[PATCH v4 ipsec-next] xfrm: remove VLA usage in __xfrm6_sort()

[PATCH v4 ipsec-next] xfrm: remove VLA usage in __xfrm6_sort()

[Kees Cook]

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>
---
v4:
- actually remove memset(). :)
v3:
- adjust Subject and commit log (Steffen)
- use "= { }" instead of memset() (Stefano)
v2:
- use XFRM_MAX_DEPTH for "count" array (Steffen and Mathias).
---
 net/ipv6/xfrm6_state.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/net/ipv6/xfrm6_state.c b/net/ipv6/xfrm6_state.c
index 16f434791763..5bdca3d5d6b7 100644
--- 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;
-- 
2.7.4


-- 
Kees Cook
Pixel Security

Re: [PATCH v4 ipsec-next] xfrm: remove VLA usage in __xfrm6_sort()

[Stefano Brivio]

On Wed, 25 Apr 2018 07:46:39 -0700
Kees Cook <keescook@chromium.org> wrote:

> 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>
> ---
> v4:
> - actually remove memset(). :)
> v3:
> - adjust Subject and commit log (Steffen)
> - use "= { }" instead of memset() (Stefano)
> v2:
> - use XFRM_MAX_DEPTH for "count" array (Steffen and Mathias).
> ---

Acked-by: Stefano Brivio <sbrivio@redhat.com>

Re: [PATCH v4 ipsec-next] xfrm: remove VLA usage in __xfrm6_sort()

[Steffen Klassert]

On Wed, Apr 25, 2018 at 04:58:52PM +0200, Stefano Brivio wrote:
> On Wed, 25 Apr 2018 07:46:39 -0700
> Kees Cook <keescook@chromium.org> wrote:
> 
> > 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>
> > ---
> > v4:
> > - actually remove memset(). :)
> > v3:
> > - adjust Subject and commit log (Steffen)
> > - use "= { }" instead of memset() (Stefano)
> > v2:
> > - use XFRM_MAX_DEPTH for "count" array (Steffen and Mathias).
> > ---
> 
> Acked-by: Stefano Brivio <sbrivio@redhat.com>

Applied to ipsec-next, thanks everyone!

Re: [PATCH v4 ipsec-next] xfrm: remove VLA usage in __xfrm6_sort()

[Steffen Klassert]

On Wed, Apr 25, 2018 at 04:58:52PM +0200, Stefano Brivio wrote:
> On Wed, 25 Apr 2018 07:46:39 -0700
> Kees Cook <keescook@chromium.org> wrote:
> 
> > 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>
> > ---
> > v4:
> > - actually remove memset(). :)
> > v3:
> > - adjust Subject and commit log (Steffen)
> > - use "= { }" instead of memset() (Stefano)
> > v2:
> > - use XFRM_MAX_DEPTH for "count" array (Steffen and Mathias).
> > ---
> 
> Acked-by: Stefano Brivio <sbrivio@redhat.com>

Applied to ipsec-next, thanks everyone!