On Tue, Jun 27, 2023 at 7:44 AM Julia Lawall Julia.Lawall@inria.fr wrote:
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. Two patches are thus dropped from the series.
drivers/dma-buf/heaps/system_heap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff -u -p a/drivers/dma-buf/heaps/system_heap.c b/drivers/dma-buf/heaps/system_heap.c --- a/drivers/dma-buf/heaps/system_heap.c +++ b/drivers/dma-buf/heaps/system_heap.c @@ -221,7 +221,7 @@ static void *system_heap_do_vmap(struct { struct sg_table *table = &buffer->sg_table; int npages = PAGE_ALIGN(buffer->len) / PAGE_SIZE;
struct page **pages = vmalloc(sizeof(struct page *) * npages);
struct page **pages = vmalloc_array(npages, sizeof(struct page *)); struct page **tmp = pages; struct sg_page_iter piter; void *vaddr;
Seems reasonable. Thanks for sending this out!
Acked-by: John Stultz jstultz@google.com
thanks -john