From: Markus Elfring <elfring@users.sourceforge.net>
Date: Sun, 21 Aug 2016 18:17:36 +0000 (+0200)
Subject: BACKPORT: Smack: Use memdup_user() rather than duplicating its implementation
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=a801bd49a55b58698b93109231bb8dbe2e8104b8;p=platform%2Fkernel%2Flinux-stable.git

BACKPORT: Smack: 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>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
(cherry-picked from upstream 63e24c497158c066583b9c06378d89ace694265a)
---

diff --git a/security/smack/smackfs.c b/security/smack/smackfs.c
index 94bd9e41c9ec..8ab5290fb8f3 100644
--- a/security/smack/smackfs.c
+++ b/security/smack/smackfs.c
@@ -2564,14 +2564,9 @@ static ssize_t smk_write_revoke_subj(struct file *file, const char __user *buf,
 	if (count == 0 || count > SMK_LONGLABEL)
 		return -EINVAL;
 
-	data = kzalloc(count, GFP_KERNEL);
-	if (data == NULL)
-		return -ENOMEM;
-
-	if (copy_from_user(data, buf, count) != 0) {
-		rc = -EFAULT;
-		goto out_data;
-	}
+	data = memdup_user(buf, count);
+	if (IS_ERR(data))
+		return PTR_ERR(data);
 
 	cp = smk_parse_smack(data, count);
 	if (IS_ERR(cp)) {