* [PATCH v2 net-next] xfrm: Fix unaligned access to stats in copy_to_user_state()
@ 2015-10-21 15:48 Sowmini Varadhan
2015-10-23 10:33 ` Steffen Klassert
0 siblings, 1 reply; 2+ messages in thread
From: Sowmini Varadhan @ 2015-10-21 15:48 UTC (permalink / raw)
To: sowmini.varadhan, netdev, linux-kernel; +Cc: steffen.klassert, herbert, davem
On sparc, deleting established SAs (e.g., by restarting ipsec)
results in unaligned access messages via xfrm_del_sa ->
km_state_notify -> xfrm_send_state_notify().
Even though struct xfrm_usersa_info is aligned on 8-byte boundaries,
netlink attributes are fundamentally only 4 byte aligned, and this
cannot be changed for nla_data() that is passed up to userspace.
As a result, the put_unaligned() macro needs to be used to
set up potentially unaligned fields such as the xfrm_stats in
copy_to_user_state()
Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com>
---
v2: review comment from thread: cannot use PTR_ALIGN as this would break
userspace assumptions about 4 byte alignment. Use *_unaligned() macros
as needed, instead.
net/xfrm/xfrm_user.c | 5 ++++-
1 files changed, 4 insertions(+), 1 deletions(-)
diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c
index a8de9e3..639e0d5 100644
--- a/net/xfrm/xfrm_user.c
+++ b/net/xfrm/xfrm_user.c
@@ -31,6 +31,7 @@
#if IS_ENABLED(CONFIG_IPV6)
#include <linux/in6.h>
#endif
+#include <asm/unaligned.h>
static int verify_one_alg(struct nlattr **attrs, enum xfrm_attr_type_t type)
{
@@ -728,7 +729,9 @@ static void copy_to_user_state(struct xfrm_state *x, struct xfrm_usersa_info *p)
memcpy(&p->sel, &x->sel, sizeof(p->sel));
memcpy(&p->lft, &x->lft, sizeof(p->lft));
memcpy(&p->curlft, &x->curlft, sizeof(p->curlft));
- memcpy(&p->stats, &x->stats, sizeof(p->stats));
+ put_unaligned(x->stats.replay_window, &p->stats.replay_window);
+ put_unaligned(x->stats.replay, &p->stats.replay);
+ put_unaligned(x->stats.integrity_failed, &p->stats.integrity_failed);
memcpy(&p->saddr, &x->props.saddr, sizeof(p->saddr));
p->mode = x->props.mode;
p->replay_window = x->props.replay_window;
--
1.7.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH v2 net-next] xfrm: Fix unaligned access to stats in copy_to_user_state()
2015-10-21 15:48 [PATCH v2 net-next] xfrm: Fix unaligned access to stats in copy_to_user_state() Sowmini Varadhan
@ 2015-10-23 10:33 ` Steffen Klassert
0 siblings, 0 replies; 2+ messages in thread
From: Steffen Klassert @ 2015-10-23 10:33 UTC (permalink / raw)
To: Sowmini Varadhan; +Cc: netdev, linux-kernel, herbert, davem
On Wed, Oct 21, 2015 at 11:48:25AM -0400, Sowmini Varadhan wrote:
>
> On sparc, deleting established SAs (e.g., by restarting ipsec)
> results in unaligned access messages via xfrm_del_sa ->
> km_state_notify -> xfrm_send_state_notify().
>
> Even though struct xfrm_usersa_info is aligned on 8-byte boundaries,
> netlink attributes are fundamentally only 4 byte aligned, and this
> cannot be changed for nla_data() that is passed up to userspace.
> As a result, the put_unaligned() macro needs to be used to
> set up potentially unaligned fields such as the xfrm_stats in
> copy_to_user_state()
>
> Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com>
> ---
> v2: review comment from thread: cannot use PTR_ALIGN as this would break
> userspace assumptions about 4 byte alignment. Use *_unaligned() macros
> as needed, instead.
This works on intel 32-bit and 64-bit as expected.
Patch applied to ipsec-next, thanks!
^ permalink raw reply [flat|nested] 2+ messages in thread
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2015-10-21 15:48 [PATCH v2 net-next] xfrm: Fix unaligned access to stats in copy_to_user_state() Sowmini Varadhan
2015-10-23 10:33 ` Steffen Klassert
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