103 lines
2.2 KiB
Go
103 lines
2.2 KiB
Go
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package main
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import (
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"net/http"
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"net/url"
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"log"
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"os"
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"strconv"
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"crypto/hmac"
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"crypto/sha256"
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"encoding/base64"
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"io"
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"github.com/gorilla/mux"
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"github.com/BurntSushi/toml"
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)
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type tomlConfig struct {
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Port int `toml:"port"`
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Secret string `toml:"secret"`
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}
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func proxyRequest(w http.ResponseWriter, r *http.Request, secret []byte) {
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vars := mux.Vars(r)
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requestUrl, err := url.QueryUnescape(vars["url"])
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if err != nil {
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log.Printf("Failed to url decode url: %s", err)
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return
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}
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macRaw, err := url.QueryUnescape(vars["hmac"])
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if err != nil {
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log.Printf("Failed to url decode HMAC: %s", err)
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return
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}
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mac := hmac.New(sha256.New, secret)
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mac.Write([]byte(requestUrl))
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expectedMac := mac.Sum(nil)
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receivedMac, err := base64.StdEncoding.DecodeString(macRaw)
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if err != nil {
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log.Printf("Failed to decode HMAC: %s", err)
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return
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}
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if !hmac.Equal(expectedMac, receivedMac) {
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log.Printf("invalid-hmac:%s", r.RemoteAddr)
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log.Printf("URL: '%s'", requestUrl)
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http.Error(w, "Invalid HMAC", http.StatusUnauthorized)
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return
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}
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client := &http.Client{}
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resp, err := client.Get(requestUrl)
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defer resp.Body.Close()
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if err != nil {
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log.Fatalf("Failed to perform GET: %s", err)
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}
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w.WriteHeader(resp.StatusCode)
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io.Copy(w, resp.Body)
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}
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func makeProxyRequestHandler(secret []byte) http.HandlerFunc {
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fn := func(w http.ResponseWriter, r *http.Request) {
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proxyRequest(w, r, secret)
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}
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return http.HandlerFunc(fn)
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}
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func exists(path string) bool {
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// Returns true if path exists. false otherwise
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_, err := os.Stat(path)
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return !os.IsNotExist(err)
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}
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func main() {
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config := tomlConfig {
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Port: 8080,
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}
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switch {
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case exists("./config.toml"):
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_, err := toml.DecodeFile("./config.toml", &config)
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if err != nil {
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log.Fatalf("Failed to read ./config.toml: %s", err)
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}
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case exists("/etc/miniproxy/config.toml"):
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_, err := toml.DecodeFile("/etc/miniproxy/config.toml", &config)
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if err != nil {
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log.Fatalf("Failed to read /etc/miniproxy/config.toml: %s", err)
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}
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}
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log.Printf("Running on :%d\n", config.Port)
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r := mux.NewRouter()
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r.UseEncodedPath()
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r.HandleFunc("/proxy/{hmac}/{url:.+}", makeProxyRequestHandler([]byte(config.Secret)))
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log.Fatal(http.ListenAndServe(":" + strconv.Itoa(config.Port), r))
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}
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