nfc: st-nci: Fix use after free bug in ndlc_remove due to race condition
authorZheng Wang <zyytlz.wz@163.com>
Sun, 12 Mar 2023 16:08:37 +0000 (00:08 +0800)
committerJakub Kicinski <kuba@kernel.org>
Wed, 15 Mar 2023 07:28:23 +0000 (00:28 -0700)
commit5000fe6c27827a61d8250a7e4a1d26c3298ef4f6
tree8a8fa841617b149e8523b1f78caf4bbe1f1552d0
parentcf18d55e535b34fd4845e87e31e1c5609db6d0a3
nfc: st-nci: Fix use after free bug in ndlc_remove due to race condition

This bug influences both st_nci_i2c_remove and st_nci_spi_remove.
Take st_nci_i2c_remove as an example.

In st_nci_i2c_probe, it called ndlc_probe and bound &ndlc->sm_work
with llt_ndlc_sm_work.

When it calls ndlc_recv or timeout handler, it will finally call
schedule_work to start the work.

When we call st_nci_i2c_remove to remove the driver, there
may be a sequence as follows:

Fix it by finishing the work before cleanup in ndlc_remove

CPU0                  CPU1

                    |llt_ndlc_sm_work
st_nci_i2c_remove   |
  ndlc_remove       |
     st_nci_remove  |
     nci_free_device|
     kfree(ndev)    |
//free ndlc->ndev   |
                    |llt_ndlc_rcv_queue
                    |nci_recv_frame
                    |//use ndlc->ndev

Fixes: 35630df68d60 ("NFC: st21nfcb: Add driver for STMicroelectronics ST21NFCB NFC chip")
Signed-off-by: Zheng Wang <zyytlz.wz@163.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20230312160837.2040857-1-zyytlz.wz@163.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
drivers/nfc/st-nci/ndlc.c