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Commit f1c2e33c authored by Julia Lawall's avatar Julia Lawall Committed by Jean Delvare
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i2c-dev: Use memdup_user 

Use memdup_user when user data is immediately copied into the allocated
region.  Note that in the second case, the ++i is no longer necessary, as
the last value is already freed if needed by the call to memdup_user.

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: default avatarJulia Lawall <julia@diku.dk>
Signed-off-by: default avatarJean Delvare <khali@linux-fr.org>
parent 35a56c5b

drivers/i2c/i2c-dev.c

+6 −16
Original line number Diff line number Diff line
@@ -167,13 +167,9 @@ static ssize_t i2cdev_write(struct file *file, const char __user *buf, 
	if (count > 8192)

		count = 8192;



	tmp = kmalloc(count, GFP_KERNEL);

	if (tmp == NULL)

		return -ENOMEM;

	if (copy_from_user(tmp, buf, count)) {

		kfree(tmp);

		return -EFAULT;

	}

	tmp = memdup_user(buf, count);

	if (IS_ERR(tmp))

		return PTR_ERR(tmp);



	pr_debug("i2c-dev: i2c-%d writing %zu bytes.\n",

		iminor(file->f_path.dentry->d_inode), count);
@@ -245,15 +241,9 @@ static noinline int i2cdev_ioctl_rdrw(struct i2c_client *client, 
			break;

		}

		data_ptrs[i] = (u8 __user *)rdwr_pa[i].buf;

		rdwr_pa[i].buf = kmalloc(rdwr_pa[i].len, GFP_KERNEL);

		if (rdwr_pa[i].buf == NULL) {

			res = -ENOMEM;

			break;

		}

		if (copy_from_user(rdwr_pa[i].buf, data_ptrs[i],

				   rdwr_pa[i].len)) {

				++i; /* Needs to be kfreed too */

				res = -EFAULT;

		rdwr_pa[i].buf = memdup_user(data_ptrs[i], rdwr_pa[i].len);

		if (IS_ERR(rdwr_pa[i].buf)) {

			res = PTR_ERR(rdwr_pa[i].buf);

			break;

		}

	}