--- /dev/null
+/*
+ * 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);
Code Review / kvmfornfv.git / blobdiff