diff options
| -rw-r--r-- | net/xfrm/xfrm_replay.c | 207 |
1 files changed, 206 insertions, 1 deletions
diff --git a/net/xfrm/xfrm_replay.c b/net/xfrm/xfrm_replay.c index 42d68f3..50589ea 100644 --- a/net/xfrm/xfrm_replay.c +++ b/net/xfrm/xfrm_replay.c @@ -1,5 +1,21 @@ /* * xfrm_replay.c - xfrm replay detection, derived from xfrm_state.c. + * + * Copyright (C) 2010 secunet Security Networks AG + * Copyright (C) 2010 Steffen Klassert <steffen.klassert@secunet.com> + * + * This program is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + * + * You should have received a copy of the GNU General Public License along with + * this program; if not, write to the Free Software Foundation, Inc., + * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA. */ #include <net/xfrm.h> @@ -125,6 +141,178 @@ static void xfrm_replay_advance(struct xfrm_state *x, __be32 net_seq) xfrm_replay_notify(x, XFRM_REPLAY_UPDATE); } +static int xfrm_replay_overflow_bmp(struct xfrm_state *x, struct sk_buff *skb) +{ + int err = 0; + struct xfrm_replay_state_esn *replay_esn = x->replay_esn; + struct net *net = xs_net(x); + + if (x->type->flags & XFRM_TYPE_REPLAY_PROT) { + XFRM_SKB_CB(skb)->seq.output.low = ++replay_esn->oseq; + if (unlikely(replay_esn->oseq == 0)) { + replay_esn->oseq--; + xfrm_audit_state_replay_overflow(x, skb); + err = -EOVERFLOW; + + return err; + } + if (xfrm_aevent_is_on(net)) + x->repl->notify(x, XFRM_REPLAY_UPDATE); + } + + return err; +} + +static int xfrm_replay_check_bmp(struct xfrm_state *x, + struct sk_buff *skb, __be32 net_seq) +{ + unsigned int bitnr, nr; + struct xfrm_replay_state_esn *replay_esn = x->replay_esn; + u32 seq = ntohl(net_seq); + u32 diff = replay_esn->seq - seq; + u32 pos = (replay_esn->seq - 1) % replay_esn->replay_window; + + if (unlikely(seq == 0)) + goto err; + + if (likely(seq > replay_esn->seq)) + return 0; + + if (diff >= replay_esn->replay_window) { + x->stats.replay_window++; + goto err; + } + + if (pos >= diff) { + bitnr = (pos - diff) % replay_esn->replay_window; + nr = bitnr >> 5; + bitnr = bitnr & 0x1F; + if (replay_esn->bmp[nr] & (1U << bitnr)) + goto err_replay; + } else { + bitnr = replay_esn->replay_window - (diff - pos); + nr = bitnr >> 5; + bitnr = bitnr & 0x1F; + if (replay_esn->bmp[nr] & (1U << bitnr)) + goto err_replay; + } + return 0; + +err_replay: + x->stats.replay++; +err: + xfrm_audit_state_replay(x, skb, net_seq); + return -EINVAL; +} + +static void xfrm_replay_advance_bmp(struct xfrm_state *x, __be32 net_seq) +{ + unsigned int bitnr, nr, i; + u32 diff; + struct xfrm_replay_state_esn *replay_esn = x->replay_esn; + u32 seq = ntohl(net_seq); + u32 pos = (replay_esn->seq - 1) % replay_esn->replay_window; + + if (!replay_esn->replay_window) + return; + + if (seq > replay_esn->seq) { + diff = seq - replay_esn->seq; + + if (diff < replay_esn->replay_window) { + for (i = 1; i < diff; i++) { + bitnr = (pos + i) % replay_esn->replay_window; + nr = bitnr >> 5; + bitnr = bitnr & 0x1F; + replay_esn->bmp[nr] &= ~(1U << bitnr); + } + + bitnr = (pos + diff) % replay_esn->replay_window; + nr = bitnr >> 5; + bitnr = bitnr & 0x1F; + replay_esn->bmp[nr] |= (1U << bitnr); + } else { + nr = replay_esn->replay_window >> 5; + for (i = 0; i <= nr; i++) + replay_esn->bmp[i] = 0; + + bitnr = (pos + diff) % replay_esn->replay_window; + nr = bitnr >> 5; + bitnr = bitnr & 0x1F; + replay_esn->bmp[nr] |= (1U << bitnr); + } + + replay_esn->seq = seq; + } else { + diff = replay_esn->seq - seq; + + if (pos >= diff) { + bitnr = (pos - diff) % replay_esn->replay_window; + nr = bitnr >> 5; + bitnr = bitnr & 0x1F; + replay_esn->bmp[nr] |= (1U << bitnr); + } else { + bitnr = replay_esn->replay_window - (diff - pos); + nr = bitnr >> 5; + bitnr = bitnr & 0x1F; + replay_esn->bmp[nr] |= (1U << bitnr); + } + } + + if (xfrm_aevent_is_on(xs_net(x))) + xfrm_replay_notify(x, XFRM_REPLAY_UPDATE); +} + +static void xfrm_replay_notify_bmp(struct xfrm_state *x, int event) +{ + struct km_event c; + struct xfrm_replay_state_esn *replay_esn = x->replay_esn; + struct xfrm_replay_state_esn *preplay_esn = x->preplay_esn; + + /* we send notify messages in case + * 1. we updated on of the sequence numbers, and the seqno difference + * is at least x->replay_maxdiff, in this case we also update the + * timeout of our timer function + * 2. if x->replay_maxage has elapsed since last update, + * and there were changes + * + * The state structure must be locked! + */ + + switch (event) { + case XFRM_REPLAY_UPDATE: + if (x->replay_maxdiff && + (replay_esn->seq - preplay_esn->seq < x->replay_maxdiff) && + (replay_esn->oseq - preplay_esn->oseq < x->replay_maxdiff)) { + if (x->xflags & XFRM_TIME_DEFER) + event = XFRM_REPLAY_TIMEOUT; + else + return; + } + + break; + + case XFRM_REPLAY_TIMEOUT: + if (memcmp(x->replay_esn, x->preplay_esn, + xfrm_replay_state_esn_len(replay_esn)) == 0) { + x->xflags |= XFRM_TIME_DEFER; + return; + } + + break; + } + + memcpy(x->preplay_esn, x->replay_esn, + xfrm_replay_state_esn_len(replay_esn)); + c.event = XFRM_MSG_NEWAE; + c.data.aevent = event; + km_state_notify(x, &c); + + if (x->replay_maxage && + !mod_timer(&x->rtimer, jiffies + x->replay_maxage)) + x->xflags &= ~XFRM_TIME_DEFER; +} + static struct xfrm_replay xfrm_replay_legacy = { .advance = xfrm_replay_advance, .check = xfrm_replay_check, @@ -132,9 +320,26 @@ static struct xfrm_replay xfrm_replay_legacy = { .overflow = xfrm_replay_overflow, }; +static struct xfrm_replay xfrm_replay_bmp = { + .advance = xfrm_replay_advance_bmp, + .check = xfrm_replay_check_bmp, + .notify = xfrm_replay_notify_bmp, + .overflow = xfrm_replay_overflow_bmp, +}; + int xfrm_init_replay(struct xfrm_state *x) { - x->repl = &xfrm_replay_legacy; + struct xfrm_replay_state_esn *replay_esn = x->replay_esn; + + if (replay_esn) { + if (replay_esn->replay_window > + replay_esn->bmp_len * sizeof(__u32)) + return -EINVAL; + + x->repl = &xfrm_replay_bmp; + } else + x->repl = &xfrm_replay_legacy; + return 0; } |
