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 <wpengfein...@gmail.com> Reviewed-by: Sudeep Dutt <sudeep.d...@intel.com> Signed-off-by: Ashutosh Dixit <ashutosh.di...@intel.com> --- 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
