Patch "wext: Fix 32 bit iwpriv compatibility issue with 64 bit Kernel" has been added to the 4.4-stable tree

This is a note to let you know that I've just added the patch titled

wext: Fix 32 bit iwpriv compatibility issue with 64 bit Kernel

to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
wext-fix-32-bit-iwpriv-compatibility-issue-with-64-bit-kernel.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Prasun Maiti <[email protected]>
Date: Mon, 6 Jun 2016 20:04:19 +0530
Subject: wext: Fix 32 bit iwpriv compatibility issue with 64 bit Kernel

From: Prasun Maiti <[email protected]>

commit 3d5fdff46c4b2b9534fa2f9fc78e90a48e0ff724 upstream.

iwpriv app uses iw_point structure to send data to Kernel. The iw_point structure holds a pointer. For compatibility Kernel converts the pointer as required for WEXT IOCTLs (SIOCIWFIRST to SIOCIWLAST). Some drivers may use iw_handler_def.private_args to populate iwpriv commands instead of iw_handler_def.private. For those case, the IOCTLs from SIOCIWFIRSTPRIV to SIOCIWLASTPRIV will follow the path ndo_do_ioctl(). Accordingly when the filled up iw_point structure comes from 32 bit iwpriv to 64 bit Kernel, Kernel will not convert the pointer and sends it to driver. So, the driver may get the invalid data.

The pointer conversion for the IOCTLs (SIOCIWFIRSTPRIV to SIOCIWLASTPRIV), which follow the path ndo_do_ioctl(), is mandatory. This patch adds pointer conversion from 32 bit to 64 bit and vice versa, if the ioctl comes from 32 bit iwpriv to 64 bit Kernel.

---
 net/wireless/wext-core.c |   25 +++++++++++++++++++++++--
 1 file changed, 23 insertions(+), 2 deletions(-)

@@ -955,8 +955,29 @@ static int wireless_process_ioctl(struct
 			return private(dev, iwr, cmd, info, handler);
 	}
 	/* Old driver API : call driver ioctl handler */
-	if (dev->netdev_ops->ndo_do_ioctl)
-		return dev->netdev_ops->ndo_do_ioctl(dev, ifr, cmd);
+	if (dev->netdev_ops->ndo_do_ioctl) {
+#ifdef CONFIG_COMPAT
+		if (info->flags & IW_REQUEST_FLAG_COMPAT) {
+			int ret = 0;
+			struct iwreq iwr_lcl;
+			struct compat_iw_point *iwp_compat = (void *) &iwr->u.data;
+
+			memcpy(&iwr_lcl, iwr, sizeof(struct iwreq));
+			iwr_lcl.u.data.pointer = compat_ptr(iwp_compat->pointer);
+			iwr_lcl.u.data.length = iwp_compat->length;
+			iwr_lcl.u.data.flags = iwp_compat->flags;
+
+			ret = dev->netdev_ops->ndo_do_ioctl(dev, (void *) &iwr_lcl, cmd);
+
+			iwp_compat->pointer = ptr_to_compat(iwr_lcl.u.data.pointer);
+			iwp_compat->length = iwr_lcl.u.data.length;
+			iwp_compat->flags = iwr_lcl.u.data.flags;
+
+			return ret;
+		} else
+#endif
+			return dev->netdev_ops->ndo_do_ioctl(dev, ifr, cmd);
+	}
 	return -EOPNOTSUPP;
 }
 

Patches currently in stable-queue which might be from [email protected] are

queue-4.4/wext-fix-32-bit-iwpriv-compatibility-issue-with-64-bit-kernel.patch