Commit 24e97d76 authored Dec 09, 2020 by Ping Cheng Committed by Greg Kroah-Hartman Jan 17, 2021

HID: wacom: Fix memory leakage caused by kfifo_alloc

commit 37309f47e2f5674f3e86cb765312ace42cfcedf5 upstream.

As reported by syzbot below, kfifo_alloc'd memory would not be freed
if a non-zero return value is triggered in wacom_probe. This patch
creates and uses devm_kfifo_alloc to allocate and free itself.

BUG: memory leak
unreferenced object 0xffff88810dc44a00 (size 512):
  comm "kworker/1:2", pid 3674, jiffies 4294943617 (age 14.100s)
  hex dump (first 32 bytes):
   00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
   00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace:
   [<0000000023e1afac>] kmalloc_array include/linux/slab.h:592 [inline]
   [<0000000023e1afac>] __kfifo_alloc+0xad/0x100 lib/kfifo.c:43
   [<00000000c477f737>] wacom_probe+0x1a1/0x3b0 drivers/hid/wacom_sys.c:2727
   [<00000000b3109aca>] hid_device_probe+0x16b/0x210 drivers/hid/hid-core.c:2281
   [<00000000aff7c640>] really_probe+0x159/0x480 drivers/base/dd.c:554
   [<00000000778d0bc3>] driver_probe_device+0x84/0x100 drivers/base/dd.c:738
   [<000000005108dbb5>] __device_attach_driver+0xee/0x110 drivers/base/dd.c:844
   [<00000000efb7c59e>] bus_for_each_drv+0xb7/0x100 drivers/base/bus.c:431
   [<0000000024ab1590>] __device_attach+0x122/0x250 drivers/base/dd.c:912
   [<000000004c7ac048>] bus_probe_device+0xc6/0xe0 drivers/base/bus.c:491
   [<00000000b93050a3>] device_add+0x5ac/0xc30 drivers/base/core.c:2936
   [<00000000e5b46ea5>] hid_add_device+0x151/0x390 drivers/hid/hid-core.c:2437
   [<00000000c6add147>] usbhid_probe+0x412/0x560 drivers/hid/usbhid/hid-core.c:1407
   [<00000000c33acdb4>] usb_probe_interface+0x177/0x370 drivers/usb/core/driver.c:396
   [<00000000aff7c640>] really_probe+0x159/0x480 drivers/base/dd.c:554
   [<00000000778d0bc3>] driver_probe_device+0x84/0x100 drivers/base/dd.c:738
   [<000000005108dbb5>] __device_attach_driver+0xee/0x110 drivers/base/dd.c:844

https://syzkaller.appspot.com/bug?extid=5b49c9695968d7250a26



Reported-by:  <syzbot+5b49c9695968d7250a26@syzkaller.appspotmail.com>
Signed-off-by: Ping Cheng <ping.cheng@wacom.com>
Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent b7d8a1a0

drivers/hid/wacom_sys.c

+32 −3

Original line number	Diff line number	Diff line
		@@ -1241,6 +1241,37 @@ static int wacom_devm_sysfs_create_group(struct wacom *wacom,
		group);
		}

		static void wacom_devm_kfifo_release(struct device dev, void res)
		{
		struct kfifo_rec_ptr_2 *devres = res;

		kfifo_free(devres);
		}

		static int wacom_devm_kfifo_alloc(struct wacom *wacom)
		{
		struct wacom_wac *wacom_wac = &wacom->wacom_wac;
		struct kfifo_rec_ptr_2 *pen_fifo = &wacom_wac->pen_fifo;
		int error;

		pen_fifo = devres_alloc(wacom_devm_kfifo_release,
		sizeof(struct kfifo_rec_ptr_2),
		GFP_KERNEL);

		if (!pen_fifo)
		return -ENOMEM;

		error = kfifo_alloc(pen_fifo, WACOM_PKGLEN_MAX, GFP_KERNEL);
		if (error) {
		devres_free(pen_fifo);
		return error;
		}

		devres_add(&wacom->hdev->dev, pen_fifo);

		return 0;
		}

		enum led_brightness wacom_leds_brightness_get(struct wacom_led *led)
		{
		struct wacom *wacom = led->wacom;
		@@ -2697,7 +2728,7 @@ static int wacom_probe(struct hid_device *hdev,
		goto fail;
		}

		error = kfifo_alloc(&wacom_wac->pen_fifo, WACOM_PKGLEN_MAX, GFP_KERNEL);
		error = wacom_devm_kfifo_alloc(wacom);
		if (error)
		goto fail;

		@@ -2764,8 +2795,6 @@ static void wacom_remove(struct hid_device *hdev)
		if (wacom->wacom_wac.features.type != REMOTE)
		wacom_release_resources(wacom);

		kfifo_free(&wacom_wac->pen_fifo);

		hid_set_drvdata(hdev, NULL);
		}