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envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists1p.gnu.org; Received-SPF: pass client-ip=170.10.129.124; envelope-from=marcandre.lureau@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: 12 X-Spam_score: 1.2 X-Spam_bar: + X-Spam_report: (1.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=0.001, RCVD_IN_SBL_CSS=3.335, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: qemu development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZohoMail-DKIM: pass (identity @redhat.com) X-ZM-MESSAGEID: 1787814470149158500 From: Marc-Andr=C3=A9 Lureau When the new cursor is the same object as the one already held by the console and the refcount is 1, cursor_unref frees it before cursor_ref can increment the count. Ref the incoming cursor before unreffing the old one so the refcount goes 1-2-1 instead of 1-0 (freed) then use-after-free. This is related to 385ac97f8fad ("ui: keep current cursor with QemuConsole"), but could have happened earlier with VNC too. Signed-off-by: Marc-Andr=C3=A9 Lureau --- ui/console.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/ui/console.c b/ui/console.c index a8a2a247d8f4..4db8f1cb431f 100644 --- a/ui/console.c +++ b/ui/console.c @@ -904,8 +904,9 @@ void qemu_console_set_cursor(QemuConsole *c, QEMUCursor= *cursor) DisplayState *s =3D c->ds; DisplayChangeListener *dcl; =20 + cursor_ref(cursor); cursor_unref(con->cursor); - con->cursor =3D cursor_ref(cursor); + con->cursor =3D cursor; QLIST_FOREACH(dcl, &s->listeners, next) { if (c !=3D dcl->con) { continue; --=20 2.55.0.543.g5ebe2ebe4ea8