From c5e3ffe09bf11a8dd79e37c0ba80453fd3e650fa Mon Sep 17 00:00:00 2001
From: Noah Petherbridge <root@kirsle.net>
Date: Wed, 14 May 2025 20:27:04 -0700
Subject: [PATCH] Safety feature to detect webcam watermark being removed

---
 src/App.vue                  |  6 +++--
 src/components/VideoFeed.vue | 43 +++++++++++++++++++++++++++++++-----
 src/lib/WebRTC.js            | 37 +++++++++++++++++++++++++++++++
 3 files changed, 79 insertions(+), 7 deletions(-)

diff --git a/src/App.vue b/src/App.vue
index 1ac7876..4c2a8e1 100644
--- a/src/App.vue
+++ b/src/App.vue
@@ -3409,7 +3409,8 @@ export default {
                         @popout="popoutVideo"
                         @open-profile="showProfileModal"
                         @set-volume="setVideoVolume"
-                        @modal-alert="modalAlert">
+                        @modal-alert="modalAlert"
+                        @watermark-removed="onDeletedWatermark">
                     </VideoFeed>
 
                     <!-- Others' videos -->
@@ -3430,7 +3431,8 @@ export default {
                         @close-video="expresslyCloseVideo"
                         @set-volume="setVideoVolume"
                         @open-profile="showProfileModal"
-                        @modal-alert="modalAlert">
+                        @modal-alert="modalAlert"
+                        @watermark-removed="onDeletedWatermark">
                     </VideoFeed>
 
                     <!-- Debugging - copy a lot of these to simulate more videos -->
diff --git a/src/components/VideoFeed.vue b/src/components/VideoFeed.vue
index 6a1f4d0..6d39d66 100644
--- a/src/components/VideoFeed.vue
+++ b/src/components/VideoFeed.vue
@@ -27,8 +27,17 @@ export default {
 
             // Mouse over status
             mouseOver: false,
+
+            // Mutation Observer, to detect if the user deletes the QR code via dev tools.
+            observer: null,
         };
     },
+    mounted() {
+        this.initWatermarkObserver();
+    },
+    beforeUnmount() {
+        this.observer?.disconnect();
+    },
     computed: {
         containerID() {
             return this.videoID + '-container';
@@ -132,13 +141,37 @@ export default {
                     "to everybody, and a second (subtle) copy of the code spans across the center/middle of the video and pulsates in " +
                     "transparency over time.",
             });
-        }
+        },
+
+        // Mutation Observer to detect if the watermark is tampered with by the viewer.
+        initWatermarkObserver() {
+            const $container = this.$refs.videoContainer,
+                $watermark = this.$refs.watermarkImage,
+                $smallImage = this.$refs.watermarkSmallImage;
+
+            if (!$container || !$watermark || !$smallImage) return;
+
+            this.observer = new MutationObserver(() => {
+                const stillPresent = $container.contains($watermark) && $container.contains($smallImage);
+                if (!stillPresent) {
+                    this.onWatermarkRemoved();
+                }
+            });
+
+            this.observer.observe($container, {
+                childList: true,
+                subtree: true,
+            });
+        },
+        onWatermarkRemoved() {
+            this.$emit('watermark-removed', this.username);
+        },
     }
 }
 </script>
 
 <template>
-    <div class="feed" :id="containerID" :class="{
+    <div class="feed" ref="videoContainer" :id="containerID" :class="{
         'popped-out': poppedOut,
         'popped-in': !poppedOut,
     }" @mouseover="mouseOver = true" @mouseleave="mouseOver = false">
@@ -151,9 +184,9 @@ export default {
             :muted="localVideo"></video>
 
         <!-- Watermark layer -->
-        <div v-if="watermarkImage">
-            <img :src="watermarkImage" class="watermark" oncontextmenu="return false">
-            <img :src="watermarkImage" class="corner-watermark seethru invert-color" @click="showWatermarkInfo()" oncontextmenu="return false">
+        <div>
+            <img :src="watermarkImage" class="watermark" ref="watermarkImage" oncontextmenu="return false">
+            <img :src="watermarkImage" class="corner-watermark seethru invert-color" ref="watermarkSmallImage" @click="showWatermarkInfo()" oncontextmenu="return false">
         </div>
 
         <!-- Caption -->
diff --git a/src/lib/WebRTC.js b/src/lib/WebRTC.js
index ac54f39..30c12b4 100644
--- a/src/lib/WebRTC.js
+++ b/src/lib/WebRTC.js
@@ -1888,6 +1888,43 @@ class WebRTCController {
                 // Set it.
                 this.webcam.videoScale = this.webcam.videoScaleOptions[currentSize][0];
             },
+
+            // Safety feature: if the user deletes the QR code watermark in their browser's dev
+            // tools, this function is called.
+            onDeletedWatermark(username) {
+                // Stop ALL videos NOW.
+                window.requestAnimationFrame(() => {
+                    this.closeOpenVideos();
+                    this.stopVideo();
+                });
+
+                // Report this to your main website.
+                this.doCustomReport({
+                    message: {
+                        channel: 'n/a',
+                        username: this.username,
+                        at: new Date(),
+                        message: 'User has deleted the webcam watermark QR code image!',
+                    },
+                    classification: 'Community Safety Violation',
+                    comment: `The user ${this.username} is trying to circumvent the webcam watermarking system!\n\n` +
+                        `It has been detected that the QR code overlay had been removed from the page, possibly via ${this.username} ` +
+                        `using their browser's dev tools to do so.\n\nSpecifically, the webcam being broadcast by @${username} has had its ` +
+                        `watermark element removed from the web page.`
+                });
+
+                // Sign out of chat.
+                setTimeout(() => {
+                    this.client.disconnect()
+                }, 5000);
+
+                // Show the user an alert modal and reload the page.
+                this.modalAlert({
+                    icon: "fa fa-skull-crossbones",
+                    title: "Something has gone wrong",
+                    message: "A critical error was detected. Please refresh the web page.",
+                });
+            },
         }
     }