Patch "staging: rtl8712: fix memory leak in rtl871x_load_fw_cb" has been added to the 5.13-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    staging: rtl8712: fix memory leak in rtl871x_load_fw_cb

to the 5.13-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     staging-rtl8712-fix-memory-leak-in-rtl871x_load_fw_c.patch
and it can be found in the queue-5.13 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit e460d54cebc21069d6259556e46c209ec4feb059
Author: Pavel Skripkin <paskripkin@xxxxxxxxx>
Date:   Mon Jun 14 01:00:19 2021 +0300

    staging: rtl8712: fix memory leak in rtl871x_load_fw_cb
    
    [ Upstream commit e02a3b945816a77702a2769a70ef5f9b06e49d54 ]
    
    There is a leak in rtl8712 driver.
    The problem was in non-freed adapter data if
    firmware load failed.
    
    This leak can be reproduced with this code:
    https://syzkaller.appspot.com/text?tag=ReproC&x=16612f02d00000,
    Autoload must fail (to not hit memory leak reported by syzkaller)
    
    There are 2 possible ways how rtl871x_load_fw_cb() and
    r871xu_dev_remove() can be called (in case of fw load error).
    
    1st case:
            r871xu_dev_remove() then rtl871x_load_fw_cb()
    
            In this case r871xu_dev_remove() will wait for
            completion and then will jump to the end, because
            rtl871x_load_fw_cb() set intfdata to NULL:
    
            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;
    
                    ... clean up code here ...
            }
    
    2nd case:
            rtl871x_load_fw_cb() then r871xu_dev_remove()
    
            In this case pnetdev (from code snippet above) will
            be zero (because rtl871x_load_fw_cb() set it to NULL)
            And clean up code won't be executed again.
    
    So, in all cases we need to free adapted data in rtl871x_load_fw_cb(),
    because disconnect function cannot take care of it. And there won't be
    any race conditions, because complete() call happens after setting
    intfdata to NULL.
    
    In previous patch I moved out free_netdev() from r8712_free_drv_sw()
    and that's why now it's possible to free adapter data and then call
    complete.
    
    Fixes: 8c213fa59199 ("staging: r8712u: Use asynchronous firmware loading")
    Signed-off-by: Pavel Skripkin <paskripkin@xxxxxxxxx>
    Link: https://lore.kernel.org/r/81e68fe0194499cc2e7692d35bc4dcf167827d8f.1623620630.git.paskripkin@xxxxxxxxx
    Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/staging/rtl8712/hal_init.c b/drivers/staging/rtl8712/hal_init.c
index 715f1fe8b472..22974277afa0 100644
--- a/drivers/staging/rtl8712/hal_init.c
+++ b/drivers/staging/rtl8712/hal_init.c
@@ -40,7 +40,10 @@ static void rtl871x_load_fw_cb(const struct firmware *firmware, void *context)
 		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);
 		return;
 	}
 	adapter->fw = firmware;