linux-kernel - [RFC PATCH 38/60] hyper_dmabuf: preventing self exporting of dma

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Message-Id: <1513711816-2618-38-git-send-email-dongwon.kim@intel.com>
Date:   Tue, 19 Dec 2017 11:29:54 -0800
From:   Dongwon Kim <dongwon.kim@...el.com>
To:     linux-kernel@...r.kernel.org
Cc:     dri-devel@...ts.freedesktop.org, xen-devel@...ts.xenproject.org,
        mateuszx.potrola@...el.com, dongwon.kim@...el.com
Subject: [RFC PATCH 38/60] hyper_dmabuf: preventing self exporting of dma_buf

Adding ID check to make sure a dma-buf is exported externally
since hyper_dmabuf only allows to export a dmabuf to a different
VM.

Signed-off-by: Dongwon Kim <dongwon.kim@...el.com>
---
 drivers/xen/hyper_dmabuf/hyper_dmabuf_ioctl.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/xen/hyper_dmabuf/hyper_dmabuf_ioctl.c b/drivers/xen/hyper_dmabuf/hyper_dmabuf_ioctl.c
index 12f7ce4..b77b156 100644
--- a/drivers/xen/hyper_dmabuf/hyper_dmabuf_ioctl.c
+++ b/drivers/xen/hyper_dmabuf/hyper_dmabuf_ioctl.c
@@ -103,6 +103,12 @@ static int hyper_dmabuf_export_remote_ioctl(struct file *filp, void *data)
 
 	export_remote_attr = (struct ioctl_hyper_dmabuf_export_remote *)data;
 
+	if (hyper_dmabuf_private.domid == export_remote_attr->remote_domain) {
+		dev_err(hyper_dmabuf_private.device,
+			"exporting to the same VM is not permitted\n");
+		return -EINVAL;
+	}
+
 	dma_buf = dma_buf_get(export_remote_attr->dmabuf_fd);
 
 	if (IS_ERR(dma_buf)) {
-- 
2.7.4