linux-kernel - [PATCH] tty/vt/keyboard: use memdup

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Date:	Fri, 20 May 2016 17:53:28 +0530
From:	Muhammad Falak R Wani <falakreyaz@...il.com>
To:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:	Jiri Slaby <jslaby@...e.com>,
	Samuel Thibault <samuel.thibault@...-lyon.org>,
	Dmitry Torokhov <dmitry.torokhov@...il.com>,
	Pavel Machek <pavel@....cz>, linux-kernel@...r.kernel.org
Subject: [PATCH] tty/vt/keyboard: use memdup_user().

Use memdup_user to duplicate a memory region from user-space to
kernel-space, instead of open coding using kmalloc & copy_from_user.

Signed-off-by: Muhammad Falak R Wani <falakreyaz@...il.com>
---
 drivers/tty/vt/keyboard.c | 14 ++++----------
 1 file changed, 4 insertions(+), 10 deletions(-)

diff --git a/drivers/tty/vt/keyboard.c b/drivers/tty/vt/keyboard.c
index f973bfc..698ea43 100644
--- a/drivers/tty/vt/keyboard.c
+++ b/drivers/tty/vt/keyboard.c
@@ -1745,16 +1745,10 @@ int vt_do_diacrit(unsigned int cmd, void __user *udp, int perm)
 			return -EINVAL;
 
 		if (ct) {
-			buf = kmalloc(ct * sizeof(struct kbdiacruc),
-								GFP_KERNEL);
-			if (buf == NULL)
-				return -ENOMEM;
-
-			if (copy_from_user(buf, a->kbdiacruc,
-					ct * sizeof(struct kbdiacruc))) {
-				kfree(buf);
-				return -EFAULT;
-			}
+			buf = memdup_user(a->kbdiacruc,
+					  ct * sizeof(struct kbdiacruc));
+			if (IS_ERR(buf))
+				return PTR_ERR(buf);
 		} 
 		spin_lock_irqsave(&kbd_event_lock, flags);
 		if (ct)
-- 
1.9.1