tun: Use memdup_user() rather than duplicating its implementation

Reuse existing functionality from memdup_user() instead of keeping
duplicate source code.

This issue was detected by using the Coccinelle software.

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Reviewed-by: Shmulik Ladkani <shmulik.ladkani@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 9c8b5bc..a1aeccb 100644 (file)
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -731,14 +731,9 @@ static int update_filter(struct tap_filter *filter, void __user *arg)
        }
 
        alen = ETH_ALEN * uf.count;
-       addr = kmalloc(alen, GFP_KERNEL);
-       if (!addr)
-               return -ENOMEM;
-
-       if (copy_from_user(addr, arg + sizeof(uf), alen)) {
-               err = -EFAULT;
-               goto done;
-       }
+       addr = memdup_user(arg + sizeof(uf), alen);
+       if (IS_ERR(addr))
+               return PTR_ERR(addr);
 
        /* The filter is updated without holding any locks. Which is
         * perfectly safe. We disable it first and in the worst