/
acl.go
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/
acl.go
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// Copyright (c) 2017 Rackspace
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
// implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package middleware
import (
"errors"
"fmt"
"net/http"
"net/url"
"strings"
"github.com/troubling/hummingbird/common"
)
// Returns a cleaned ACL header value, validating that it meets the formatting
// requirements for standard Hummingbird ACL strings.
func CleanACL(name string, value string) (string, error) {
name = strings.ToLower(name)
var values []string
for _, rawValue := range strings.Split(value, ",") {
rawValue = strings.TrimSpace(rawValue)
if rawValue == "" {
continue
}
if !strings.Contains(rawValue, ":") {
values = append(values, rawValue)
continue
}
v := strings.SplitN(rawValue, ":", 2)
v[0] = strings.TrimSpace(v[0])
v[1] = strings.TrimSpace(v[1])
if v[0] == "" || !strings.HasPrefix(v[0], ".") {
values = append(values, rawValue)
} else if common.StringInSlice(v[0], []string{".r", ".ref", ".referer", ".referrer"}) {
if strings.Contains(name, "write") {
return "", fmt.Errorf("Referrers not allowed in write ACL: %s", rawValue)
}
negate := false
if v[1] != "" && strings.HasPrefix(v[1], "-") {
negate = true
v[1] = strings.TrimSpace(v[1][1:])
}
if v[1] != "" && v[1] != "*" && strings.HasPrefix(v[1], "*") {
v[1] = strings.TrimSpace(v[1][1:])
}
if v[1] == "" || v[1] == "." {
return "", fmt.Errorf("No host/domain value after referrer designation in ACL: %s", rawValue)
}
if negate {
values = append(values, fmt.Sprintf(".r:-%s", v[1]))
} else {
values = append(values, fmt.Sprintf(".r:%s", v[1]))
}
} else {
return "", fmt.Errorf("Unknown designator %s in ACL: %s", v[0], rawValue)
}
}
return strings.Join(values, ","), nil
}
// Parses a standard Hummingbird ACL string into a referrers list and groups list.
func ParseACL(acl string) ([]string, []string) {
referrers := []string{}
groups := []string{}
if acl != "" {
for _, value := range strings.Split(acl, ",") {
if strings.HasPrefix(value, ".r:") {
referrers = append(referrers, value[len(".r:"):])
} else {
groups = append(groups, value)
}
}
}
return referrers, groups
}
//Returns True if the referrer should be allowed based on the referrerACL list
func ReferrerAllowed(referrer string, referrerACL []string) bool {
allow := false
if len(referrerACL) > 0 {
rHost := "unknown"
if u, err := url.Parse(referrer); err == nil {
rHost = u.Hostname()
}
for _, mHost := range referrerACL {
if strings.HasPrefix(mHost, "-") {
mHost = mHost[1:]
if mHost == rHost || (strings.HasPrefix(mHost, ".") && strings.HasSuffix(rHost, mHost)) {
allow = false
}
} else if mHost == "*" || mHost == rHost || (strings.HasPrefix(mHost, ".") && strings.HasSuffix(rHost, mHost)) {
allow = true
}
}
}
return allow
}
func AuthorizeUnconfirmedIdentity(r *http.Request, obj string, referrers []string, roles []string) (bool, error) {
if ReferrerAllowed(r.Referer(), referrers) {
if obj != "" || common.StringInSlice(".rlistings", roles) {
return true, nil
}
return false, nil
}
return false, errors.New("unable to confirm identity")
}