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Subject[PATCH] hidraw: Fix crash on HIDIOCGFEATURE with a destroyed device
Date
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.

Signed-off-by: Rodrigo Rivas Costa <rodrigorivascosta@gmail.com>
---
drivers/hid/hidraw.c | 5 +++++
1 file changed, 5 insertions(+)

diff --git a/drivers/hid/hidraw.c b/drivers/hid/hidraw.c
index 5fbe0f81ab2e..01b5a9f01814 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) {
--
2.16.3
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