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From: Dan Carpenter <dan.carpenter@oracle.com>
To: "Michael S. Tsirkin" <mst@redhat.com>,
	Xie Yongji <xieyongji@bytedance.com>
Cc: Jason Wang <jasowang@redhat.com>,
	Stefano Garzarella <sgarzare@redhat.com>,
	Parav Pandit <parav@nvidia.com>,
	virtualization@lists.linux-foundation.org,
	kernel-janitors@vger.kernel.org
Subject: [PATCH] vduse: check that offset is within bounds in get_config()
Date: Wed, 8 Dec 2021 18:09:56 +0300	[thread overview]
Message-ID: <20211208150956.GA29160@kili> (raw)

This condition checks "len" but it does not check "offset" and that
could result in an out of bounds read if "offset > dev->config_size".
The problem is that since both variables are unsigned the
"dev->config_size - offset" subtraction would result in a very high
unsigned value.

I think these checks might not be necessary because "len" and "offset"
are supposed to already have been validated using the
vhost_vdpa_config_validate() function.  But I do not know the code
perfectly, and I like to be safe.

Fixes: c8a6153b6c59 ("vduse: Introduce VDUSE - vDPA Device in Userspace")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
 drivers/vdpa/vdpa_user/vduse_dev.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c
index c9204c62f339..6693a2c9e4a6 100644
--- a/drivers/vdpa/vdpa_user/vduse_dev.c
+++ b/drivers/vdpa/vdpa_user/vduse_dev.c
@@ -655,7 +655,8 @@ static void vduse_vdpa_get_config(struct vdpa_device *vdpa, unsigned int offset,
 {
 	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
 
-	if (len > dev->config_size - offset)
+	if (offset > dev->config_size ||
+	    len > dev->config_size - offset)
 		return;
 
 	memcpy(buf, dev->config + offset, len);
-- 
2.20.1


WARNING: multiple messages have this Message-ID (diff)
From: Dan Carpenter <dan.carpenter@oracle.com>
To: "Michael S. Tsirkin" <mst@redhat.com>,
	Xie Yongji <xieyongji@bytedance.com>
Cc: kernel-janitors@vger.kernel.org,
	virtualization@lists.linux-foundation.org
Subject: [PATCH] vduse: check that offset is within bounds in get_config()
Date: Wed, 8 Dec 2021 18:09:56 +0300	[thread overview]
Message-ID: <20211208150956.GA29160@kili> (raw)

This condition checks "len" but it does not check "offset" and that
could result in an out of bounds read if "offset > dev->config_size".
The problem is that since both variables are unsigned the
"dev->config_size - offset" subtraction would result in a very high
unsigned value.

I think these checks might not be necessary because "len" and "offset"
are supposed to already have been validated using the
vhost_vdpa_config_validate() function.  But I do not know the code
perfectly, and I like to be safe.

Fixes: c8a6153b6c59 ("vduse: Introduce VDUSE - vDPA Device in Userspace")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
 drivers/vdpa/vdpa_user/vduse_dev.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c
index c9204c62f339..6693a2c9e4a6 100644
--- a/drivers/vdpa/vdpa_user/vduse_dev.c
+++ b/drivers/vdpa/vdpa_user/vduse_dev.c
@@ -655,7 +655,8 @@ static void vduse_vdpa_get_config(struct vdpa_device *vdpa, unsigned int offset,
 {
 	struct vduse_dev *dev = vdpa_to_vduse(vdpa);
 
-	if (len > dev->config_size - offset)
+	if (offset > dev->config_size ||
+	    len > dev->config_size - offset)
 		return;
 
 	memcpy(buf, dev->config + offset, len);
-- 
2.20.1

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             reply	other threads:[~2021-12-08 15:10 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-12-08 15:09 Dan Carpenter [this message]
2021-12-08 15:09 ` [PATCH] vduse: check that offset is within bounds in get_config() Dan Carpenter

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