[PATCH 4.9 096/153] can: gs_usb: Dont use stack memory for USB transfers

Greg Kroah-Hartman
2017-03-10T09:22:31Z

From: Ethan Zonca <e@ethanzonca.com>

commit c919a3069c775c1c876bec55e00b2305d5125caa upstream.

Fixes: 05ca5270005c can: gs_usb: add ethtool set_phys_id callback to locate physical device

The gs_usb driver is performing USB transfers using buffers allocated on
the stack. This causes the driver to not function with vmapped stacks.
Instead, allocate memory for the transfer buffers.

Signed-off-by: Ethan Zonca <e@ethanzonca.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/net/can/usb/gs_usb.c | 40 +++++++++++++++++++++++++++++-----------
1 file changed, 29 insertions(+), 11 deletions(-)

--- a/drivers/net/can/usb/gs_usb.c
+++ b/drivers/net/can/usb/gs_usb.c
@@ -908,10 +908,14 @@ static int gs_usb_probe(struct usb_inter
struct gs_usb *dev;
int rc = -ENOMEM;
unsigned int icount, i;
- struct gs_host_config hconf = {
- .byte_order = 0x0000beef,
- };
- struct gs_device_config dconf;
+ struct gs_host_config *hconf;
+ struct gs_device_config *dconf;
+
+ hconf = kmalloc(sizeof(*hconf), GFP_KERNEL);
+ if (!hconf)
+ return -ENOMEM;
+
+ hconf->byte_order = 0x0000beef;

/* send host config */
rc = usb_control_msg(interface_to_usbdev(intf),
@@ -920,16 +924,22 @@ static int gs_usb_probe(struct usb_inter
USB_DIR_OUT|USB_TYPE_VENDOR|USB_RECIP_INTERFACE,
1,
intf->altsetting[0].desc.bInterfaceNumber,
- &hconf,
- sizeof(hconf),
+ hconf,
+ sizeof(*hconf),
1000);

+ kfree(hconf);
+
if (rc < 0) {
dev_err(&intf->dev, "Couldn't send data format (err=%d)\n",
rc);
return rc;
}

+ dconf = kmalloc(sizeof(*dconf), GFP_KERNEL);
+ if (!dconf)
+ return -ENOMEM;
+
/* read device config */
rc = usb_control_msg(interface_to_usbdev(intf),
usb_rcvctrlpipe(interface_to_usbdev(intf), 0),
@@ -937,28 +947,33 @@ static int gs_usb_probe(struct usb_inter
USB_DIR_IN|USB_TYPE_VENDOR|USB_RECIP_INTERFACE,
1,
intf->altsetting[0].desc.bInterfaceNumber,
- &dconf,
- sizeof(dconf),
+ dconf,
+ sizeof(*dconf),
1000);
if (rc < 0) {
dev_err(&intf->dev, "Couldn't get device config: (err=%d)\n",
rc);
+ kfree(dconf);
return rc;
}

- icount = dconf.icount + 1;
+ icount = dconf->icount + 1;
dev_info(&intf->dev, "Configuring for %d interfaces\n", icount);

if (icount > GS_MAX_INTF) {
dev_err(&intf->dev,
"Driver cannot handle more that %d CAN interfaces\n",
GS_MAX_INTF);
+ kfree(dconf);
return -EINVAL;
}

dev = kzalloc(sizeof(*dev), GFP_KERNEL);
- if (!dev)
+ if (!dev) {
+ kfree(dconf);
return -ENOMEM;
+ }
+
init_usb_anchor(&dev->rx_submitted);

atomic_set(&dev->active_channels, 0);
@@ -967,7 +982,7 @@ static int gs_usb_probe(struct usb_inter
dev->udev = interface_to_usbdev(intf);

for (i = 0; i < icount; i++) {
- dev->canch[i] = gs_make_candev(i, intf, &dconf);
+ dev->canch[i] = gs_make_candev(i, intf, dconf);
if (IS_ERR_OR_NULL(dev->canch[i])) {
/* save error code to return later */
rc = PTR_ERR(dev->canch[i]);
@@ -978,12 +993,15 @@ static int gs_usb_probe(struct usb_inter
gs_destroy_candev(dev->canch[i]);

usb_kill_anchored_urbs(&dev->rx_submitted);
+ kfree(dconf);
kfree(dev);
return rc;
}
dev->canch[i]->parent = dev;
}

+ kfree(dconf);
+
return 0;
}