[PATCH 1/7] Input: pegasus_notetaker: fix endpoint sanity check

Johan Hovold
2019-12-10T11:38:15Z

The driver was checking the number of endpoints of the first alternate
setting instead of the current one, something which could be used by a
malicious device (or USB descriptor fuzzer) to trigger a NULL-pointer
dereference.

Fixes: 1afca2b66aac ("Input: add Pegasus Notetaker tablet driver")
Cc: stable <stable@vger.kernel.org> # 4.8
Cc: Martin Kepplinger <martink@posteo.de>
Signed-off-by: Johan Hovold <johan@kernel.org>
---
drivers/input/tablet/pegasus_notetaker.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/input/tablet/pegasus_notetaker.c b/drivers/input/tablet/pegasus_notetaker.c
index a1f3a0cb197e..38f087404f7a 100644
--- a/drivers/input/tablet/pegasus_notetaker.c
+++ b/drivers/input/tablet/pegasus_notetaker.c
@@ -275,7 +275,7 @@ static int pegasus_probe(struct usb_interface *intf,
return -ENODEV;

/* Sanity check that the device has an endpoint */
- if (intf->altsetting[0].desc.bNumEndpoints < 1) {
+ if (intf->cur_altsetting->desc.bNumEndpoints < 1) {
dev_err(&intf->dev, "Invalid number of endpoints\n");
return -EINVAL;
}
--
2.24.0