i2c-dev: Use memdup_user

Use memdup_user rather than duplicating its implementation.
This is a little bit restricted to reduce false positives.

The semantic patch that makes this output is available
in scripts/coccinelle/api/memdup_user.cocci.

More information about semantic patching is available at
http://coccinelle.lip6.fr/

Signed-off-by: Thomas Meyer <thomas@m3y3r.de>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

1 files changed, 4 insertions, 9 deletions

diff --git a/drivers/i2c/i2c-dev.c b/drivers/i2c/i2c-dev.c
index 57a45ce84b2d..10e7f1e76586 100644
--- a/drivers/i2c/i2c-dev.c
+++ b/drivers/i2c/i2c-dev.c
@@ -251,15 +251,10 @@ static noinline int i2cdev_ioctl_rdrw(struct i2c_client *client,
         if (rdwr_arg.nmsgs > I2C_RDRW_IOCTL_MAX_MSGS)
                 return -EINVAL;
 
-        rdwr_pa = kmalloc(rdwr_arg.nmsgs * sizeof(struct i2c_msg), GFP_KERNEL);
-        if (!rdwr_pa)
-                return -ENOMEM;
-
-        if (copy_from_user(rdwr_pa, rdwr_arg.msgs,
-                           rdwr_arg.nmsgs * sizeof(struct i2c_msg))) {
-                kfree(rdwr_pa);
-                return -EFAULT;
-        }
+        rdwr_pa = memdup_user(rdwr_arg.msgs,
+                              rdwr_arg.nmsgs * sizeof(struct i2c_msg));
+        if (IS_ERR(rdwr_pa))
+                return PTR_ERR(rdwr_pa);
 
         data_ptrs = kmalloc(rdwr_arg.nmsgs * sizeof(u8 __user *), GFP_KERNEL);
         if (data_ptrs == NULL) {