From: Duoming Zhou duoming@zju.edu.cn
commit d270453a0d9ec10bb8a802a142fb1b3601a83098 upstream.
There are destructive operations such as nfcmrvl_fw_dnld_abort and gpio_free in nfcmrvl_nci_unregister_dev. The resources such as firmware, gpio and so on could be destructed while the upper layer functions such as nfcmrvl_fw_dnld_start and nfcmrvl_nci_recv_frame is executing, which leads to double-free, use-after-free and null-ptr-deref bugs.
There are three situations that could lead to double-free bugs.
The first situation is shown below:
(Thread 1) | (Thread 2) nfcmrvl_fw_dnld_start | ... | nfcmrvl_nci_unregister_dev release_firmware() | nfcmrvl_fw_dnld_abort kfree(fw) //(1) | fw_dnld_over | release_firmware ... | kfree(fw) //(2) | ...
The second situation is shown below:
(Thread 1) | (Thread 2) nfcmrvl_fw_dnld_start | ... | mod_timer | (wait a time) | fw_dnld_timeout | nfcmrvl_nci_unregister_dev fw_dnld_over | nfcmrvl_fw_dnld_abort release_firmware | fw_dnld_over kfree(fw) //(1) | release_firmware ... | kfree(fw) //(2)
The third situation is shown below:
(Thread 1) | (Thread 2) nfcmrvl_nci_recv_frame | if(..->fw_download_in_progress)| nfcmrvl_fw_dnld_recv_frame | queue_work | | fw_dnld_rx_work | nfcmrvl_nci_unregister_dev fw_dnld_over | nfcmrvl_fw_dnld_abort release_firmware | fw_dnld_over kfree(fw) //(1) | release_firmware | kfree(fw) //(2)
The firmware struct is deallocated in position (1) and deallocated in position (2) again.
The crash trace triggered by POC is like below:
BUG: KASAN: double-free or invalid-free in fw_dnld_over Call Trace: kfree fw_dnld_over nfcmrvl_nci_unregister_dev nci_uart_tty_close tty_ldisc_kill tty_ldisc_hangup __tty_hangup.part.0 tty_release ...
What's more, there are also use-after-free and null-ptr-deref bugs in nfcmrvl_fw_dnld_start. If we deallocate firmware struct, gpio or set null to the members of priv->fw_dnld in nfcmrvl_nci_unregister_dev, then, we dereference firmware, gpio or the members of priv->fw_dnld in nfcmrvl_fw_dnld_start, the UAF or NPD bugs will happen.
This patch reorders destructive operations after nci_unregister_device in order to synchronize between cleanup routine and firmware download routine.
The nci_unregister_device is well synchronized. If the device is detaching, the firmware download routine will goto error. If firmware download routine is executing, nci_unregister_device will wait until firmware download routine is finished.
Fixes: 3194c6870158 ("NFC: nfcmrvl: add firmware download support") Signed-off-by: Duoming Zhou duoming@zju.edu.cn Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/nfc/nfcmrvl/main.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/nfc/nfcmrvl/main.c +++ b/drivers/nfc/nfcmrvl/main.c @@ -194,6 +194,7 @@ void nfcmrvl_nci_unregister_dev(struct n { struct nci_dev *ndev = priv->ndev;
+ nci_unregister_device(ndev); if (priv->ndev->nfc_dev->fw_download_in_progress) nfcmrvl_fw_dnld_abort(priv);
@@ -202,7 +203,6 @@ void nfcmrvl_nci_unregister_dev(struct n if (gpio_is_valid(priv->config.reset_n_io)) gpio_free(priv->config.reset_n_io);
- nci_unregister_device(ndev); nci_free_device(ndev); kfree(priv); }