[v19,14/15] vfio/type1: untag user pointers in vaddr_get_pfn
diff mbox series

Message ID 87422b4d72116a975896f2b19b00f38acbd28f33.1563904656.git.andreyknvl@google.com
State New
Headers show
Series
  • arm64: untag user pointers passed to the kernel
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Commit Message

Andrey Konovalov July 23, 2019, 5:58 p.m. UTC
This patch is a part of a series that extends kernel ABI to allow to pass
tagged user pointers (with the top byte set to something else other than
0x00) as syscall arguments.

vaddr_get_pfn() uses provided user pointers for vma lookups, which can
only by done with untagged pointers.

Untag user pointers in this function.

Reviewed-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
---
 drivers/vfio/vfio_iommu_type1.c | 2 ++
 1 file changed, 2 insertions(+)

Patch
diff mbox series

diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index 054391f30fa8..67a24b4d0fa4 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -368,6 +368,8 @@  static int vaddr_get_pfn(struct mm_struct *mm, unsigned long vaddr,
 
 	down_read(&mm->mmap_sem);
 
+	vaddr = untagged_addr(vaddr);
+
 	vma = find_vma_intersection(mm, vaddr, vaddr + 1);
 
 	if (vma && vma->vm_flags & VM_PFNMAP) {