V4L/DVB (12489): pwc - fix few use-after-free and memory leaks

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>

diff --git a/drivers/media/video/pwc/pwc-if.c b/drivers/media/video/pwc/pwc-if.c
index 8d17cf6..f976df4 100644 (file)
--- a/drivers/media/video/pwc/pwc-if.c
+++ b/drivers/media/video/pwc/pwc-if.c
@@ -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;
@@ -1072,6 +1073,7 @@ err:
 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);
@@ -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 */
@@ -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)
@@ -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);
@@ -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
@@ -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;
@@ -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);
@@ -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);
@@ -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;
@@ -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);
@@ -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 */

diff --git a/drivers/media/video/pwc/pwc.h b/drivers/media/video/pwc/pwc.h
index 844565b..0902355 100644 (file)
--- a/drivers/media/video/pwc/pwc.h
+++ b/drivers/media/video/pwc/pwc.h
@@ -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 ***/