||
// Fallback：如果请求头没有，尝试从表单字段读取（纯 HTML form 提交通道）
|
||
if headerToken == "" {
|
||
headerToken = c.PostForm(csrfMetaName)
|
||
}
|
||
if headerToken == "" {
|
||
c.AbortWithStatusJSON(http.StatusForbidden, gin.H{
|
||
"success": false, "message": "CSRF 验证失败：缺少令牌",
|
||
})
|
||
return
|
||
}
|
||
|
||
// 恒定时间比较防时序攻击
|
||
if !constantTimeEq(cookieToken, headerToken) {
|
||
c.AbortWithStatusJSON(http.StatusForbidden, gin.H{
|
||
"success": false, "message": "CSRF 验证失败",
|
||
})
|
||
return
|
||
}
|
||
|
||
// 注入到上下文，供前端 <meta> 使用
|
||
c.Set(csrfMetaName, cookieToken)
|
||
c.Next()
|
||
}
|
||
}
|
||
|
||
// SetCSRFToken 在首次页面访问时下发 CSRF Cookie（由页面路由中间件调用）
|
||
// 注意：此 Cookie HttpOnly=false，JS 可读——这是 Double Submit 模式的必要条件
|
||
func SetCSRFToken(c *gin.Context, cfg *config.Config) string {
|
||
secure := cfg.Server.Mode != "debug"
|
||
|
||
// 如果已有 token 且未过期，复用（但必须注入 context，供模板 meta 标签使用）
|
||
if existing, err := c.Cookie(csrfCookieName); err == nil && existing != "" {
|
||
c.Set(csrfMetaName, existing)
|
||
return existing
|
||
}
|
||
|
||
token, err := generateCSRFToken()
|
||
if err != nil {
|
||
// 极端情况：随机数生成失败，使用短 token
|
||
token = "fallback-" + hex.EncodeToString([]byte("metazone"))
|
||
}
|
||
|
||
c.SetSameSite(http.SameSiteStrictMode)
|
||
// 30 天有效期，与 refresh token 对齐
|
||
maxAge := int(cfg.JWT.RememberExpire * 3600)
|
||
c.SetCookie(csrfCookieName, token, maxAge, "/", "", secure, false)
|
||
|
||
c.Set(csrfMetaName, token)
|
||
return token
|
||
}
|
||
|
||
// generateCSRFToken 生成 64 字符十六进制随机 CSRF token
|
||
func generateCSRFToken() (string, error) {
|
||
b := make([]byte, csrfTokenLen)
|
||
if _, err := rand.Read(b); err != nil {
|
||
return "", err
|
||
}
|
||
return hex.EncodeToString(b), nil
|
||
}
|
||
|
||
// constantTimeEq 恒定时间字符串比较（防时序攻击）
|
||
func constantTimeEq(a, b string) bool {
|
||
if len(a) != len(b) {
|
||
return false
|
||
}
|
||
var result byte
|
||
for i := 0; i < len(a); i++ {
|
||
result |= a[i] ^ b[i]
|
||
}
|
||
return result == 0
|
||
}
|