2018-04-25 14:49:27

by Kees Cook

Subject: [PATCH v4 ipsec-next] 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 <[email protected]>
Signed-off-by: Kees Cook <[email protected]>
---
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

2018-04-25 15:01:09

by Stefano Brivio

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

On Wed, 25 Apr 2018 07:46:39 -0700
Kees Cook <[email protected]> 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 <[email protected]>
> Signed-off-by: Kees Cook <[email protected]>
> ---
> 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 <[email protected]>

2018-04-26 08:35:13

by Steffen Klassert

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

On Wed, Apr 25, 2018 at 04:58:52PM +0200, Stefano Brivio wrote:
> On Wed, 25 Apr 2018 07:46:39 -0700
> Kees Cook <[email protected]> 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 <[email protected]>
> > Signed-off-by: Kees Cook <[email protected]>
> > ---
> > 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 <[email protected]>

Applied to ipsec-next, thanks everyone!