From: Markus Elfring <elfring@users.sourceforge.net>
Date: Sat, 20 Aug 2016 06:54:15 +0000 (+0200)
Subject: tun: Use memdup_user() rather than duplicating its implementation
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=28e8190d2fb3918b5d46acafeb1968cd26e30dad;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git

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 9c8b5bc2b9d8..a1aeccbce6d4 100644
--- 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