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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 13023C4332F for ; Mon, 4 Oct 2021 13:12:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E7CE06320E for ; Mon, 4 Oct 2021 13:12:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235287AbhJDNOK (ORCPT ); Mon, 4 Oct 2021 09:14:10 -0400 Received: from mail.kernel.org ([198.145.29.99]:47450 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235878AbhJDNLo (ORCPT ); Mon, 4 Oct 2021 09:11:44 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 2610661B71; Mon, 4 Oct 2021 13:04:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1633352673; bh=r3o2RCWkW/45aVMhlbCjcIRd4LXHGCu7gTCngs+oZPw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=2MG4WNF07tpGs1lVI3JC4ff/bvIzxR3l1HZx70wSoBLB9Nn3KwWr3S10Y1gzbZ6nB 1KIwCMp4apW6PK87k1Fxdyv3hB+LfHZd044kXxKNCKBjyB9yySbh2cLtijSrZOvZAn DJ6D7vRESHhUQ1slGdcST2Jtk4vaJ6Ym0YnGvh30= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Samuel Iglesias Gonsalvez , Johan Hovold Subject: [PATCH 4.19 76/95] ipack: ipoctal: fix stack information leak Date: Mon, 4 Oct 2021 14:52:46 +0200 Message-Id: <20211004125036.061004958@linuxfoundation.org> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20211004125033.572932188@linuxfoundation.org> References: <20211004125033.572932188@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Johan Hovold commit a89936cce87d60766a75732a9e7e25c51164f47c upstream. The tty driver name is used also after registering the driver and must specifically not be allocated on the stack to avoid leaking information to user space (or triggering an oops). Drivers should not try to encode topology information in the tty device name but this one snuck in through staging without anyone noticing and another driver has since copied this malpractice. Fixing the ABI is a separate issue, but this at least plugs the security hole. Fixes: ba4dc61fe8c5 ("Staging: ipack: add support for IP-OCTAL mezzanine board") Cc: stable@vger.kernel.org # 3.5 Acked-by: Samuel Iglesias Gonsalvez Signed-off-by: Johan Hovold Link: https://lore.kernel.org/r/20210917114622.5412-2-johan@kernel.org Signed-off-by: Greg Kroah-Hartman --- drivers/ipack/devices/ipoctal.c | 19 ++++++++++++++----- 1 file changed, 14 insertions(+), 5 deletions(-) --- a/drivers/ipack/devices/ipoctal.c +++ b/drivers/ipack/devices/ipoctal.c @@ -269,7 +269,6 @@ static int ipoctal_inst_slot(struct ipoc int res; int i; struct tty_driver *tty; - char name[20]; struct ipoctal_channel *channel; struct ipack_region *region; void __iomem *addr; @@ -360,8 +359,11 @@ static int ipoctal_inst_slot(struct ipoc /* Fill struct tty_driver with ipoctal data */ tty->owner = THIS_MODULE; tty->driver_name = KBUILD_MODNAME; - sprintf(name, KBUILD_MODNAME ".%d.%d.", bus_nr, slot); - tty->name = name; + tty->name = kasprintf(GFP_KERNEL, KBUILD_MODNAME ".%d.%d.", bus_nr, slot); + if (!tty->name) { + res = -ENOMEM; + goto err_put_driver; + } tty->major = 0; tty->minor_start = 0; @@ -377,8 +379,7 @@ static int ipoctal_inst_slot(struct ipoc res = tty_register_driver(tty); if (res) { dev_err(&ipoctal->dev->dev, "Can't register tty driver.\n"); - put_tty_driver(tty); - return res; + goto err_free_name; } /* Save struct tty_driver for use it when uninstalling the device */ @@ -415,6 +416,13 @@ static int ipoctal_inst_slot(struct ipoc ipoctal_irq_handler, ipoctal); return 0; + +err_free_name: + kfree(tty->name); +err_put_driver: + put_tty_driver(tty); + + return res; } static inline int ipoctal_copy_write_buffer(struct ipoctal_channel *channel, @@ -703,6 +711,7 @@ static void __ipoctal_remove(struct ipoc } tty_unregister_driver(ipoctal->tty_drv); + kfree(ipoctal->tty_drv->name); put_tty_driver(ipoctal->tty_drv); kfree(ipoctal); }