From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id CE8C9C7EE29 for ; Thu, 25 May 2023 18:47:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242810AbjEYSrZ (ORCPT ); Thu, 25 May 2023 14:47:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33958 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242607AbjEYSoy (ORCPT ); Thu, 25 May 2023 14:44:54 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F1003E7A; Thu, 25 May 2023 11:41:06 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id D790860BD4; Thu, 25 May 2023 18:40:12 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3D922C433D2; Thu, 25 May 2023 18:40:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1685040012; bh=MTeMm/00dl6GcC+szTUjiyco7o/tEkA6zATOo5g29Rk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=VpQaP1hb9heMSm2N3xfvA2dNkq/m37HfEoaAub0ql6Fem/wJI+OW3SaYvlZqy2ozC jn6Yf0ehfQQ2RzIOmnp5MCpl6uTOG/R7E/zjDPzrC716zfWKpM0C+0HNpi9/aKsZRk 0wl2D7xgeoq8uyZTJETFupI5+m3AQmyjhap3pN6bubTwxUUr4PpJnWuu1YbPdsi22z DMqXsrOeSkkMRIYpYFlwIMf+Y+1SfiLIQhMvARhvr9u4RJIdH0ADUjVYA5IJRiVVsP TyvUMeZeTQuBfWsDT5Tq6Tt8PgFW56qdlC2DKyUJj+DCdHD8GzuY2pwXJob8XmLg4S QrlcY0ixr1qrg== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Takashi Iwai , Yu Hao , Mauro Carvalho Chehab , Sasha Levin , robert_s@gmx.net, imv4bel@gmail.com, chenzhongjin@huawei.com, linma@zju.edu.cn, linux-media@vger.kernel.org Subject: [PATCH AUTOSEL 5.15 22/43] media: dvb-core: Fix kernel WARNING for blocking operation in wait_event*() Date: Thu, 25 May 2023 14:38:33 -0400 Message-Id: <20230525183854.1855431-22-sashal@kernel.org> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230525183854.1855431-1-sashal@kernel.org> References: <20230525183854.1855431-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Takashi Iwai [ Upstream commit b8c75e4a1b325ea0a9433fa8834be97b5836b946 ] Using a semaphore in the wait_event*() condition is no good idea. It hits a kernel WARN_ON() at prepare_to_wait_event() like: do not call blocking ops when !TASK_RUNNING; state=1 set at prepare_to_wait_event+0x6d/0x690 For avoiding the potential deadlock, rewrite to an open-coded loop instead. Unlike the loop in wait_event*(), this uses wait_woken() after the condition check, hence the task state stays consistent. CVE-2023-31084 was assigned to this bug. Link: https://lore.kernel.org/r/CA+UBctCu7fXn4q41O_3=id1+OdyQ85tZY1x+TkT-6OVBL6KAUw@mail.gmail.com/ Link: https://lore.kernel.org/linux-media/20230512151800.1874-1-tiwai@suse.de Reported-by: Yu Hao Closes: https://nvd.nist.gov/vuln/detail/CVE-2023-31084 Signed-off-by: Takashi Iwai Signed-off-by: Mauro Carvalho Chehab Signed-off-by: Sasha Levin --- drivers/media/dvb-core/dvb_frontend.c | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-) diff --git a/drivers/media/dvb-core/dvb_frontend.c b/drivers/media/dvb-core/dvb_frontend.c index 09facc78d88aa..fea62bce97468 100644 --- a/drivers/media/dvb-core/dvb_frontend.c +++ b/drivers/media/dvb-core/dvb_frontend.c @@ -293,14 +293,22 @@ static int dvb_frontend_get_event(struct dvb_frontend *fe, } if (events->eventw == events->eventr) { - int ret; + struct wait_queue_entry wait; + int ret = 0; if (flags & O_NONBLOCK) return -EWOULDBLOCK; - ret = wait_event_interruptible(events->wait_queue, - dvb_frontend_test_event(fepriv, events)); - + init_waitqueue_entry(&wait, current); + add_wait_queue(&events->wait_queue, &wait); + while (!dvb_frontend_test_event(fepriv, events)) { + wait_woken(&wait, TASK_INTERRUPTIBLE, 0); + if (signal_pending(current)) { + ret = -ERESTARTSYS; + break; + } + } + remove_wait_queue(&events->wait_queue, &wait); if (ret < 0) return ret; } -- 2.39.2