/
handlers.go
177 lines (150 loc) · 5.92 KB
/
handlers.go
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package openshiftkubeapiserver
import (
"bytes"
"encoding/json"
"errors"
"fmt"
"net/http"
"regexp"
"github.com/emicklei/go-restful"
"github.com/golang/glog"
authenticationv1 "k8s.io/api/authentication/v1"
kapierrors "k8s.io/apimachinery/pkg/api/errors"
"k8s.io/apimachinery/pkg/runtime"
"k8s.io/apimachinery/pkg/runtime/schema"
"k8s.io/apimachinery/pkg/util/sets"
kauthorizer "k8s.io/apiserver/pkg/authorization/authorizer"
apirequest "k8s.io/apiserver/pkg/endpoints/request"
"k8s.io/kubernetes/pkg/api/legacyscheme"
coreapi "k8s.io/kubernetes/pkg/apis/core"
authorizationapi "github.com/openshift/origin/pkg/authorization/apis/authorization"
configapi "github.com/openshift/origin/pkg/cmd/server/apis/config"
)
type userAgentFilter struct {
regex *regexp.Regexp
message string
verbs sets.String
}
func newUserAgentFilter(config configapi.UserAgentMatchRule) (userAgentFilter, error) {
regex, err := regexp.Compile(config.Regex)
if err != nil {
return userAgentFilter{}, err
}
userAgentFilter := userAgentFilter{regex: regex, verbs: sets.NewString(config.HTTPVerbs...)}
return userAgentFilter, nil
}
func (f *userAgentFilter) matches(verb, userAgent string) bool {
if len(f.verbs) > 0 && !f.verbs.Has(verb) {
return false
}
return f.regex.MatchString(userAgent)
}
// versionSkewFilter adds a filter that may deny requests from skewed
// oc clients, since we know that those clients will strip unknown fields which can lead to unexpected outcomes
func versionSkewFilter(handler http.Handler, userAgentMatchingConfig configapi.UserAgentMatchingConfig) http.Handler {
filterConfig := userAgentMatchingConfig
if len(filterConfig.RequiredClients) == 0 && len(filterConfig.DeniedClients) == 0 {
return handler
}
defaultMessage := filterConfig.DefaultRejectionMessage
if len(defaultMessage) == 0 {
defaultMessage = "the cluster administrator has disabled access for this client, please upgrade or consult your administrator"
}
// the structure of the legacyClientPolicyConfig is pretty easy to write, but its inefficient to use at runtime
// pre-process the config elements to make a more efficicent structure.
allowedFilters := []userAgentFilter{}
deniedFilters := []userAgentFilter{}
for _, config := range filterConfig.RequiredClients {
userAgentFilter, err := newUserAgentFilter(config)
if err != nil {
glog.Errorf("Failure to compile User-Agent regex %v: %v", config.Regex, err)
continue
}
allowedFilters = append(allowedFilters, userAgentFilter)
}
for _, config := range filterConfig.DeniedClients {
userAgentFilter, err := newUserAgentFilter(config.UserAgentMatchRule)
if err != nil {
glog.Errorf("Failure to compile User-Agent regex %v: %v", config.Regex, err)
continue
}
userAgentFilter.message = config.RejectionMessage
if len(userAgentFilter.message) == 0 {
userAgentFilter.message = defaultMessage
}
deniedFilters = append(deniedFilters, userAgentFilter)
}
return http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
ctx := req.Context()
if requestInfo, ok := apirequest.RequestInfoFrom(ctx); ok && requestInfo != nil && !requestInfo.IsResourceRequest {
handler.ServeHTTP(w, req)
return
}
userAgent := req.Header.Get("User-Agent")
if len(allowedFilters) > 0 {
foundMatch := false
for _, filter := range allowedFilters {
if filter.matches(req.Method, userAgent) {
foundMatch = true
break
}
}
if !foundMatch {
forbidden(defaultMessage, nil, w, req)
return
}
}
for _, filter := range deniedFilters {
if filter.matches(req.Method, userAgent) {
forbidden(filter.message, nil, w, req)
return
}
}
handler.ServeHTTP(w, req)
})
}
// legacyImpersonateUserScopeHeader is the header name older servers were using
// just for scopes, so we need to translate it from clients that may still be
// using it.
const legacyImpersonateUserScopeHeader = "Impersonate-User-Scope"
// translateLegacyScopeImpersonation is a filter that will translates user scope impersonation for openshift into the equivalent kube headers.
func translateLegacyScopeImpersonation(handler http.Handler) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
for _, scope := range req.Header[legacyImpersonateUserScopeHeader] {
req.Header[authenticationv1.ImpersonateUserExtraHeaderPrefix+authorizationapi.ScopesKey] =
append(req.Header[authenticationv1.ImpersonateUserExtraHeaderPrefix+authorizationapi.ScopesKey], scope)
}
handler.ServeHTTP(w, req)
})
}
// forbidden renders a simple forbidden error to the response
func forbidden(reason string, attributes kauthorizer.Attributes, w http.ResponseWriter, req *http.Request) {
resource := ""
group := ""
name := ""
// the attributes can be empty for two basic reasons:
// 1. malformed API request
// 2. not an API request at all
// In these cases, just assume default that will work better than nothing
if attributes != nil {
group = attributes.GetAPIGroup()
resource = attributes.GetResource()
name = attributes.GetName()
}
// Reason is an opaque string that describes why access is allowed or forbidden (forbidden by the time we reach here).
// We don't have direct access to kind or name (not that those apply either in the general case)
// We create a NewForbidden to stay close the API, but then we override the message to get a serialization
// that makes sense when a human reads it.
forbiddenError := kapierrors.NewForbidden(schema.GroupResource{Group: group, Resource: resource}, name, errors.New("") /*discarded*/)
forbiddenError.ErrStatus.Message = reason
formatted := &bytes.Buffer{}
output, err := runtime.Encode(legacyscheme.Codecs.LegacyCodec(coreapi.SchemeGroupVersion), &forbiddenError.ErrStatus)
if err != nil {
fmt.Fprintf(formatted, "%s", forbiddenError.Error())
} else {
json.Indent(formatted, output, "", " ")
}
w.Header().Set("Content-Type", restful.MIME_JSON)
w.WriteHeader(http.StatusForbidden)
w.Write(formatted.Bytes())
}