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 D3058C678D5 for ; Tue, 7 Mar 2023 17:37:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231935AbjCGRhn (ORCPT ); Tue, 7 Mar 2023 12:37:43 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38458 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231633AbjCGRhT (ORCPT ); Tue, 7 Mar 2023 12:37:19 -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 42C3B28235 for ; Tue, 7 Mar 2023 09:33:17 -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 C6A3361506 for ; Tue, 7 Mar 2023 17:33:16 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C56A9C433D2; Tue, 7 Mar 2023 17:33:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1678210396; bh=GdBlhJ/snvFCqOM2/O9UwlEjnaEQy6gCZehggfshJIo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=AnLoheKdVqxvx1pjrs1gkBQuSIxwWuRPVchFVdn0z2Td/WthxDf9wFoEsbf8VZuHy YlvlhnEjmh4k6+MRBLSZq/m5wXyLYjaeOfC8ySWw3iA5plKLu+IVfHwTnCEVMRxPVN zTqnGMwiozYzE/j0cBR+SSGxHuUzCEzAbd9+J2ac= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Wang Hai , Sasha Levin Subject: [PATCH 6.2 0496/1001] kobject: Fix slab-out-of-bounds in fill_kobj_path() Date: Tue, 7 Mar 2023 17:54:28 +0100 Message-Id: <20230307170042.910565233@linuxfoundation.org> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230307170022.094103862@linuxfoundation.org> References: <20230307170022.094103862@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: Wang Hai [ Upstream commit 3bb2a01caa813d3a1845d378bbe4169ef280d394 ] In kobject_get_path(), if kobj->name is changed between calls get_kobj_path_length() and fill_kobj_path() and the length becomes longer, then fill_kobj_path() will have an out-of-bounds bug. The actual current problem occurs when the ixgbe probe. In ixgbe_mii_bus_init(), if the length of netdev->dev.kobj.name length becomes longer, out-of-bounds will occur. cpu0 cpu1 ixgbe_probe register_netdev(netdev) netdev_register_kobject device_add kobject_uevent // Sending ADD events systemd-udevd // rename netdev dev_change_name device_rename kobject_rename ixgbe_mii_bus_init | mdiobus_register | __mdiobus_register | device_register | device_add | kobject_uevent | kobject_get_path | len = get_kobj_path_length // old name | path = kzalloc(len, gfp_mask); | kobj->name = name; /* name length becomes * longer */ fill_kobj_path /* kobj path length is * longer than path, * resulting in out of * bounds when filling path */ This is the kasan report: ================================================================== BUG: KASAN: slab-out-of-bounds in fill_kobj_path+0x50/0xc0 Write of size 7 at addr ff1100090573d1fd by task kworker/28:1/673 Workqueue: events work_for_cpu_fn Call Trace: dump_stack_lvl+0x34/0x48 print_address_description.constprop.0+0x86/0x1e7 print_report+0x36/0x4f kasan_report+0xad/0x130 kasan_check_range+0x35/0x1c0 memcpy+0x39/0x60 fill_kobj_path+0x50/0xc0 kobject_get_path+0x5a/0xc0 kobject_uevent_env+0x140/0x460 device_add+0x5c7/0x910 __mdiobus_register+0x14e/0x490 ixgbe_probe.cold+0x441/0x574 [ixgbe] local_pci_probe+0x78/0xc0 work_for_cpu_fn+0x26/0x40 process_one_work+0x3b6/0x6a0 worker_thread+0x368/0x520 kthread+0x165/0x1a0 ret_from_fork+0x1f/0x30 This reproducer triggers that bug: while: do rmmod ixgbe sleep 0.5 modprobe ixgbe sleep 0.5 When calling fill_kobj_path() to fill path, if the name length of kobj becomes longer, return failure and retry. This fixes the problem. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Wang Hai Link: https://lore.kernel.org/r/20221220012143.52141-1-wanghai38@huawei.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- lib/kobject.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/lib/kobject.c b/lib/kobject.c index 985ee1c4f2c60..d20ce15eec2d0 100644 --- a/lib/kobject.c +++ b/lib/kobject.c @@ -112,7 +112,7 @@ static int get_kobj_path_length(const struct kobject *kobj) return length; } -static void fill_kobj_path(const struct kobject *kobj, char *path, int length) +static int fill_kobj_path(const struct kobject *kobj, char *path, int length) { const struct kobject *parent; @@ -121,12 +121,16 @@ static void fill_kobj_path(const struct kobject *kobj, char *path, int length) int cur = strlen(kobject_name(parent)); /* back up enough to print this name with '/' */ length -= cur; + if (length <= 0) + return -EINVAL; memcpy(path + length, kobject_name(parent), cur); *(path + --length) = '/'; } pr_debug("kobject: '%s' (%p): %s: path = '%s'\n", kobject_name(kobj), kobj, __func__, path); + + return 0; } /** @@ -141,13 +145,17 @@ char *kobject_get_path(const struct kobject *kobj, gfp_t gfp_mask) char *path; int len; +retry: len = get_kobj_path_length(kobj); if (len == 0) return NULL; path = kzalloc(len, gfp_mask); if (!path) return NULL; - fill_kobj_path(kobj, path, len); + if (fill_kobj_path(kobj, path, len)) { + kfree(path); + goto retry; + } return path; } -- 2.39.2