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 414D5C46467 for ; Mon, 16 Jan 2023 17:19:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234509AbjAPRTO (ORCPT ); Mon, 16 Jan 2023 12:19:14 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45330 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234435AbjAPRSO (ORCPT ); Mon, 16 Jan 2023 12:18:14 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8D2FA2C663 for ; Mon, 16 Jan 2023 08:57:58 -0800 (PST) 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 B8A1C61055 for ; Mon, 16 Jan 2023 16:57:57 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C464EC433D2; Mon, 16 Jan 2023 16:57:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1673888277; bh=ermBIJuKq6MVNzmRSivKUMIfW6T7kHME4U41VF0/+iE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=FttSDPwXKyptUUDMibx1RBTYEu6kQ8i72MW4ldabkMTeEEDBnolYZLOjqytHtIxvi VuhBXyS9E38MNYsSjgxlWy3TTHCAfE3jJNNDNncNZhqDYMdOhQwV3v4hNjhN+bYQm9 bEinxFOKEAViGTPQ4Qu1DH+SZuYXAqcSN6FIsKU8= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Clement Lecigne , Takashi Iwai , Jaroslav Kysela , stable@kernel.org Subject: [PATCH 4.19 468/521] ALSA: pcm: Move rwsem lock inside snd_ctl_elem_read to prevent UAF Date: Mon, 16 Jan 2023 16:52:10 +0100 Message-Id: <20230116154908.118583798@linuxfoundation.org> X-Mailer: git-send-email 2.39.0 In-Reply-To: <20230116154847.246743274@linuxfoundation.org> References: <20230116154847.246743274@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Clement Lecigne [ Note: this is a fix that works around the bug equivalently as the two upstream commits: 1fa4445f9adf ("ALSA: control - introduce snd_ctl_notify_one() helper") 56b88b50565c ("ALSA: pcm: Move rwsem lock inside snd_ctl_elem_read to prevent UAF") but in a simpler way to fit with older stable trees -- tiwai ] Add missing locking in ctl_elem_read_user/ctl_elem_write_user which can be easily triggered and turned into an use-after-free. Example code paths with SNDRV_CTL_IOCTL_ELEM_READ: 64-bits: snd_ctl_ioctl snd_ctl_elem_read_user [takes controls_rwsem] snd_ctl_elem_read [lock properly held, all good] [drops controls_rwsem] 32-bits (compat): snd_ctl_ioctl_compat snd_ctl_elem_write_read_compat ctl_elem_write_read snd_ctl_elem_read [missing lock, not good] CVE-2023-0266 was assigned for this issue. Signed-off-by: Clement Lecigne Cc: stable@kernel.org # 5.12 and older Signed-off-by: Takashi Iwai Reviewed-by: Jaroslav Kysela Signed-off-by: Greg Kroah-Hartman --- sound/core/control_compat.c | 4 ++++ 1 file changed, 4 insertions(+) --- a/sound/core/control_compat.c +++ b/sound/core/control_compat.c @@ -319,7 +319,9 @@ static int ctl_elem_read_user(struct snd err = snd_power_wait(card, SNDRV_CTL_POWER_D0); if (err < 0) goto error; + down_read(&card->controls_rwsem); err = snd_ctl_elem_read(card, data); + up_read(&card->controls_rwsem); if (err < 0) goto error; err = copy_ctl_value_to_user(userdata, valuep, data, type, count); @@ -347,7 +349,9 @@ static int ctl_elem_write_user(struct sn err = snd_power_wait(card, SNDRV_CTL_POWER_D0); if (err < 0) goto error; + down_write(&card->controls_rwsem); err = snd_ctl_elem_write(card, file, data); + up_write(&card->controls_rwsem); if (err < 0) goto error; err = copy_ctl_value_to_user(userdata, valuep, data, type, count);