services/arv-git-httpd/auth_handler.go

   1 // Copyright (C) The Arvados Authors. All rights reserved.
   2 //
   3 // SPDX-License-Identifier: AGPL-3.0
   4
   5 package main
   6
   7 import (
   8         "log"
   9         "net/http"
  10         "os"
  11         "strings"
  12         "sync"
  13         "time"
  14
  15         "git.curoverse.com/arvados.git/sdk/go/arvadosclient"
  16         "git.curoverse.com/arvados.git/sdk/go/auth"
  17         "git.curoverse.com/arvados.git/sdk/go/httpserver"
  18 )
  19
  20 type authHandler struct {
  21         handler    http.Handler
  22         clientPool *arvadosclient.ClientPool
  23         setupOnce  sync.Once
  24 }
  25
  26 func (h *authHandler) setup() {
  27         ac, err := arvadosclient.New(&theConfig.Client)
  28         if err != nil {
  29                 log.Fatal(err)
  30         }
  31         h.clientPool = &arvadosclient.ClientPool{Prototype: ac}
  32 }
  33
  34 func (h *authHandler) ServeHTTP(wOrig http.ResponseWriter, r *http.Request) {
  35         h.setupOnce.Do(h.setup)
  36
  37         var statusCode int
  38         var statusText string
  39         var apiToken string
  40         var repoName string
  41         var validApiToken bool
  42
  43         w := httpserver.WrapResponseWriter(wOrig)
  44
  45         if r.Method == "OPTIONS" {
  46                 method := r.Header.Get("Access-Control-Request-Method")
  47                 if method != "GET" && method != "POST" {
  48                         w.WriteHeader(http.StatusMethodNotAllowed)
  49                         return
  50                 }
  51                 w.Header().Set("Access-Control-Allow-Headers", "Authorization, Content-Type")
  52                 w.Header().Set("Access-Control-Allow-Methods", "GET, POST")
  53                 w.Header().Set("Access-Control-Allow-Origin", "*")
  54                 w.Header().Set("Access-Control-Max-Age", "86400")
  55                 w.WriteHeader(http.StatusOK)
  56                 return
  57         }
  58
  59         if r.Header.Get("Origin") != "" {
  60                 // Allow simple cross-origin requests without user
  61                 // credentials ("user credentials" as defined by CORS,
  62                 // i.e., cookies, HTTP authentication, and client-side
  63                 // SSL certificates. See
  64                 // http://www.w3.org/TR/cors/#user-credentials).
  65                 w.Header().Set("Access-Control-Allow-Origin", "*")
  66         }
  67
  68         defer func() {
  69                 if w.WroteStatus() == 0 {
  70                         // Nobody has called WriteHeader yet: that
  71                         // must be our job.
  72                         w.WriteHeader(statusCode)
  73                         w.Write([]byte(statusText))
  74                 }
  75
  76                 // If the given password is a valid token, log the first 10 characters of the token.
  77                 // Otherwise: log the string <invalid> if a password is given, else an empty string.
  78                 passwordToLog := ""
  79                 if !validApiToken {
  80                         if len(apiToken) > 0 {
  81                                 passwordToLog = "<invalid>"
  82                         }
  83                 } else {
  84                         passwordToLog = apiToken[0:10]
  85                 }
  86
  87                 httpserver.Log(r.RemoteAddr, passwordToLog, w.WroteStatus(), statusText, repoName, r.Method, r.URL.Path)
  88         }()
  89
  90         creds := auth.NewCredentialsFromHTTPRequest(r)
  91         if len(creds.Tokens) == 0 {
  92                 statusCode, statusText = http.StatusUnauthorized, "no credentials provided"
  93                 w.Header().Add("WWW-Authenticate", "Basic realm=\"git\"")
  94                 return
  95         }
  96         apiToken = creds.Tokens[0]
  97
  98         // Access to paths "/foo/bar.git/*" and "/foo/bar/.git/*" are
  99         // protected by the permissions on the repository named
 100         // "foo/bar".
 101         pathParts := strings.SplitN(r.URL.Path[1:], ".git/", 2)
 102         if len(pathParts) != 2 {
 103                 statusCode, statusText = http.StatusNotFound, "not found"
 104                 return
 105         }
 106         repoName = pathParts[0]
 107         repoName = strings.TrimRight(repoName, "/")
 108
 109         arv := h.clientPool.Get()
 110         if arv == nil {
 111                 statusCode, statusText = http.StatusInternalServerError, "connection pool failed: "+h.clientPool.Err().Error()
 112                 return
 113         }
 114         defer h.clientPool.Put(arv)
 115
 116         // Ask API server whether the repository is readable using
 117         // this token (by trying to read it!)
 118         arv.ApiToken = apiToken
 119         reposFound := arvadosclient.Dict{}
 120         if err := arv.List("repositories", arvadosclient.Dict{
 121                 "filters": [][]string{{"name", "=", repoName}},
 122         }, &reposFound); err != nil {
 123                 statusCode, statusText = http.StatusInternalServerError, err.Error()
 124                 return
 125         }
 126         validApiToken = true
 127         if avail, ok := reposFound["items_available"].(float64); !ok {
 128                 statusCode, statusText = http.StatusInternalServerError, "bad list response from API"
 129                 return
 130         } else if avail < 1 {
 131                 statusCode, statusText = http.StatusNotFound, "not found"
 132                 return
 133         } else if avail > 1 {
 134                 statusCode, statusText = http.StatusInternalServerError, "name collision"
 135                 return
 136         }
 137
 138         repoUUID := reposFound["items"].([]interface{})[0].(map[string]interface{})["uuid"].(string)
 139
 140         isWrite := strings.HasSuffix(r.URL.Path, "/git-receive-pack")
 141         if !isWrite {
 142                 statusText = "read"
 143         } else {
 144                 err := arv.Update("repositories", repoUUID, arvadosclient.Dict{
 145                         "repository": arvadosclient.Dict{
 146                                 "modified_at": time.Now().String(),
 147                         },
 148                 }, &arvadosclient.Dict{})
 149                 if err != nil {
 150                         statusCode, statusText = http.StatusForbidden, err.Error()
 151                         return
 152                 }
 153                 statusText = "write"
 154         }
 155
 156         // Regardless of whether the client asked for "/foo.git" or
 157         // "/foo/.git", we choose whichever variant exists in our repo
 158         // root, and we try {uuid}.git and {uuid}/.git first. If none
 159         // of these exist, we 404 even though the API told us the repo
 160         // _should_ exist (presumably this means the repo was just
 161         // created, and gitolite sync hasn't run yet).
 162         rewrittenPath := ""
 163         tryDirs := []string{
 164                 "/" + repoUUID + ".git",
 165                 "/" + repoUUID + "/.git",
 166                 "/" + repoName + ".git",
 167                 "/" + repoName + "/.git",
 168         }
 169         for _, dir := range tryDirs {
 170                 if fileInfo, err := os.Stat(theConfig.RepoRoot + dir); err != nil {
 171                         if !os.IsNotExist(err) {
 172                                 statusCode, statusText = http.StatusInternalServerError, err.Error()
 173                                 return
 174                         }
 175                 } else if fileInfo.IsDir() {
 176                         rewrittenPath = dir + "/" + pathParts[1]
 177                         break
 178                 }
 179         }
 180         if rewrittenPath == "" {
 181                 log.Println("WARNING:", repoUUID,
 182                         "git directory not found in", theConfig.RepoRoot, tryDirs)
 183                 // We say "content not found" to disambiguate from the
 184                 // earlier "API says that repo does not exist" error.
 185                 statusCode, statusText = http.StatusNotFound, "content not found"
 186                 return
 187         }
 188         r.URL.Path = rewrittenPath
 189
 190         h.handler.ServeHTTP(w, r)
 191 }