From: Pavel Skripkin paskripkin@gmail.com

mainline inclusion from mainline-v5.16-rc1 commit c052cc1a069c3e575619cf64ec427eb41176ca70 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9RCV5 CVE: CVE-2021-47479

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...

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Syzbot reported use-after-free in rtl8712_dl_fw(). The problem was in race condition between r871xu_dev_remove() ->ndo_open() callback.

It's easy to see from crash log, that driver accesses released firmware in ->ndo_open() callback. It may happen, since driver was releasing firmware _before_ unregistering netdev. Fix it by moving unregister_netdev() before cleaning up resources.

Call Trace: ... rtl871x_open_fw drivers/staging/rtl8712/hal_init.c:83 [inline] rtl8712_dl_fw+0xd95/0xe10 drivers/staging/rtl8712/hal_init.c:170 rtl8712_hal_init drivers/staging/rtl8712/hal_init.c:330 [inline] rtl871x_hal_init+0xae/0x180 drivers/staging/rtl8712/hal_init.c:394 netdev_open+0xe6/0x6c0 drivers/staging/rtl8712/os_intfs.c:380 __dev_open+0x2bc/0x4d0 net/core/dev.c:1484

Freed by task 1306: ... release_firmware+0x1b/0x30 drivers/base/firmware_loader/main.c:1053 r871xu_dev_remove+0xcc/0x2c0 drivers/staging/rtl8712/usb_intf.c:599 usb_unbind_interface+0x1d8/0x8d0 drivers/usb/core/driver.c:458

Fixes: 8c213fa59199 ("staging: r8712u: Use asynchronous firmware loading") Cc: stable stable@vger.kernel.org Reported-and-tested-by: syzbot+c55162be492189fb4f51@syzkaller.appspotmail.com Signed-off-by: Pavel Skripkin paskripkin@gmail.com Link: https://lore.kernel.org/r/20211019211718.26354-1-paskripkin@gmail.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Conflicts: drivers/staging/rtl8712/usb_intf.c [The conflict occurs because commit b4383c971bc5("staging: rtl8712: handle firmware load failure") is not merged] Signed-off-by: Jialin Zhang zhangjialin11@huawei.com --- drivers/staging/rtl8712/usb_intf.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/staging/rtl8712/usb_intf.c b/drivers/staging/rtl8712/usb_intf.c index 5e2cdc25401b..709d687180bf 100644 --- a/drivers/staging/rtl8712/usb_intf.c +++ b/drivers/staging/rtl8712/usb_intf.c @@ -623,13 +623,13 @@ static void r871xu_dev_remove(struct usb_interface *pusb_intf) if (pnetdev) { struct _adapter *padapter = netdev_priv(pnetdev);

+ unregister_netdev(pnetdev); /* will call netdev_close() */ usb_set_intfdata(pusb_intf, NULL); release_firmware(padapter->fw); /* never exit with a firmware callback pending */ wait_for_completion(&padapter->rtl8712_fw_ready); if (drvpriv.drv_registered) padapter->bSurpriseRemoved = true; - unregister_netdev(pnetdev); /* will call netdev_close() */ flush_scheduled_work(); udelay(1); /* Stop driver mlme relation timer */