From 428d2459cceb77357b81c242ca22462a6a904817 Mon Sep 17 00:00:00 2001 From: Petr Vaněk Date: Sat, 30 May 2020 14:39:12 +0200 Subject: xfrm: introduce oseq-may-wrap flag MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit RFC 4303 in section 3.3.3 suggests to disable anti-replay for manually distributed ICVs in which case the sender does not need to monitor or reset the counter. However, the sender still increments the counter and when it reaches the maximum value, the counter rolls over back to zero. This patch introduces new extra_flag XFRM_SA_XFLAG_OSEQ_MAY_WRAP which allows sequence number to cycle in outbound packets if set. This flag is used only in legacy and bmp code, because esn should not be negotiated if anti-replay is disabled (see note in 3.3.3 section). Signed-off-by: Petr Vaněk Acked-by: Christophe Gouault Signed-off-by: Steffen Klassert --- net/xfrm/xfrm_replay.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) (limited to 'net/xfrm/xfrm_replay.c') diff --git a/net/xfrm/xfrm_replay.c b/net/xfrm/xfrm_replay.c index 98943f8d01aa..c6a4338a0d08 100644 --- a/net/xfrm/xfrm_replay.c +++ b/net/xfrm/xfrm_replay.c @@ -89,7 +89,8 @@ static int xfrm_replay_overflow(struct xfrm_state *x, struct sk_buff *skb) if (x->type->flags & XFRM_TYPE_REPLAY_PROT) { XFRM_SKB_CB(skb)->seq.output.low = ++x->replay.oseq; XFRM_SKB_CB(skb)->seq.output.hi = 0; - if (unlikely(x->replay.oseq == 0)) { + if (unlikely(x->replay.oseq == 0) && + !(x->props.extra_flags & XFRM_SA_XFLAG_OSEQ_MAY_WRAP)) { x->replay.oseq--; xfrm_audit_state_replay_overflow(x, skb); err = -EOVERFLOW; @@ -168,7 +169,8 @@ static int xfrm_replay_overflow_bmp(struct xfrm_state *x, struct sk_buff *skb) if (x->type->flags & XFRM_TYPE_REPLAY_PROT) { XFRM_SKB_CB(skb)->seq.output.low = ++replay_esn->oseq; XFRM_SKB_CB(skb)->seq.output.hi = 0; - if (unlikely(replay_esn->oseq == 0)) { + if (unlikely(replay_esn->oseq == 0) && + !(x->props.extra_flags & XFRM_SA_XFLAG_OSEQ_MAY_WRAP)) { replay_esn->oseq--; xfrm_audit_state_replay_overflow(x, skb); err = -EOVERFLOW; @@ -572,7 +574,8 @@ static int xfrm_replay_overflow_offload(struct xfrm_state *x, struct sk_buff *sk XFRM_SKB_CB(skb)->seq.output.hi = 0; xo->seq.hi = 0; - if (unlikely(oseq < x->replay.oseq)) { + if (unlikely(oseq < x->replay.oseq) && + !(x->props.extra_flags & XFRM_SA_XFLAG_OSEQ_MAY_WRAP)) { xfrm_audit_state_replay_overflow(x, skb); err = -EOVERFLOW; @@ -611,7 +614,8 @@ static int xfrm_replay_overflow_offload_bmp(struct xfrm_state *x, struct sk_buff XFRM_SKB_CB(skb)->seq.output.hi = 0; xo->seq.hi = 0; - if (unlikely(oseq < replay_esn->oseq)) { + if (unlikely(oseq < replay_esn->oseq) && + !(x->props.extra_flags & XFRM_SA_XFLAG_OSEQ_MAY_WRAP)) { xfrm_audit_state_replay_overflow(x, skb); err = -EOVERFLOW; -- cgit v1.2.3