linux-kernel - [PATCH 12/17] s390/debug: Use memdup_user() rather than duplicating its implementation

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Message-ID: <f70a1782-993e-6643-c8aa-ac9e36ce54be@users.sourceforge.net>
Date:   Sat, 3 Sep 2016 14:30:02 +0200
From:   SF Markus Elfring <elfring@...rs.sourceforge.net>
To:     linux-s390@...r.kernel.org,
        David Hildenbrand <dahi@...ux.vnet.ibm.com>,
        Heiko Carstens <heiko.carstens@...ibm.com>,
        Joe Perches <joe@...ches.com>,
        Martin Schwidefsky <schwidefsky@...ibm.com>
Cc:     LKML <linux-kernel@...r.kernel.org>,
        kernel-janitors@...r.kernel.org,
        Julia Lawall <julia.lawall@...6.fr>,
        Paolo Bonzini <pbonzini@...hat.com>
Subject: [PATCH 12/17] s390/debug: Use memdup_user() rather than duplicating
 its implementation

From: Markus Elfring <elfring@...rs.sourceforge.net>
Date: Fri, 2 Sep 2016 08:45:26 +0200

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

Signed-off-by: Markus Elfring <elfring@...rs.sourceforge.net>
---
 arch/s390/kernel/debug.c | 10 +++-------
 1 file changed, 3 insertions(+), 7 deletions(-)

diff --git a/arch/s390/kernel/debug.c b/arch/s390/kernel/debug.c
index 4a12faf..a9fcf72 100644
--- a/arch/s390/kernel/debug.c
+++ b/arch/s390/kernel/debug.c
@@ -1162,13 +1162,9 @@ debug_get_user_string(const char __user *user_buf, size_t user_len)
 {
 	char* buffer;
 
-	buffer = kmalloc(user_len + 1, GFP_KERNEL);
-	if (!buffer)
-		return ERR_PTR(-ENOMEM);
-	if (copy_from_user(buffer, user_buf, user_len) != 0) {
-		kfree(buffer);
-		return ERR_PTR(-EFAULT);
-	}
+	buffer = memdup_user(user_buf, user_len + 1);
+	if (IS_ERR(buffer))
+		return PTR_ERR(buffer);
 	/* got the string, now strip linefeed. */
 	if (buffer[user_len - 1] == '\n')
 		buffer[user_len - 1] = 0;
-- 
2.9.3