Affected: Linux

In the Linux kernel, the following vulnerability has been resolved:

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