diff options
Diffstat (limited to 'kernel/net/xfrm/xfrm_replay.c')
-rw-r--r-- | kernel/net/xfrm/xfrm_replay.c | 605 |
1 files changed, 605 insertions, 0 deletions
diff --git a/kernel/net/xfrm/xfrm_replay.c b/kernel/net/xfrm/xfrm_replay.c new file mode 100644 index 000000000..4fd725a0c --- /dev/null +++ b/kernel/net/xfrm/xfrm_replay.c @@ -0,0 +1,605 @@ +/* + * 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 <linux/export.h> +#include <net/xfrm.h> + +u32 xfrm_replay_seqhi(struct xfrm_state *x, __be32 net_seq) +{ + u32 seq, seq_hi, bottom; + struct xfrm_replay_state_esn *replay_esn = x->replay_esn; + + if (!(x->props.flags & XFRM_STATE_ESN)) + return 0; + + seq = ntohl(net_seq); + seq_hi = replay_esn->seq_hi; + bottom = replay_esn->seq - replay_esn->replay_window + 1; + + if (likely(replay_esn->seq >= replay_esn->replay_window - 1)) { + /* A. same subspace */ + if (unlikely(seq < bottom)) + seq_hi++; + } else { + /* B. window spans two subspaces */ + if (unlikely(seq >= bottom)) + seq_hi--; + } + + return seq_hi; +} + +static void xfrm_replay_notify(struct xfrm_state *x, int event) +{ + struct km_event c; + /* 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 || + ((x->replay.seq - x->preplay.seq < x->replay_maxdiff) && + (x->replay.oseq - x->preplay.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, &x->preplay, + sizeof(struct xfrm_replay_state)) == 0) { + x->xflags |= XFRM_TIME_DEFER; + return; + } + + break; + } + + memcpy(&x->preplay, &x->replay, sizeof(struct xfrm_replay_state)); + 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 int xfrm_replay_overflow(struct xfrm_state *x, struct sk_buff *skb) +{ + int err = 0; + struct net *net = xs_net(x); + + 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)) { + x->replay.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(struct xfrm_state *x, + struct sk_buff *skb, __be32 net_seq) +{ + u32 diff; + u32 seq = ntohl(net_seq); + + if (!x->props.replay_window) + return 0; + + if (unlikely(seq == 0)) + goto err; + + if (likely(seq > x->replay.seq)) + return 0; + + diff = x->replay.seq - seq; + if (diff >= x->props.replay_window) { + x->stats.replay_window++; + goto err; + } + + if (x->replay.bitmap & (1U << diff)) { + x->stats.replay++; + goto err; + } + return 0; + +err: + xfrm_audit_state_replay(x, skb, net_seq); + return -EINVAL; +} + +static void xfrm_replay_advance(struct xfrm_state *x, __be32 net_seq) +{ + u32 diff; + u32 seq = ntohl(net_seq); + + if (!x->props.replay_window) + return; + + if (seq > x->replay.seq) { + diff = seq - x->replay.seq; + if (diff < x->props.replay_window) + x->replay.bitmap = ((x->replay.bitmap) << diff) | 1; + else + x->replay.bitmap = 1; + x->replay.seq = seq; + } else { + diff = x->replay.seq - seq; + x->replay.bitmap |= (1U << diff); + } + + if (xfrm_aevent_is_on(xs_net(x))) + x->repl->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; + XFRM_SKB_CB(skb)->seq.output.hi = 0; + 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 pos; + u32 seq = ntohl(net_seq); + u32 diff = replay_esn->seq - seq; + + if (!replay_esn->replay_window) + return 0; + + 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; + } + + pos = (replay_esn->seq - 1) % replay_esn->replay_window; + + if (pos >= diff) + bitnr = (pos - diff) % replay_esn->replay_window; + 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; + + if (!replay_esn->replay_window) + return; + + pos = (replay_esn->seq - 1) % replay_esn->replay_window; + + 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); + } + } else { + nr = (replay_esn->replay_window - 1) >> 5; + for (i = 0; i <= nr; i++) + replay_esn->bmp[i] = 0; + } + + bitnr = (pos + diff) % replay_esn->replay_window; + replay_esn->seq = seq; + } else { + diff = replay_esn->seq - seq; + + if (pos >= diff) + bitnr = (pos - diff) % replay_esn->replay_window; + 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))) + x->repl->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 void xfrm_replay_notify_esn(struct xfrm_state *x, int event) +{ + u32 seq_diff, oseq_diff; + 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) { + if (replay_esn->seq_hi == preplay_esn->seq_hi) + seq_diff = replay_esn->seq - preplay_esn->seq; + else + seq_diff = ~preplay_esn->seq + replay_esn->seq + + 1; + + if (replay_esn->oseq_hi == preplay_esn->oseq_hi) + oseq_diff = replay_esn->oseq + - preplay_esn->oseq; + else + oseq_diff = ~preplay_esn->oseq + + replay_esn->oseq + 1; + + if (seq_diff >= x->replay_maxdiff || + oseq_diff >= x->replay_maxdiff) + break; + } + + 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 int xfrm_replay_overflow_esn(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; + XFRM_SKB_CB(skb)->seq.output.hi = replay_esn->oseq_hi; + + if (unlikely(replay_esn->oseq == 0)) { + XFRM_SKB_CB(skb)->seq.output.hi = ++replay_esn->oseq_hi; + + if (replay_esn->oseq_hi == 0) { + replay_esn->oseq--; + replay_esn->oseq_hi--; + 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_esn(struct xfrm_state *x, + struct sk_buff *skb, __be32 net_seq) +{ + unsigned int bitnr, nr; + u32 diff; + struct xfrm_replay_state_esn *replay_esn = x->replay_esn; + u32 pos; + u32 seq = ntohl(net_seq); + u32 wsize = replay_esn->replay_window; + u32 top = replay_esn->seq; + u32 bottom = top - wsize + 1; + + if (!wsize) + return 0; + + if (unlikely(seq == 0 && replay_esn->seq_hi == 0 && + (replay_esn->seq < replay_esn->replay_window - 1))) + goto err; + + diff = top - seq; + + if (likely(top >= wsize - 1)) { + /* A. same subspace */ + if (likely(seq > top) || seq < bottom) + return 0; + } else { + /* B. window spans two subspaces */ + if (likely(seq > top && seq < bottom)) + return 0; + if (seq >= bottom) + diff = ~seq + top + 1; + } + + if (diff >= replay_esn->replay_window) { + x->stats.replay_window++; + goto err; + } + + pos = (replay_esn->seq - 1) % replay_esn->replay_window; + + if (pos >= diff) + bitnr = (pos - diff) % replay_esn->replay_window; + 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 int xfrm_replay_recheck_esn(struct xfrm_state *x, + struct sk_buff *skb, __be32 net_seq) +{ + if (unlikely(XFRM_SKB_CB(skb)->seq.input.hi != + htonl(xfrm_replay_seqhi(x, net_seq)))) { + x->stats.replay_window++; + return -EINVAL; + } + + return xfrm_replay_check_esn(x, skb, net_seq); +} + +static void xfrm_replay_advance_esn(struct xfrm_state *x, __be32 net_seq) +{ + unsigned int bitnr, nr, i; + int wrap; + u32 diff, pos, seq, seq_hi; + struct xfrm_replay_state_esn *replay_esn = x->replay_esn; + + if (!replay_esn->replay_window) + return; + + seq = ntohl(net_seq); + pos = (replay_esn->seq - 1) % replay_esn->replay_window; + seq_hi = xfrm_replay_seqhi(x, net_seq); + wrap = seq_hi - replay_esn->seq_hi; + + if ((!wrap && seq > replay_esn->seq) || wrap > 0) { + if (likely(!wrap)) + diff = seq - replay_esn->seq; + else + diff = ~replay_esn->seq + seq + 1; + + 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); + } + } else { + nr = (replay_esn->replay_window - 1) >> 5; + for (i = 0; i <= nr; i++) + replay_esn->bmp[i] = 0; + } + + bitnr = (pos + diff) % replay_esn->replay_window; + replay_esn->seq = seq; + + if (unlikely(wrap > 0)) + replay_esn->seq_hi++; + } else { + diff = replay_esn->seq - seq; + + if (pos >= diff) + bitnr = (pos - diff) % replay_esn->replay_window; + 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))) + x->repl->notify(x, XFRM_REPLAY_UPDATE); +} + +static struct xfrm_replay xfrm_replay_legacy = { + .advance = xfrm_replay_advance, + .check = xfrm_replay_check, + .recheck = xfrm_replay_check, + .notify = xfrm_replay_notify, + .overflow = xfrm_replay_overflow, +}; + +static struct xfrm_replay xfrm_replay_bmp = { + .advance = xfrm_replay_advance_bmp, + .check = xfrm_replay_check_bmp, + .recheck = xfrm_replay_check_bmp, + .notify = xfrm_replay_notify_bmp, + .overflow = xfrm_replay_overflow_bmp, +}; + +static struct xfrm_replay xfrm_replay_esn = { + .advance = xfrm_replay_advance_esn, + .check = xfrm_replay_check_esn, + .recheck = xfrm_replay_recheck_esn, + .notify = xfrm_replay_notify_esn, + .overflow = xfrm_replay_overflow_esn, +}; + +int xfrm_init_replay(struct xfrm_state *x) +{ + struct xfrm_replay_state_esn *replay_esn = x->replay_esn; + + if (replay_esn) { + if (replay_esn->replay_window > + replay_esn->bmp_len * sizeof(__u32) * 8) + return -EINVAL; + + if (x->props.flags & XFRM_STATE_ESN) { + if (replay_esn->replay_window == 0) + return -EINVAL; + x->repl = &xfrm_replay_esn; + } else + x->repl = &xfrm_replay_bmp; + } else + x->repl = &xfrm_replay_legacy; + + return 0; +} +EXPORT_SYMBOL(xfrm_init_replay); |