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decompose OIDCCallback method

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This commit is contained in:
Grigoriy Mikhalkin 2022-07-11 23:25:13 +02:00
parent 3f0639c87d
commit 395caaad42
1 changed files with 187 additions and 53 deletions
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240
oidc.go
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@ -136,6 +136,82 @@ func (h *Headscale) OIDCCallback(
writer http.ResponseWriter,
req *http.Request,
) {
code, state, ok := validateOIDCCallbackParams(writer, req)
if !ok {
return
}
rawIDToken, ok := h.getIDTokenForOIDCCallback(writer, code, state)
if !ok {
return
}
idToken, ok := h.verifyIDTokenForOIDCCallback(writer, rawIDToken)
if !ok {
return
}
// TODO: we can use userinfo at some point to grab additional information about the user (groups membership, etc)
// userInfo, err := oidcProvider.UserInfo(context.Background(), oauth2.StaticTokenSource(oauth2Token))
// if err != nil {
// c.String(http.StatusBadRequest, fmt.Sprintf("Failed to retrieve userinfo"))
// return
// }
claims, ok := extractIDTokenClaims(writer, idToken)
if !ok {
return
}
if ok := validateOIDCAllowedDomains(writer, h.cfg.OIDC.AllowedDomains, claims); !ok {
return
}
if ok := validateOIDCAllowedUsers(writer, h.cfg.OIDC.AllowedUsers, claims); !ok {
return
}
machineKey, ok := h.validateMachineForOIDCCallback(writer, state, claims)
if !ok {
return
}
namespaceName, ok := getNamespaceName(writer, claims, h.cfg.OIDC.StripEmaildomain)
if !ok {
return
}
// register the machine if it's new
log.Debug().Msg("Registering new machine after successful callback")
namespace, ok := h.findOrCreateNewNamespaceForOIDCCallback(writer, namespaceName)
if !ok {
return
}
if ok := h.registerMachineForOIDCCallback(writer, namespace, machineKey); !ok {
return
}
content, ok := renderOIDCCallbackTemplate(writer, claims)
if !ok {
return
}
writer.Header().Set("Content-Type", "text/html; charset=utf-8")
writer.WriteHeader(http.StatusOK)
if _, err := writer.Write(content.Bytes()); err != nil {
log.Error().
Caller().
Err(err).
Msg("Failed to write response")
}
}
func validateOIDCCallbackParams(
writer http.ResponseWriter,
req *http.Request,
) (string, string, bool) {
code := req.URL.Query().Get("code")
state := req.URL.Query().Get("state")
@ -150,9 +226,16 @@ func (h *Headscale) OIDCCallback(
Msg("Failed to write response")
}
return
return "", "", false
}
return code, state, true
}
func (h *Headscale) getIDTokenForOIDCCallback(
writer http.ResponseWriter,
code, state string,
) (string, bool) {
oauth2Token, err := h.oauth2Config.Exchange(context.Background(), code)
if err != nil {
log.Error().
@ -169,7 +252,7 @@ func (h *Headscale) OIDCCallback(
Msg("Failed to write response")
}
return
return "", false
}
log.Trace().
@ -190,11 +273,17 @@ func (h *Headscale) OIDCCallback(
Msg("Failed to write response")
}
return
return "", false
}
verifier := h.oidcProvider.Verifier(&oidc.Config{ClientID: h.cfg.OIDC.ClientID})
return rawIDToken, true
}
func (h *Headscale) verifyIDTokenForOIDCCallback(
writer http.ResponseWriter,
rawIDToken string,
) (*oidc.IDToken, bool) {
verifier := h.oidcProvider.Verifier(&oidc.Config{ClientID: h.cfg.OIDC.ClientID})
idToken, err := verifier.Verify(context.Background(), rawIDToken)
if err != nil {
log.Error().
@ -211,19 +300,18 @@ func (h *Headscale) OIDCCallback(
Msg("Failed to write response")
}
return
return nil, false
}
// TODO: we can use userinfo at some point to grab additional information about the user (groups membership, etc)
// userInfo, err := oidcProvider.UserInfo(context.Background(), oauth2.StaticTokenSource(oauth2Token))
// if err != nil {
// c.String(http.StatusBadRequest, fmt.Sprintf("Failed to retrieve userinfo"))
// return
// }
return idToken, true
}
// Extract custom claims
func extractIDTokenClaims(
writer http.ResponseWriter,
idToken *oidc.IDToken,
) (*IDTokenClaims, bool) {
var claims IDTokenClaims
if err = idToken.Claims(&claims); err != nil {
if err := idToken.Claims(claims); err != nil {
log.Error().
Err(err).
Caller().
@ -238,13 +326,22 @@ func (h *Headscale) OIDCCallback(
Msg("Failed to write response")
}
return
return nil, false
}
// If AllowedDomains is provided, check that the authenticated principal ends with @<alloweddomain>.
if len(h.cfg.OIDC.AllowedDomains) > 0 {
return &claims, true
}
// validateOIDCAllowedDomains checks that if AllowedDomains is provided,
// that the authenticated principal ends with @<alloweddomain>.
func validateOIDCAllowedDomains(
writer http.ResponseWriter,
allowedDomains []string,
claims *IDTokenClaims,
) bool {
if len(allowedDomains) > 0 {
if at := strings.LastIndex(claims.Email, "@"); at < 0 ||
!IsStringInSlice(h.cfg.OIDC.AllowedDomains, claims.Email[at+1:]) {
!IsStringInSlice(allowedDomains, claims.Email[at+1:]) {
log.Error().Msg("authenticated principal does not match any allowed domain")
writer.Header().Set("Content-Type", "text/plain; charset=utf-8")
writer.WriteHeader(http.StatusBadRequest)
@ -256,13 +353,22 @@ func (h *Headscale) OIDCCallback(
Msg("Failed to write response")
}
return
return false
}
}
// If AllowedUsers is provided, check that the authenticated princial is part of that list.
if len(h.cfg.OIDC.AllowedUsers) > 0 &&
!IsStringInSlice(h.cfg.OIDC.AllowedUsers, claims.Email) {
return true
}
// validateOIDCAllowedUsers checks that if AllowedUsers is provided,
// that the authenticated principal is part of that list.
func validateOIDCAllowedUsers(
writer http.ResponseWriter,
allowedUsers []string,
claims *IDTokenClaims,
) bool {
if len(allowedUsers) > 0 &&
!IsStringInSlice(allowedUsers, claims.Email) {
log.Error().Msg("authenticated principal does not match any allowed user")
writer.Header().Set("Content-Type", "text/plain; charset=utf-8")
writer.WriteHeader(http.StatusBadRequest)
@ -274,12 +380,23 @@ func (h *Headscale) OIDCCallback(
Msg("Failed to write response")
}
return
return false
}
return true
}
// validateMachine retrieves machine information if it exist
// The error is not important, because if it does not
// exist, then this is a new machine and we will move
// on to registration.
func (h *Headscale) validateMachineForOIDCCallback(
writer http.ResponseWriter,
state string,
claims *IDTokenClaims,
) (*key.MachinePublic, bool) {
// retrieve machinekey from state cache
machineKeyIf, machineKeyFound := h.registrationCache.Get(state)
if !machineKeyFound {
log.Error().
Msg("requested machine state key expired before authorisation completed")
@ -293,13 +410,12 @@ func (h *Headscale) OIDCCallback(
Msg("Failed to write response")
}
return
return nil, false
}
machineKeyFromCache, machineKeyOK := machineKeyIf.(string)
var machineKey key.MachinePublic
err = machineKey.UnmarshalText(
machineKeyFromCache, machineKeyOK := machineKeyIf.(string)
err := machineKey.UnmarshalText(
[]byte(MachinePublicKeyEnsurePrefix(machineKeyFromCache)),
)
if err != nil {
@ -315,7 +431,7 @@ func (h *Headscale) OIDCCallback(
Msg("Failed to write response")
}
return
return nil, false
}
if !machineKeyOK {
@ -330,7 +446,7 @@ func (h *Headscale) OIDCCallback(
Msg("Failed to write response")
}
return
return nil, false
}
// retrieve machine information if it exist
@ -353,7 +469,7 @@ func (h *Headscale) OIDCCallback(
Msg("Failed to refresh machine")
http.Error(writer, "Failed to refresh machine", http.StatusInternalServerError)
return
return nil, false
}
var content bytes.Buffer
@ -377,7 +493,7 @@ func (h *Headscale) OIDCCallback(
Msg("Failed to write response")
}
return
return nil, false
}
writer.Header().Set("Content-Type", "text/html; charset=utf-8")
@ -390,12 +506,20 @@ func (h *Headscale) OIDCCallback(
Msg("Failed to write response")
}
return
return nil, false
}
return &machineKey, true
}
func getNamespaceName(
writer http.ResponseWriter,
claims *IDTokenClaims,
stripEmaildomain bool,
) (string, bool) {
namespaceName, err := NormalizeToFQDNRules(
claims.Email,
h.cfg.OIDC.StripEmaildomain,
stripEmaildomain,
)
if err != nil {
log.Error().Err(err).Caller().Msgf("couldn't normalize email")
@ -409,12 +533,16 @@ func (h *Headscale) OIDCCallback(
Msg("Failed to write response")
}
return
return "", false
}
// register the machine if it's new
log.Debug().Msg("Registering new machine after successful callback")
return namespaceName, true
}
func (h *Headscale) findOrCreateNewNamespaceForOIDCCallback(
writer http.ResponseWriter,
namespaceName string,
) (*Namespace, bool) {
namespace, err := h.GetNamespace(namespaceName)
if errors.Is(err, errNamespaceNotFound) {
namespace, err = h.CreateNamespace(namespaceName)
@ -434,7 +562,7 @@ func (h *Headscale) OIDCCallback(
Msg("Failed to write response")
}
return
return nil, false
}
} else if err != nil {
log.Error().
@ -452,17 +580,24 @@ func (h *Headscale) OIDCCallback(
Msg("Failed to write response")
}
return
return nil, false
}
machineKeyStr := MachinePublicKeyStripPrefix(machineKey)
return namespace, true
}
_, err = h.RegisterMachineFromAuthCallback(
func (h *Headscale) registerMachineForOIDCCallback(
writer http.ResponseWriter,
namespace *Namespace,
machineKey *key.MachinePublic,
) bool {
machineKeyStr := MachinePublicKeyStripPrefix(*machineKey)
if _, err := h.RegisterMachineFromAuthCallback(
machineKeyStr,
namespace.Name,
RegisterMethodOIDC,
)
if err != nil {
); err != nil {
log.Error().
Caller().
Err(err).
@ -477,9 +612,16 @@ func (h *Headscale) OIDCCallback(
Msg("Failed to write response")
}
return
return false
}
return true
}
func renderOIDCCallbackTemplate(
writer http.ResponseWriter,
claims *IDTokenClaims,
) (*bytes.Buffer, bool) {
var content bytes.Buffer
if err := oidcCallbackTemplate.Execute(&content, oidcCallbackTemplateConfig{
User: claims.Email,
@ -501,16 +643,8 @@ func (h *Headscale) OIDCCallback(
Msg("Failed to write response")
}
return
return nil, false
}
writer.Header().Set("Content-Type", "text/html; charset=utf-8")
writer.WriteHeader(http.StatusOK)
_, err = writer.Write(content.Bytes())
if err != nil {
log.Error().
Caller().
Err(err).
Msg("Failed to write response")
}
return &content, true
}