fix(notifications): check every img src and uncache previewHEADmaster

The sanitizer matched the first \bsrc anywhere in the tag, so a
data-src="file:///tmp/decoy" before a remote src won the match and kept
the whole tag while Qt, which ignores data-src, fetched the remote
image. Scan every src assignment in the tag and keep it only if all of
them are local. Also set cache: false on the balloon preview, since the
daemon overwrites the same path on a replace and QQuickPixmapCache keys
on URL, so a replaced notification could show the previous image.

1 files changed, 13 insertions, 7 deletions

diff --git a/shared/Notify.qml b/shared/Notify.qml
index 237d8c9..1abe57d 100644
--- a/shared/Notify.qml
+++ b/shared/Notify.qml
@@ -70,9 +70,11 @@ Singleton {
     // remote <img src> (http(s), protocol-relative //host, ftp, data, or an
     // entity-encoded scheme) would make the shell fetch or embed something the
     // sender chose, which leaks that the notification was shown. Deny by
-    // default: a tag survives only if its src decodes to a file: URL or a
-    // leading-slash absolute path. Entities are decoded before the test, so an
-    // encoded scheme cannot slip past.
+    // default: a tag survives only if every src it carries decodes to a file:
+    // URL or a leading-slash absolute path. Every src assignment is checked,
+    // not just the first, so a decoy attribute cannot shadow a remote one;
+    // entities are decoded before the test, so an encoded scheme cannot slip
+    // past.
     function sanitize(body) {
         function decode(s) {
             return s.replace(/&(?:#x([0-9a-f]+)|#(\d+)|(amp|colon|sol|tab|quot));/gi,
@@ -83,10 +85,14 @@ Singleton {
                 });
         }
         return (body || "").replace(/<img\b[^>]*>/gi, function (tag) {
-            const m = tag.match(/\bsrc\s*=\s*(?:"([^"]*)"|'([^']*)'|([^\s>]+))/i);
-            if (!m) return "";
-            const src = decode(m[1] !== undefined ? m[1] : m[2] !== undefined ? m[2] : m[3]);
-            return /^file:/i.test(src) || (src.charAt(0) === "/" && src.charAt(1) !== "/") ? tag : "";
+            const re = /(?:^|\s)src\s*=\s*(?:"([^"]*)"|'([^']*)'|([^\s>]+))/gi;
+            let m, found = false, local = true;
+            while ((m = re.exec(tag))) {
+                found = true;
+                const src = decode(m[1] !== undefined ? m[1] : m[2] !== undefined ? m[2] : m[3]);
+                if (!(/^file:/i.test(src) || (src.charAt(0) === "/" && src.charAt(1) !== "/"))) local = false;
+            }
+            return (found && local) ? tag : "";
         });
     }