diff options
| author | Tudor Brindus <me@tbrindus.ca> | 2021-02-10 20:42:18 -0500 |
|---|---|---|
| committer | Simon Ser <contact@emersion.fr> | 2021-02-15 13:50:14 +0100 |
| commit | 7d52b4d0b5592a3bc87e097c44b8629695bc9cad (patch) | |
| tree | 9aa2baf74b4e1e5e502103a23c5a9e965af13d74 | |
| parent | 4a9e70ccde1263d628be2d960dab511377cfbc6c (diff) | |
xwayland/selection: ignore requests for anything but the newest data
Our internal state machine gets screwed up if selection events are not
monotonically increasing in time, and we can enter a self-copy loop from
the proxy window that exhausts all pipes.
Snippet of logs when this occurs:
00:00:46.238 [wlr] [xwayland/selection/incoming.c:487] XCB_XFIXES_SELECTION_NOTIFY (selection=277, owner=4194626)
00:00:46.238 [wlr] [xwayland/selection/incoming.c:487] XCB_XFIXES_SELECTION_NOTIFY (selection=277, owner=2097153)
00:00:46.238 [wlr] [xwayland/selection/outgoing.c:378] XCB_SELECTION_REQUEST (time=58979563 owner=2097153, requestor=2097153 selection=277, target=279, property=278)
00:00:46.238 [wlr] [xwayland/selection/outgoing.c:397] ignoring old request from timestamp 58979563; expecting > 58979563
00:00:46.238 [wlr] [xwayland/selection/outgoing.c:29] SendEvent destination=2097153 SelectionNotify(31) time=58979563 requestor=2097153 selection=277 target=279 property=0
00:00:46.238 [wlr] [xwayland/selection/incoming.c:453] XCB_SELECTION_NOTIFY (selection=277, property=0, target=279)
Note that 2097153 is `selection->window`, and 4194626 is Emacs.
The race occurs if the selection owner changes back to our proxy window
between when we get `XCB_XFIXES_SELECTION_NOTIFY` for Emacs and when we
call `xcb_convert_selection` in `incoming.c:source_send` -- the
ConvertSelection request can end up hitting our proxy window, but the
timestamp will be rejected.
Fixes #2192.
| -rw-r--r-- | xwayland/selection/outgoing.c | 15 |
1 files changed, 14 insertions, 1 deletions
diff --git a/xwayland/selection/outgoing.c b/xwayland/selection/outgoing.c index 7c5c5f40..87c0fb06 100644 --- a/xwayland/selection/outgoing.c +++ b/xwayland/selection/outgoing.c @@ -392,9 +392,22 @@ void xwm_handle_selection_request(struct wlr_xwm *xwm, goto fail_notify_requestor; } + if (req->requestor == selection->window) { + wlr_log(WLR_ERROR, "selection request should have been caught before"); + goto fail_notify_requestor; + } + if (selection->window != req->owner) { + if (req->time != XCB_CURRENT_TIME && req->time < selection->timestamp) { + wlr_log(WLR_DEBUG, "ignored old request from timestamp %d; expected > %d", + req->time, selection->timestamp); + goto fail_notify_requestor; + } + wlr_log(WLR_DEBUG, "received selection request with invalid owner"); - goto fail_notify_requestor; + // Don't fail (`goto fail_notify_requestor`) the selection request if we're + // no longer the selection owner. + return; } // No xwayland surface focused, deny access to clipboard |