May 22 2010

drivers/net/wan: Use memdup_user 

Author: Julia Lawall <julia@diku.dk>

Use memdup_user when user data is immediately copied into the
allocated region.

The semantic patch that makes this change is as follows:
(http://coccinelle.lip6.fr/)

// 
@@
expression from,to,size,flag;
position p;
identifier l1,l2;
@@

-  to = \(kmalloc@p\|kzalloc@p\)(size,flag);
+  to = memdup_user(from,size);
   if (
-      to==NULL
+      IS_ERR(to)
                 || ...) {
   <+... when != goto l1;
-  -ENOMEM
+  PTR_ERR(to)
   ...+>
   }
-  if (copy_from_user(to, from, size) != 0) {
-    <+... when != goto l2;
-    -EFAULT
-    ...+>
-  }
// 

Signed-off-by: Julia Lawall 
Signed-off-by: David S. Miller 

---
 drivers/net/wan/sdla.c | 11 +++--------
 1 file changed, 3 insertions(+), 8 deletions(-)
 
diff --git a/drivers/net/wan/sdla.c b/drivers/net/wan/sdla.c
index 43ae6f4..e155938 100644
--- a/drivers/net/wan/sdla.c
+++ b/drivers/net/wan/sdla.c
@@ -1211,14 +1211,9 @@ static int sdla_xfer(struct net_device *dev, struct sdla_mem __user *info, int r
 	}
 	else
 	{
-		temp = kmalloc(mem.len, GFP_KERNEL);
-		if (!temp)
-			return(-ENOMEM);
-		if(copy_from_user(temp, mem.data, mem.len))
-		{
-			kfree(temp);
-			return -EFAULT;
-		}
+		temp = memdup_user(mem.data, mem.len);
+		if (IS_ERR(temp))
+			return PTR_ERR(temp);
 		sdla_write(dev, mem.addr, temp, mem.len);
 		kfree(temp);
 	}

qlambert