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Subject[PATCH v2 20/24] comedi: use vmalloc_array and vcalloc
Date
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@inria.fr>

---
v2: Use vmalloc_array and vcalloc instead of array_size.
This also leaves a multiplication of a constant by a sizeof
as is. The position of this patch in the series changed
accordingly.

drivers/comedi/comedi_buf.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff -u -p a/drivers/comedi/comedi_buf.c b/drivers/comedi/comedi_buf.c
--- a/drivers/comedi/comedi_buf.c
+++ b/drivers/comedi/comedi_buf.c
@@ -89,7 +89,7 @@ comedi_buf_map_alloc(struct comedi_devic
bm->dma_hw_dev = get_device(dev->hw_dev);
}

- bm->page_list = vzalloc(sizeof(*buf) * n_pages);
+ bm->page_list = vcalloc(n_pages, sizeof(*buf));
if (!bm->page_list)
goto err;

@@ -169,7 +169,7 @@ static void __comedi_buf_alloc(struct co
buf = &bm->page_list[0];
async->prealloc_buf = buf->virt_addr;
} else {
- pages = vmalloc(sizeof(struct page *) * n_pages);
+ pages = vmalloc_array(n_pages, sizeof(struct page *));
if (!pages)
return;

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