mirror of
https://github.com/matrix-org/dendrite
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b20386123e
* Move currentstateserver API to roomserver Stub out DB functions for now, nothing uses the roomserver version yet. * Allow it to startup * Implement some current-state-server storage interface functions * Add missing package
164 lines
5.5 KiB
Go
164 lines
5.5 KiB
Go
// Copyright 2020 The Matrix.org Foundation C.I.C.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package acls
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import (
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"context"
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"encoding/json"
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"fmt"
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"net"
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"regexp"
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"strings"
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"sync"
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"github.com/matrix-org/gomatrixserverlib"
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"github.com/sirupsen/logrus"
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)
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type ServerACLDatabase interface {
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// GetKnownRooms returns a list of all rooms we know about.
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GetKnownRooms(ctx context.Context) ([]string, error)
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// GetStateEvent returns the state event of a given type for a given room with a given state key
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// If no event could be found, returns nil
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// If there was an issue during the retrieval, returns an error
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GetStateEvent(ctx context.Context, roomID, evType, stateKey string) (*gomatrixserverlib.HeaderedEvent, error)
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}
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type ServerACLs struct {
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acls map[string]*serverACL // room ID -> ACL
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aclsMutex sync.RWMutex // protects the above
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}
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func NewServerACLs(db ServerACLDatabase) *ServerACLs {
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ctx := context.TODO()
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acls := &ServerACLs{
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acls: make(map[string]*serverACL),
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}
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// Look up all of the rooms that the current state server knows about.
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rooms, err := db.GetKnownRooms(ctx)
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if err != nil {
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logrus.WithError(err).Fatalf("Failed to get known rooms")
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}
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// For each room, let's see if we have a server ACL state event. If we
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// do then we'll process it into memory so that we have the regexes to
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// hand.
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for _, room := range rooms {
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state, err := db.GetStateEvent(ctx, room, "m.room.server_acl", "")
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if err != nil {
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logrus.WithError(err).Errorf("Failed to get server ACLs for room %q", room)
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continue
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}
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if state != nil {
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acls.OnServerACLUpdate(&state.Event)
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}
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}
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return acls
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}
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type ServerACL struct {
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Allowed []string `json:"allow"`
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Denied []string `json:"deny"`
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AllowIPLiterals bool `json:"allow_ip_literals"`
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}
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type serverACL struct {
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ServerACL
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allowedRegexes []*regexp.Regexp
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deniedRegexes []*regexp.Regexp
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}
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func compileACLRegex(orig string) (*regexp.Regexp, error) {
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escaped := regexp.QuoteMeta(orig)
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escaped = strings.Replace(escaped, "\\?", ".", -1)
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escaped = strings.Replace(escaped, "\\*", ".*", -1)
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return regexp.Compile(escaped)
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}
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func (s *ServerACLs) OnServerACLUpdate(state *gomatrixserverlib.Event) {
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acls := &serverACL{}
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if err := json.Unmarshal(state.Content(), &acls.ServerACL); err != nil {
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logrus.WithError(err).Errorf("Failed to unmarshal state content for server ACLs")
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return
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}
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// The spec calls only for * (zero or more chars) and ? (exactly one char)
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// to be supported as wildcard components, so we will escape all of the regex
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// special characters and then replace * and ? with their regex counterparts.
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// https://matrix.org/docs/spec/client_server/r0.6.1#m-room-server-acl
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for _, orig := range acls.Allowed {
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if expr, err := compileACLRegex(orig); err != nil {
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logrus.WithError(err).Errorf("Failed to compile allowed regex")
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} else {
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acls.allowedRegexes = append(acls.allowedRegexes, expr)
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}
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}
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for _, orig := range acls.Denied {
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if expr, err := compileACLRegex(orig); err != nil {
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logrus.WithError(err).Errorf("Failed to compile denied regex")
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} else {
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acls.deniedRegexes = append(acls.deniedRegexes, expr)
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}
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}
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logrus.WithFields(logrus.Fields{
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"allow_ip_literals": acls.AllowIPLiterals,
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"num_allowed": len(acls.allowedRegexes),
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"num_denied": len(acls.deniedRegexes),
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}).Debugf("Updating server ACLs for %q", state.RoomID())
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s.aclsMutex.Lock()
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defer s.aclsMutex.Unlock()
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s.acls[state.RoomID()] = acls
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}
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func (s *ServerACLs) IsServerBannedFromRoom(serverName gomatrixserverlib.ServerName, roomID string) bool {
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s.aclsMutex.RLock()
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// First of all check if we have an ACL for this room. If we don't then
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// no servers are banned from the room.
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acls, ok := s.acls[roomID]
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if !ok {
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s.aclsMutex.RUnlock()
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return false
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}
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s.aclsMutex.RUnlock()
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// Split the host and port apart. This is because the spec calls on us to
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// validate the hostname only in cases where the port is also present.
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if serverNameOnly, _, err := net.SplitHostPort(string(serverName)); err == nil {
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serverName = gomatrixserverlib.ServerName(serverNameOnly)
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}
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// Check if the hostname is an IPv4 or IPv6 literal. We cheat here by adding
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// a /0 prefix length just to trick ParseCIDR into working. If we find that
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// the server is an IP literal and we don't allow those then stop straight
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// away.
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if _, _, err := net.ParseCIDR(fmt.Sprintf("%s/0", serverName)); err == nil {
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if !acls.AllowIPLiterals {
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return true
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}
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}
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// Check if the hostname matches one of the denied regexes. If it does then
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// the server is banned from the room.
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for _, expr := range acls.deniedRegexes {
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if expr.MatchString(string(serverName)) {
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return true
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}
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}
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// Check if the hostname matches one of the allowed regexes. If it does then
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// the server is NOT banned from the room.
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for _, expr := range acls.allowedRegexes {
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if expr.MatchString(string(serverName)) {
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return false
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}
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}
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// If we've got to this point then we haven't matched any regexes or an IP
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// hostname if disallowed. The spec calls for default-deny here.
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return true
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}
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