Dan Carpenter
2021-Dec-08 15:09 UTC
[PATCH] vduse: check that offset is within bounds in get_config()
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 at 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