9fdc4883d9
To support multiple versions of replay detection, we move the replay detection functions to a separate file and make them accessible via function pointers contained in the struct xfrm_replay. Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com> Acked-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
142 lines
3 KiB
C
142 lines
3 KiB
C
/*
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* xfrm_replay.c - xfrm replay detection, derived from xfrm_state.c.
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*/
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#include <net/xfrm.h>
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static void xfrm_replay_notify(struct xfrm_state *x, int event)
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{
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struct km_event c;
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/* we send notify messages in case
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* 1. we updated on of the sequence numbers, and the seqno difference
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* is at least x->replay_maxdiff, in this case we also update the
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* timeout of our timer function
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* 2. if x->replay_maxage has elapsed since last update,
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* and there were changes
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*
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* The state structure must be locked!
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*/
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switch (event) {
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case XFRM_REPLAY_UPDATE:
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if (x->replay_maxdiff &&
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(x->replay.seq - x->preplay.seq < x->replay_maxdiff) &&
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(x->replay.oseq - x->preplay.oseq < x->replay_maxdiff)) {
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if (x->xflags & XFRM_TIME_DEFER)
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event = XFRM_REPLAY_TIMEOUT;
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else
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return;
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}
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break;
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case XFRM_REPLAY_TIMEOUT:
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if (memcmp(&x->replay, &x->preplay,
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sizeof(struct xfrm_replay_state)) == 0) {
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x->xflags |= XFRM_TIME_DEFER;
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return;
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}
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break;
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}
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memcpy(&x->preplay, &x->replay, sizeof(struct xfrm_replay_state));
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c.event = XFRM_MSG_NEWAE;
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c.data.aevent = event;
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km_state_notify(x, &c);
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if (x->replay_maxage &&
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!mod_timer(&x->rtimer, jiffies + x->replay_maxage))
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x->xflags &= ~XFRM_TIME_DEFER;
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}
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static int xfrm_replay_overflow(struct xfrm_state *x, struct sk_buff *skb)
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{
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int err = 0;
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struct net *net = xs_net(x);
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if (x->type->flags & XFRM_TYPE_REPLAY_PROT) {
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XFRM_SKB_CB(skb)->seq.output.low = ++x->replay.oseq;
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if (unlikely(x->replay.oseq == 0)) {
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x->replay.oseq--;
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xfrm_audit_state_replay_overflow(x, skb);
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err = -EOVERFLOW;
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return err;
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}
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if (xfrm_aevent_is_on(net))
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x->repl->notify(x, XFRM_REPLAY_UPDATE);
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}
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return err;
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}
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static int xfrm_replay_check(struct xfrm_state *x,
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struct sk_buff *skb, __be32 net_seq)
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{
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u32 diff;
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u32 seq = ntohl(net_seq);
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if (unlikely(seq == 0))
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goto err;
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if (likely(seq > x->replay.seq))
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return 0;
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diff = x->replay.seq - seq;
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if (diff >= min_t(unsigned int, x->props.replay_window,
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sizeof(x->replay.bitmap) * 8)) {
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x->stats.replay_window++;
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goto err;
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}
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if (x->replay.bitmap & (1U << diff)) {
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x->stats.replay++;
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goto err;
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}
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return 0;
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err:
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xfrm_audit_state_replay(x, skb, net_seq);
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return -EINVAL;
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}
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static void xfrm_replay_advance(struct xfrm_state *x, __be32 net_seq)
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{
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u32 diff;
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u32 seq = ntohl(net_seq);
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if (!x->props.replay_window)
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return;
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if (seq > x->replay.seq) {
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diff = seq - x->replay.seq;
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if (diff < x->props.replay_window)
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x->replay.bitmap = ((x->replay.bitmap) << diff) | 1;
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else
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x->replay.bitmap = 1;
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x->replay.seq = seq;
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} else {
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diff = x->replay.seq - seq;
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x->replay.bitmap |= (1U << diff);
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}
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if (xfrm_aevent_is_on(xs_net(x)))
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xfrm_replay_notify(x, XFRM_REPLAY_UPDATE);
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}
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static struct xfrm_replay xfrm_replay_legacy = {
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.advance = xfrm_replay_advance,
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.check = xfrm_replay_check,
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.notify = xfrm_replay_notify,
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.overflow = xfrm_replay_overflow,
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};
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int xfrm_init_replay(struct xfrm_state *x)
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{
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x->repl = &xfrm_replay_legacy;
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return 0;
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}
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EXPORT_SYMBOL(xfrm_init_replay);
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