From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E9BF2200A5 for ; Mon, 6 Nov 2023 13:05:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="FKk5k51n" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 667D6C433C8; Mon, 6 Nov 2023 13:05:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1699275945; bh=MJrbKStsnbV385cTdSvn5fw0jW7qqWEjNM1fQfQqvCo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=FKk5k51ncHqlAqmEikIu+1oyElWWtOTOvtqc+qhaRyiqbPQmIQauYfg4vV8UTUXpR Qgy/Utr79/T51LJyZDfxFbudiKmrlSIKkAvi0aRfM0BOTthzhygn5VbGgXBZ42GVUt q72UNO+MtDpL8NkyfecrrbfjBvJDDnCZk6zlhxss= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Wang Hai , Oleksandr Tymoshenko Subject: [PATCH 4.14 17/48] kobject: Fix slab-out-of-bounds in fill_kobj_path() Date: Mon, 6 Nov 2023 14:03:08 +0100 Message-ID: <20231106130258.445487114@linuxfoundation.org> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20231106130257.862199836@linuxfoundation.org> References: <20231106130257.862199836@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Wang Hai commit 3bb2a01caa813d3a1845d378bbe4169ef280d394 upstream. 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: Oleksandr Tymoshenko Signed-off-by: Greg Kroah-Hartman --- lib/kobject.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) --- a/lib/kobject.c +++ b/lib/kobject.c @@ -118,7 +118,7 @@ static int get_kobj_path_length(struct k return length; } -static void fill_kobj_path(struct kobject *kobj, char *path, int length) +static int fill_kobj_path(struct kobject *kobj, char *path, int length) { struct kobject *parent; @@ -127,12 +127,16 @@ static void fill_kobj_path(struct kobjec 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; } /** @@ -148,13 +152,17 @@ char *kobject_get_path(struct kobject *k 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; }