linux-kernel - [PATCH] xen/privcmd: Use memdup_array_user() in alloc

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Date: Sun, 28 Jan 2024 18:09:30 +0100
From: Markus Elfring <Markus.Elfring@....de>
To: xen-devel@...ts.xenproject.org, kernel-janitors@...r.kernel.org,
 Jürgen Groß <jgross@...e.com>,
 Oleksandr Tyshchenko <oleksandr_tyshchenko@...m.com>,
 Stefano Stabellini <sstabellini@...nel.org>
Cc: LKML <linux-kernel@...r.kernel.org>
Subject: [PATCH] xen/privcmd: Use memdup_array_user() in alloc_ioreq()

From: Markus Elfring <elfring@...rs.sourceforge.net>
Date: Sun, 28 Jan 2024 17:50:43 +0100

* The function “memdup_array_user” was added with the
  commit 313ebe47d75558511aa1237b6e35c663b5c0ec6f ("string.h: add
  array-wrappers for (v)memdup_user()").
  Thus use it accordingly.

  This issue was detected by using the Coccinelle software.

* Delete a label which became unnecessary with this refactoring.

Signed-off-by: Markus Elfring <elfring@...rs.sourceforge.net>
---
 drivers/xen/privcmd.c | 15 +++++----------
 1 file changed, 5 insertions(+), 10 deletions(-)

diff --git a/drivers/xen/privcmd.c b/drivers/xen/privcmd.c
index 35b6e306026a..2c8f6d047c11 100644
--- a/drivers/xen/privcmd.c
+++ b/drivers/xen/privcmd.c
@@ -1223,18 +1223,13 @@ struct privcmd_kernel_ioreq *alloc_ioreq(struct privcmd_ioeventfd *ioeventfd)
 	kioreq->ioreq = (struct ioreq *)(page_to_virt(pages[0]));
 	mmap_write_unlock(mm);

-	size = sizeof(*ports) * kioreq->vcpus;
-	ports = kzalloc(size, GFP_KERNEL);
-	if (!ports) {
-		ret = -ENOMEM;
+	ports = memdup_array_user(u64_to_user_ptr(ioeventfd->ports),
+				  kioreq->vcpus, sizeof(*ports));
+	if (IS_ERR(ports) {
+		ret = PTR_ERR(ports);
 		goto error_kfree;
 	}

-	if (copy_from_user(ports, u64_to_user_ptr(ioeventfd->ports), size)) {
-		ret = -EFAULT;
-		goto error_kfree_ports;
-	}
-
 	for (i = 0; i < kioreq->vcpus; i++) {
 		kioreq->ports[i].vcpu = i;
 		kioreq->ports[i].port = ports[i];
@@ -1256,7 +1251,7 @@ struct privcmd_kernel_ioreq *alloc_ioreq(struct privcmd_ioeventfd *ioeventfd)
 error_unbind:
 	while (--i >= 0)
 		unbind_from_irqhandler(irq_from_evtchn(ports[i]), &kioreq->ports[i]);
-error_kfree_ports:
+
 	kfree(ports);
 error_kfree:
 	kfree(kioreq);
--
2.43.0