2017-03-07 12:12:19

by trajaraman

Subject: [PATCH] xfrm: Added the auth and enc update support in "state update"

From: Thiruvadi rajaraman <[email protected]>

The "ip xfrm state update" process doesn't update the new authendication
and encryption keys as well as it doesn't return an error.

Test logs: (Default)
==========
~# ip xfrm state list
~# ip xfrm state add src fe80::/10 dst ff02::3 proto esp spi 1235 mode transport auth sha1 0xAABBCCDDEEFF0010 enc des 0xAABBCCDDEEFF0010
~# ip xfrm state list
src fe80:: dst ff02::3
proto esp spi 0x000004d3 reqid 0 mode transport
replay-window 0
auth-trunc hmac(sha1) 0xaabbccddeeff0010 96
enc cbc(des) 0xaabbccddeeff0010
sel src ::/0 dst ::/0
~#

~# ip xfrm state update src fe80::/10 dst ff02::3 proto esp spi 1235 mode transport auth sha1 0xAABBCCDDEEFF0015 enc des 0xAABBCCDDEEFF0020
src fe80:: dst ff02::3
proto esp spi 0x000004d3 reqid 0 mode transport
replay-window 0
auth-trunc hmac(sha1) 0xaabbccddeeff0010 96 ----> [ Auth key doesn't changed and remains same ]
enc cbc(des) 0xaabbccddeeff0010 ----> [ Enc key doesn't changed and remains same ]
sel src ::/0 dst ::/0

The issue resolved by updating the x1->aalg, x1->ealg with new keys.

Test logs: ( with fix patch )
==========
~# ip xfrm state list
~# ip xfrm state add src fe80::/10 dst ff02::3 proto esp spi 1235 mode transport auth sha1 0xAABBCCDDEEFF0010 enc des 0xAABBCCDDEEFF0010
~# ip xfrm state list
src fe80:: dst ff02::3
proto esp spi 0x000004d3 reqid 0 mode transport
replay-window 0
auth-trunc hmac(sha1) 0xaabbccddeeff0010 96
enc cbc(des) 0xaabbccddeeff0010
sel src ::/0 dst ::/0

~# ip xfrm state update src fe80::/10 dst ff02::3 proto esp spi 1235 mode transport auth sha1 0xAABBCCDDEEFF0015 enc des 0xAABBCCDDEEFF0020
~# ip xfrm state list
src fe80:: dst ff02::3
proto esp spi 0x000004d3 reqid 0 mode transport
replay-window 0
auth-trunc hmac(sha1) 0xaabbccddeeff0015 96 ----> [ Updated to new Auth key ]
enc cbc(des) 0xaabbccddeeff0020 ----> [ Updated to new Enc key ]
sel src ::/0 dst ::/0
---
net/xfrm/xfrm_state.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/net/xfrm/xfrm_state.c b/net/xfrm/xfrm_state.c
index 419bf5d..1c80fc2 100644
--- a/net/xfrm/xfrm_state.c
+++ b/net/xfrm/xfrm_state.c
@@ -1388,6 +1388,10 @@ int xfrm_state_update(struct xfrm_state *x)
memcpy(&x1->lft, &x->lft, sizeof(x1->lft));
x1->km.dying = 0;

+ /* To update Authendication and Encryption keys */
+ x1->aalg = kmemdup( x->aalg, xfrm_alg_auth_len(x->aalg), GFP_KERNEL);
+ x1->ealg = kmemdup( x->ealg, xfrm_alg_len(x->ealg), GFP_KERNEL);
+
tasklet_hrtimer_start(&x1->mtimer, ktime_set(1, 0), HRTIMER_MODE_REL);
if (x1->curlft.use_time)
xfrm_state_check_expire(x1);
--
1.9.1

2017-03-07 14:25:11

by Steffen Klassert

Subject: Re: [PATCH] xfrm: Added the auth and enc update support in "state update"

On Tue, Mar 07, 2017 at 05:33:13PM +0530, [email protected] wrote:
> From: Thiruvadi rajaraman <[email protected]>
>
> The "ip xfrm state update" process doesn't update the new authendication
> and encryption keys as well as it doesn't return an error.
>
> Test logs: (Default)
> ==========
> ~# ip xfrm state list
> ~# ip xfrm state add src fe80::/10 dst ff02::3 proto esp spi 1235 mode transport auth sha1 0xAABBCCDDEEFF0010 enc des 0xAABBCCDDEEFF0010
> ~# ip xfrm state list
> src fe80:: dst ff02::3
> proto esp spi 0x000004d3 reqid 0 mode transport
> replay-window 0
> auth-trunc hmac(sha1) 0xaabbccddeeff0010 96
> enc cbc(des) 0xaabbccddeeff0010
> sel src ::/0 dst ::/0
> ~#
>
> ~# ip xfrm state update src fe80::/10 dst ff02::3 proto esp spi 1235 mode transport auth sha1 0xAABBCCDDEEFF0015 enc des 0xAABBCCDDEEFF0020
> src fe80:: dst ff02::3
> proto esp spi 0x000004d3 reqid 0 mode transport
> replay-window 0
> auth-trunc hmac(sha1) 0xaabbccddeeff0010 96 ----> [ Auth key doesn't changed and remains same ]
> enc cbc(des) 0xaabbccddeeff0010 ----> [ Enc key doesn't changed and remains same ]

This is intentional, the original state is not XFRM_STATE_ACQ,
so you are not allowed to update keys without requesting for
a new SPI. The original code was written 15 years ago, based
on RFC 2367 (PF_KEY) which says we must return -EINVAL in this
case. So if we change this, we should return an error.