|
| 1 | +package api |
| 2 | + |
| 3 | +import ( |
| 4 | + "context" |
| 5 | + "errors" |
| 6 | + "net/http" |
| 7 | + "net/http/httputil" |
| 8 | + "net/url" |
| 9 | + "regexp" |
| 10 | + "sync" |
| 11 | + |
| 12 | + "golang.org/x/oauth2" |
| 13 | + "golang.org/x/oauth2/bitbucket" |
| 14 | +) |
| 15 | + |
| 16 | +type BitBucketGateway struct { |
| 17 | + proxy *httputil.ReverseProxy |
| 18 | +} |
| 19 | + |
| 20 | +func NewBitBucketGateway() *BitBucketGateway { |
| 21 | + return &BitBucketGateway{ |
| 22 | + proxy: &httputil.ReverseProxy{ |
| 23 | + Director: bitbucketDirector, |
| 24 | + Transport: &BitBucketTransport{}, |
| 25 | + }, |
| 26 | + } |
| 27 | +} |
| 28 | + |
| 29 | +var bitbucketPathRegexp = regexp.MustCompile("^/bitbucket/?") |
| 30 | +var bitbucketAllowedRegexp = regexp.MustCompile("^/bitbucket/src/?") |
| 31 | + |
| 32 | +var bitbucketTokenExpirationMessageRegexp = regexp.MustCompile("(?i)^access token expired") |
| 33 | +var currentAccessToken *oauth2.Token |
| 34 | + |
| 35 | +type notifyRefreshTokenSource struct { |
| 36 | + new oauth2.TokenSource |
| 37 | + mu sync.Mutex // guards t |
| 38 | + t *oauth2.Token |
| 39 | +} |
| 40 | + |
| 41 | +func (s *notifyRefreshTokenSource) Token() (*oauth2.Token, error) { |
| 42 | + s.mu.Lock() |
| 43 | + defer s.mu.Unlock() |
| 44 | + if s.t.Valid() { |
| 45 | + return s.t, nil |
| 46 | + } |
| 47 | + t, err := s.new.Token() |
| 48 | + if err != nil { |
| 49 | + return nil, err |
| 50 | + } |
| 51 | + s.t = t |
| 52 | + return t, nil |
| 53 | +} |
| 54 | + |
| 55 | +var currentTokenSource *notifyRefreshTokenSource |
| 56 | + |
| 57 | +func getTokenSource(ctx context.Context) *notifyRefreshTokenSource { |
| 58 | + config := getConfig(ctx) |
| 59 | + if currentTokenSource != nil { |
| 60 | + return currentTokenSource |
| 61 | + } |
| 62 | + |
| 63 | + blankToken := &oauth2.Token{ |
| 64 | + AccessToken: "", |
| 65 | + RefreshToken: config.BitBucket.RefreshToken, |
| 66 | + } |
| 67 | + oauthConfig := &oauth2.Config{ |
| 68 | + ClientID: config.BitBucket.ClientID, |
| 69 | + ClientSecret: config.BitBucket.ClientSecret, |
| 70 | + Endpoint: bitbucket.Endpoint, |
| 71 | + } |
| 72 | + tokenSource := ¬ifyRefreshTokenSource{ |
| 73 | + new: oauthConfig.TokenSource(ctx, blankToken), |
| 74 | + t: blankToken, |
| 75 | + } |
| 76 | + currentTokenSource = tokenSource |
| 77 | + return tokenSource |
| 78 | +} |
| 79 | + |
| 80 | +func bitbucketDirector(r *http.Request) { |
| 81 | + ctx := r.Context() |
| 82 | + target := getProxyTarget(ctx) |
| 83 | + accessToken := getAccessToken(ctx) |
| 84 | + |
| 85 | + targetQuery := target.RawQuery |
| 86 | + r.Host = target.Host |
| 87 | + r.URL.Scheme = target.Scheme |
| 88 | + r.URL.Host = target.Host |
| 89 | + r.URL.Path = singleJoiningSlash(target.Path, bitbucketPathRegexp.ReplaceAllString(r.URL.Path, "/")) |
| 90 | + if targetQuery == "" || r.URL.RawQuery == "" { |
| 91 | + r.URL.RawQuery = targetQuery + r.URL.RawQuery |
| 92 | + } else { |
| 93 | + r.URL.RawQuery = targetQuery + "&" + r.URL.RawQuery |
| 94 | + } |
| 95 | + if _, ok := r.Header["User-Agent"]; !ok { |
| 96 | + r.Header.Set("User-Agent", "") |
| 97 | + } |
| 98 | + |
| 99 | + if r.Method != http.MethodOptions { |
| 100 | + r.Header.Set("Authorization", "Bearer "+accessToken) |
| 101 | + } |
| 102 | + |
| 103 | + log := getLogEntry(r) |
| 104 | + log.Infof("Proxying to BitBucket: %v", r.URL.String(), r.Header.Get("Authorization")) |
| 105 | +} |
| 106 | + |
| 107 | +func (bb *BitBucketGateway) ServeHTTP(w http.ResponseWriter, r *http.Request) { |
| 108 | + ctx := r.Context() |
| 109 | + config := getConfig(ctx) |
| 110 | + if config == nil || config.BitBucket.RefreshToken == "" { |
| 111 | + handleError(notFoundError("No BitBucket Settings Configured"), w, r) |
| 112 | + return |
| 113 | + } |
| 114 | + |
| 115 | + if err := bb.authenticate(w, r); err != nil { |
| 116 | + handleError(unauthorizedError(err.Error()), w, r) |
| 117 | + return |
| 118 | + } |
| 119 | + |
| 120 | + endpoint := config.BitBucket.Endpoint |
| 121 | + apiURL := singleJoiningSlash(endpoint, "/repositories/"+config.BitBucket.Repo) |
| 122 | + target, err := url.Parse(apiURL) |
| 123 | + if err != nil { |
| 124 | + handleError(internalServerError("Unable to process BitBucket endpoint"), w, r) |
| 125 | + return |
| 126 | + } |
| 127 | + |
| 128 | + tokenSource := getTokenSource(ctx) |
| 129 | + token, err := tokenSource.Token() |
| 130 | + if err != nil { |
| 131 | + handleError(internalServerError("Unable to process BitBucket endpoint"), w, r) |
| 132 | + } |
| 133 | + |
| 134 | + ctx = withProxyTarget(ctx, target) |
| 135 | + ctx = withAccessToken(ctx, token.AccessToken) |
| 136 | + bb.proxy.ServeHTTP(w, r.WithContext(ctx)) |
| 137 | +} |
| 138 | + |
| 139 | +func (bb *BitBucketGateway) authenticate(w http.ResponseWriter, r *http.Request) error { |
| 140 | + ctx := r.Context() |
| 141 | + claims := getClaims(ctx) |
| 142 | + config := getConfig(ctx) |
| 143 | + |
| 144 | + if claims == nil { |
| 145 | + return errors.New("Access to endpoint not allowed: no claims found in Bearer token") |
| 146 | + } |
| 147 | + |
| 148 | + if !bitbucketAllowedRegexp.MatchString(r.URL.Path) { |
| 149 | + return errors.New("Access to endpoint not allowed: this part of BitBucket's API has been restricted") |
| 150 | + } |
| 151 | + |
| 152 | + if len(config.Roles) == 0 { |
| 153 | + return nil |
| 154 | + } |
| 155 | + |
| 156 | + roles, ok := claims.AppMetaData["roles"] |
| 157 | + if ok { |
| 158 | + roleStrings, _ := roles.([]interface{}) |
| 159 | + for _, data := range roleStrings { |
| 160 | + role, _ := data.(string) |
| 161 | + for _, adminRole := range config.Roles { |
| 162 | + if role == adminRole { |
| 163 | + return nil |
| 164 | + } |
| 165 | + } |
| 166 | + } |
| 167 | + } |
| 168 | + |
| 169 | + return errors.New("Access to endpoint not allowed: your role doesn't allow access") |
| 170 | +} |
| 171 | + |
| 172 | +type BitBucketTransport struct{} |
| 173 | + |
| 174 | +func (t *BitBucketTransport) RoundTrip(r *http.Request) (*http.Response, error) { |
| 175 | + resp, err := http.DefaultTransport.RoundTrip(r) |
| 176 | + if err == nil { |
| 177 | + // remove CORS headers from BitBucket and use our own |
| 178 | + resp.Header.Del("Access-Control-Allow-Origin") |
| 179 | + } |
| 180 | + return resp, err |
| 181 | +} |
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