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 X-Spam-Level: X-Spam-Status: No, score=-12.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 72869C63697 for ; Tue, 17 Nov 2020 13:10:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1FC432468F for ; Tue, 17 Nov 2020 13:10:30 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="oT5iSBee" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728975AbgKQNJ4 (ORCPT ); Tue, 17 Nov 2020 08:09:56 -0500 Received: from mail.kernel.org ([198.145.29.99]:38816 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728893AbgKQNJp (ORCPT ); Tue, 17 Nov 2020 08:09:45 -0500 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 77711246CD; Tue, 17 Nov 2020 13:09:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1605618585; bh=oAei7ARmQ4PjubjY81OMJ31y/uh0iQAxfq2TpidQzbQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=oT5iSBeeiumLXp56YUJkCm7AsjtVDN8sBDyf4DhuUcbUGTiDJ5+mN91M/BwBZ6HHe CHRJUA1onD7BENY4VyTFVyoczle4kV0QtQzIbOC0OHYM5dyx8qgiwco1Z2zLov3oCh 5JB9TuIHtn/F9V35dEWYjMykyOY6Rx5bbVWZ5P8I= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Linus Walleij , Elena Petrova , Will Deacon , Ben Hutchings , Sasha Levin Subject: [PATCH 4.9 18/78] pinctrl: devicetree: Avoid taking direct reference to device name string Date: Tue, 17 Nov 2020 14:04:44 +0100 Message-Id: <20201117122109.991915504@linuxfoundation.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201117122109.116890262@linuxfoundation.org> References: <20201117122109.116890262@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: Will Deacon commit be4c60b563edee3712d392aaeb0943a768df7023 upstream. When populating the pinctrl mapping table entries for a device, the 'dev_name' field for each entry is initialised to point directly at the string returned by 'dev_name()' for the device and subsequently used by 'create_pinctrl()' when looking up the mappings for the device being probed. This is unreliable in the presence of calls to 'dev_set_name()', which may reallocate the device name string leaving the pinctrl mappings with a dangling reference. This then leads to a use-after-free every time the name is dereferenced by a device probe: | BUG: KASAN: invalid-access in strcmp+0x20/0x64 | Read of size 1 at addr 13ffffc153494b00 by task modprobe/590 | Pointer tag: [13], memory tag: [fe] | | Call trace: | __kasan_report+0x16c/0x1dc | kasan_report+0x10/0x18 | check_memory_region | __hwasan_load1_noabort+0x4c/0x54 | strcmp+0x20/0x64 | create_pinctrl+0x18c/0x7f4 | pinctrl_get+0x90/0x114 | devm_pinctrl_get+0x44/0x98 | pinctrl_bind_pins+0x5c/0x450 | really_probe+0x1c8/0x9a4 | driver_probe_device+0x120/0x1d8 Follow the example of sysfs, and duplicate the device name string before stashing it away in the pinctrl mapping entries. Cc: Linus Walleij Reported-by: Elena Petrova Tested-by: Elena Petrova Signed-off-by: Will Deacon Link: https://lore.kernel.org/r/20191002124206.22928-1-will@kernel.org Signed-off-by: Linus Walleij [bwh: Backported to 4.9: adjust context] Signed-off-by: Ben Hutchings Signed-off-by: Sasha Levin --- drivers/pinctrl/devicetree.c | 26 ++++++++++++++++++++------ 1 file changed, 20 insertions(+), 6 deletions(-) diff --git a/drivers/pinctrl/devicetree.c b/drivers/pinctrl/devicetree.c index 54dad89fc9bfe..d32aedfc6dd03 100644 --- a/drivers/pinctrl/devicetree.c +++ b/drivers/pinctrl/devicetree.c @@ -40,6 +40,13 @@ struct pinctrl_dt_map { static void dt_free_map(struct pinctrl_dev *pctldev, struct pinctrl_map *map, unsigned num_maps) { + int i; + + for (i = 0; i < num_maps; ++i) { + kfree_const(map[i].dev_name); + map[i].dev_name = NULL; + } + if (pctldev) { const struct pinctrl_ops *ops = pctldev->desc->pctlops; ops->dt_free_map(pctldev, map, num_maps); @@ -73,7 +80,13 @@ static int dt_remember_or_free_map(struct pinctrl *p, const char *statename, /* Initialize common mapping table entry fields */ for (i = 0; i < num_maps; i++) { - map[i].dev_name = dev_name(p->dev); + const char *devname; + + devname = kstrdup_const(dev_name(p->dev), GFP_KERNEL); + if (!devname) + goto err_free_map; + + map[i].dev_name = devname; map[i].name = statename; if (pctldev) map[i].ctrl_dev_name = dev_name(pctldev->dev); @@ -81,11 +94,8 @@ static int dt_remember_or_free_map(struct pinctrl *p, const char *statename, /* Remember the converted mapping table entries */ dt_map = kzalloc(sizeof(*dt_map), GFP_KERNEL); - if (!dt_map) { - dev_err(p->dev, "failed to alloc struct pinctrl_dt_map\n"); - dt_free_map(pctldev, map, num_maps); - return -ENOMEM; - } + if (!dt_map) + goto err_free_map; dt_map->pctldev = pctldev; dt_map->map = map; @@ -93,6 +103,10 @@ static int dt_remember_or_free_map(struct pinctrl *p, const char *statename, list_add_tail(&dt_map->node, &p->dt_maps); return pinctrl_register_map(map, num_maps, false); + +err_free_map: + dt_free_map(pctldev, map, num_maps); + return -ENOMEM; } struct pinctrl_dev *of_pinctrl_get(struct device_node *np) -- 2.27.0