From: Rodrigo Rivas Costa <rodrigorivascosta@gmail.com>
Date: Thu, 5 Apr 2018 23:09:36 +0000 (+0200)
Subject: HID: hidraw: Fix crash on HIDIOCGFEATURE with a destroyed device
X-Git-Tag: v4.17-rc2~24^2~3
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=a955358d54695e4ad9f7d6489a7ac4d69a8fc711;p=users%2Fhch%2Fmisc.git

HID: hidraw: Fix crash on HIDIOCGFEATURE with a destroyed device

Doing `ioctl(HIDIOCGFEATURE)` in a tight loop on a hidraw device
and then disconnecting the device, or unloading the driver, can
cause a NULL pointer dereference.

When a hidraw device is destroyed it sets 0 to `dev->exist`.
Most functions check 'dev->exist' before doing its work, but
`hidraw_get_report()` was missing that check.

Cc: stable@vger.kernel.org
Signed-off-by: Rodrigo Rivas Costa <rodrigorivascosta@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
---

diff --git a/drivers/hid/hidraw.c b/drivers/hid/hidraw.c
index fbfcc8009432..b39844adea47 100644
--- a/drivers/hid/hidraw.c
+++ b/drivers/hid/hidraw.c
@@ -192,6 +192,11 @@ static ssize_t hidraw_get_report(struct file *file, char __user *buffer, size_t
 	int ret = 0, len;
 	unsigned char report_number;
 
+	if (!hidraw_table[minor] || !hidraw_table[minor]->exist) {
+		ret = -ENODEV;
+		goto out;
+	}
+
 	dev = hidraw_table[minor]->hid;
 
 	if (!dev->ll_driver->raw_request) {