6.6-stable review patch. If anyone has any objections, please let me know.
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From: Jing Xia jing.xia@unisoc.com
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@kernel.org Signed-off-by: Jing Xia jing.xia@unisoc.com Signed-off-by: Xuewen Yan xuewen.yan@unisoc.com Link: https://lore.kernel.org/r/20231220024603.186078-1-jing.xia@unisoc.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- 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; }