From: Antonio Ospite <ospite@studenti.unina.it>
Date: Tue, 5 Oct 2010 15:20:16 +0000 (+0200)
Subject: HID: hidraw, fix a NULL pointer dereference in hidraw_ioctl
X-Git-Tag: v2.6.32.27~34
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=7cbf7431e259aa462db37fbefc146fbf2a416805;p=karo-tx-linux.git

HID: hidraw, fix a NULL pointer dereference in hidraw_ioctl

commit d20d5ffab92f00188f360c44c791a5ffb988247c upstream.

BUG: unable to handle kernel NULL pointer dereference at 0000000000000028
IP: [<ffffffffa02c66b4>] hidraw_ioctl+0xfc/0x32c [hid]
[...]

This is reproducible by disconnecting the device while userspace does
ioctl in a loop and doesn't check return values in order to exit the
loop.

Signed-off-by: Antonio Ospite <ospite@studenti.unina.it>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---

diff --git a/drivers/hid/hidraw.c b/drivers/hid/hidraw.c
index cdd136942bca..3b53475a2b3d 100644
--- a/drivers/hid/hidraw.c
+++ b/drivers/hid/hidraw.c
@@ -237,11 +237,16 @@ static long hidraw_ioctl(struct file *file, unsigned int cmd,
 	struct inode *inode = file->f_path.dentry->d_inode;
 	unsigned int minor = iminor(inode);
 	long ret = 0;
-	/* FIXME: What stops hidraw_table going NULL */
-	struct hidraw *dev = hidraw_table[minor];
+	struct hidraw *dev;
 	void __user *user_arg = (void __user*) arg;
 
 	lock_kernel();
+	dev = hidraw_table[minor];
+	if (!dev) {
+		ret = -ENODEV;
+		goto out;
+	}
+
 	switch (cmd) {
 		case HIDIOCGRDESCSIZE:
 			if (put_user(dev->hid->rsize, (int __user *)arg))
@@ -314,6 +319,7 @@ static long hidraw_ioctl(struct file *file, unsigned int cmd,
 
 		ret = -ENOTTY;
 	}
+out:
 	unlock_kernel();
 	return ret;
 }