From 3bb2a01caa813d3a1845d378bbe4169ef280d394 Mon Sep 17 00:00:00 2001 From: Wang Hai Date: Tue, 20 Dec 2022 09:21:43 +0800 Subject: kobject: Fix slab-out-of-bounds in fill_kobj_path() 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 --- lib/kobject.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) (limited to 'lib/kobject.c') diff --git a/lib/kobject.c b/lib/kobject.c index 985ee1c4f2c6..d20ce15eec2d 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; } -- cgit v1.2.3 From dda6b81f17ad8e72f8bc151c876cd335a471e268 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Thomas=20Wei=C3=9Fschuh?= Date: Sat, 4 Feb 2023 21:59:50 +0000 Subject: kobject: make dynamic_kobj_ktype and kset_ktype const MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Since commit ee6d3dd4ed48 ("driver core: make kobj_type constant.") the driver core allows the usage of const struct kobj_type. Take advantage of this to constify the structure definitions to prevent modification at runtime. Signed-off-by: Thomas Weißschuh Link: https://lore.kernel.org/r/20230204-kobj_type-kobj-v1-1-ddd1b4ef8ab5@weissschuh.net Signed-off-by: Greg Kroah-Hartman --- lib/kobject.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'lib/kobject.c') diff --git a/lib/kobject.c b/lib/kobject.c index d20ce15eec2d..6e2f0bee3560 100644 --- a/lib/kobject.c +++ b/lib/kobject.c @@ -737,7 +737,7 @@ static void dynamic_kobj_release(struct kobject *kobj) kfree(kobj); } -static struct kobj_type dynamic_kobj_ktype = { +static const struct kobj_type dynamic_kobj_ktype = { .release = dynamic_kobj_release, .sysfs_ops = &kobj_sysfs_ops, }; @@ -921,7 +921,7 @@ static void kset_get_ownership(const struct kobject *kobj, kuid_t *uid, kgid_t * kobject_get_ownership(kobj->parent, uid, gid); } -static struct kobj_type kset_ktype = { +static const struct kobj_type kset_ktype = { .sysfs_ops = &kobj_sysfs_ops, .release = kset_release, .get_ownership = kset_get_ownership, -- cgit v1.2.3