Implement User Avatar spoofing of XMPP users (#1090)

* Implement User Avatar spoofing of XMPP users

4 files changed, 83 insertions, 3 deletions

diff --git a/bridge/xmpp/handler.go b/bridge/xmpp/handler.go
new file mode 100644
index 00000000..731998d9
--- /dev/null
+++ b/bridge/xmpp/handler.go
@@ -0,0 +1,34 @@
+package bxmpp
+
+import (
+	"github.com/42wim/matterbridge/bridge/config"
+	"github.com/42wim/matterbridge/bridge/helper"
+	"github.com/matterbridge/go-xmpp"
+)
+
+// handleDownloadAvatar downloads the avatar of userid from channel
+// sends a EVENT_AVATAR_DOWNLOAD message to the gateway if successful.
+// logs an error message if it fails
+func (b *Bxmpp) handleDownloadAvatar(avatar xmpp.AvatarData) {
+	rmsg := config.Message{
+		Username: "system",
+		Text:     "avatar",
+		Channel:  b.parseChannel(avatar.From),
+		Account:  b.Account,
+		UserID:   avatar.From,
+		Event:    config.EventAvatarDownload,
+		Extra:    make(map[string][]interface{}),
+	}
+	if _, ok := b.avatarMap[avatar.From]; !ok {
+		b.Log.Debugf("Avatar.From: %s", avatar.From)
+
+		err := helper.HandleDownloadSize(b.Log, &rmsg, avatar.From+".png", int64(len(avatar.Data)), b.General)
+		if err != nil {
+			b.Log.Error(err)
+			return
+		}
+		helper.HandleDownloadData(b.Log, &rmsg, avatar.From+".png", rmsg.Text, "", &avatar.Data, b.General)
+		b.Log.Debugf("Avatar download complete")
+		b.Remote <- rmsg
+	}
+}
diff --git a/bridge/xmpp/helpers.go b/bridge/xmpp/helpers.go
new file mode 100644
index 00000000..eb6a5366
--- /dev/null
+++ b/bridge/xmpp/helpers.go
@@ -0,0 +1,30 @@
+package bxmpp
+
+import (
+	"regexp"
+
+	"github.com/42wim/matterbridge/bridge/config"
+)
+
+var pathRegex = regexp.MustCompile("[^a-zA-Z0-9]+")
+
+// GetAvatar constructs a URL for a given user-avatar if it is available in the cache.
+func getAvatar(av map[string]string, userid string, general *config.Protocol) string {
+	if hash, ok := av[userid]; ok {
+		// NOTE: This does not happen in bridge/helper/helper.go but messes up XMPP
+		id := pathRegex.ReplaceAllString(userid, "_")
+		return general.MediaServerDownload + "/" + hash + "/" + id + ".png"
+	}
+	return ""
+}
+
+func (b *Bxmpp) cacheAvatar(msg *config.Message) string {
+	fi := msg.Extra["file"][0].(config.FileInfo)
+	/* if we have a sha we have successfully uploaded the file to the media server,
+	so we can now cache the sha */
+	if fi.SHA != "" {
+		b.Log.Debugf("Added %s to %s in avatarMap", fi.SHA, msg.UserID)
+		b.avatarMap[msg.UserID] = fi.SHA
+	}
+	return ""
+}
diff --git a/bridge/xmpp/xmpp.go b/bridge/xmpp/xmpp.go
index b5263017..7122534f 100644
--- a/bridge/xmpp/xmpp.go
+++ b/bridge/xmpp/xmpp.go
@@ -23,12 +23,15 @@ type Bxmpp struct {
 	xmppMap   map[string]string
 	connected bool
 	sync.RWMutex
+
+	avatarMap map[string]string
 }
 
 func New(cfg *bridge.Config) bridge.Bridger {
 	return &Bxmpp{
-		Config:  cfg,
-		xmppMap: make(map[string]string),
+		Config:    cfg,
+		xmppMap:   make(map[string]string),
+		avatarMap: make(map[string]string),
 	}
 }
 
@@ -69,6 +72,10 @@ func (b *Bxmpp) Send(msg config.Message) (string, error) {
 	}
 	b.Log.Debugf("=> Receiving %#v", msg)
 
+	if msg.Event == config.EventAvatarDownload {
+		return b.cacheAvatar(&msg), nil
+	}
+
 	// Upload a file (in XMPP case send the upload URL because XMPP has no native upload support).
 	if msg.Extra != nil {
 		for _, rmsg := range helper.HandleExtra(&msg, b.General) {
@@ -230,6 +237,12 @@ func (b *Bxmpp) handleXMPP() error {
 					event = config.EventTopicChange
 				}
 
+				avatar := getAvatar(b.avatarMap, v.Remote, b.General)
+				if avatar == "" {
+					b.Log.Debugf("Requesting avatar data")
+					b.xc.AvatarRequestData(v.Remote)
+				}
+
 				msgID := v.ID
 				if v.ReplaceID != "" {
 					msgID = v.ReplaceID
@@ -239,6 +252,7 @@ func (b *Bxmpp) handleXMPP() error {
 					Text:     v.Text,
 					Channel:  b.parseChannel(v.Remote),
 					Account:  b.Account,
+					Avatar:   avatar,
 					UserID:   v.Remote,
 					ID:       msgID,
 					Event:    event,
@@ -255,6 +269,8 @@ func (b *Bxmpp) handleXMPP() error {
 				b.Log.Debugf("<= Message is %#v", rmsg)
 				b.Remote <- rmsg
 			}
+		case xmpp.AvatarData:
+			b.handleDownloadAvatar(v)
 		case xmpp.Presence:
 			// Do nothing.
 		}
diff --git a/gateway/handlers.go b/gateway/handlers.go
index 26d3f189..edc2bf44 100644
--- a/gateway/handlers.go
+++ b/gateway/handlers.go
@@ -169,7 +169,7 @@ func (gw *Gateway) ignoreEvent(event string, dest *bridge.Bridge) bool {
 	switch event {
 	case config.EventAvatarDownload:
 		// Avatar downloads are only relevant for telegram and mattermost for now
-		if dest.Protocol != "mattermost" && dest.Protocol != "telegram" {
+		if dest.Protocol != "mattermost" && dest.Protocol != "telegram" && dest.Protocol != "xmpp" {
 			return true
 		}
 	case config.EventJoinLeave: