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Subject[094/127] HID: hidraw, fix a NULL pointer dereference in hidraw_ioctl
2.6.32-stable review patch.  If anyone has any objections, please let us know.

------------------

From: Antonio Ospite <ospite@studenti.unina.it>

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>

---
drivers/hid/hidraw.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)

--- a/drivers/hid/hidraw.c
+++ b/drivers/hid/hidraw.c
@@ -237,11 +237,16 @@ static long hidraw_ioctl(struct file *fi
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 *fi

ret = -ENOTTY;
}
+out:
unlock_kernel();
return ret;
}



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