From: Duoming Zhou <duoming@zju.edu.cn>
To: krzk@kernel.org, linux-kernel@vger.kernel.org
Cc: netdev@vger.kernel.org, akpm@linux-foundation.org,
davem@davemloft.net, gregkh@linuxfoundation.org,
alexander.deucher@amd.com, broonie@kernel.org,
Duoming Zhou <duoming@zju.edu.cn>
Subject: [PATCH] drivers: nfc: nfcmrvl: fix double free bug in nfcmrvl_nci_unregister_dev()
Date: Sun, 10 Apr 2022 16:31:25 +0800 [thread overview]
Message-ID: <20220410083125.62909-1-duoming@zju.edu.cn> (raw)
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) |
... | 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 is finished.
Signed-off-by: Duoming Zhou <duoming@zju.edu.cn>
---
drivers/nfc/nfcmrvl/main.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
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);
--
2.17.1
next reply other threads:[~2022-04-10 8:31 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-10 8:31 Duoming Zhou [this message]
2022-04-10 9:27 ` [PATCH] drivers: nfc: nfcmrvl: fix double free bug in nfcmrvl_nci_unregister_dev() Krzysztof Kozlowski
2022-04-10 12:33 ` duoming
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