diff options
Diffstat (limited to 'net/xfrm/xfrm_replay.c')
| -rw-r--r-- | net/xfrm/xfrm_replay.c | 190 |
1 files changed, 189 insertions, 1 deletions
diff --git a/net/xfrm/xfrm_replay.c b/net/xfrm/xfrm_replay.c index 50589ea..2f5be5b 100644 --- a/net/xfrm/xfrm_replay.c +++ b/net/xfrm/xfrm_replay.c @@ -20,6 +20,31 @@ #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; @@ -313,6 +338,160 @@ static void xfrm_replay_notify_bmp(struct xfrm_state *x, int event) 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 seq = ntohl(net_seq); + u32 pos = (replay_esn->seq - 1) % replay_esn->replay_window; + u32 wsize = replay_esn->replay_window; + u32 top = replay_esn->seq; + u32 bottom = top - wsize + 1; + + 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; + } + + 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_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); + } + + 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; + + if (unlikely(wrap > 0)) + replay_esn->seq_hi++; + } 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 struct xfrm_replay xfrm_replay_legacy = { .advance = xfrm_replay_advance, .check = xfrm_replay_check, @@ -327,6 +506,13 @@ static struct xfrm_replay xfrm_replay_bmp = { .overflow = xfrm_replay_overflow_bmp, }; +static struct xfrm_replay xfrm_replay_esn = { + .advance = xfrm_replay_advance_esn, + .check = xfrm_replay_check_esn, + .notify = xfrm_replay_notify_bmp, + .overflow = xfrm_replay_overflow_esn, +}; + int xfrm_init_replay(struct xfrm_state *x) { struct xfrm_replay_state_esn *replay_esn = x->replay_esn; @@ -336,11 +522,13 @@ int xfrm_init_replay(struct xfrm_state *x) replay_esn->bmp_len * sizeof(__u32)) return -EINVAL; + if ((x->props.flags & XFRM_STATE_ESN) && x->replay_esn) + x->repl = &xfrm_replay_esn; + else x->repl = &xfrm_replay_bmp; } else x->repl = &xfrm_replay_legacy; - return 0; } EXPORT_SYMBOL(xfrm_init_replay); |
