Re: [PATCH 1/1] RDMA/core: Fix "KASAN: slab-use-after-free Read in ib_register_device" problem

[Zhu Yanjun <yanjun.zhu@linux.dev>]

在 2025/5/5 19:31, Leon Romanovsky 写道:
> On Thu, May 01, 2025 at 12:36:02PM +0200, Zhu Yanjun wrote:
>> Call Trace:
>>
>>   __dump_stack lib/dump_stack.c:94 [inline]
>>   dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
>>   print_address_description mm/kasan/report.c:408 [inline]
>>   print_report+0xc3/0x670 mm/kasan/report.c:521
>>   kasan_report+0xe0/0x110 mm/kasan/report.c:634
>>   strlen+0x93/0xa0 lib/string.c:420
>>   __fortify_strlen include/linux/fortify-string.h:268 [inline]
>>   get_kobj_path_length lib/kobject.c:118 [inline]
>>   kobject_get_path+0x3f/0x2a0 lib/kobject.c:158
>>   kobject_uevent_env+0x289/0x1870 lib/kobject_uevent.c:545
>>   ib_register_device drivers/infiniband/core/device.c:1472 [inline]
>>   ib_register_device+0x8cf/0xe00 drivers/infiniband/core/device.c:1393
>>   rxe_register_device+0x275/0x320 drivers/infiniband/sw/rxe/rxe_verbs.c:1552
>>   rxe_net_add+0x8e/0xe0 drivers/infiniband/sw/rxe/rxe_net.c:550
>>   rxe_newlink+0x70/0x190 drivers/infiniband/sw/rxe/rxe.c:225
>>   nldev_newlink+0x3a3/0x680 drivers/infiniband/core/nldev.c:1796
>>   rdma_nl_rcv_msg+0x387/0x6e0 drivers/infiniband/core/netlink.c:195
>>   rdma_nl_rcv_skb.constprop.0.isra.0+0x2e5/0x450
>>   netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline]
>>   netlink_unicast+0x53a/0x7f0 net/netlink/af_netlink.c:1339
>>   netlink_sendmsg+0x8d1/0xdd0 net/netlink/af_netlink.c:1883
>>   sock_sendmsg_nosec net/socket.c:712 [inline]
>>   __sock_sendmsg net/socket.c:727 [inline]
>>   ____sys_sendmsg+0xa95/0xc70 net/socket.c:2566
>>   ___sys_sendmsg+0x134/0x1d0 net/socket.c:2620
>>   __sys_sendmsg+0x16d/0x220 net/socket.c:2652
>>   do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
>>   do_syscall_64+0xcd/0x260 arch/x86/entry/syscall_64.c:94
>>   entry_SYSCALL_64_after_hwframe+0x77/0x7f
>>
>> This problem is similar to the problem that the commit
>> 1d6a9e7449e2 ("RDMA/core: Fix use-after-free when rename device name")
>> fixes.
>>
>> The root cause is: the function ib_device_rename renames the name with
>> lock. But in the function kobject_uevent, this name is accessed without
>> lock protection at the same time.
>>
>> The solution is to add the lock protection when this name is accessed in
>> the function kobject_uevent.
>>
>> Fixes: 779e0bf47632 ("RDMA/core: Do not indicate device ready when device enablement fails")
>> Reported-by: syzbot+e2ce9e275ecc70a30b72@syzkaller.appspotmail.com
>> Closes: https://syzkaller.appspot.com/bug?extid=e2ce9e275ecc70a30b72
>> Signed-off-by: Zhu Yanjun <yanjun.zhu@linux.dev>
>> ---
>>   drivers/infiniband/core/device.c | 4 ++++
>>   1 file changed, 4 insertions(+)
>>
>> diff --git a/drivers/infiniband/core/device.c b/drivers/infiniband/core/device.c
>> index b4e3e4beb7f4..59d84829dd66 100644
>> --- a/drivers/infiniband/core/device.c
>> +++ b/drivers/infiniband/core/device.c
>> @@ -1468,8 +1468,12 @@ int ib_register_device(struct ib_device *device, const char *name,
>>   		return ret;
>>   	}
>>   	dev_set_uevent_suppress(&device->dev, false);
>> +
>> +	/* device->dev.kobj->name should be protected by devices_rwsem */
>> +	down_read(&devices_rwsem);
>>   	/* Mark for userspace that device is ready */
>>   	kobject_uevent(&device->dev.kobj, KOBJ_ADD);
>> +	up_read(&devices_rwsem);
>>   
>>   	ib_device_notify_register(device);
> The change looks right to me, but I would ask you to put
> kobject_uevent() into ib_device_notify_register() instead of adding
> rwsem. It will ensure that both uevent and netlink will get same name.

Got it. Will do.

I will send out the latest very soon.

Zhu Yanjun

>
> Thanks
>
>>   	ib_device_put(device);
>> -- 
>> 2.34.1
>>
>>
-- 
Best Regards,
Yanjun.Zhu