On 11/1/21 06:02, Dongliang Mu wrote:
Hi all,
My local syzkaller instance found one bug named "memory leak in
em28xx_init_dev" in 5.14-rc5. Kernel configuration and PoC file are
attached(I don't check if the latest kernel is vulnerable, but it
should be). The trace from memleak is as follows:
backtrace:
[<ffffffff842cc66d>] kmalloc include/linux/slab.h:591 [inline]
[<ffffffff842cc66d>] kzalloc include/linux/slab.h:721 [inline]
[<ffffffff842cc66d>] em28xx_media_device_init
drivers/media/usb/em28xx/em28xx-cards.c:3444 [inline]
[<ffffffff842cc66d>] em28xx_init_dev.isra.0+0x366/0x9bf
drivers/media/usb/em28xx/em28xx-cards.c:3624
[<ffffffff842cd1bd>] em28xx_usb_probe.cold+0x4f7/0xf95
drivers/media/usb/em28xx/em28xx-cards.c:3979
[<ffffffff82bf0815>] usb_probe_interface+0x185/0x350
drivers/usb/core/driver.c:396
Looks like missing clean up on error handling path.
->probe()
em28xx_init_dev()
em28xx_media_device_init() <- dev->media_dev allocated
*error somewhere in em28xx_init_dev()*
And then nothing unwinds em28xx_media_device_init() call, since
disconnect won't be called in case of failure in ->probe()
Just build tested, but, I guess, something like this should work.
With regards,
Pavel Skripkin
diff --git a/drivers/media/usb/em28xx/em28xx-cards.c b/drivers/media/usb/em28xx/em28xx-cards.c
index c1e0dccb7408..f22e5ca2d1b3 100644
--- a/drivers/media/usb/em28xx/em28xx-cards.c
+++ b/drivers/media/usb/em28xx/em28xx-cards.c
@@ -3626,7 +3626,7 @@ static int em28xx_init_dev(struct em28xx *dev, struct usb_device *udev,
if (dev->is_audio_only) {
retval = em28xx_audio_setup(dev);
if (retval)
- return -ENODEV;
+ goto deinit_media;
em28xx_init_extension(dev);
return 0;
@@ -3645,7 +3645,7 @@ static int em28xx_init_dev(struct em28xx *dev, struct usb_device *udev,
dev_err(&dev->intf->dev,
"%s: em28xx_i2c_register bus 0 - error [%d]!\n",
__func__, retval);
- return retval;
+ goto deinit_media;
}
/* register i2c bus 1 */
@@ -3663,7 +3663,7 @@ static int em28xx_init_dev(struct em28xx *dev, struct usb_device *udev,
em28xx_i2c_unregister(dev, 0);
- return retval;
+ goto deinit_media;
}
}
@@ -3671,6 +3671,10 @@ static int em28xx_init_dev(struct em28xx *dev, struct usb_device *udev,
em28xx_card_setup(dev);
return 0;
+
+deinit_media:
+ em28xx_unregister_media_device(dev);
+ return retval;
}
static int em28xx_duplicate_dev(struct em28xx *dev)
