This is a note to let you know that I've just added the patch titled
class: fix possible memory leak in __class_register()
to the 4.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
class-fix-possible-memory-leak-in-__class_register.patch
and it can be found in the queue-4.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 958af88b67a2973387f54dfef40f932f604e5cd3
Author: Yang Yingliang <yangyingliang@xxxxxxxxxx>
Date: Wed Oct 26 16:28:03 2022 +0800
class: fix possible memory leak in __class_register()
[ Upstream commit 8c3e8a6bdb5253b97ad532570f8b5db5f7a06407 ]
If class_add_groups() returns error, the 'cp->subsys' need be
unregister, and the 'cp' need be freed.
We can not call kset_unregister() here, because the 'cls' will
be freed in callback function class_release() and it's also
freed in caller's error path, it will cause double free.
So fix this by calling kobject_del() and kfree_const(name) to
cleanup kobject. Besides, call kfree() to free the 'cp'.
Fault injection test can trigger this:
unreferenced object 0xffff888102fa8190 (size 8):
comm "modprobe", pid 502, jiffies 4294906074 (age 49.296s)
hex dump (first 8 bytes):
70 6b 74 63 64 76 64 00 pktcdvd.
backtrace:
[<00000000e7c7703d>] __kmalloc_track_caller+0x1ae/0x320
[<000000005e4d70bc>] kstrdup+0x3a/0x70
[<00000000c2e5e85a>] kstrdup_const+0x68/0x80
[<000000000049a8c7>] kvasprintf_const+0x10b/0x190
[<0000000029123163>] kobject_set_name_vargs+0x56/0x150
[<00000000747219c9>] kobject_set_name+0xab/0xe0
[<0000000005f1ea4e>] __class_register+0x15c/0x49a
unreferenced object 0xffff888037274000 (size 1024):
comm "modprobe", pid 502, jiffies 4294906074 (age 49.296s)
hex dump (first 32 bytes):
00 40 27 37 80 88 ff ff 00 40 27 37 80 88 ff ff .@'7.....@'7....
00 00 00 00 ad 4e ad de ff ff ff ff 00 00 00 00 .....N..........
backtrace:
[<00000000151f9600>] kmem_cache_alloc_trace+0x17c/0x2f0
[<00000000ecf3dd95>] __class_register+0x86/0x49a
Fixes: ced6473e7486 ("driver core: class: add class_groups support")
Signed-off-by: Yang Yingliang <yangyingliang@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20221026082803.3458760-1-yangyingliang@xxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/base/class.c b/drivers/base/class.c
index 52eb8e644acd..93f22fba0d5c 100644
--- a/drivers/base/class.c
+++ b/drivers/base/class.c
@@ -187,6 +187,11 @@ int __class_register(struct class *cls, struct lock_class_key *key)
}
error = class_add_groups(class_get(cls), cls->class_groups);
class_put(cls);
+ if (error) {
+ kobject_del(&cp->subsys.kobj);
+ kfree_const(cp->subsys.kobj.name);
+ kfree(cp);
+ }
return error;
}
EXPORT_SYMBOL_GPL(__class_register);
