net/xfrm/xfrm_replay.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * xfrm_replay.c - xfrm replay detection, derived from xfrm_state.c.
   4  *
   5  * Copyright (C) 2010 secunet Security Networks AG
   6  * Copyright (C) 2010 Steffen Klassert <steffen.klassert@secunet.com>
   7  */
   8
   9 #include <linux/export.h>
  10 #include <net/xfrm.h>
  11
  12 u32 xfrm_replay_seqhi(struct xfrm_state *x, __be32 net_seq)
  13 {
  14         u32 seq, seq_hi, bottom;
  15         struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
  16
  17         if (!(x->props.flags & XFRM_STATE_ESN))
  18                 return 0;
  19
  20         seq = ntohl(net_seq);
  21         seq_hi = replay_esn->seq_hi;
  22         bottom = replay_esn->seq - replay_esn->replay_window + 1;
  23
  24         if (likely(replay_esn->seq >= replay_esn->replay_window - 1)) {
  25                 /* A. same subspace */
  26                 if (unlikely(seq < bottom))
  27                         seq_hi++;
  28         } else {
  29                 /* B. window spans two subspaces */
  30                 if (unlikely(seq >= bottom))
  31                         seq_hi--;
  32         }
  33
  34         return seq_hi;
  35 }
  36 EXPORT_SYMBOL(xfrm_replay_seqhi);
  37 ;
  38 static void xfrm_replay_notify(struct xfrm_state *x, int event)
  39 {
  40         struct km_event c;
  41         /* we send notify messages in case
  42          *  1. we updated on of the sequence numbers, and the seqno difference
  43          *     is at least x->replay_maxdiff, in this case we also update the
  44          *     timeout of our timer function
  45          *  2. if x->replay_maxage has elapsed since last update,
  46          *     and there were changes
  47          *
  48          *  The state structure must be locked!
  49          */
  50
  51         switch (event) {
  52         case XFRM_REPLAY_UPDATE:
  53                 if (!x->replay_maxdiff ||
  54                     ((x->replay.seq - x->preplay.seq < x->replay_maxdiff) &&
  55                     (x->replay.oseq - x->preplay.oseq < x->replay_maxdiff))) {
  56                         if (x->xflags & XFRM_TIME_DEFER)
  57                                 event = XFRM_REPLAY_TIMEOUT;
  58                         else
  59                                 return;
  60                 }
  61
  62                 break;
  63
  64         case XFRM_REPLAY_TIMEOUT:
  65                 if (memcmp(&x->replay, &x->preplay,
  66                            sizeof(struct xfrm_replay_state)) == 0) {
  67                         x->xflags |= XFRM_TIME_DEFER;
  68                         return;
  69                 }
  70
  71                 break;
  72         }
  73
  74         memcpy(&x->preplay, &x->replay, sizeof(struct xfrm_replay_state));
  75         c.event = XFRM_MSG_NEWAE;
  76         c.data.aevent = event;
  77         km_state_notify(x, &c);
  78
  79         if (x->replay_maxage &&
  80             !mod_timer(&x->rtimer, jiffies + x->replay_maxage))
  81                 x->xflags &= ~XFRM_TIME_DEFER;
  82 }
  83
  84 static int xfrm_replay_overflow(struct xfrm_state *x, struct sk_buff *skb)
  85 {
  86         int err = 0;
  87         struct net *net = xs_net(x);
  88
  89         if (x->type->flags & XFRM_TYPE_REPLAY_PROT) {
  90                 XFRM_SKB_CB(skb)->seq.output.low = ++x->replay.oseq;
  91                 XFRM_SKB_CB(skb)->seq.output.hi = 0;
  92                 if (unlikely(x->replay.oseq == 0) &&
  93                     !(x->props.extra_flags & XFRM_SA_XFLAG_OSEQ_MAY_WRAP)) {
  94                         x->replay.oseq--;
  95                         xfrm_audit_state_replay_overflow(x, skb);
  96                         err = -EOVERFLOW;
  97
  98                         return err;
  99                 }
 100                 if (xfrm_aevent_is_on(net))
 101                         x->repl->notify(x, XFRM_REPLAY_UPDATE);
 102         }
 103
 104         return err;
 105 }
 106
 107 static int xfrm_replay_check(struct xfrm_state *x,
 108                       struct sk_buff *skb, __be32 net_seq)
 109 {
 110         u32 diff;
 111         u32 seq = ntohl(net_seq);
 112
 113         if (!x->props.replay_window)
 114                 return 0;
 115
 116         if (unlikely(seq == 0))
 117                 goto err;
 118
 119         if (likely(seq > x->replay.seq))
 120                 return 0;
 121
 122         diff = x->replay.seq - seq;
 123         if (diff >= x->props.replay_window) {
 124                 x->stats.replay_window++;
 125                 goto err;
 126         }
 127
 128         if (x->replay.bitmap & (1U << diff)) {
 129                 x->stats.replay++;
 130                 goto err;
 131         }
 132         return 0;
 133
 134 err:
 135         xfrm_audit_state_replay(x, skb, net_seq);
 136         return -EINVAL;
 137 }
 138
 139 static void xfrm_replay_advance(struct xfrm_state *x, __be32 net_seq)
 140 {
 141         u32 diff;
 142         u32 seq = ntohl(net_seq);
 143
 144         if (!x->props.replay_window)
 145                 return;
 146
 147         if (seq > x->replay.seq) {
 148                 diff = seq - x->replay.seq;
 149                 if (diff < x->props.replay_window)
 150                         x->replay.bitmap = ((x->replay.bitmap) << diff) | 1;
 151                 else
 152                         x->replay.bitmap = 1;
 153                 x->replay.seq = seq;
 154         } else {
 155                 diff = x->replay.seq - seq;
 156                 x->replay.bitmap |= (1U << diff);
 157         }
 158
 159         if (xfrm_aevent_is_on(xs_net(x)))
 160                 x->repl->notify(x, XFRM_REPLAY_UPDATE);
 161 }
 162
 163 static int xfrm_replay_overflow_bmp(struct xfrm_state *x, struct sk_buff *skb)
 164 {
 165         int err = 0;
 166         struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
 167         struct net *net = xs_net(x);
 168
 169         if (x->type->flags & XFRM_TYPE_REPLAY_PROT) {
 170                 XFRM_SKB_CB(skb)->seq.output.low = ++replay_esn->oseq;
 171                 XFRM_SKB_CB(skb)->seq.output.hi = 0;
 172                 if (unlikely(replay_esn->oseq == 0) &&
 173                     !(x->props.extra_flags & XFRM_SA_XFLAG_OSEQ_MAY_WRAP)) {
 174                         replay_esn->oseq--;
 175                         xfrm_audit_state_replay_overflow(x, skb);
 176                         err = -EOVERFLOW;
 177
 178                         return err;
 179                 }
 180                 if (xfrm_aevent_is_on(net))
 181                         x->repl->notify(x, XFRM_REPLAY_UPDATE);
 182         }
 183
 184         return err;
 185 }
 186
 187 static int xfrm_replay_check_bmp(struct xfrm_state *x,
 188                                  struct sk_buff *skb, __be32 net_seq)
 189 {
 190         unsigned int bitnr, nr;
 191         struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
 192         u32 pos;
 193         u32 seq = ntohl(net_seq);
 194         u32 diff =  replay_esn->seq - seq;
 195
 196         if (!replay_esn->replay_window)
 197                 return 0;
 198
 199         if (unlikely(seq == 0))
 200                 goto err;
 201
 202         if (likely(seq > replay_esn->seq))
 203                 return 0;
 204
 205         if (diff >= replay_esn->replay_window) {
 206                 x->stats.replay_window++;
 207                 goto err;
 208         }
 209
 210         pos = (replay_esn->seq - 1) % replay_esn->replay_window;
 211
 212         if (pos >= diff)
 213                 bitnr = (pos - diff) % replay_esn->replay_window;
 214         else
 215                 bitnr = replay_esn->replay_window - (diff - pos);
 216
 217         nr = bitnr >> 5;
 218         bitnr = bitnr & 0x1F;
 219         if (replay_esn->bmp[nr] & (1U << bitnr))
 220                 goto err_replay;
 221
 222         return 0;
 223
 224 err_replay:
 225         x->stats.replay++;
 226 err:
 227         xfrm_audit_state_replay(x, skb, net_seq);
 228         return -EINVAL;
 229 }
 230
 231 static void xfrm_replay_advance_bmp(struct xfrm_state *x, __be32 net_seq)
 232 {
 233         unsigned int bitnr, nr, i;
 234         u32 diff;
 235         struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
 236         u32 seq = ntohl(net_seq);
 237         u32 pos;
 238
 239         if (!replay_esn->replay_window)
 240                 return;
 241
 242         pos = (replay_esn->seq - 1) % replay_esn->replay_window;
 243
 244         if (seq > replay_esn->seq) {
 245                 diff = seq - replay_esn->seq;
 246
 247                 if (diff < replay_esn->replay_window) {
 248                         for (i = 1; i < diff; i++) {
 249                                 bitnr = (pos + i) % replay_esn->replay_window;
 250                                 nr = bitnr >> 5;
 251                                 bitnr = bitnr & 0x1F;
 252                                 replay_esn->bmp[nr] &=  ~(1U << bitnr);
 253                         }
 254                 } else {
 255                         nr = (replay_esn->replay_window - 1) >> 5;
 256                         for (i = 0; i <= nr; i++)
 257                                 replay_esn->bmp[i] = 0;
 258                 }
 259
 260                 bitnr = (pos + diff) % replay_esn->replay_window;
 261                 replay_esn->seq = seq;
 262         } else {
 263                 diff = replay_esn->seq - seq;
 264
 265                 if (pos >= diff)
 266                         bitnr = (pos - diff) % replay_esn->replay_window;
 267                 else
 268                         bitnr = replay_esn->replay_window - (diff - pos);
 269         }
 270
 271         nr = bitnr >> 5;
 272         bitnr = bitnr & 0x1F;
 273         replay_esn->bmp[nr] |= (1U << bitnr);
 274
 275         if (xfrm_aevent_is_on(xs_net(x)))
 276                 x->repl->notify(x, XFRM_REPLAY_UPDATE);
 277 }
 278
 279 static void xfrm_replay_notify_bmp(struct xfrm_state *x, int event)
 280 {
 281         struct km_event c;
 282         struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
 283         struct xfrm_replay_state_esn *preplay_esn = x->preplay_esn;
 284
 285         /* we send notify messages in case
 286          *  1. we updated on of the sequence numbers, and the seqno difference
 287          *     is at least x->replay_maxdiff, in this case we also update the
 288          *     timeout of our timer function
 289          *  2. if x->replay_maxage has elapsed since last update,
 290          *     and there were changes
 291          *
 292          *  The state structure must be locked!
 293          */
 294
 295         switch (event) {
 296         case XFRM_REPLAY_UPDATE:
 297                 if (!x->replay_maxdiff ||
 298                     ((replay_esn->seq - preplay_esn->seq < x->replay_maxdiff) &&
 299                     (replay_esn->oseq - preplay_esn->oseq
 300                      < x->replay_maxdiff))) {
 301                         if (x->xflags & XFRM_TIME_DEFER)
 302                                 event = XFRM_REPLAY_TIMEOUT;
 303                         else
 304                                 return;
 305                 }
 306
 307                 break;
 308
 309         case XFRM_REPLAY_TIMEOUT:
 310                 if (memcmp(x->replay_esn, x->preplay_esn,
 311                            xfrm_replay_state_esn_len(replay_esn)) == 0) {
 312                         x->xflags |= XFRM_TIME_DEFER;
 313                         return;
 314                 }
 315
 316                 break;
 317         }
 318
 319         memcpy(x->preplay_esn, x->replay_esn,
 320                xfrm_replay_state_esn_len(replay_esn));
 321         c.event = XFRM_MSG_NEWAE;
 322         c.data.aevent = event;
 323         km_state_notify(x, &c);
 324
 325         if (x->replay_maxage &&
 326             !mod_timer(&x->rtimer, jiffies + x->replay_maxage))
 327                 x->xflags &= ~XFRM_TIME_DEFER;
 328 }
 329
 330 static void xfrm_replay_notify_esn(struct xfrm_state *x, int event)
 331 {
 332         u32 seq_diff, oseq_diff;
 333         struct km_event c;
 334         struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
 335         struct xfrm_replay_state_esn *preplay_esn = x->preplay_esn;
 336
 337         /* we send notify messages in case
 338          *  1. we updated on of the sequence numbers, and the seqno difference
 339          *     is at least x->replay_maxdiff, in this case we also update the
 340          *     timeout of our timer function
 341          *  2. if x->replay_maxage has elapsed since last update,
 342          *     and there were changes
 343          *
 344          *  The state structure must be locked!
 345          */
 346
 347         switch (event) {
 348         case XFRM_REPLAY_UPDATE:
 349                 if (x->replay_maxdiff) {
 350                         if (replay_esn->seq_hi == preplay_esn->seq_hi)
 351                                 seq_diff = replay_esn->seq - preplay_esn->seq;
 352                         else
 353                                 seq_diff = ~preplay_esn->seq + replay_esn->seq
 354                                            + 1;
 355
 356                         if (replay_esn->oseq_hi == preplay_esn->oseq_hi)
 357                                 oseq_diff = replay_esn->oseq
 358                                             - preplay_esn->oseq;
 359                         else
 360                                 oseq_diff = ~preplay_esn->oseq
 361                                             + replay_esn->oseq + 1;
 362
 363                         if (seq_diff >= x->replay_maxdiff ||
 364                             oseq_diff >= x->replay_maxdiff)
 365                                 break;
 366                 }
 367
 368                 if (x->xflags & XFRM_TIME_DEFER)
 369                         event = XFRM_REPLAY_TIMEOUT;
 370                 else
 371                         return;
 372
 373                 break;
 374
 375         case XFRM_REPLAY_TIMEOUT:
 376                 if (memcmp(x->replay_esn, x->preplay_esn,
 377                            xfrm_replay_state_esn_len(replay_esn)) == 0) {
 378                         x->xflags |= XFRM_TIME_DEFER;
 379                         return;
 380                 }
 381
 382                 break;
 383         }
 384
 385         memcpy(x->preplay_esn, x->replay_esn,
 386                xfrm_replay_state_esn_len(replay_esn));
 387         c.event = XFRM_MSG_NEWAE;
 388         c.data.aevent = event;
 389         km_state_notify(x, &c);
 390
 391         if (x->replay_maxage &&
 392             !mod_timer(&x->rtimer, jiffies + x->replay_maxage))
 393                 x->xflags &= ~XFRM_TIME_DEFER;
 394 }
 395
 396 static int xfrm_replay_overflow_esn(struct xfrm_state *x, struct sk_buff *skb)
 397 {
 398         int err = 0;
 399         struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
 400         struct net *net = xs_net(x);
 401
 402         if (x->type->flags & XFRM_TYPE_REPLAY_PROT) {
 403                 XFRM_SKB_CB(skb)->seq.output.low = ++replay_esn->oseq;
 404                 XFRM_SKB_CB(skb)->seq.output.hi = replay_esn->oseq_hi;
 405
 406                 if (unlikely(replay_esn->oseq == 0)) {
 407                         XFRM_SKB_CB(skb)->seq.output.hi = ++replay_esn->oseq_hi;
 408
 409                         if (replay_esn->oseq_hi == 0) {
 410                                 replay_esn->oseq--;
 411                                 replay_esn->oseq_hi--;
 412                                 xfrm_audit_state_replay_overflow(x, skb);
 413                                 err = -EOVERFLOW;
 414
 415                                 return err;
 416                         }
 417                 }
 418                 if (xfrm_aevent_is_on(net))
 419                         x->repl->notify(x, XFRM_REPLAY_UPDATE);
 420         }
 421
 422         return err;
 423 }
 424
 425 static int xfrm_replay_check_esn(struct xfrm_state *x,
 426                                  struct sk_buff *skb, __be32 net_seq)
 427 {
 428         unsigned int bitnr, nr;
 429         u32 diff;
 430         struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
 431         u32 pos;
 432         u32 seq = ntohl(net_seq);
 433         u32 wsize = replay_esn->replay_window;
 434         u32 top = replay_esn->seq;
 435         u32 bottom = top - wsize + 1;
 436
 437         if (!wsize)
 438                 return 0;
 439
 440         if (unlikely(seq == 0 && replay_esn->seq_hi == 0 &&
 441                      (replay_esn->seq < replay_esn->replay_window - 1)))
 442                 goto err;
 443
 444         diff = top - seq;
 445
 446         if (likely(top >= wsize - 1)) {
 447                 /* A. same subspace */
 448                 if (likely(seq > top) || seq < bottom)
 449                         return 0;
 450         } else {
 451                 /* B. window spans two subspaces */
 452                 if (likely(seq > top && seq < bottom))
 453                         return 0;
 454                 if (seq >= bottom)
 455                         diff = ~seq + top + 1;
 456         }
 457
 458         if (diff >= replay_esn->replay_window) {
 459                 x->stats.replay_window++;
 460                 goto err;
 461         }
 462
 463         pos = (replay_esn->seq - 1) % replay_esn->replay_window;
 464
 465         if (pos >= diff)
 466                 bitnr = (pos - diff) % replay_esn->replay_window;
 467         else
 468                 bitnr = replay_esn->replay_window - (diff - pos);
 469
 470         nr = bitnr >> 5;
 471         bitnr = bitnr & 0x1F;
 472         if (replay_esn->bmp[nr] & (1U << bitnr))
 473                 goto err_replay;
 474
 475         return 0;
 476
 477 err_replay:
 478         x->stats.replay++;
 479 err:
 480         xfrm_audit_state_replay(x, skb, net_seq);
 481         return -EINVAL;
 482 }
 483
 484 static int xfrm_replay_recheck_esn(struct xfrm_state *x,
 485                                    struct sk_buff *skb, __be32 net_seq)
 486 {
 487         if (unlikely(XFRM_SKB_CB(skb)->seq.input.hi !=
 488                      htonl(xfrm_replay_seqhi(x, net_seq)))) {
 489                         x->stats.replay_window++;
 490                         return -EINVAL;
 491         }
 492
 493         return xfrm_replay_check_esn(x, skb, net_seq);
 494 }
 495
 496 static void xfrm_replay_advance_esn(struct xfrm_state *x, __be32 net_seq)
 497 {
 498         unsigned int bitnr, nr, i;
 499         int wrap;
 500         u32 diff, pos, seq, seq_hi;
 501         struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
 502
 503         if (!replay_esn->replay_window)
 504                 return;
 505
 506         seq = ntohl(net_seq);
 507         pos = (replay_esn->seq - 1) % replay_esn->replay_window;
 508         seq_hi = xfrm_replay_seqhi(x, net_seq);
 509         wrap = seq_hi - replay_esn->seq_hi;
 510
 511         if ((!wrap && seq > replay_esn->seq) || wrap > 0) {
 512                 if (likely(!wrap))
 513                         diff = seq - replay_esn->seq;
 514                 else
 515                         diff = ~replay_esn->seq + seq + 1;
 516
 517                 if (diff < replay_esn->replay_window) {
 518                         for (i = 1; i < diff; i++) {
 519                                 bitnr = (pos + i) % replay_esn->replay_window;
 520                                 nr = bitnr >> 5;
 521                                 bitnr = bitnr & 0x1F;
 522                                 replay_esn->bmp[nr] &=  ~(1U << bitnr);
 523                         }
 524                 } else {
 525                         nr = (replay_esn->replay_window - 1) >> 5;
 526                         for (i = 0; i <= nr; i++)
 527                                 replay_esn->bmp[i] = 0;
 528                 }
 529
 530                 bitnr = (pos + diff) % replay_esn->replay_window;
 531                 replay_esn->seq = seq;
 532
 533                 if (unlikely(wrap > 0))
 534                         replay_esn->seq_hi++;
 535         } else {
 536                 diff = replay_esn->seq - seq;
 537
 538                 if (pos >= diff)
 539                         bitnr = (pos - diff) % replay_esn->replay_window;
 540                 else
 541                         bitnr = replay_esn->replay_window - (diff - pos);
 542         }
 543
 544         xfrm_dev_state_advance_esn(x);
 545
 546         nr = bitnr >> 5;
 547         bitnr = bitnr & 0x1F;
 548         replay_esn->bmp[nr] |= (1U << bitnr);
 549
 550         if (xfrm_aevent_is_on(xs_net(x)))
 551                 x->repl->notify(x, XFRM_REPLAY_UPDATE);
 552 }
 553
 554 #ifdef CONFIG_XFRM_OFFLOAD
 555 static int xfrm_replay_overflow_offload(struct xfrm_state *x, struct sk_buff *skb)
 556 {
 557         int err = 0;
 558         struct net *net = xs_net(x);
 559         struct xfrm_offload *xo = xfrm_offload(skb);
 560         __u32 oseq = x->replay.oseq;
 561
 562         if (!xo)
 563                 return xfrm_replay_overflow(x, skb);
 564
 565         if (x->type->flags & XFRM_TYPE_REPLAY_PROT) {
 566                 if (!skb_is_gso(skb)) {
 567                         XFRM_SKB_CB(skb)->seq.output.low = ++oseq;
 568                         xo->seq.low = oseq;
 569                 } else {
 570                         XFRM_SKB_CB(skb)->seq.output.low = oseq + 1;
 571                         xo->seq.low = oseq + 1;
 572                         oseq += skb_shinfo(skb)->gso_segs;
 573                 }
 574
 575                 XFRM_SKB_CB(skb)->seq.output.hi = 0;
 576                 xo->seq.hi = 0;
 577                 if (unlikely(oseq < x->replay.oseq) &&
 578                     !(x->props.extra_flags & XFRM_SA_XFLAG_OSEQ_MAY_WRAP)) {
 579                         xfrm_audit_state_replay_overflow(x, skb);
 580                         err = -EOVERFLOW;
 581
 582                         return err;
 583                 }
 584
 585                 x->replay.oseq = oseq;
 586
 587                 if (xfrm_aevent_is_on(net))
 588                         x->repl->notify(x, XFRM_REPLAY_UPDATE);
 589         }
 590
 591         return err;
 592 }
 593
 594 static int xfrm_replay_overflow_offload_bmp(struct xfrm_state *x, struct sk_buff *skb)
 595 {
 596         int err = 0;
 597         struct xfrm_offload *xo = xfrm_offload(skb);
 598         struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
 599         struct net *net = xs_net(x);
 600         __u32 oseq = replay_esn->oseq;
 601
 602         if (!xo)
 603                 return xfrm_replay_overflow_bmp(x, skb);
 604
 605         if (x->type->flags & XFRM_TYPE_REPLAY_PROT) {
 606                 if (!skb_is_gso(skb)) {
 607                         XFRM_SKB_CB(skb)->seq.output.low = ++oseq;
 608                         xo->seq.low = oseq;
 609                 } else {
 610                         XFRM_SKB_CB(skb)->seq.output.low = oseq + 1;
 611                         xo->seq.low = oseq + 1;
 612                         oseq += skb_shinfo(skb)->gso_segs;
 613                 }
 614
 615                 XFRM_SKB_CB(skb)->seq.output.hi = 0;
 616                 xo->seq.hi = 0;
 617                 if (unlikely(oseq < replay_esn->oseq) &&
 618                     !(x->props.extra_flags & XFRM_SA_XFLAG_OSEQ_MAY_WRAP)) {
 619                         xfrm_audit_state_replay_overflow(x, skb);
 620                         err = -EOVERFLOW;
 621
 622                         return err;
 623                 } else {
 624                         replay_esn->oseq = oseq;
 625                 }
 626
 627                 if (xfrm_aevent_is_on(net))
 628                         x->repl->notify(x, XFRM_REPLAY_UPDATE);
 629         }
 630
 631         return err;
 632 }
 633
 634 static int xfrm_replay_overflow_offload_esn(struct xfrm_state *x, struct sk_buff *skb)
 635 {
 636         int err = 0;
 637         struct xfrm_offload *xo = xfrm_offload(skb);
 638         struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
 639         struct net *net = xs_net(x);
 640         __u32 oseq = replay_esn->oseq;
 641         __u32 oseq_hi = replay_esn->oseq_hi;
 642
 643         if (!xo)
 644                 return xfrm_replay_overflow_esn(x, skb);
 645
 646         if (x->type->flags & XFRM_TYPE_REPLAY_PROT) {
 647                 if (!skb_is_gso(skb)) {
 648                         XFRM_SKB_CB(skb)->seq.output.low = ++oseq;
 649                         XFRM_SKB_CB(skb)->seq.output.hi = oseq_hi;
 650                         xo->seq.low = oseq;
 651                         xo->seq.hi = oseq_hi;
 652                 } else {
 653                         XFRM_SKB_CB(skb)->seq.output.low = oseq + 1;
 654                         XFRM_SKB_CB(skb)->seq.output.hi = oseq_hi;
 655                         xo->seq.low = oseq + 1;
 656                         xo->seq.hi = oseq_hi;
 657                         oseq += skb_shinfo(skb)->gso_segs;
 658                 }
 659
 660                 if (unlikely(oseq < replay_esn->oseq)) {
 661                         XFRM_SKB_CB(skb)->seq.output.hi = ++oseq_hi;
 662                         xo->seq.hi = oseq_hi;
 663                         replay_esn->oseq_hi = oseq_hi;
 664                         if (replay_esn->oseq_hi == 0) {
 665                                 replay_esn->oseq--;
 666                                 replay_esn->oseq_hi--;
 667                                 xfrm_audit_state_replay_overflow(x, skb);
 668                                 err = -EOVERFLOW;
 669
 670                                 return err;
 671                         }
 672                 }
 673
 674                 replay_esn->oseq = oseq;
 675
 676                 if (xfrm_aevent_is_on(net))
 677                         x->repl->notify(x, XFRM_REPLAY_UPDATE);
 678         }
 679
 680         return err;
 681 }
 682
 683 static const struct xfrm_replay xfrm_replay_legacy = {
 684         .advance        = xfrm_replay_advance,
 685         .check          = xfrm_replay_check,
 686         .recheck        = xfrm_replay_check,
 687         .notify         = xfrm_replay_notify,
 688         .overflow       = xfrm_replay_overflow_offload,
 689 };
 690
 691 static const struct xfrm_replay xfrm_replay_bmp = {
 692         .advance        = xfrm_replay_advance_bmp,
 693         .check          = xfrm_replay_check_bmp,
 694         .recheck        = xfrm_replay_check_bmp,
 695         .notify         = xfrm_replay_notify_bmp,
 696         .overflow       = xfrm_replay_overflow_offload_bmp,
 697 };
 698
 699 static const struct xfrm_replay xfrm_replay_esn = {
 700         .advance        = xfrm_replay_advance_esn,
 701         .check          = xfrm_replay_check_esn,
 702         .recheck        = xfrm_replay_recheck_esn,
 703         .notify         = xfrm_replay_notify_esn,
 704         .overflow       = xfrm_replay_overflow_offload_esn,
 705 };
 706 #else
 707 static const struct xfrm_replay xfrm_replay_legacy = {
 708         .advance        = xfrm_replay_advance,
 709         .check          = xfrm_replay_check,
 710         .recheck        = xfrm_replay_check,
 711         .notify         = xfrm_replay_notify,
 712         .overflow       = xfrm_replay_overflow,
 713 };
 714
 715 static const struct xfrm_replay xfrm_replay_bmp = {
 716         .advance        = xfrm_replay_advance_bmp,
 717         .check          = xfrm_replay_check_bmp,
 718         .recheck        = xfrm_replay_check_bmp,
 719         .notify         = xfrm_replay_notify_bmp,
 720         .overflow       = xfrm_replay_overflow_bmp,
 721 };
 722
 723 static const struct xfrm_replay xfrm_replay_esn = {
 724         .advance        = xfrm_replay_advance_esn,
 725         .check          = xfrm_replay_check_esn,
 726         .recheck        = xfrm_replay_recheck_esn,
 727         .notify         = xfrm_replay_notify_esn,
 728         .overflow       = xfrm_replay_overflow_esn,
 729 };
 730 #endif
 731
 732 int xfrm_init_replay(struct xfrm_state *x)
 733 {
 734         struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
 735
 736         if (replay_esn) {
 737                 if (replay_esn->replay_window >
 738                     replay_esn->bmp_len * sizeof(__u32) * 8)
 739                         return -EINVAL;
 740
 741                 if (x->props.flags & XFRM_STATE_ESN) {
 742                         if (replay_esn->replay_window == 0)
 743                                 return -EINVAL;
 744                         x->repl = &xfrm_replay_esn;
 745                 } else {
 746                         x->repl = &xfrm_replay_bmp;
 747                 }
 748         } else {
 749                 x->repl = &xfrm_replay_legacy;
 750         }
 751
 752         return 0;
 753 }
 754 EXPORT_SYMBOL(xfrm_init_replay);