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>

1 files changed, 3 insertions, 8 deletions

diff --git a/security/smack/smackfs.c b/security/smack/smackfs.c
index e249a66db533..6492fe96cae4 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)) {