linux-kernel - [PATCH] staging: gdm72xx: add userspace data struct

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Message-Id: <1449738672-24429-1-git-send-email-nauxuron@wimdewith.com>
Date:	Thu, 10 Dec 2015 10:11:12 +0100
From:	Wim de With <nauxuron@...dewith.com>
To:	gregkh@...uxfoundation.org
Cc:	devel@...verdev.osuosl.org, linux-kernel@...r.kernel.org,
	Wim de With <nauxuron@...dewith.com>
Subject: [PATCH] staging: gdm72xx: add userspace data struct

This fixes the sparse warnings about dereferencing a userspace pointer.

However, gdm_wimax_ioctl_get_data and gdm_wimax_ioctl_set_data both
carefully check whether the pointers and data are valid, gdm_update_fsm
does not. It simply casts userspace data to struct fsm_s. I haven't
fixed this, and am not sure what to do about it.

Signed-off-by: Wim de With <nauxuron@...dewith.com>
---
 drivers/staging/gdm72xx/gdm_wimax.c | 17 +++++++++++++----
 drivers/staging/gdm72xx/wm_ioctl.h  |  7 ++++++-
 2 files changed, 19 insertions(+), 5 deletions(-)

diff --git a/drivers/staging/gdm72xx/gdm_wimax.c b/drivers/staging/gdm72xx/gdm_wimax.c
index d9ddced..16eac61 100644
--- a/drivers/staging/gdm72xx/gdm_wimax.c
+++ b/drivers/staging/gdm72xx/gdm_wimax.c
@@ -368,7 +368,7 @@ static void kdelete(void **buf)
 	}
 }
 
-static int gdm_wimax_ioctl_get_data(struct data_s *dst, struct data_s *src)
+static int gdm_wimax_ioctl_get_data(struct udata_s *dst, struct data_s *src)
 {
 	int size;
 
@@ -384,7 +384,7 @@ static int gdm_wimax_ioctl_get_data(struct data_s *dst, struct data_s *src)
 	return 0;
 }
 
-static int gdm_wimax_ioctl_set_data(struct data_s *dst, struct data_s *src)
+static int gdm_wimax_ioctl_set_data(struct data_s *dst, struct udata_s *src)
 {
 	if (!src->size) {
 		dst->size = 0;
@@ -460,6 +460,7 @@ static int gdm_wimax_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
 	struct wm_req_s *req = (struct wm_req_s *)ifr;
 	struct nic *nic = netdev_priv(dev);
 	int ret;
+	void *fsm_buf;
 
 	if (cmd != SIOCWMIOCTL)
 		return -EOPNOTSUPP;
@@ -482,8 +483,16 @@ static int gdm_wimax_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
 				/* NOTE: gdm_update_fsm should be called
 				 * before gdm_wimax_ioctl_set_data is called.
 				 */
-				gdm_update_fsm(dev,
-					       req->data.buf);
+				fsm_buf = kmalloc(sizeof(fsm_s), GFP_KERNEL);
+				if (!fsm_buf)
+					return -ENOMEM;
+				if (copy_from_user(fsm_buf, req->data.buf,
+						   sizeof(fsm_s))) {
+					kfree(fsm_buf);
+					return -EFAULT;
+				}
+				gdm_update_fsm(dev, fsm_buf);
+				kfree(fsm_buf);
 			}
 			ret = gdm_wimax_ioctl_set_data(
 				&nic->sdk_data[req->data_id], &req->data);
diff --git a/drivers/staging/gdm72xx/wm_ioctl.h b/drivers/staging/gdm72xx/wm_ioctl.h
index ed8f649..631cb1d 100644
--- a/drivers/staging/gdm72xx/wm_ioctl.h
+++ b/drivers/staging/gdm72xx/wm_ioctl.h
@@ -78,13 +78,18 @@ struct data_s {
 	void	*buf;
 };
 
+struct udata_s {
+	int		size;
+	void __user	*buf;
+};
+
 struct wm_req_s {
 	union {
 		char ifrn_name[IFNAMSIZ];
 	} ifr_ifrn;
 	unsigned short	cmd;
 	unsigned short	data_id;
-	struct data_s	data;
+	struct udata_s	data;
 
 /* NOTE: sizeof(struct wm_req_s) must be less than sizeof(struct ifreq). */
 };
-- 
2.6.3

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