The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From e9e6aa51b2735d83a67d9fa0119cf11abef80d99 Mon Sep 17 00:00:00 2001

From: Pavel Skripkin paskripkin@gmail.com Date: Wed, 21 Jul 2021 22:34:47 +0300 Subject: [PATCH] staging: rtl8712: error handling refactoring

There was strange error handling logic in case of fw load failure. For some reason fw loader callback was doing clean up stuff when fw is not available. I don't see any reason behind doing this. Since this driver doesn't have EEPROM firmware let's just disconnect it in case of fw load failure. Doing clean up stuff in 2 different place which can run concurently is not good idea and syzbot found 2 bugs related to this strange approach.

So, in this pacth I deleted all clean up code from fw callback and made a call to device_release_driver() under device_lock(parent) in case of fw load failure. This approach is more generic and it defend driver from UAF bugs, since all clean up code is moved to one place.

Fixes: e02a3b945816 ("staging: rtl8712: fix memory leak in rtl871x_load_fw_cb") Fixes: 8c213fa59199 ("staging: r8712u: Use asynchronous firmware loading") Cc: stable stable@vger.kernel.org Reported-and-tested-by: syzbot+5872a520e0ce0a7c7230@syzkaller.appspotmail.com Reported-and-tested-by: syzbot+cc699626e48a6ebaf295@syzkaller.appspotmail.com Signed-off-by: Pavel Skripkin paskripkin@gmail.com Link: https://lore.kernel.org/r/d49ecc56e97c4df181d7bd4d240b031f315eacc3.162689591... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

diff --git a/drivers/staging/rtl8712/hal_init.c b/drivers/staging/rtl8712/hal_init.c index 22974277afa0..4eff3fdecdb8 100644 --- a/drivers/staging/rtl8712/hal_init.c +++ b/drivers/staging/rtl8712/hal_init.c @@ -29,21 +29,31 @@ #define FWBUFF_ALIGN_SZ 512 #define MAX_DUMP_FWSZ (48 * 1024)

+static void rtl871x_load_fw_fail(struct _adapter *adapter) +{ + struct usb_device *udev = adapter->dvobjpriv.pusbdev; + struct device *dev = &udev->dev; + struct device *parent = dev->parent; + + complete(&adapter->rtl8712_fw_ready); + + dev_err(&udev->dev, "r8712u: Firmware request failed\n"); + + if (parent) + device_lock(parent); + + device_release_driver(dev); + + if (parent) + device_unlock(parent); +} + static void rtl871x_load_fw_cb(const struct firmware *firmware, void *context) { struct _adapter *adapter = context;

if (!firmware) { - struct usb_device *udev = adapter->dvobjpriv.pusbdev; - struct usb_interface *usb_intf = adapter->pusb_intf; - - dev_err(&udev->dev, "r8712u: Firmware request failed\n"); - usb_put_dev(udev); - usb_set_intfdata(usb_intf, NULL); - r8712_free_drv_sw(adapter); - adapter->dvobj_deinit(adapter); - complete(&adapter->rtl8712_fw_ready); - free_netdev(adapter->pnetdev); + rtl871x_load_fw_fail(adapter); return; } adapter->fw = firmware; diff --git a/drivers/staging/rtl8712/usb_intf.c b/drivers/staging/rtl8712/usb_intf.c index 643f21eb1128..505ebeb643dc 100644 --- a/drivers/staging/rtl8712/usb_intf.c +++ b/drivers/staging/rtl8712/usb_intf.c @@ -591,36 +591,30 @@ static void r871xu_dev_remove(struct usb_interface *pusb_intf) { struct net_device *pnetdev = usb_get_intfdata(pusb_intf); struct usb_device *udev = interface_to_usbdev(pusb_intf); + struct _adapter *padapter = netdev_priv(pnetdev); + + /* never exit with a firmware callback pending */ + wait_for_completion(&padapter->rtl8712_fw_ready); + usb_set_intfdata(pusb_intf, NULL); + release_firmware(padapter->fw); + if (drvpriv.drv_registered) + padapter->surprise_removed = true; + if (pnetdev->reg_state != NETREG_UNINITIALIZED) + unregister_netdev(pnetdev); /* will call netdev_close() */ + r8712_flush_rwctrl_works(padapter); + r8712_flush_led_works(padapter); + udelay(1); + /* Stop driver mlme relation timer */ + r8712_stop_drv_timers(padapter); + r871x_dev_unload(padapter); + r8712_free_drv_sw(padapter); + free_netdev(pnetdev); + + /* decrease the reference count of the usb device structure + * when disconnect + */ + usb_put_dev(udev);

- if (pnetdev) { - struct _adapter *padapter = netdev_priv(pnetdev); - - /* never exit with a firmware callback pending */ - wait_for_completion(&padapter->rtl8712_fw_ready); - pnetdev = usb_get_intfdata(pusb_intf); - usb_set_intfdata(pusb_intf, NULL); - if (!pnetdev) - goto firmware_load_fail; - release_firmware(padapter->fw); - if (drvpriv.drv_registered) - padapter->surprise_removed = true; - if (pnetdev->reg_state != NETREG_UNINITIALIZED) - unregister_netdev(pnetdev); /* will call netdev_close() */ - r8712_flush_rwctrl_works(padapter); - r8712_flush_led_works(padapter); - udelay(1); - /* Stop driver mlme relation timer */ - r8712_stop_drv_timers(padapter); - r871x_dev_unload(padapter); - r8712_free_drv_sw(padapter); - free_netdev(pnetdev); - - /* decrease the reference count of the usb device structure - * when disconnect - */ - usb_put_dev(udev); - } -firmware_load_fail: /* If we didn't unplug usb dongle and remove/insert module, driver * fails on sitesurvey for the first time when device is up. * Reset usb port for sitesurvey fail issue.