linux-kernel - [PATCH] Smack: Use memdup_user() rather than duplicating its implementation

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Date:   Sun, 21 Aug 2016 20:26:15 +0200
From:   SF Markus Elfring <elfring@...rs.sourceforge.net>
To:     linux-security-module@...r.kernel.org,
        Casey Schaufler <casey@...aufler-ca.com>,
        James Morris <james.l.morris@...cle.com>,
        "Serge E. Hallyn" <serge@...lyn.com>
Cc:     LKML <linux-kernel@...r.kernel.org>,
        kernel-janitors@...r.kernel.org,
        Julia Lawall <julia.lawall@...6.fr>,
        Nicolas Palix <nicolas.palix@...g.fr>
Subject: [PATCH] Smack: Use memdup_user() rather than duplicating its
 implementation

From: Markus Elfring <elfring@...rs.sourceforge.net>
Date: Sun, 21 Aug 2016 20:17:36 +0200

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@...rs.sourceforge.net>
---
 security/smack/smackfs.c | 11 +++--------
 1 file changed, 3 insertions(+), 8 deletions(-)

diff --git a/security/smack/smackfs.c b/security/smack/smackfs.c
index e249a66..6492fe9 100644
--- a/security/smack/smackfs.c
+++ b/security/smack/smackfs.c
@@ -2523,14 +2523,9 @@ 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)) {
-- 
2.9.3