From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794062833; b=VheyDhmm1v8CPC6bcEiKNLnXEtuyGlFyPsiqzC7u3y+hBaLMFTZkSp+nMYUq4hGW97vn QeYn2NQE/gcFZnu+7GpygKvuF8cckXy4xkV2OlY/cSLLBf5vg4+oB6yke7pMmrcbTC8mf Se8G9LMzHj3xhxV8BN+/3vhJMtnC92IBw9xqpZju5O3i8joLUMd6VY08MqNl4XOaEwiD1 urpKh5uBXf2vTFavihlOevJZD05QoPpfFU/j8U67kxclnk/PbyqMWlwpDrginW8wG/0tC RPdaHO+H7z8hoMCCDoYKKcp48oL3kVZEuOHeVknH4HCsfwDH/l2jtu44YHEwaFk+xvw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794062833; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=UrS4zz5LB3ixmeJQbmcxW50eaMvlqXww1ujpUkqpY7o=; b=N3TeI0eYeuwNuKE4pBOepRAl4f2OH50QENH/BHaM2BU7SFXkYpi6PVrntFSWHyQplqa2 5yE+gqQVRaRyBYkTndFHpSFSqzEcfyg6DeumL9NWojb06/Mi/RHaQnotlE8Xcvv7iTYcw +KsvDwupWITB6TtDquRzudK2Ic2ZZrMltXvp0jRZGB0jFkYSHChAgmQaA6UrNmFKFqMdx cVouO5hYDD3jhDP5r7/hMU3LCWcy2PMjMX+AjARPkOBBtbtERyOg7RByp5woGFNtTR6t5 /WVcOlfomB0f4dLyQy+R4sP+9gI1TZFNwTJJvOcvp8F4WNom1HVHZapTgDjxsSNJEpA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=ReBOlIBG; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C53C0606A334; Sat, 7 Nov 2026 14:47:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=ReBOlIBG Received: by smtp.kernel.org (Postfix) with ESMTPSA id EB7491F0089F; Sat, 7 Nov 2026 14:47:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1794062832; bh=UrS4zz5LB3ixmeJQbmcxW50eaMvlqXww1ujpUkqpY7o=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=ReBOlIBGtLKM4alcDGl8rwEWO+V2L6piZtVZYZOM6oCooR/kFtT2TSvUdYzKe/ZEm oBqOyZegQ7Q8f4tIUxBVJj+tqTBvIh/J73vYVITdhY4c/FpF1Zclnh1PgpHaVxZeUT UbOOLP7MQwLcBS1Avx1xZs5NfVtjmVknKHsrt964= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, syzbot+c7fc4794e59786f5b4dc@syzkaller.appspotmail.com, Jeffin Philip , Hans Verkuil , Sasha Levin Subject: [PATCH 6.18 088/869] media: vidtv: fix uaf in vidtv_bridge_on_new_pkts_avail Date: Sat, 7 Nov 2026 08:46:10 -0500 Message-ID: <20261107134855.715353458@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261107134852.069646174@linuxfoundation.org> References: <20261107134852.069646174@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jeffin Philip [ Upstream commit 2af02ccd048b77713695d7817cf645ca50bf349e ] Attempting to unbind a dvbdevice that is in the process of feeding data causes a UAF as we free the underlying device without stopping the feed first. Fix this by stopping the stream first using vidtv_stop_streaming(). However, our codepath in the reproducer (mentioned in the below reply) does not decrement our users (dmxdev->dvr_dvbdev->users) to 1 after it has been incremented to 2 by our read() in the reproducer, that is only possible on .release. This can cause a task hang as dvb_dmxdev_release() uses wait_event() in the wait_queue unless we use a close(fd)(in the reproducer). Is this a problem? Please advise. Reported-by: syzbot+c7fc4794e59786f5b4dc@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=c7fc4794e59786f5b4dc Fixes: f90cf6079bf6 ("media: vidtv: add a bridge driver") Cc: stable@vger.kernel.org Signed-off-by: Jeffin Philip Signed-off-by: Hans Verkuil Signed-off-by: Sasha Levin --- drivers/media/test-drivers/vidtv/vidtv_bridge.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/media/test-drivers/vidtv/vidtv_bridge.c b/drivers/media/test-drivers/vidtv/vidtv_bridge.c index d6b90290bd4dd..60310ece35302 100644 --- a/drivers/media/test-drivers/vidtv/vidtv_bridge.c +++ b/drivers/media/test-drivers/vidtv/vidtv_bridge.c @@ -551,6 +551,8 @@ static void vidtv_bridge_remove(struct platform_device *pdev) mutex_destroy(&dvb->feed_lock); + vidtv_stop_streaming(dvb); + for (i = 0; i < NUM_FE; ++i) { dvb_unregister_frontend(dvb->fe[i]); dvb_frontend_detach(dvb->fe[i]); -- 2.53.0