[PATCH v2 01/24] lib/test_vmalloc.c: use vmalloc_array and vcalloc

From: Julia Lawall
Date: Tue Jun 27 2023 - 10:45:34 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.

lib/test_vmalloc.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)

diff -u -p a/lib/test_vmalloc.c b/lib/test_vmalloc.c
--- a/lib/test_vmalloc.c
+++ b/lib/test_vmalloc.c
@@ -156,7 +156,7 @@ static int random_size_alloc_test(void)

for (i = 0; i < test_loop_count; i++) {
n = get_random_u32_inclusive(1, 100);
- p = vmalloc(n * PAGE_SIZE);
+ p = vmalloc_array(n, PAGE_SIZE);

if (!p)
return -1;
@@ -221,11 +221,11 @@ static int full_fit_alloc_test(void)
junk_length = fls(num_online_cpus());
junk_length *= (32 * 1024 * 1024 / PAGE_SIZE);

- ptr = vmalloc(sizeof(void *) * junk_length);
+ ptr = vmalloc_array(junk_length, sizeof(void *));
if (!ptr)
return rv;

- junk_ptr = vmalloc(sizeof(void *) * junk_length);
+ junk_ptr = vmalloc_array(junk_length, sizeof(void *));
if (!junk_ptr) {
vfree(ptr);
return rv;
@@ -271,7 +271,8 @@ static int fix_size_alloc_test(void)
if (use_huge)
ptr = vmalloc_huge((nr_pages > 0 ? nr_pages:1) * PAGE_SIZE, GFP_KERNEL);
else
- ptr = vmalloc((nr_pages > 0 ? nr_pages:1) * PAGE_SIZE);
+ ptr = vmalloc_array(nr_pages > 0 ? nr_pages : 1,
+ PAGE_SIZE);

if (!ptr)
return -1;