From 1ed0782e93dafb0a3d5ef3a02c9c3999825817ee Mon Sep 17 00:00:00 2001 From: Johan Klokkhammer Helsing Date: Wed, 18 Sep 2019 08:56:57 +0200 Subject: Client: Don't crash with long window titles using UTF-16 characters Previously, we set the max length in QString character length, which means UTF-16 characters (of potentially three bytes) counts as one character. The max limit of libwayland, however, is in bytes (and the string itself is converted to UTF-8). Fix it by dividing the character limit by three because in the worst case each UTF-16 character will use three bytes when UTF-8 encoded. Fixes: QTBUG-78478 Change-Id: Idf4721894e0fe6f3cd92bdc6ada7b0ea4199ea63 Reviewed-by: Paul Olav Tvete --- src/client/qwaylandwindow.cpp | 6 ++++-- tests/auto/client/client/tst_client.cpp | 11 +++++++++++ 2 files changed, 15 insertions(+), 2 deletions(-) diff --git a/src/client/qwaylandwindow.cpp b/src/client/qwaylandwindow.cpp index ccfcaf933..ae26ba049 100644 --- a/src/client/qwaylandwindow.cpp +++ b/src/client/qwaylandwindow.cpp @@ -298,8 +298,10 @@ void QWaylandWindow::setWindowTitle(const QString &title) const QString formatted = formatWindowTitle(title, separator); const int libwaylandMaxBufferSize = 4096; - // Some parts of the buffer is used for metadata, so subtract 100 to be on the safe side - const int maxLength = libwaylandMaxBufferSize - 100; + // Some parts of the buffer is used for metadata, so subtract 100 to be on the safe side. + // Also, QString is in utf-16, which means that in the worst case each character will be + // three bytes when converted to utf-8 (which is what libwayland uses), so divide by three. + const int maxLength = libwaylandMaxBufferSize / 3 - 100; auto truncated = QStringRef(&formatted).left(maxLength); if (truncated.length() < formatted.length()) { diff --git a/tests/auto/client/client/tst_client.cpp b/tests/auto/client/client/tst_client.cpp index 08120c8c2..83b9e6ce0 100644 --- a/tests/auto/client/client/tst_client.cpp +++ b/tests/auto/client/client/tst_client.cpp @@ -178,6 +178,7 @@ private slots: void hiddenPopupParent(); void glWindow(); void longWindowTitle(); + void longWindowTitleWithUtf16Characters(); private: MockCompositor *compositor = nullptr; @@ -494,6 +495,16 @@ void tst_WaylandClient::longWindowTitle() QTRY_VERIFY(compositor->surface()); } +void tst_WaylandClient::longWindowTitleWithUtf16Characters() +{ + QWindow window; + QString absurdlyLongTitle = QString("δΈ‰").repeated(10000); + Q_ASSERT(absurdlyLongTitle.length() == 10000); // just making sure the test isn't broken + window.setTitle(absurdlyLongTitle); + window.show(); + QTRY_VERIFY(compositor->surface()); +} + int main(int argc, char **argv) { setenv("XDG_RUNTIME_DIR", ".", 1); -- cgit v1.2.3