On the quest to remove all VLAs from the kernel[1], this switches to
a pair of kmalloc regions instead of using the stack. This also moves
the get_random_bytes() after all allocations (and drops the needless
"nbytes" variable).
[1] https://lkml.org/lkml/2018/3/7/621
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
{
int ret = 0;
struct ecc_point *product, *pk;
{
int ret = 0;
struct ecc_point *product, *pk;
- u64 priv[ndigits];
- u64 rand_z[ndigits];
- unsigned int nbytes;
const struct ecc_curve *curve = ecc_get_curve(curve_id);
if (!private_key || !public_key || !curve) {
const struct ecc_curve *curve = ecc_get_curve(curve_id);
if (!private_key || !public_key || !curve) {
- nbytes = ndigits << ECC_DIGITS_TO_BYTES_SHIFT;
+ priv = kmalloc_array(ndigits, sizeof(*priv), GFP_KERNEL);
+ if (!priv) {
+ ret = -ENOMEM;
+ goto out;
+ }
- get_random_bytes(rand_z, nbytes);
+ rand_z = kmalloc_array(ndigits, sizeof(*rand_z), GFP_KERNEL);
+ if (!rand_z) {
+ ret = -ENOMEM;
+ goto kfree_out;
+ }
pk = ecc_alloc_point(ndigits);
if (!pk) {
ret = -ENOMEM;
pk = ecc_alloc_point(ndigits);
if (!pk) {
ret = -ENOMEM;
}
product = ecc_alloc_point(ndigits);
}
product = ecc_alloc_point(ndigits);
goto err_alloc_product;
}
goto err_alloc_product;
}
+ get_random_bytes(rand_z, ndigits << ECC_DIGITS_TO_BYTES_SHIFT);
+
ecc_swap_digits(public_key, pk->x, ndigits);
ecc_swap_digits(&public_key[ndigits], pk->y, ndigits);
ecc_swap_digits(private_key, priv, ndigits);
ecc_swap_digits(public_key, pk->x, ndigits);
ecc_swap_digits(&public_key[ndigits], pk->y, ndigits);
ecc_swap_digits(private_key, priv, ndigits);
ecc_free_point(product);
err_alloc_product:
ecc_free_point(pk);
ecc_free_point(product);
err_alloc_product:
ecc_free_point(pk);
+kfree_out:
+ kzfree(priv);
+ kzfree(rand_z);