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Merge branch 'msm-fixes-4.8' of git://people.freedesktop.org/~robclark/linux into drm-fixes 

copy from user fixes.

* 'msm-fixes-4.8' of git://people.freedesktop.org/~robclark/linux:
  drm/msm: protect against faults from copy_from_user() in submit ioctl
  drm/msm: fix use of copy_from_user() while holding spinlock
This commit is contained in:
Dave Airlie 2016-09-01 06:34:09 +10:00
parent 8509eb1961 d78d383ab3
commit 27dd73503f
3 changed files with 40 additions and 5 deletions
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6
drivers/gpu/drm/msm/msm_drv.h
View File

@ -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 {

9
drivers/gpu/drm/msm/msm_gem.c
View File

@ -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
*/

30
drivers/gpu/drm/msm/msm_gem_submit.c
View File

@ -64,6 +64,14 @@ void msm_gem_submit_free(struct msm_gem_submit *submit)
kfree(submit);
}
static inline unsigned long __must_check
copy_from_user_inatomic(void *to, const void __user *from, unsigned long n)
{
if (access_ok(VERIFY_READ, from, n))
return __copy_from_user_inatomic(to, from, n);
return -EFAULT;
}
static int submit_lookup_objects(struct msm_gem_submit *submit,
struct drm_msm_gem_submit *args, struct drm_file *file)
{
@ -71,6 +79,7 @@ static int submit_lookup_objects(struct msm_gem_submit *submit,
int ret = 0;
spin_lock(&file->table_lock);
pagefault_disable();
for (i = 0; i < args->nr_bos; i++) {
struct drm_msm_gem_submit_bo submit_bo;
@ -84,10 +93,15 @@ static int submit_lookup_objects(struct msm_gem_submit *submit,
*/
submit->bos[i].flags = 0;
ret = copy_from_user(&submit_bo, userptr, sizeof(submit_bo));
if (ret) {
ret = -EFAULT;
goto out_unlock;
ret = copy_from_user_inatomic(&submit_bo, userptr, sizeof(submit_bo));
if (unlikely(ret)) {
pagefault_enable();
spin_unlock(&file->table_lock);
ret = copy_from_user(&submit_bo, userptr, sizeof(submit_bo));
if (ret)
goto out;
spin_lock(&file->table_lock);
pagefault_disable();
}
if (submit_bo.flags & ~MSM_SUBMIT_BO_FLAGS) {
@ -127,9 +141,12 @@ static int submit_lookup_objects(struct msm_gem_submit *submit,
}
out_unlock:
submit->nr_bos = i;
pagefault_enable();
spin_unlock(&file->table_lock);
out:
submit->nr_bos = i;
return ret;
}
@ -377,6 +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;
@ -468,6 +487,7 @@ out:
if (ret)
msm_gem_submit_free(submit);
out_unlock:
priv->struct_mutex_task = NULL;
mutex_unlock(&dev->struct_mutex);
return ret;
}