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From 965275cd87f8008f129509c6d6fd0096e8ac2d96 Mon Sep 17 00:00:00 2001
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From: =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= <marcandre.lureau@redhat.com>
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Date: Mon, 14 Feb 2022 15:59:17 +0400
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Subject: [PATCH 3/6] ui/clipboard: fix use-after-free regression
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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RH-Author: Gerd Hoffmann <kraxel@redhat.com>
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RH-MergeRequest: 75: fix vnc cut+paste crash
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RH-Commit: [3/4] d8f68e0eb60d9aaa9a703d969f215816bf35f6f0 (kraxel/centos-qemu-kvm)
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RH-Bugzilla: 2042820
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RH-Acked-by: Marc-André Lureau <marcandre.lureau@redhat.com>
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RH-Acked-by: Daniel P. Berrangé <berrange@redhat.com>
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RH-Acked-by: Miroslav Rezanina <mrezanin@redhat.com>
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The same info may be used to update the clipboard, and may be freed
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before being ref'ed again.
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Fixes: 70a54b01693ed ("ui: avoid compiler warnings from unused clipboard info variable")
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Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
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Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
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Message-Id: <20220214115917.1679568-1-marcandre.lureau@redhat.com>
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Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
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---
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 ui/clipboard.c | 6 ++++--
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 1 file changed, 4 insertions(+), 2 deletions(-)
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diff --git a/ui/clipboard.c b/ui/clipboard.c
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index 7672058e84..d7dae13760 100644
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--- a/ui/clipboard.c
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+++ b/ui/clipboard.c
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@@ -48,8 +48,10 @@ void qemu_clipboard_update(QemuClipboardInfo *info)
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     notifier_list_notify(&clipboard_notifiers, info);
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-    qemu_clipboard_info_unref(cbinfo[info->selection]);
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-    cbinfo[info->selection] = qemu_clipboard_info_ref(info);
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+    if (cbinfo[info->selection] != info) {
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+        qemu_clipboard_info_unref(cbinfo[info->selection]);
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+        cbinfo[info->selection] = qemu_clipboard_info_ref(info);
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+    }
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 }
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 QemuClipboardInfo *qemu_clipboard_info(QemuClipboardSelection selection)
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-- 
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2.27.0
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