The MIC VOP driver does two successive reads from user space to read a
variable length data structure. Kernel memory corruption can result if
the data structure changes between the two reads. This patch disallows
the chance of this happening.
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=116651
Reported by: Pengfei Wang <[email protected]>
Reviewed-by: Sudeep Dutt <[email protected]>
Signed-off-by: Ashutosh Dixit <[email protected]>
---
drivers/misc/mic/vop/vop_vringh.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/drivers/misc/mic/vop/vop_vringh.c b/drivers/misc/mic/vop/vop_vringh.c
index e94c7fb..88e4523 100644
--- a/drivers/misc/mic/vop/vop_vringh.c
+++ b/drivers/misc/mic/vop/vop_vringh.c
@@ -945,6 +945,11 @@ static long vop_ioctl(struct file *f, unsigned int cmd, unsigned long arg)
ret = -EFAULT;
goto free_ret;
}
+ /* Ensure desc has not changed between the two reads */
+ if (memcmp(&dd, dd_config, sizeof(dd))) {
+ ret = -EINVAL;
+ goto free_ret;
+ }
mutex_lock(&vdev->vdev_mutex);
mutex_lock(&vi->vop_mutex);
ret = vop_virtio_add_device(vdev, dd_config);
--
2.0.0.rc3.2.g998f840