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USB: gadget: Fix use-after-free during usb config switch

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In the process of switching USB config from rndis to other config,
if the hardware does not support the ->pullup callback, or the
hardware encounters a low probability fault, both of them may cause
the ->pullup callback to fail, which will then cause a system panic
(use after free).

The gadget drivers sometimes need to be unloaded regardless of the
hardware's behavior.

Analysis as follows:
=======================================================================
(1) write /config/usb_gadget/g1/UDC "none"

gether_disconnect+0x2c/0x1f8
rndis_disable+0x4c/0x74
composite_disconnect+0x74/0xb0
configfs_composite_disconnect+0x60/0x7c
usb_gadget_disconnect+0x70/0x124
usb_gadget_unregister_driver+0xc8/0x1d8
gadget_dev_desc_UDC_store+0xec/0x1e4

(2) rm /config/usb_gadget/g1/configs/b.1/f1

rndis_deregister+0x28/0x54
rndis_free+0x44/0x7c
usb_put_function+0x14/0x1c
config_usb_cfg_unlink+0xc4/0xe0
configfs_unlink+0x124/0x1c8
vfs_unlink+0x114/0x1dc

(3) rmdir /config/usb_gadget/g1/functions/rndis.gs4

panic+0x1fc/0x3d0
do_page_fault+0xa8/0x46c
do_mem_abort+0x3c/0xac
el1_sync_handler+0x40/0x78
0xffffff801138f880
rndis_close+0x28/0x34
eth_stop+0x74/0x110
dev_close_many+0x48/0x194
rollback_registered_many+0x118/0x814
unregister_netdev+0x20/0x30
gether_cleanup+0x1c/0x38
rndis_attr_release+0xc/0x14
kref_put+0x74/0xb8
configfs_rmdir+0x314/0x374

If gadget->ops->pullup() return an error, function rndis_close() will be
called, then it will causes a use-after-free problem.
=======================================================================

Fixes: 0a55187a1e ("USB: gadget core: Issue ->disconnect() callback from usb_gadget_disconnect()")
Signed-off-by: Jiantao Zhang <water.zhangjiantao@huawei.com>
Signed-off-by: TaoXue <xuetao09@huawei.com>
Link: https://lore.kernel.org/r/20221121130805.10735-1-water.zhangjiantao@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Jiantao Zhang 2022-11-21 13:08:05 +00:00 committed by Greg Kroah-Hartman
parent 581c848b61
commit afdc12887f
1 changed files with 6 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
drivers/usb/gadget/udc/core.c
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@ -734,13 +734,13 @@ int usb_gadget_disconnect(struct usb_gadget *gadget)
}
ret = gadget->ops->pullup(gadget, 0);
if (!ret) {
if (!ret)
gadget->connected = 0;
mutex_lock(&udc_lock);
if (gadget->udc->driver)
gadget->udc->driver->disconnect(gadget);
mutex_unlock(&udc_lock);
}
mutex_lock(&udc_lock);
if (gadget->udc->driver)
gadget->udc->driver->disconnect(gadget);
mutex_unlock(&udc_lock);
out:
trace_usb_gadget_disconnect(gadget, ret);