|
| 1 | +package main |
| 2 | + |
| 3 | +import ( |
| 4 | + "context" |
| 5 | + "encoding/base64" |
| 6 | + "encoding/json" |
| 7 | + "fmt" |
| 8 | + "html/template" |
| 9 | + "log" |
| 10 | + "net/http" |
| 11 | + "net/url" |
| 12 | + "os" |
| 13 | + "strings" |
| 14 | + |
| 15 | + "github.com/Jille/convreq" |
| 16 | + "github.com/Jille/convreq/respond" |
| 17 | + "github.com/Jille/rufs/security" |
| 18 | + "github.com/coreos/go-oidc/v3/oidc" |
| 19 | + "golang.org/x/oauth2" |
| 20 | +) |
| 21 | + |
| 22 | +var ( |
| 23 | + ca *security.CAKeyPair |
| 24 | + |
| 25 | + oidcProvider *oidc.Provider |
| 26 | + oauthConfig oauth2.Config |
| 27 | +) |
| 28 | + |
| 29 | +type Config struct { |
| 30 | + Certdir string `json:"certdir"` |
| 31 | + OIDCProvider string `json:"oidc_provider"` |
| 32 | + ClientID string `json:"client_id"` |
| 33 | + ClientSecret string `json:"client_secret"` |
| 34 | + ReturnURL string `json:"return_url"` |
| 35 | + Port int `json:"port"` |
| 36 | +} |
| 37 | + |
| 38 | +func main() { |
| 39 | + if len(os.Args) != 2 { |
| 40 | + log.Fatalf("Usage: %s <configfile>", os.Args[0]) |
| 41 | + } |
| 42 | + c, err := os.ReadFile(os.Args[1]) |
| 43 | + if err != nil { |
| 44 | + log.Fatalf("Failed to read config file %q: %v", os.Args[1], err) |
| 45 | + } |
| 46 | + var cfg Config |
| 47 | + if err := json.Unmarshal(c, &cfg); err != nil { |
| 48 | + log.Fatalf("Failed to read config file %q: %v", os.Args[1], err) |
| 49 | + } |
| 50 | + |
| 51 | + if cfg.Certdir == "" { |
| 52 | + log.Fatalf("Configuration setting \"certdir\" is empty") |
| 53 | + } |
| 54 | + if cfg.OIDCProvider == "" { |
| 55 | + log.Fatalf("Configuration setting \"oidc_provider\" is empty") |
| 56 | + } |
| 57 | + if cfg.ClientID == "" { |
| 58 | + log.Fatalf("Configuration setting \"client_id\" is empty") |
| 59 | + } |
| 60 | + if cfg.ClientSecret == "" { |
| 61 | + log.Fatalf("Configuration setting \"client_secret\" is empty") |
| 62 | + } |
| 63 | + if cfg.ReturnURL == "" { |
| 64 | + log.Fatalf("Configuration setting \"return_url\" is empty") |
| 65 | + } |
| 66 | + if cfg.Port == 0 { |
| 67 | + log.Fatalf("Configuration setting \"port\" is not set") |
| 68 | + } |
| 69 | + |
| 70 | + ca, err = security.LoadCAKeyPair(cfg.Certdir) |
| 71 | + if err != nil { |
| 72 | + log.Fatalf("Failed to load CA key pair: %v", err) |
| 73 | + } |
| 74 | + |
| 75 | + oidcProvider, err = oidc.NewProvider(context.Background(), cfg.OIDCProvider) |
| 76 | + if err != nil { |
| 77 | + log.Fatalf("Failed to discover openid connect provider: %v", err) |
| 78 | + } |
| 79 | + oauthConfig = oauth2.Config{ |
| 80 | + ClientID: cfg.ClientID, |
| 81 | + ClientSecret: cfg.ClientSecret, |
| 82 | + Endpoint: oidcProvider.Endpoint(), |
| 83 | + RedirectURL: cfg.ReturnURL, |
| 84 | + Scopes: []string{"openid"}, |
| 85 | + } |
| 86 | + |
| 87 | + http.Handle("/oauth2_return", convreq.Wrap(oauth2Return)) |
| 88 | + http.Handle("/request_token", convreq.Wrap(requestToken)) |
| 89 | + http.Handle("/", convreq.Wrap(mainPage)) |
| 90 | + log.Fatal(http.ListenAndServe(fmt.Sprintf(":%d", cfg.Port), nil)) |
| 91 | +} |
| 92 | + |
| 93 | +type requestTokenGet struct { |
| 94 | + Hostname string `schema:"hostname"` |
| 95 | + ReturnURL string `schema:"return_url"` |
| 96 | +} |
| 97 | + |
| 98 | +func requestToken(get requestTokenGet) convreq.HttpResponse { |
| 99 | + s := base64.URLEncoding.EncodeToString([]byte(get.Hostname)) + ":" + base64.URLEncoding.EncodeToString([]byte(get.ReturnURL)) |
| 100 | + u := oauthConfig.AuthCodeURL(s) |
| 101 | + return respond.Redirect(302, u) |
| 102 | +} |
| 103 | + |
| 104 | +type oauth2ReturnGet struct { |
| 105 | + Code string `schema:"code"` |
| 106 | + State string `schema:"state"` |
| 107 | +} |
| 108 | + |
| 109 | +func oauth2Return(ctx context.Context, get oauth2ReturnGet) convreq.HttpResponse { |
| 110 | + t, err := oauthConfig.Exchange(ctx, get.Code) |
| 111 | + if err != nil { |
| 112 | + return respond.BadRequest("Oauth failed: " + err.Error()) |
| 113 | + } |
| 114 | + userInfo, err := oidcProvider.UserInfo(ctx, oauth2.StaticTokenSource(t)) |
| 115 | + if err != nil { |
| 116 | + return respond.Error(err) |
| 117 | + } |
| 118 | + var ui UserInfo |
| 119 | + if err := userInfo.Claims(&ui); err != nil { |
| 120 | + return respond.Error(err) |
| 121 | + } |
| 122 | + |
| 123 | + sp := strings.Split(get.State, ":") |
| 124 | + hostname, err := base64.URLEncoding.DecodeString(sp[0]) |
| 125 | + if err != nil { |
| 126 | + return respond.BadRequest("bad state") |
| 127 | + } |
| 128 | + returnURL, err := base64.URLEncoding.DecodeString(sp[1]) |
| 129 | + if err != nil { |
| 130 | + return respond.BadRequest("bad state") |
| 131 | + } |
| 132 | + |
| 133 | + username := strings.Split(ui.PreferredUsername, "@")[0] |
| 134 | + username = strings.ReplaceAll(username, "-", "") |
| 135 | + username += "-" + string(hostname) |
| 136 | + |
| 137 | + token := ca.CreateToken(username) |
| 138 | + |
| 139 | + u, err := url.Parse(string(returnURL)) |
| 140 | + if err != nil { |
| 141 | + return respond.BadRequest("Invalid return_url: " + err.Error()) |
| 142 | + } |
| 143 | + q := u.Query() |
| 144 | + q.Set("username", username) |
| 145 | + q.Set("token", token) |
| 146 | + q.Set("circle", ca.Name()) |
| 147 | + q.Set("fingerprint", ca.Fingerprint()) |
| 148 | + |
| 149 | + if len(returnURL) == 0 { |
| 150 | + var ret string |
| 151 | + for k, vs := range q { |
| 152 | + ret += k + ":" + vs[0] + "\n" |
| 153 | + } |
| 154 | + return respond.String(ret) |
| 155 | + } |
| 156 | + |
| 157 | + u.RawQuery = q.Encode() |
| 158 | + return respond.Redirect(302, u.String()) |
| 159 | +} |
| 160 | + |
| 161 | +type UserInfo struct { |
| 162 | + Name string `json:"name"` |
| 163 | + PreferredUsername string `json:"preferred_username"` |
| 164 | +} |
| 165 | + |
| 166 | +type mainPageGet struct { |
| 167 | + Hostname string `schema:"hostname"` |
| 168 | + ReturnURL string `schema:"return_url"` |
| 169 | +} |
| 170 | + |
| 171 | +var mainPageTpl = template.Must(template.New("").Parse(` |
| 172 | + <html> |
| 173 | + <head> |
| 174 | + </head> |
| 175 | + <body> |
| 176 | + <form method="GET" action="/request_token"> |
| 177 | + Hostname: <input name="hostname" value="{{.Hostname}}" /> |
| 178 | + <input type="hidden" name="return_url" value="{{.ReturnURL}}" /> |
| 179 | + <input type="submit" value="Continue" /> |
| 180 | + </form> |
| 181 | + </body> |
| 182 | + </html> |
| 183 | + `)) |
| 184 | + |
| 185 | +func mainPage(get mainPageGet) convreq.HttpResponse { |
| 186 | + return respond.RenderTemplate(mainPageTpl, get) |
| 187 | +} |
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