[PATCH 10/27] drivers/infiniband/core: Use memdup_user

[PATCH 10/27] drivers/infiniband/core: Use memdup_user

[Julia Lawall]

From: 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/)

// <smpl>
@@
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
-    ...+>
-  }
// </smpl>

Signed-off-by: Julia Lawall <julia@diku.dk>

---
 drivers/infiniband/core/ucm.c |   11 +++--------
 1 file changed, 3 insertions(+), 8 deletions(-)

diff --git a/drivers/infiniband/core/ucm.c b/drivers/infiniband/core/ucm.c
index 4647484..08f948d 100644
--- a/drivers/infiniband/core/ucm.c
+++ b/drivers/infiniband/core/ucm.c
@@ -706,14 +706,9 @@ static int ib_ucm_alloc_data(const void **dest, u64 src, u32 len)
 	if (!len)
 		return 0;
 
-	data = kmalloc(len, GFP_KERNEL);
-	if (!data)
-		return -ENOMEM;
-
-	if (copy_from_user(data, (void __user *)(unsigned long)src, len)) {
-		kfree(data);
-		return -EFAULT;
-	}
+	data = memdup_user((void __user *)(unsigned long)src, len);
+	if (IS_ERR(data))
+		return PTR_ERR(data);
 
 	*dest = data;
 	return 0;

Re: [PATCH 10/27] drivers/infiniband/core: Use memdup_user

[walter harms]

Julia Lawall schrieb:
> From: 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/)
> 
> // <smpl>
> @@
> 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
> -    ...+>
> -  }
> // </smpl>
> 
> Signed-off-by: Julia Lawall <julia@diku.dk>
> 
> ---
>  drivers/infiniband/core/ucm.c |   11 +++--------
>  1 file changed, 3 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/infiniband/core/ucm.c b/drivers/infiniband/core/ucm.c
> index 4647484..08f948d 100644
> --- a/drivers/infiniband/core/ucm.c
> +++ b/drivers/infiniband/core/ucm.c
> @@ -706,14 +706,9 @@ static int ib_ucm_alloc_data(const void **dest, u64 src, u32 len)
>  	if (!len)
>  		return 0;
>  
> -	data = kmalloc(len, GFP_KERNEL);
> -	if (!data)
> -		return -ENOMEM;
> -
> -	if (copy_from_user(data, (void __user *)(unsigned long)src, len)) {
> -		kfree(data);
> -		return -EFAULT;
> -	}
> +	data = memdup_user((void __user *)(unsigned long)src, len);
> +	if (IS_ERR(data))
> +		return PTR_ERR(data);
>  
>  	*dest = data;
>  	return 0;
> --

This cast look strange, can it happen that (unsigned long)<(u64) ?
(is there a 32bit infiniband) ?

just my 2 cents,
 wh

Re: [PATCH 10/27] drivers/infiniband/core: Use memdup_user

[Roland Dreier]

 > > +	data = memdup_user((void __user *)(unsigned long)src, len);
 > > +	if (IS_ERR(data))
 > > +		return PTR_ERR(data);

 > This cast look strange, can it happen that (unsigned long)<(u64) ?
 > (is there a 32bit infiniband) ?

There is 32-bit infiniband.  Linux kernel assumes that unsigned long is
equivalent to uintptr_t -- in other words all pointers are the same size
as longs.  So when casting from integer to pointer we add a cast to
unsigned long to avoid a warning precisely in the 32-bit case -- we
would get a warning about cast to pointer from integer of different size
when casting from 64-bit integer to 32-bit pointer.
-- 
Roland Dreier <rolandd@cisco.com> || For corporate legal information go to:
http://www.cisco.com/web/about/doing_business/legal/cri/index.html

Re: [PATCH 10/27] drivers/infiniband/core: Use memdup_user

[Roland Dreier]

thanks, applied.
-- 
Roland Dreier <rolandd@cisco.com> || For corporate legal information go to:
http://www.cisco.com/web/about/doing_business/legal/cri/index.html