initial work on OIDC (SSO) integration
This commit is contained in:
Raal Goff
parent
83815f567d
commit
e7a2501fe8
6 changed files with 347 additions and 4 deletions
310
oidc.go
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310
oidc.go
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@ -0,0 +1,310 @@
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package headscale
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import (
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"crypto/rand"
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"encoding/hex"
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"encoding/json"
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"errors"
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"fmt"
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"github.com/gin-gonic/gin"
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"github.com/patrickmn/go-cache"
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"github.com/rs/zerolog/log"
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"github.com/s12v/go-jwks"
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"gopkg.in/square/go-jose.v2/jwt"
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"gorm.io/gorm"
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"io"
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"net/http"
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"net/url"
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"strings"
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"time"
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)
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type OpenIDConfiguration struct {
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Issuer string `json:"issuer"`
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AuthorizationEndpoint string `json:"authorization_endpoint"`
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TokenEndpoint string `json:"token_endpoint"`
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JWKSURI string `json:"jwks_uri"`
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}
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type OpenIDTokens struct {
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AccessToken string `json:"access_token"`
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ExpiresIn int `json:"expires_in"`
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IdToken string `json:"id_token"`
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NotBeforePolicy int `json:"not-before-policy,omitempty"`
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RefreshExpiresIn int `json:"refresh_expires_in"`
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RefreshToken string `json:"refresh_token"`
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Scope string `json:"scope"`
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SessionState string `json:"session_state,omitempty"`
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TokenType string `json:"token_type,omitempty"`
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}
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type AccessToken struct {
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jwt.Claims
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Name string `json:"name,omitempty"`
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Groups []string `json:"groups,omitempty"`
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Email string `json:"email"`
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Username string `json:"preferred_username,omitempty"`
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}
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var oidcConfig *OpenIDConfiguration
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var stateCache *cache.Cache
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var jwksSource *jwks.WebSource
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var jwksClient jwks.JWKSClient
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func verifyToken(token string) (*AccessToken, error) {
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if jwksClient == nil {
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jwksSource = jwks.NewWebSource(oidcConfig.JWKSURI)
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jwksClient = jwks.NewDefaultClient(
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jwksSource,
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time.Hour, // Refresh keys every 1 hour
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12*time.Hour, // Expire keys after 12 hours
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)
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}
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//decode jwt
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tok, err := jwt.ParseSigned(token)
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if err != nil {
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return nil, err
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}
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if tok.Headers[0].KeyID != "" {
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log.Debug().Msgf("Checking KID %s\n", tok.Headers[0].KeyID)
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jwk, err := jwksClient.GetSignatureKey(tok.Headers[0].KeyID)
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if err != nil {
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return nil, err
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}
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claims := AccessToken{}
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err = tok.Claims(jwk.Certificates[0].PublicKey, &claims)
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if err != nil {
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return nil, err
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} else {
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err = claims.Validate(jwt.Expected{
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Time: time.Now(),
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})
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if err != nil {
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return nil, err
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}
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return &claims, nil
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}
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} else {
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return nil, err
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}
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}
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func getOIDCConfig(oidcConfigURL string) (*OpenIDConfiguration, error) {
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client := &http.Client{}
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req, err := http.NewRequest("GET", oidcConfigURL, nil)
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if err != nil {
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log.Error().Msgf("%v", err)
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return nil, err
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}
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log.Debug().Msgf("Requesting OIDC Config from %s", oidcConfigURL)
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oidcConfigResp, err := client.Do(req)
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if err != nil {
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log.Error().Msgf("%v", err)
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return nil, err
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}
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defer oidcConfigResp.Body.Close()
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var oidcConfig OpenIDConfiguration
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err = json.NewDecoder(oidcConfigResp.Body).Decode(&oidcConfig)
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if err != nil {
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log.Error().Msgf("%v", err)
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return nil, err
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}
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return &oidcConfig, nil
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}
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func (h *Headscale) exchangeCodeForTokens(code string, redirectURI string) (*OpenIDTokens, error) {
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var err error
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if oidcConfig == nil {
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oidcConfig, err = getOIDCConfig(fmt.Sprintf("%s.well-known/openid-configuration", h.cfg.OIDCEndpoint))
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if err != nil {
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return nil, err
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}
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}
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params := url.Values{}
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params.Add("grant_type", "authorization_code")
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params.Add("code", code)
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params.Add("client_id", h.cfg.OIDCClientID)
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params.Add("client_secret", h.cfg.OIDCClientSecret)
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params.Add("redirect_uri", redirectURI)
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client := &http.Client{}
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req, err := http.NewRequest("POST", oidcConfig.TokenEndpoint, strings.NewReader(params.Encode()))
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req.Header.Add("Content-Type", "application/x-www-form-urlencoded")
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if err != nil {
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log.Error().Msgf("%v", err)
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return nil, err
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}
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tokenResp, err := client.Do(req)
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if err != nil {
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log.Error().Msgf("%v", err)
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return nil, err
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}
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defer tokenResp.Body.Close()
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if tokenResp.StatusCode != 200 {
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b, _ := io.ReadAll(tokenResp.Body)
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log.Error().Msgf("%s", b)
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}
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var tokens OpenIDTokens
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err = json.NewDecoder(tokenResp.Body).Decode(&tokens)
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if err != nil {
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log.Error().Msgf("%v", err)
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return nil, err
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}
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log.Info().Msg("Successfully exchanged code for tokens")
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return &tokens, nil
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}
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// RegisterOIDC redirects to the OIDC provider for authentication
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// Puts machine key in cache so the callback can retrieve it using the oidc state param
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// Listens in /oidc/register/:mKey
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func (h *Headscale) RegisterOIDC(c *gin.Context) {
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mKeyStr := c.Param("mKey")
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if mKeyStr == "" {
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c.String(http.StatusBadRequest, "Wrong params")
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return
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}
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var err error
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// grab oidc config if it hasn't been already
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if oidcConfig == nil {
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oidcConfig, err = getOIDCConfig(fmt.Sprintf("%s.well-known/openid-configuration", h.cfg.OIDCEndpoint))
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if err != nil {
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c.String(http.StatusInternalServerError, "Could not retrieve OIDC Config")
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return
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}
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}
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b := make([]byte, 16)
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_, err = rand.Read(b)
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stateStr := hex.EncodeToString(b)[:32]
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// init the state cache if it hasn't been already
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if stateCache == nil {
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stateCache = cache.New(time.Minute*5, time.Minute*10)
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}
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// place the machine key into the state cache, so it can be retrieved later
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stateCache.Set(stateStr, mKeyStr, time.Minute*5)
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params := url.Values{}
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params.Add("response_type", "code")
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params.Add("client_id", h.cfg.OIDCClientID)
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params.Add("redirect_uri", fmt.Sprintf("%s/oidc/callback", h.cfg.ServerURL))
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params.Add("scope", "openid")
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params.Add("state", stateStr)
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authUrl := fmt.Sprintf("%s?%s", oidcConfig.AuthorizationEndpoint, params.Encode())
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log.Debug().Msg(authUrl)
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c.Redirect(http.StatusFound, authUrl)
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}
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// OIDCCallback handles the callback from the OIDC endpoint
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// Retrieves the mkey from the state cache, if the machine is not registered, presents a confirmation
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// Listens in /oidc/callback
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func (h *Headscale) OIDCCallback(c *gin.Context) {
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code := c.Query("code")
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state := c.Query("state")
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if code == "" || state == "" {
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c.String(http.StatusBadRequest, "Wrong params")
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return
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}
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redirectURI := fmt.Sprintf("%s/oidc/callback", h.cfg.ServerURL)
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tokens, err := h.exchangeCodeForTokens(code, redirectURI)
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if err != nil {
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c.String(http.StatusBadRequest, "Could not exchange code for token")
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return
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}
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//verify tokens
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claims, err := verifyToken(tokens.AccessToken)
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if err != nil {
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c.String(http.StatusBadRequest, "invalid tokens")
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return
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}
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//retrieve machinekey from state cache
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mKeyIf, mKeyFound := stateCache.Get(state)
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if !mKeyFound {
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c.String(http.StatusBadRequest, "state has expired")
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return
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}
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mKeyStr, mKeyOK := mKeyIf.(string)
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if !mKeyOK {
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c.String(http.StatusInternalServerError, "could not get machine key from cache")
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return
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}
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// retrieve machine information
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var m Machine
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if result := h.db.Preload("Namespace").First(&m, "machine_key = ?", mKeyStr); errors.Is(result.Error, gorm.ErrRecordNotFound) {
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log.Error().Msg("machine key not found in database")
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c.String(http.StatusInternalServerError, "could not get machine info from database")
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return
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}
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//look for a namespace of the users email for now
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if !m.Registered {
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ns, err := h.GetNamespace(claims.Email)
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if err != nil {
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ns, err = h.CreateNamespace(claims.Email)
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}
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ip, err := h.getAvailableIP()
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if err != nil {
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c.String(http.StatusInternalServerError, "could not get an IP from the pool")
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return
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}
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m.IPAddress = ip.String()
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m.NamespaceID = ns.ID
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m.Registered = true
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m.RegisterMethod = "oidc"
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h.db.Save(&m)
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}
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c.Data(http.StatusOK, "text/html; charset=utf-8", []byte(fmt.Sprintf(`
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<html>
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<body>
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<h1>headscale</h1>
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<p>
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Authenticated, you can now close this window.
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</p>
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</body>
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</html>
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`)))
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}
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