xfrm: remove VLA usage in __xfrm6_sort()

In the quest to remove all stack VLA usage removed from the kernel[1],
just use XFRM_MAX_DEPTH as already done for the "class" array. In one
case, it'll do this loop up to 5, the other caller up to 6.

[1] https://lkml.org/lkml/2018/3/7/621

Co-developed-by: Andreas Christoforou <andreaschristofo@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Stefano Brivio <sbrivio@redhat.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

diff --git a/net/ipv6/xfrm6_state.c b/net/ipv6/xfrm6_state.c
index 16f4347..5bdca3d 100644 (file)
--- a/net/ipv6/xfrm6_state.c
+++ b/net/ipv6/xfrm6_state.c
@@ -60,11 +60,9 @@ xfrm6_init_temprop(struct xfrm_state *x, const struct xfrm_tmpl *tmpl,
 static int
 __xfrm6_sort(void **dst, void **src, int n, int (*cmp)(void *p), int maxclass)
 {
-       int i;
+       int count[XFRM_MAX_DEPTH] = { };
        int class[XFRM_MAX_DEPTH];
-       int count[maxclass];
-
-       memset(count, 0, sizeof(count));
+       int i;
 
        for (i = 0; i < n; i++) {
                int c;