| Message ID | 20221121130805.10735-1-water.zhangjiantao@huawei.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | afdc12887f2b2ecf20d065a7d81ad29824155083 |
| Headers | show |
| Series | [v4] USB: gadget: Fix use-after-free during usb config switch | expand |
diff --git a/drivers/usb/gadget/udc/core.c b/drivers/usb/gadget/udc/core.c index c63c0c2cf649..bf9878e1a72a 100644 --- a/drivers/usb/gadget/udc/core.c +++ b/drivers/usb/gadget/udc/core.c @@ -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);
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: 0a55187a1ec8 ("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> --- V3 -> V4: Solved format and mailbox configuration issues. V2 -> V3: Solved the format issues of Fixes and backtraces. V1 -> V2: V1 will affect the original function, V2 just move the callback after "if" statement, so that the original function will not be affected. And fixed formatting issues. drivers/usb/gadget/udc/core.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-)