grafana/pkg/services/accesscontrol/middleware/middleware.go
2021-05-12 23:00:27 +02:00

90 lines
2.6 KiB
Go

package middleware
import (
"bytes"
"fmt"
"net/http"
"text/template"
"time"
"github.com/grafana/grafana/pkg/util"
macaron "gopkg.in/macaron.v1"
"github.com/grafana/grafana/pkg/models"
"github.com/grafana/grafana/pkg/services/accesscontrol"
)
func Middleware(ac accesscontrol.AccessControl) func(macaron.Handler, string, ...string) macaron.Handler {
return func(fallback macaron.Handler, permission string, scopes ...string) macaron.Handler {
if ac.IsDisabled() {
return fallback
}
return func(c *models.ReqContext) {
// We need this otherwise templated scopes get initialized only once, during the first call
runtimeScope := make([]string, len(scopes))
for i, scope := range scopes {
var buf bytes.Buffer
tmpl, err := template.New("scope").Parse(scope)
if err != nil {
c.JsonApiErr(http.StatusInternalServerError, "Internal server error", err)
return
}
err = tmpl.Execute(&buf, c.AllParams())
if err != nil {
c.JsonApiErr(http.StatusInternalServerError, "Internal server error", err)
return
}
runtimeScope[i] = buf.String()
}
hasAccess, err := ac.Evaluate(c.Req.Context(), c.SignedInUser, permission, runtimeScope...)
if err != nil {
Deny(c, permission, runtimeScope, err)
return
}
if !hasAccess {
Deny(c, permission, runtimeScope, nil)
return
}
}
}
}
func Deny(c *models.ReqContext, permission string, scopes []string, err error) {
id := newID()
if err != nil {
c.Logger.Error("Error from access control system", "error", err, "accessErrorID", id)
} else {
c.Logger.Info("Access denied",
"userID", c.UserId,
"permission", permission,
"scopes", scopes,
"accessErrorID", id)
}
// If the user triggers an error in the access control system, we
// don't want the user to be aware of that, so the user gets the
// same information from the system regardless of if it's an
// internal server error or access denied.
c.JSON(http.StatusForbidden, map[string]string{
"title": "Access denied", // the component needs to pick this up
"message": fmt.Sprintf("Your user account does not have permissions to do the action. We recorded your attempt with log message %s. Contact your administrator for help.", id),
"accessErrorId": id,
})
}
func newID() string {
// Less ambiguity than alphanumerical.
numerical := []byte("0123456789")
id, err := util.GetRandomString(10, numerical...)
if err != nil {
// this should not happen, but if it does, a timestamp is as
// useful as anything.
id = fmt.Sprintf("%d", time.Now().UnixNano())
}
return "ACE" + id
}