[PATCH 0/7] NFC: fix device allocation and nfcmrvl crashes

[PATCH 0/7] NFC: fix device allocation and nfcmrvl crashes

[Johan Hovold]

This started out with the observation that the nfcmrvl_uart driver
unconditionally dereferenced the tty class device despite the fact that
not every tty has an associated struct device (Unix98 ptys). Some
further changes were needed in the common nfcmrvl code to fully address
this, some of which also incidentally fixed a few related bugs (e.g.
resource leaks in error paths).

While fixing this I stumbled over a regression in NFC core that lead to
broken registration error paths and misnamed workqueues.

Note that this has only been tested by configuring the n_hci line
discipline for different ttys without any actual NFC hardware connected.

Johan


Johan Hovold (7):
  NFC: fix broken device allocation
  NFC: nfcmrvl_uart: add missing tty-device sanity check
  NFC: nfcmrvl: do not use device-managed resources
  NFC: nfcmrvl: use nfc-device for firmware download
  NFC: nfcmrvl: fix firmware-management initialisation
  NFC: nfcmrvl_uart: fix device-node leak during probe
  NFC: nfcmrvl_usb: use interface as phy device

 drivers/nfc/nfcmrvl/fw_dnld.c |  7 +++++--
 drivers/nfc/nfcmrvl/main.c    | 25 +++++++++++++------------
 drivers/nfc/nfcmrvl/uart.c    | 11 +++++++----
 drivers/nfc/nfcmrvl/usb.c     |  4 +---
 net/nfc/core.c                | 31 ++++++++++++++++++-------------
 net/nfc/nci/core.c            |  3 +--
 6 files changed, 45 insertions(+), 36 deletions(-)

-- 
2.12.2

[PATCH 1/7] NFC: fix broken device allocation

[Johan Hovold]

Commit 7eda8b8e9677 ("NFC: Use IDR library to assing NFC devices IDs")
moved device-id allocation and struct-device initialisation from
nfc_allocate_device() to nfc_register_device().

This broke just about every nfc-device-registration error path, which
continue to call nfc_free_device() that tries to put the device
reference of the now uninitialised (but zeroed) struct device:

kobject: '(null)' (ce316420): is not initialized, yet kobject_put() is being called.

The late struct-device initialisation also meant that various work
queues whose names are derived from the nfc device name were also
misnamed:

  421 root         0 SW<  [(null)_nci_cmd_]
  422 root         0 SW<  [(null)_nci_rx_w]
  423 root         0 SW<  [(null)_nci_tx_w]

Move the id-allocation and struct-device initialisation back to
nfc_allocate_device() and fix up the single call site which did not use
nfc_free_device() in its registration error path.

Fixes: 7eda8b8e9677 ("NFC: Use IDR library to assing NFC devices IDs")
Cc: stable <stable@vger.kernel.org>     # 3.8
Cc: Samuel Ortiz <sameo@linux.intel.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
---
 net/nfc/core.c     | 31 ++++++++++++++++++-------------
 net/nfc/nci/core.c |  3 +--
 2 files changed, 19 insertions(+), 15 deletions(-)

diff --git a/net/nfc/core.c b/net/nfc/core.c
index 122bb81da918..5cf33df888c3 100644
--- a/net/nfc/core.c
+++ b/net/nfc/core.c
@@ -982,6 +982,8 @@ static void nfc_release(struct device *d)
 			kfree(se);
 	}
 
+	ida_simple_remove(&nfc_index_ida, dev->idx);
+
 	kfree(dev);
 }
 
@@ -1056,6 +1058,7 @@ struct nfc_dev *nfc_allocate_device(struct nfc_ops *ops,
 				    int tx_headroom, int tx_tailroom)
 {
 	struct nfc_dev *dev;
+	int rc;
 
 	if (!ops->start_poll || !ops->stop_poll || !ops->activate_target ||
 	    !ops->deactivate_target || !ops->im_transceive)
@@ -1068,6 +1071,15 @@ struct nfc_dev *nfc_allocate_device(struct nfc_ops *ops,
 	if (!dev)
 		return NULL;
 
+	rc = ida_simple_get(&nfc_index_ida, 0, 0, GFP_KERNEL);
+	if (rc < 0)
+		goto err_free_dev;
+	dev->idx = rc;
+
+	dev->dev.class = &nfc_class;
+	dev_set_name(&dev->dev, "nfc%d", dev->idx);
+	device_initialize(&dev->dev);
+
 	dev->ops = ops;
 	dev->supported_protocols = supported_protocols;
 	dev->tx_headroom = tx_headroom;
@@ -1090,6 +1102,11 @@ struct nfc_dev *nfc_allocate_device(struct nfc_ops *ops,
 	}
 
 	return dev;
+
+err_free_dev:
+	kfree(dev);
+
+	return ERR_PTR(rc);
 }
 EXPORT_SYMBOL(nfc_allocate_device);
 
@@ -1104,14 +1121,6 @@ int nfc_register_device(struct nfc_dev *dev)
 
 	pr_debug("dev_name=%s\n", dev_name(&dev->dev));
 
-	dev->idx = ida_simple_get(&nfc_index_ida, 0, 0, GFP_KERNEL);
-	if (dev->idx < 0)
-		return dev->idx;
-
-	dev->dev.class = &nfc_class;
-	dev_set_name(&dev->dev, "nfc%d", dev->idx);
-	device_initialize(&dev->dev);
-
 	mutex_lock(&nfc_devlist_mutex);
 	nfc_devlist_generation++;
 	rc = device_add(&dev->dev);
@@ -1149,12 +1158,10 @@ EXPORT_SYMBOL(nfc_register_device);
  */
 void nfc_unregister_device(struct nfc_dev *dev)
 {
-	int rc, id;
+	int rc;
 
 	pr_debug("dev_name=%s\n", dev_name(&dev->dev));
 
-	id = dev->idx;
-
 	if (dev->rfkill) {
 		rfkill_unregister(dev->rfkill);
 		rfkill_destroy(dev->rfkill);
@@ -1179,8 +1186,6 @@ void nfc_unregister_device(struct nfc_dev *dev)
 	nfc_devlist_generation++;
 	device_del(&dev->dev);
 	mutex_unlock(&nfc_devlist_mutex);
-
-	ida_simple_remove(&nfc_index_ida, id);
 }
 EXPORT_SYMBOL(nfc_unregister_device);
 
diff --git a/net/nfc/nci/core.c b/net/nfc/nci/core.c
index 61fff422424f..85a3d9ed4c29 100644
--- a/net/nfc/nci/core.c
+++ b/net/nfc/nci/core.c
@@ -1173,8 +1173,7 @@ struct nci_dev *nci_allocate_device(struct nci_ops *ops,
 	return ndev;
 
 free_nfc:
-	kfree(ndev->nfc_dev);
-
+	nfc_free_device(ndev->nfc_dev);
 free_nci:
 	kfree(ndev);
 	return NULL;
-- 
2.12.2

[PATCH 2/7] NFC: nfcmrvl_uart: add missing tty-device sanity check

[Johan Hovold]

Make sure to check the tty-device pointer before trying to access the
parent device to avoid dereferencing a NULL-pointer when the tty is one
end of a Unix98 pty.

Fixes: e097dc624f78 ("NFC: nfcmrvl: add UART driver")
Cc: stable <stable@vger.kernel.org>     # 4.2
Cc: Vincent Cuissard <cuissard@marvell.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/nfc/nfcmrvl/uart.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/nfc/nfcmrvl/uart.c b/drivers/nfc/nfcmrvl/uart.c
index 83a99e38e7bd..6c0c301611c4 100644
--- a/drivers/nfc/nfcmrvl/uart.c
+++ b/drivers/nfc/nfcmrvl/uart.c
@@ -109,6 +109,7 @@ static int nfcmrvl_nci_uart_open(struct nci_uart *nu)
 	struct nfcmrvl_private *priv;
 	struct nfcmrvl_platform_data *pdata = NULL;
 	struct nfcmrvl_platform_data config;
+	struct device *dev = nu->tty->dev;
 
 	/*
 	 * Platform data cannot be used here since usually it is already used
@@ -116,9 +117,8 @@ static int nfcmrvl_nci_uart_open(struct nci_uart *nu)
 	 * and check if DT entries were added.
 	 */
 
-	if (nu->tty->dev->parent && nu->tty->dev->parent->of_node)
-		if (nfcmrvl_uart_parse_dt(nu->tty->dev->parent->of_node,
-					  &config) == 0)
+	if (dev && dev->parent && dev->parent->of_node)
+		if (nfcmrvl_uart_parse_dt(dev->parent->of_node, &config) == 0)
 			pdata = &config;
 
 	if (!pdata) {
@@ -131,7 +131,7 @@ static int nfcmrvl_nci_uart_open(struct nci_uart *nu)
 	}
 
 	priv = nfcmrvl_nci_register_dev(NFCMRVL_PHY_UART, nu, &uart_ops,
-					nu->tty->dev, pdata);
+					dev, pdata);
 	if (IS_ERR(priv))
 		return PTR_ERR(priv);
 
-- 
2.12.2

[PATCH 3/7] NFC: nfcmrvl: do not use device-managed resources

[Johan Hovold]

This specifically fixes a NULL-pointer dereference when using the n_nci
line discipline on one end of a Unix98 pty as well as resource leaks in
the registration error paths.

Device-managed resources is a bad fit for this driver as devices can be
registered from the n_nci line discipline. Firstly, a tty may not even
have a corresponding device (should it be part of a Unix98 pty)
something which would lead to a NULL-pointer dereference when
registering resources.

Secondly, if the tty has a class device, its lifetime exceeds that of
the line discipline, which means that resources would leak every time
the line discipline is closed (or if registration fails).

Currently, the devres interface was only being used to request a reset
gpio despite the fact that it was already explicitly freed in
nfcmrvl_nci_unregister_dev() (along with the private data), something
which also prevented the resource leak at close.

Fixes: b2fe288eac72 ("NFC: nfcmrvl: free reset gpio")
Fixes: 4a2b947f56b3 ("NFC: nfcmrvl: add chip reset management")
Cc: stable <stable@vger.kernel.org>     # 4.2: b2fe288eac72
Cc: Vincent Cuissard <cuissard@marvell.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/nfc/nfcmrvl/main.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/drivers/nfc/nfcmrvl/main.c b/drivers/nfc/nfcmrvl/main.c
index 51c8240a1672..8d4294fc3005 100644
--- a/drivers/nfc/nfcmrvl/main.c
+++ b/drivers/nfc/nfcmrvl/main.c
@@ -124,10 +124,9 @@ struct nfcmrvl_private *nfcmrvl_nci_register_dev(enum nfcmrvl_phy phy,
 	memcpy(&priv->config, pdata, sizeof(*pdata));
 
 	if (priv->config.reset_n_io) {
-		rc = devm_gpio_request_one(dev,
-					   priv->config.reset_n_io,
-					   GPIOF_OUT_INIT_LOW,
-					   "nfcmrvl_reset_n");
+		rc = gpio_request_one(priv->config.reset_n_io,
+				      GPIOF_OUT_INIT_LOW,
+				      "nfcmrvl_reset_n");
 		if (rc < 0)
 			nfc_err(dev, "failed to request reset_n io\n");
 	}
@@ -195,7 +194,7 @@ void nfcmrvl_nci_unregister_dev(struct nfcmrvl_private *priv)
 	nfcmrvl_fw_dnld_deinit(priv);
 
 	if (priv->config.reset_n_io)
-		devm_gpio_free(priv->dev, priv->config.reset_n_io);
+		gpio_free(priv->config.reset_n_io);
 
 	nci_unregister_device(ndev);
 	nci_free_device(ndev);
-- 
2.12.2

Re: [PATCH 3/7] NFC: nfcmrvl: do not use device-managed resources

[Johan Hovold]

On Wed, Mar 29, 2017 at 06:21:08PM +0200, Johan Hovold wrote:
> This specifically fixes a NULL-pointer dereference when using the n_nci
> line discipline on one end of a Unix98 pty as well as resource leaks in
> the registration error paths.

I noticed I forgot to actually fix up the error paths, so will send a v2
tomorrow.

Johan

[PATCH 4/7] NFC: nfcmrvl: use nfc-device for firmware download

[Johan Hovold]

Use the nfc- rather than phy-device in firmware-management code that
needs a valid struct device.

This specifically fixes a NULL-pointer dereference in
nfcmrvl_fw_dnld_init() during registration when the underlying tty is
one end of a Unix98 pty.

Note that the driver still uses the phy device for any debugging, which
is fine for now.

Fixes: 3194c6870158 ("NFC: nfcmrvl: add firmware download support")
Cc: stable <stable@vger.kernel.org>     # 4.4
Cc: Vincent Cuissard <cuissard@marvell.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/nfc/nfcmrvl/fw_dnld.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/nfc/nfcmrvl/fw_dnld.c b/drivers/nfc/nfcmrvl/fw_dnld.c
index f8dcdf4b24f6..af62c4c854f3 100644
--- a/drivers/nfc/nfcmrvl/fw_dnld.c
+++ b/drivers/nfc/nfcmrvl/fw_dnld.c
@@ -459,7 +459,7 @@ int	nfcmrvl_fw_dnld_init(struct nfcmrvl_private *priv)
 
 	INIT_WORK(&priv->fw_dnld.rx_work, fw_dnld_rx_work);
 	snprintf(name, sizeof(name), "%s_nfcmrvl_fw_dnld_rx_wq",
-		 dev_name(priv->dev));
+		 dev_name(&priv->ndev->nfc_dev->dev));
 	priv->fw_dnld.rx_wq = create_singlethread_workqueue(name);
 	if (!priv->fw_dnld.rx_wq)
 		return -ENOMEM;
@@ -496,6 +496,7 @@ int nfcmrvl_fw_dnld_start(struct nci_dev *ndev, const char *firmware_name)
 {
 	struct nfcmrvl_private *priv = nci_get_drvdata(ndev);
 	struct nfcmrvl_fw_dnld *fw_dnld = &priv->fw_dnld;
+	int res;
 
 	if (!priv->support_fw_dnld)
 		return -ENOTSUPP;
@@ -511,7 +512,9 @@ int nfcmrvl_fw_dnld_start(struct nci_dev *ndev, const char *firmware_name)
 	 */
 
 	/* Retrieve FW binary */
-	if (request_firmware(&fw_dnld->fw, firmware_name, priv->dev) < 0) {
+	res = request_firmware(&fw_dnld->fw, firmware_name,
+			       &ndev->nfc_dev->dev);
+	if (res < 0) {
 		nfc_err(priv->dev, "failed to retrieve FW %s", firmware_name);
 		return -ENOENT;
 	}
-- 
2.12.2

[PATCH 5/7] NFC: nfcmrvl: fix firmware-management initialisation

[Johan Hovold]

The nci-device was never deregistered in the event that
fw-initialisation failed.

Fix this by moving the firmware initialisation before device
registration since the firmware work queue should be available before
registering.

Note that this depends on a recent fix that moved device-name
initialisation back to to nci_allocate_device() as the
firmware-workqueue name is now derived from the nfc-device name.

Fixes: 3194c6870158 ("NFC: nfcmrvl: add firmware download support")
Cc: stable <stable@vger.kernel.org>     # 4.4
Cc: Vincent Cuissard <cuissard@marvell.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/nfc/nfcmrvl/main.c | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/drivers/nfc/nfcmrvl/main.c b/drivers/nfc/nfcmrvl/main.c
index 8d4294fc3005..f20220bab6b6 100644
--- a/drivers/nfc/nfcmrvl/main.c
+++ b/drivers/nfc/nfcmrvl/main.c
@@ -156,26 +156,28 @@ struct nfcmrvl_private *nfcmrvl_nci_register_dev(enum nfcmrvl_phy phy,
 		goto error;
 	}
 
+	rc = nfcmrvl_fw_dnld_init(priv);
+	if (rc) {
+		nfc_err(dev, "failed to initialize FW download %d\n", rc);
+		goto error_free_dev;
+	}
+
 	nci_set_drvdata(priv->ndev, priv);
 
 	rc = nci_register_device(priv->ndev);
 	if (rc) {
 		nfc_err(dev, "nci_register_device failed %d\n", rc);
-		goto error_free_dev;
+		goto error_fw_dnld_deinit;
 	}
 
 	/* Ensure that controller is powered off */
 	nfcmrvl_chip_halt(priv);
 
-	rc = nfcmrvl_fw_dnld_init(priv);
-	if (rc) {
-		nfc_err(dev, "failed to initialize FW download %d\n", rc);
-		goto error_free_dev;
-	}
-
 	nfc_info(dev, "registered with nci successfully\n");
 	return priv;
 
+error_fw_dnld_deinit:
+	nfcmrvl_fw_dnld_deinit(priv);
 error_free_dev:
 	nci_free_device(priv->ndev);
 error:
-- 
2.12.2

[PATCH 6/7] NFC: nfcmrvl_uart: fix device-node leak during probe

[Johan Hovold]

Make sure to release the device-node reference when done parsing the
node.

Fixes: e097dc624f78 ("NFC: nfcmrvl: add UART driver")
Cc: Vincent Cuissard <cuissard@marvell.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/nfc/nfcmrvl/uart.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/nfc/nfcmrvl/uart.c b/drivers/nfc/nfcmrvl/uart.c
index 6c0c301611c4..91162f8e0366 100644
--- a/drivers/nfc/nfcmrvl/uart.c
+++ b/drivers/nfc/nfcmrvl/uart.c
@@ -84,6 +84,7 @@ static int nfcmrvl_uart_parse_dt(struct device_node *node,
 	ret = nfcmrvl_parse_dt(matched_node, pdata);
 	if (ret < 0) {
 		pr_err("Failed to get generic entries\n");
+		of_node_put(matched_node);
 		return ret;
 	}
 
@@ -97,6 +98,8 @@ static int nfcmrvl_uart_parse_dt(struct device_node *node,
 	else
 		pdata->break_control = 0;
 
+	of_node_put(matched_node);
+
 	return 0;
 }
 
-- 
2.12.2

[PATCH 7/7] NFC: nfcmrvl_usb: use interface as phy device

[Johan Hovold]

Use the USB-interface rather than parent USB-device device, which is
what this driver binds to, when registering the nci device.

Note that using the right device is important when dealing with device-
managed resources as the interface can be unbound independently of the
parent device.

Also note that private device pointer had already been set by
nfcmrvl_nci_register_dev() so the redundant assignment can therefore be
removed.

Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/nfc/nfcmrvl/usb.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/nfc/nfcmrvl/usb.c b/drivers/nfc/nfcmrvl/usb.c
index 585a0f20835b..728b3321842d 100644
--- a/drivers/nfc/nfcmrvl/usb.c
+++ b/drivers/nfc/nfcmrvl/usb.c
@@ -341,15 +341,13 @@ static int nfcmrvl_probe(struct usb_interface *intf,
 	init_usb_anchor(&drv_data->deferred);
 
 	priv = nfcmrvl_nci_register_dev(NFCMRVL_PHY_USB, drv_data, &usb_ops,
-					&drv_data->udev->dev, &config);
+					&intf->dev, &config);
 	if (IS_ERR(priv))
 		return PTR_ERR(priv);
 
 	drv_data->priv = priv;
 	drv_data->priv->support_fw_dnld = false;
 
-	priv->dev = &drv_data->udev->dev;
-
 	usb_set_intfdata(intf, drv_data);
 
 	return 0;
-- 
2.12.2