drm/msm: protect against faults from copy_from_user() in submit ioctl
An evil userspace could try to cause deadlock by passing an unfaulted-in GEM bo as submit->bos (or submit->cmds) table. Which will trigger msm_gem_fault() while we already hold struct_mutex. See: https://github.com/freedreno/msmtest/blob/master/evilsubmittest.c Cc: stable@vger.kernel.org Signed-off-by: Rob Clark <robdclark@gmail.com>
This commit is contained in:
Родитель
89f82cbb0d
Коммит
d78d383ab3
|
@ -157,6 +157,12 @@ struct msm_drm_private {
|
|||
struct shrinker shrinker;
|
||||
|
||||
struct msm_vblank_ctrl vblank_ctrl;
|
||||
|
||||
/* task holding struct_mutex.. currently only used in submit path
|
||||
* to detect and reject faults from copy_from_user() for submit
|
||||
* ioctl.
|
||||
*/
|
||||
struct task_struct *struct_mutex_task;
|
||||
};
|
||||
|
||||
struct msm_format {
|
||||
|
|
|
@ -196,11 +196,20 @@ int msm_gem_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
|
|||
{
|
||||
struct drm_gem_object *obj = vma->vm_private_data;
|
||||
struct drm_device *dev = obj->dev;
|
||||
struct msm_drm_private *priv = dev->dev_private;
|
||||
struct page **pages;
|
||||
unsigned long pfn;
|
||||
pgoff_t pgoff;
|
||||
int ret;
|
||||
|
||||
/* This should only happen if userspace tries to pass a mmap'd
|
||||
* but unfaulted gem bo vaddr into submit ioctl, triggering
|
||||
* a page fault while struct_mutex is already held. This is
|
||||
* not a valid use-case so just bail.
|
||||
*/
|
||||
if (priv->struct_mutex_task == current)
|
||||
return VM_FAULT_SIGBUS;
|
||||
|
||||
/* Make sure we don't parallel update on a fault, nor move or remove
|
||||
* something from beneath our feet
|
||||
*/
|
||||
|
|
|
@ -394,6 +394,8 @@ int msm_ioctl_gem_submit(struct drm_device *dev, void *data,
|
|||
if (ret)
|
||||
return ret;
|
||||
|
||||
priv->struct_mutex_task = current;
|
||||
|
||||
submit = submit_create(dev, gpu, args->nr_bos, args->nr_cmds);
|
||||
if (!submit) {
|
||||
ret = -ENOMEM;
|
||||
|
@ -485,6 +487,7 @@ out:
|
|||
if (ret)
|
||||
msm_gem_submit_free(submit);
|
||||
out_unlock:
|
||||
priv->struct_mutex_task = NULL;
|
||||
mutex_unlock(&dev->struct_mutex);
|
||||
return ret;
|
||||
}
|
||||
|
|
Загрузка…
Ссылка в новой задаче