linux-kernel - [PATCH] VMCI: use memdup

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Date:	Fri, 20 May 2016 17:48:56 +0530
From:	Muhammad Falak R Wani <falakreyaz@...il.com>
To:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:	Alessandro Zummo <a.zummo@...ertech.it>,
	Mike Snitzer <snitzer@...hat.com>,
	Alexandre Belloni <alexandre.belloni@...e-electrons.com>,
	Joel Becker <jlbec@...lplan.org>, linux-kernel@...r.kernel.org
Subject: [PATCH] VMCI: 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/misc/vmw_vmci/vmci_host.c | 14 ++++----------
 1 file changed, 4 insertions(+), 10 deletions(-)

diff --git a/drivers/misc/vmw_vmci/vmci_host.c b/drivers/misc/vmw_vmci/vmci_host.c
index 9ec262a..ec09010 100644
--- a/drivers/misc/vmw_vmci/vmci_host.c
+++ b/drivers/misc/vmw_vmci/vmci_host.c
@@ -381,18 +381,12 @@ static int vmci_host_do_send_datagram(struct vmci_host_dev *vmci_host_dev,
 		return -EINVAL;
 	}
 
-	dg = kmalloc(send_info.len, GFP_KERNEL);
-	if (!dg) {
+	dg = memdup_user((void __user *)(uintptr_t)send_info.addr,
+			 send_info.len);
+	if (IS_ERR(dg)) {
 		vmci_ioctl_err(
 			"cannot allocate memory to dispatch datagram\n");
-		return -ENOMEM;
-	}
-
-	if (copy_from_user(dg, (void __user *)(uintptr_t)send_info.addr,
-			   send_info.len)) {
-		vmci_ioctl_err("error getting datagram\n");
-		kfree(dg);
-		return -EFAULT;
+		return PTR_ERR(dg);
 	}
 
 	if (VMCI_DG_SIZE(dg) != send_info.len) {
-- 
1.9.1