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V4L/DVB (12489): pwc - fix few use-after-free and memory leaks
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I just happen to peek inside the PWC driver and did not like what I saw
there. Please consider applying the patch below.

Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
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Dmitry Torokhov authored and Mauro Carvalho Chehab committed Sep 12, 2009
1 parent 35c3057 commit 89dec01
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Showing 2 changed files with 36 additions and 43 deletions.
78 changes: 35 additions & 43 deletions drivers/media/video/pwc/pwc-if.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1057,7 +1057,8 @@ static int pwc_create_sysfs_files(struct video_device *vdev)
goto err;
if (pdev->features & FEATURE_MOTOR_PANTILT) {
rc = device_create_file(&vdev->dev, &dev_attr_pan_tilt);
if (rc) goto err_button;
if (rc)
goto err_button;
}

return 0;
Expand All @@ -1072,6 +1073,7 @@ static int pwc_create_sysfs_files(struct video_device *vdev)
static void pwc_remove_sysfs_files(struct video_device *vdev)
{
struct pwc_device *pdev = video_get_drvdata(vdev);

if (pdev->features & FEATURE_MOTOR_PANTILT)
device_remove_file(&vdev->dev, &dev_attr_pan_tilt);
device_remove_file(&vdev->dev, &dev_attr_button);
Expand Down Expand Up @@ -1229,13 +1231,11 @@ static void pwc_cleanup(struct pwc_device *pdev)
video_unregister_device(pdev->vdev);

#ifdef CONFIG_USB_PWC_INPUT_EVDEV
if (pdev->button_dev) {
if (pdev->button_dev)
input_unregister_device(pdev->button_dev);
input_free_device(pdev->button_dev);
kfree(pdev->button_dev->phys);
pdev->button_dev = NULL;
}
#endif

kfree(pdev);
}

/* Note that all cleanup is done in the reverse order as in _open */
Expand Down Expand Up @@ -1281,8 +1281,6 @@ static int pwc_video_close(struct file *file)
PWC_DEBUG_OPEN("<< video_close() vopen=%d\n", pdev->vopen);
} else {
pwc_cleanup(pdev);
/* Free memory (don't set pdev to 0 just yet) */
kfree(pdev);
/* search device_hint[] table if we occupy a slot, by any chance */
for (hint = 0; hint < MAX_DEV_HINTS; hint++)
if (device_hint[hint].pdev == pdev)
Expand Down Expand Up @@ -1499,13 +1497,10 @@ static int usb_pwc_probe(struct usb_interface *intf, const struct usb_device_id
struct usb_device *udev = interface_to_usbdev(intf);
struct pwc_device *pdev = NULL;
int vendor_id, product_id, type_id;
int i, hint, rc;
int hint, rc;
int features = 0;
int video_nr = -1; /* default: use next available device */
char serial_number[30], *name;
#ifdef CONFIG_USB_PWC_INPUT_EVDEV
char *phys = NULL;
#endif

vendor_id = le16_to_cpu(udev->descriptor.idVendor);
product_id = le16_to_cpu(udev->descriptor.idProduct);
Expand Down Expand Up @@ -1757,8 +1752,7 @@ static int usb_pwc_probe(struct usb_interface *intf, const struct usb_device_id
pdev->vframes = default_fps;
strcpy(pdev->serial, serial_number);
pdev->features = features;
if (vendor_id == 0x046D && product_id == 0x08B5)
{
if (vendor_id == 0x046D && product_id == 0x08B5) {
/* Logitech QuickCam Orbit
The ranges have been determined experimentally; they may differ from cam to cam.
Also, the exact ranges left-right and up-down are different for my cam
Expand All @@ -1780,8 +1774,8 @@ static int usb_pwc_probe(struct usb_interface *intf, const struct usb_device_id
pdev->vdev = video_device_alloc();
if (!pdev->vdev) {
PWC_ERROR("Err, cannot allocate video_device struture. Failing probe.");
kfree(pdev);
return -ENOMEM;
rc = -ENOMEM;
goto err_free_mem;
}
memcpy(pdev->vdev, &pwc_template, sizeof(pwc_template));
pdev->vdev->parent = &intf->dev;
Expand All @@ -1806,25 +1800,23 @@ static int usb_pwc_probe(struct usb_interface *intf, const struct usb_device_id
}

pdev->vdev->release = video_device_release;
i = video_register_device(pdev->vdev, VFL_TYPE_GRABBER, video_nr);
if (i < 0) {
PWC_ERROR("Failed to register as video device (%d).\n", i);
rc = i;
goto err;
}
else {
PWC_INFO("Registered as /dev/video%d.\n", pdev->vdev->num);
rc = video_register_device(pdev->vdev, VFL_TYPE_GRABBER, video_nr);
if (rc < 0) {
PWC_ERROR("Failed to register as video device (%d).\n", rc);
goto err_video_release;
}

PWC_INFO("Registered as /dev/video%d.\n", pdev->vdev->num);

/* occupy slot */
if (hint < MAX_DEV_HINTS)
device_hint[hint].pdev = pdev;

PWC_DEBUG_PROBE("probe() function returning struct at 0x%p.\n", pdev);
usb_set_intfdata (intf, pdev);
usb_set_intfdata(intf, pdev);
rc = pwc_create_sysfs_files(pdev->vdev);
if (rc)
goto err_unreg;
goto err_video_unreg;

/* Set the leds off */
pwc_set_leds(pdev, 0, 0);
Expand All @@ -1835,16 +1827,16 @@ static int usb_pwc_probe(struct usb_interface *intf, const struct usb_device_id
pdev->button_dev = input_allocate_device();
if (!pdev->button_dev) {
PWC_ERROR("Err, insufficient memory for webcam snapshot button device.");
return -ENOMEM;
rc = -ENOMEM;
pwc_remove_sysfs_files(pdev->vdev);
goto err_video_unreg;
}

usb_make_path(udev, pdev->button_phys, sizeof(pdev->button_phys));
strlcat(pdev->button_phys, "/input0", sizeof(pdev->button_phys));

pdev->button_dev->name = "PWC snapshot button";
phys = kasprintf(GFP_KERNEL,"usb-%s-%s", pdev->udev->bus->bus_name, pdev->udev->devpath);
if (!phys) {
input_free_device(pdev->button_dev);
return -ENOMEM;
}
pdev->button_dev->phys = phys;
pdev->button_dev->phys = pdev->button_phys;
usb_to_input_id(pdev->udev, &pdev->button_dev->id);
pdev->button_dev->dev.parent = &pdev->udev->dev;
pdev->button_dev->evbit[0] = BIT_MASK(EV_KEY);
Expand All @@ -1853,25 +1845,27 @@ static int usb_pwc_probe(struct usb_interface *intf, const struct usb_device_id
rc = input_register_device(pdev->button_dev);
if (rc) {
input_free_device(pdev->button_dev);
kfree(pdev->button_dev->phys);
pdev->button_dev = NULL;
return rc;
pwc_remove_sysfs_files(pdev->vdev);
goto err_video_unreg;
}
#endif

return 0;

err_unreg:
err_video_unreg:
if (hint < MAX_DEV_HINTS)
device_hint[hint].pdev = NULL;
video_unregister_device(pdev->vdev);
err:
video_device_release(pdev->vdev); /* Drip... drip... drip... */
kfree(pdev); /* Oops, no memory leaks please */
pdev->vdev = NULL; /* So we don't try to release it below */
err_video_release:
video_device_release(pdev->vdev);
err_free_mem:
kfree(pdev);
return rc;
}

/* The user janked out the cable... */
/* The user yanked out the cable... */
static void usb_pwc_disconnect(struct usb_interface *intf)
{
struct pwc_device *pdev;
Expand Down Expand Up @@ -1902,7 +1896,7 @@ static void usb_pwc_disconnect(struct usb_interface *intf)
/* Alert waiting processes */
wake_up_interruptible(&pdev->frameq);
/* Wait until device is closed */
if(pdev->vopen) {
if (pdev->vopen) {
mutex_lock(&pdev->modlock);
pdev->unplugged = 1;
mutex_unlock(&pdev->modlock);
Expand All @@ -1911,8 +1905,6 @@ static void usb_pwc_disconnect(struct usb_interface *intf)
/* Device is closed, so we can safely unregister it */
PWC_DEBUG_PROBE("Unregistering video device in disconnect().\n");
pwc_cleanup(pdev);
/* Free memory (don't set pdev to 0 just yet) */
kfree(pdev);

disconnect_out:
/* search device_hint[] table if we occupy a slot, by any chance */
Expand Down
1 change: 1 addition & 0 deletions drivers/media/video/pwc/pwc.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -253,6 +253,7 @@ struct pwc_device
int snapshot_button_status; /* set to 1 when the user push the button, reset to 0 when this value is read */
#ifdef CONFIG_USB_PWC_INPUT_EVDEV
struct input_dev *button_dev; /* webcam snapshot button input */
char button_phys[64];
#endif

/*** Misc. data ***/
Expand Down

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