From 298d275d4d9bea3524ff4bc76678c140611d8a8d Mon Sep 17 00:00:00 2001 From: Juergen Gross Date: Wed, 25 Oct 2017 17:08:07 +0200 Subject: [PATCH] xen/gntdev: avoid out of bounds access in case of partial gntdev_mmap() In case gntdev_mmap() succeeds only partially in mapping grant pages it will leave some vital information uninitialized needed later for cleanup. This will lead to an out of bounds array access when unmapping the already mapped pages. So just initialize the data needed for unmapping the pages a little bit earlier. Cc: Reported-by: Arthur Borsboom Signed-off-by: Juergen Gross Reviewed-by: Boris Ostrovsky Signed-off-by: Boris Ostrovsky --- drivers/xen/gntdev.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c index 8236059..57efbd3 100644 --- a/drivers/xen/gntdev.c +++ b/drivers/xen/gntdev.c @@ -1024,6 +1024,7 @@ static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma) mutex_unlock(&priv->lock); if (use_ptemod) { + map->pages_vm_start = vma->vm_start; err = apply_to_page_range(vma->vm_mm, vma->vm_start, vma->vm_end - vma->vm_start, find_grant_ptes, map); @@ -1061,7 +1062,6 @@ static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma) set_grant_ptes_as_special, NULL); } #endif - map->pages_vm_start = vma->vm_start; } return 0; -- 2.7.4