Message ID | 20220410135214.74216-1-duoming@zju.edu.cn (mailing list archive) |
---|---|
State | Changes Requested |
Delegated to: | Netdev Maintainers |
Headers | show |
Series | [V2] drivers: nfc: nfcmrvl: fix double free bug in nfcmrvl_nci_unregister_dev() | expand |
On 10/04/2022 15:52, Duoming Zhou wrote: > There is a potential double bug in nfcmrvl usb driver between > unregister and resume operation. > > The race that cause that double free bug can be shown as below: > > (FREE) | (USE) > | nfcmrvl_resume > | nfcmrvl_submit_bulk_urb > | nfcmrvl_bulk_complete > | nfcmrvl_nci_recv_frame > | nfcmrvl_fw_dnld_recv_frame > | queue_work > | fw_dnld_rx_work > | fw_dnld_over > | release_firmware > | kfree(fw); //(1) > nfcmrvl_disconnect | > nfcmrvl_nci_unregister_dev | > nfcmrvl_fw_dnld_abort | > fw_dnld_over | ... > if (priv->fw_dnld.fw) | > release_firmware | > kfree(fw); //(2) | > ... | priv->fw_dnld.fw = NULL; > Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org> Best regards, Krzysztof
Hello, On Sun, 2022-04-10 at 21:52 +0800, Duoming Zhou wrote: > There is a potential double bug in nfcmrvl usb driver between > unregister and resume operation. > > The race that cause that double free bug can be shown as below: > > (FREE) | (USE) > | nfcmrvl_resume > | nfcmrvl_submit_bulk_urb > | nfcmrvl_bulk_complete > | nfcmrvl_nci_recv_frame > | nfcmrvl_fw_dnld_recv_frame > | queue_work > | fw_dnld_rx_work > | fw_dnld_over > | release_firmware > | kfree(fw); //(1) > nfcmrvl_disconnect | > nfcmrvl_nci_unregister_dev | > nfcmrvl_fw_dnld_abort | > fw_dnld_over | ... > if (priv->fw_dnld.fw) | > release_firmware | > kfree(fw); //(2) | > ... | priv->fw_dnld.fw = NULL; > > When nfcmrvl usb driver is resuming, we detach the device. > The release_firmware() will deallocate firmware in position (1), > but firmware will be deallocated again in position (2), which > leads to double free. > > This patch reorders nfcmrvl_fw_dnld_deinit() before nfcmrvl_fw_dnld_abort() > in order to prevent double free bug. Because destroy_workqueue() will > not return until all work items are finished. The priv->fw_dnld.fw will > be set to NULL after work items are finished and fw_dnld_over() called by > nfcmrvl_nci_unregister_dev() will check whether priv->fw_dnld.fw is NULL. > So the double free bug could be prevented. > > Signed-off-by: Duoming Zhou <duoming@zju.edu.cn> This looks like a -net candidates, could you please add a suitable fixes tag? Thanks! Paolo
Hello, On Tue, 12 Apr 2022 00:28:16 -0700 Paolo Abeni wrote: > > There is a potential double bug in nfcmrvl usb driver between > > unregister and resume operation. > > > > The race that cause that double free bug can be shown as below: > > > > (FREE) | (USE) > > | nfcmrvl_resume > > | nfcmrvl_submit_bulk_urb > > | nfcmrvl_bulk_complete > > | nfcmrvl_nci_recv_frame > > | nfcmrvl_fw_dnld_recv_frame > > | queue_work > > | fw_dnld_rx_work > > | fw_dnld_over > > | release_firmware > > | kfree(fw); //(1) > > nfcmrvl_disconnect | > > nfcmrvl_nci_unregister_dev | > > nfcmrvl_fw_dnld_abort | > > fw_dnld_over | ... > > if (priv->fw_dnld.fw) | > > release_firmware | > > kfree(fw); //(2) | > > ... | priv->fw_dnld.fw = NULL; > > > > When nfcmrvl usb driver is resuming, we detach the device. > > The release_firmware() will deallocate firmware in position (1), > > but firmware will be deallocated again in position (2), which > > leads to double free. > > > > This patch reorders nfcmrvl_fw_dnld_deinit() before nfcmrvl_fw_dnld_abort() > > in order to prevent double free bug. Because destroy_workqueue() will > > not return until all work items are finished. The priv->fw_dnld.fw will > > be set to NULL after work items are finished and fw_dnld_over() called by > > nfcmrvl_nci_unregister_dev() will check whether priv->fw_dnld.fw is NULL. > > So the double free bug could be prevented. > > > > Signed-off-by: Duoming Zhou <duoming@zju.edu.cn> > > This looks like a -net candidates, could you please add a suitable > fixes tag? I found my patch is not a comprehensive fix, because the fw_dnld_timeout() could also reach fw_dnld_over(), which leads to double free bugs among fw_dnld_rx_work(), fw_dnld_timeout() and nfcmrvl_nci_unregister_dev(). I sent a patch set "Fix double free bugs in nfcmrvl module" just now, and add a fixes tag in it. Best regards, Duoming Zhou
diff --git a/drivers/nfc/nfcmrvl/main.c b/drivers/nfc/nfcmrvl/main.c index 2fcf545012b..d8342271f50 100644 --- a/drivers/nfc/nfcmrvl/main.c +++ b/drivers/nfc/nfcmrvl/main.c @@ -183,11 +183,10 @@ void nfcmrvl_nci_unregister_dev(struct nfcmrvl_private *priv) { struct nci_dev *ndev = priv->ndev; + nfcmrvl_fw_dnld_deinit(priv); if (priv->ndev->nfc_dev->fw_download_in_progress) nfcmrvl_fw_dnld_abort(priv); - nfcmrvl_fw_dnld_deinit(priv); - if (gpio_is_valid(priv->config.reset_n_io)) gpio_free(priv->config.reset_n_io);
There is a potential double bug in nfcmrvl usb driver between unregister and resume operation. The race that cause that double free bug can be shown as below: (FREE) | (USE) | nfcmrvl_resume | nfcmrvl_submit_bulk_urb | nfcmrvl_bulk_complete | nfcmrvl_nci_recv_frame | nfcmrvl_fw_dnld_recv_frame | queue_work | fw_dnld_rx_work | fw_dnld_over | release_firmware | kfree(fw); //(1) nfcmrvl_disconnect | nfcmrvl_nci_unregister_dev | nfcmrvl_fw_dnld_abort | fw_dnld_over | ... if (priv->fw_dnld.fw) | release_firmware | kfree(fw); //(2) | ... | priv->fw_dnld.fw = NULL; When nfcmrvl usb driver is resuming, we detach the device. The release_firmware() will deallocate firmware in position (1), but firmware will be deallocated again in position (2), which leads to double free. This patch reorders nfcmrvl_fw_dnld_deinit() before nfcmrvl_fw_dnld_abort() in order to prevent double free bug. Because destroy_workqueue() will not return until all work items are finished. The priv->fw_dnld.fw will be set to NULL after work items are finished and fw_dnld_over() called by nfcmrvl_nci_unregister_dev() will check whether priv->fw_dnld.fw is NULL. So the double free bug could be prevented. Signed-off-by: Duoming Zhou <duoming@zju.edu.cn> --- Changes in V2: - Make commit message more clearer. drivers/nfc/nfcmrvl/main.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)