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| package main
import (
"bytes"
"io"
"log"
"mime"
"net/http"
"regexp"
"strings"
)
const backendURL = "http://127.0.0.1:8000"
const backendHost = "127.0.0.1:8000"
var blockedIPs = map[string]bool{
"1.1.1.1": true,
}
var sqlInjectionPattern = regexp.MustCompile(`(?i)(union.*select|select.*from|insert.*into|update.*set|delete.*from|drop\s+table|--|#|\*\/|\/\*)`)
var rcePattern = regexp.MustCompile(`(?i)(\b(?:os|exec|system|eval|passthru|shell_exec|phpinfo|popen|proc_open|pcntl_exec|assert)\s*\(.+\))`)
var hotfixPattern = regexp.MustCompile(`(?i)(select)`)
var blockedUserAgents = []string{
"sqlmap",
"nmap",
"curl",
}
func isBlockedIP(ip string) bool {
return blockedIPs[ip]
}
func isMaliciousRequest(r *http.Request) bool {
for key, values := range r.URL.Query() {
for _, value := range values {
if sqlInjectionPattern.MatchString(value) {
log.Printf("阻止 SQL 注入: 参数 %s=%s", key, value)
return true
}
if rcePattern.MatchString(value) {
log.Printf("阻止 RCE 攻击: 参数 %s=%s", key, value)
return true
}
if hotfixPattern.MatchString(value) {
log.Printf("参数 %s=%s", key, value)
return true
}
}
}
if r.Method == http.MethodPost {
ct := r.Header.Get("Content-Type")
mediaType, _, err := mime.ParseMediaType(ct)
if err != nil {
log.Printf("解析 Content-Type 失败: %v", err)
return true
}
if mediaType == "multipart/form-data" {
if err := r.ParseMultipartForm(65535); err != nil {
log.Printf("解析 POST 参数失败: %v", err)
return true
}
} else {
if err := r.ParseForm(); err != nil {
log.Printf("解析 POST 参数失败: %v", err)
return true
}
}
for key, values := range r.PostForm {
log.Printf("POST 参数 %s=%v", key, values)
for _, value := range values {
if sqlInjectionPattern.MatchString(value) {
log.Printf("阻止 SQL 注入: POST 参数 %s=%s", key, value)
return true
}
if rcePattern.MatchString(value) {
log.Printf("阻止 RCE 攻击: POST 参数 %s=%s", key, value)
return true
}
if hotfixPattern.MatchString(value) {
log.Printf("POST 参数 %s=%s", key, value)
return true
}
}
}
}
return false
}
func isBlockedUserAgent(userAgent string) bool {
for _, blocked := range blockedUserAgents {
if strings.Contains(strings.ToLower(userAgent), blocked) {
return true
}
}
return false
}
func reverseProxyHandler(w http.ResponseWriter, r *http.Request) {
clientIP := r.RemoteAddr
if isBlockedIP(clientIP) {
http.Error(w, "Forbidden", http.StatusForbidden)
log.Printf("阻止的 IP: %s", clientIP)
return
}
bodyBytes, err := io.ReadAll(r.Body)
if err != nil {
http.Error(w, "Bad Request", http.StatusBadRequest)
return
}
r.Body = io.NopCloser(bytes.NewBuffer(bodyBytes))
if isMaliciousRequest(r) {
http.Error(w, "Malicious request detected", http.StatusForbidden)
return
}
if isBlockedUserAgent(r.UserAgent()) {
http.Error(w, "Forbidden User-Agent", http.StatusForbidden)
log.Printf("阻止的 User-Agent: %s", r.UserAgent())
return
}
proxyReq, err := http.NewRequest(r.Method, backendURL+r.RequestURI, bytes.NewBuffer(bodyBytes))
if err != nil {
http.Error(w, "Bad Gateway", http.StatusBadGateway)
return
}
proxyReq.Header = r.Header
client := &http.Client{
CheckRedirect: func(req *http.Request, via []*http.Request) error {
return http.ErrUseLastResponse
},
}
resp, err := client.Do(proxyReq)
if err != nil {
http.Error(w, "Bad Gateway", http.StatusBadGateway)
return
}
defer resp.Body.Close()
for key, values := range resp.Header {
for _, value := range values {
if key == "Location" {
value = strings.Replace(value, backendHost, r.Host, -1)
}
w.Header().Add(key, value)
}
}
w.WriteHeader(resp.StatusCode)
io.Copy(w, resp.Body)
}
func main() {
http.HandleFunc("/", reverseProxyHandler)
log.Println("Listen on 0.0.0.0:8080")
log.Fatal(http.ListenAndServe(":8080", nil))
}
|