[PATCH v2 16/24] drm/i915/gvt: use vmalloc_array and vcalloc

From: Julia Lawall
Date: Tue Jun 27 2023 - 10:46:40 EST


Use vmalloc_array and vcalloc to protect against
multiplication overflows.

The changes were done using the following Coccinelle
semantic patch:

// <smpl>
@initialize:ocaml@
@@

let rename alloc =
match alloc with
"vmalloc" -> "vmalloc_array"
| "vzalloc" -> "vcalloc"
| _ -> failwith "unknown"

@@
size_t e1,e2;
constant C1, C2;
expression E1, E2, COUNT, x1, x2, x3;
typedef u8;
typedef __u8;
type t = {u8,__u8,char,unsigned char};
identifier alloc = {vmalloc,vzalloc};
fresh identifier realloc = script:ocaml(alloc) { rename alloc };
@@

(
alloc(x1*x2*x3)
|
alloc(C1 * C2)
|
alloc((sizeof(t)) * (COUNT), ...)
|
- alloc((e1) * (e2))
+ realloc(e1, e2)
|
- alloc((e1) * (COUNT))
+ realloc(COUNT, e1)
|
- alloc((E1) * (E2))
+ realloc(E1, E2)
)
// </smpl>

Signed-off-by: Julia Lawall <Julia.Lawall@xxxxxxxx>

---
v2: Use vmalloc_array and vcalloc instead of array_size.
This also leaves a multiplication of a constant by a sizeof
as is. Two patches are thus dropped from the series.

drivers/gpu/drm/i915/gvt/gtt.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

diff -u -p a/drivers/gpu/drm/i915/gvt/gtt.c b/drivers/gpu/drm/i915/gvt/gtt.c
--- a/drivers/gpu/drm/i915/gvt/gtt.c
+++ b/drivers/gpu/drm/i915/gvt/gtt.c
@@ -1969,14 +1969,16 @@ static struct intel_vgpu_mm *intel_vgpu_
return ERR_PTR(-ENOMEM);
}

- mm->ggtt_mm.host_ggtt_aperture = vzalloc((vgpu_aperture_sz(vgpu) >> PAGE_SHIFT) * sizeof(u64));
+ mm->ggtt_mm.host_ggtt_aperture = vcalloc(vgpu_aperture_sz(vgpu) >> PAGE_SHIFT,
+ sizeof(u64));
if (!mm->ggtt_mm.host_ggtt_aperture) {
vfree(mm->ggtt_mm.virtual_ggtt);
vgpu_free_mm(mm);
return ERR_PTR(-ENOMEM);
}

- mm->ggtt_mm.host_ggtt_hidden = vzalloc((vgpu_hidden_sz(vgpu) >> PAGE_SHIFT) * sizeof(u64));
+ mm->ggtt_mm.host_ggtt_hidden = vcalloc(vgpu_hidden_sz(vgpu) >> PAGE_SHIFT,
+ sizeof(u64));
if (!mm->ggtt_mm.host_ggtt_hidden) {
vfree(mm->ggtt_mm.host_ggtt_aperture);
vfree(mm->ggtt_mm.virtual_ggtt);