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>

2 files changed, 36 insertions, 43 deletions

diff --git a/drivers/media/video/pwc/pwc-if.c b/drivers/media/video/pwc/pwc-if.c
index 8d17cf613306..f976df452a34 100644
--- 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 844565bde53b..0902355dfa77 100644
--- 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 ***/