This is a note to let you know that I've just added the patch titled
class: fix use-after-free in class_register()
to the 6.6-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-use-after-free-in-class_register.patch
and it can be found in the queue-6.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 93ec4a3b76404bce01bd5c9032bef5df6feb1d62 Mon Sep 17 00:00:00 2001
From: Jing Xia <jing.xia@xxxxxxxxxx>
Date: Wed, 20 Dec 2023 10:46:03 +0800
Subject: class: fix use-after-free in class_register()
From: Jing Xia <jing.xia@xxxxxxxxxx>
commit 93ec4a3b76404bce01bd5c9032bef5df6feb1d62 upstream.
The lock_class_key is still registered and can be found in
lock_keys_hash hlist after subsys_private is freed in error
handler path.A task who iterate over the lock_keys_hash
later may cause use-after-free.So fix that up and unregister
the lock_class_key before kfree(cp).
On our platform, a driver fails to kset_register because of
creating duplicate filename '/class/xxx'.With Kasan enabled,
it prints a invalid-access bug report.
KASAN bug report:
BUG: KASAN: invalid-access in lockdep_register_key+0x19c/0x1bc
Write of size 8 at addr 15ffff808b8c0368 by task modprobe/252
Pointer tag: [15], memory tag: [fe]
CPU: 7 PID: 252 Comm: modprobe Tainted: G W
6.6.0-mainline-maybe-dirty #1
Call trace:
dump_backtrace+0x1b0/0x1e4
show_stack+0x2c/0x40
dump_stack_lvl+0xac/0xe0
print_report+0x18c/0x4d8
kasan_report+0xe8/0x148
__hwasan_store8_noabort+0x88/0x98
lockdep_register_key+0x19c/0x1bc
class_register+0x94/0x1ec
init_module+0xbc/0xf48 [rfkill]
do_one_initcall+0x17c/0x72c
do_init_module+0x19c/0x3f8
..
Memory state around the buggy address:
ffffff808b8c0100: 8a 8a 8a 8a 8a 8a 8a 8a 8a 8a 8a 8a 8a 8a 8a 8a
ffffff808b8c0200: 8a 8a 8a 8a 8a 8a 8a 8a fe fe fe fe fe fe fe fe
>ffffff808b8c0300: fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe
^
ffffff808b8c0400: 03 03 03 03 03 03 03 03 03 03 03 03 03 03 03 03
As CONFIG_KASAN_GENERIC is not set, Kasan reports invalid-access
not use-after-free here.In this case, modprobe is manipulating
the corrupted lock_keys_hash hlish where lock_class_key is already
freed before.
It's worth noting that this only can happen if lockdep is enabled,
which is not true for normal system.
Fixes: dcfbb67e48a2 ("driver core: class: use lock_class_key already present in struct subsys_private")
Cc: stable <stable@xxxxxxxxxx>
Signed-off-by: Jing Xia <jing.xia@xxxxxxxxxx>
Signed-off-by: Xuewen Yan <xuewen.yan@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20231220024603.186078-1-jing.xia@xxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/base/class.c | 1 +
1 file changed, 1 insertion(+)
--- a/drivers/base/class.c
+++ b/drivers/base/class.c
@@ -215,6 +215,7 @@ int class_register(const struct class *c
return 0;
err_out:
+ lockdep_unregister_key(key);
kfree(cp);
return error;
}
Patches currently in stable-queue which might be from jing.xia@xxxxxxxxxx are
queue-6.6/class-fix-use-after-free-in-class_register.patch
