linux/net/ipv6/esp6.c
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   1/*
   2 * Copyright (C)2002 USAGI/WIDE Project
   3 *
   4 * This program is free software; you can redistribute it and/or modify
   5 * it under the terms of the GNU General Public License as published by
   6 * the Free Software Foundation; either version 2 of the License, or
   7 * (at your option) any later version.
   8 *
   9 * This program is distributed in the hope that it will be useful,
  10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 * GNU General Public License for more details.
  13 *
  14 * You should have received a copy of the GNU General Public License
  15 * along with this program; if not, see <http://www.gnu.org/licenses/>.
  16 *
  17 * Authors
  18 *
  19 *      Mitsuru KANDA @USAGI       : IPv6 Support
  20 *      Kazunori MIYAZAWA @USAGI   :
  21 *      Kunihiro Ishiguro <kunihiro@ipinfusion.com>
  22 *
  23 *      This file is derived from net/ipv4/esp.c
  24 */
  25
  26#define pr_fmt(fmt) "IPv6: " fmt
  27
  28#include <crypto/aead.h>
  29#include <crypto/authenc.h>
  30#include <linux/err.h>
  31#include <linux/module.h>
  32#include <net/ip.h>
  33#include <net/xfrm.h>
  34#include <net/esp.h>
  35#include <linux/scatterlist.h>
  36#include <linux/kernel.h>
  37#include <linux/pfkeyv2.h>
  38#include <linux/random.h>
  39#include <linux/slab.h>
  40#include <linux/spinlock.h>
  41#include <net/ip6_route.h>
  42#include <net/icmp.h>
  43#include <net/ipv6.h>
  44#include <net/protocol.h>
  45#include <linux/icmpv6.h>
  46
  47#include <linux/highmem.h>
  48
  49struct esp_skb_cb {
  50        struct xfrm_skb_cb xfrm;
  51        void *tmp;
  52};
  53
  54#define ESP_SKB_CB(__skb) ((struct esp_skb_cb *)&((__skb)->cb[0]))
  55
  56static u32 esp6_get_mtu(struct xfrm_state *x, int mtu);
  57
  58/*
  59 * Allocate an AEAD request structure with extra space for SG and IV.
  60 *
  61 * For alignment considerations the upper 32 bits of the sequence number are
  62 * placed at the front, if present. Followed by the IV, the request and finally
  63 * the SG list.
  64 *
  65 * TODO: Use spare space in skb for this where possible.
  66 */
  67static void *esp_alloc_tmp(struct crypto_aead *aead, int nfrags, int seqihlen)
  68{
  69        unsigned int len;
  70
  71        len = seqihlen;
  72
  73        len += crypto_aead_ivsize(aead);
  74
  75        if (len) {
  76                len += crypto_aead_alignmask(aead) &
  77                       ~(crypto_tfm_ctx_alignment() - 1);
  78                len = ALIGN(len, crypto_tfm_ctx_alignment());
  79        }
  80
  81        len += sizeof(struct aead_request) + crypto_aead_reqsize(aead);
  82        len = ALIGN(len, __alignof__(struct scatterlist));
  83
  84        len += sizeof(struct scatterlist) * nfrags;
  85
  86        return kmalloc(len, GFP_ATOMIC);
  87}
  88
  89static inline __be32 *esp_tmp_seqhi(void *tmp)
  90{
  91        return PTR_ALIGN((__be32 *)tmp, __alignof__(__be32));
  92}
  93
  94static inline u8 *esp_tmp_iv(struct crypto_aead *aead, void *tmp, int seqhilen)
  95{
  96        return crypto_aead_ivsize(aead) ?
  97               PTR_ALIGN((u8 *)tmp + seqhilen,
  98                         crypto_aead_alignmask(aead) + 1) : tmp + seqhilen;
  99}
 100
 101static inline struct aead_request *esp_tmp_req(struct crypto_aead *aead, u8 *iv)
 102{
 103        struct aead_request *req;
 104
 105        req = (void *)PTR_ALIGN(iv + crypto_aead_ivsize(aead),
 106                                crypto_tfm_ctx_alignment());
 107        aead_request_set_tfm(req, aead);
 108        return req;
 109}
 110
 111static inline struct scatterlist *esp_req_sg(struct crypto_aead *aead,
 112                                             struct aead_request *req)
 113{
 114        return (void *)ALIGN((unsigned long)(req + 1) +
 115                             crypto_aead_reqsize(aead),
 116                             __alignof__(struct scatterlist));
 117}
 118
 119static void esp_ssg_unref(struct xfrm_state *x, void *tmp)
 120{
 121        __be32 *seqhi;
 122        struct crypto_aead *aead = x->data;
 123        int seqhilen = 0;
 124        u8 *iv;
 125        struct aead_request *req;
 126        struct scatterlist *sg;
 127
 128        if (x->props.flags & XFRM_STATE_ESN)
 129                seqhilen += sizeof(__be32);
 130
 131        seqhi = esp_tmp_seqhi(tmp);
 132        iv = esp_tmp_iv(aead, tmp, seqhilen);
 133        req = esp_tmp_req(aead, iv);
 134
 135        /* Unref skb_frag_pages in the src scatterlist if necessary.
 136         * Skip the first sg which comes from skb->data.
 137         */
 138        if (req->src != req->dst)
 139                for (sg = sg_next(req->src); sg; sg = sg_next(sg))
 140                        put_page(sg_page(sg));
 141}
 142
 143static void esp_output_done(struct crypto_async_request *base, int err)
 144{
 145        struct sk_buff *skb = base->data;
 146        void *tmp;
 147        struct dst_entry *dst = skb_dst(skb);
 148        struct xfrm_state *x = dst->xfrm;
 149
 150        tmp = ESP_SKB_CB(skb)->tmp;
 151        esp_ssg_unref(x, tmp);
 152        kfree(tmp);
 153        xfrm_output_resume(skb, err);
 154}
 155
 156/* Move ESP header back into place. */
 157static void esp_restore_header(struct sk_buff *skb, unsigned int offset)
 158{
 159        struct ip_esp_hdr *esph = (void *)(skb->data + offset);
 160        void *tmp = ESP_SKB_CB(skb)->tmp;
 161        __be32 *seqhi = esp_tmp_seqhi(tmp);
 162
 163        esph->seq_no = esph->spi;
 164        esph->spi = *seqhi;
 165}
 166
 167static void esp_output_restore_header(struct sk_buff *skb)
 168{
 169        esp_restore_header(skb, skb_transport_offset(skb) - sizeof(__be32));
 170}
 171
 172static struct ip_esp_hdr *esp_output_set_esn(struct sk_buff *skb,
 173                                             struct xfrm_state *x,
 174                                             struct ip_esp_hdr *esph,
 175                                             __be32 *seqhi)
 176{
 177        /* For ESN we move the header forward by 4 bytes to
 178         * accomodate the high bits.  We will move it back after
 179         * encryption.
 180         */
 181        if ((x->props.flags & XFRM_STATE_ESN)) {
 182                struct xfrm_offload *xo = xfrm_offload(skb);
 183
 184                esph = (void *)(skb_transport_header(skb) - sizeof(__be32));
 185                *seqhi = esph->spi;
 186                if (xo)
 187                        esph->seq_no = htonl(xo->seq.hi);
 188                else
 189                        esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.hi);
 190        }
 191
 192        esph->spi = x->id.spi;
 193
 194        return esph;
 195}
 196
 197static void esp_output_done_esn(struct crypto_async_request *base, int err)
 198{
 199        struct sk_buff *skb = base->data;
 200
 201        esp_output_restore_header(skb);
 202        esp_output_done(base, err);
 203}
 204
 205static void esp_output_fill_trailer(u8 *tail, int tfclen, int plen, __u8 proto)
 206{
 207        /* Fill padding... */
 208        if (tfclen) {
 209                memset(tail, 0, tfclen);
 210                tail += tfclen;
 211        }
 212        do {
 213                int i;
 214                for (i = 0; i < plen - 2; i++)
 215                        tail[i] = i + 1;
 216        } while (0);
 217        tail[plen - 2] = plen - 2;
 218        tail[plen - 1] = proto;
 219}
 220
 221int esp6_output_head(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp)
 222{
 223        u8 *tail;
 224        u8 *vaddr;
 225        int nfrags;
 226        struct page *page;
 227        struct ip_esp_hdr *esph;
 228        struct sk_buff *trailer;
 229        int tailen = esp->tailen;
 230
 231        esph = ip_esp_hdr(skb);
 232
 233        if (!skb_cloned(skb)) {
 234                if (tailen <= skb_availroom(skb)) {
 235                        nfrags = 1;
 236                        trailer = skb;
 237                        tail = skb_tail_pointer(trailer);
 238
 239                        goto skip_cow;
 240                } else if ((skb_shinfo(skb)->nr_frags < MAX_SKB_FRAGS)
 241                           && !skb_has_frag_list(skb)) {
 242                        int allocsize;
 243                        struct sock *sk = skb->sk;
 244                        struct page_frag *pfrag = &x->xfrag;
 245
 246                        esp->inplace = false;
 247
 248                        allocsize = ALIGN(tailen, L1_CACHE_BYTES);
 249
 250                        spin_lock_bh(&x->lock);
 251
 252                        if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) {
 253                                spin_unlock_bh(&x->lock);
 254                                goto cow;
 255                        }
 256
 257                        page = pfrag->page;
 258                        get_page(page);
 259
 260                        vaddr = kmap_atomic(page);
 261
 262                        tail = vaddr + pfrag->offset;
 263
 264                        esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto);
 265
 266                        kunmap_atomic(vaddr);
 267
 268                        spin_unlock_bh(&x->lock);
 269
 270                        nfrags = skb_shinfo(skb)->nr_frags;
 271
 272                        __skb_fill_page_desc(skb, nfrags, page, pfrag->offset,
 273                                             tailen);
 274                        skb_shinfo(skb)->nr_frags = ++nfrags;
 275
 276                        pfrag->offset = pfrag->offset + allocsize;
 277                        nfrags++;
 278
 279                        skb->len += tailen;
 280                        skb->data_len += tailen;
 281                        skb->truesize += tailen;
 282                        if (sk)
 283                                atomic_add(tailen, &sk->sk_wmem_alloc);
 284
 285                        goto out;
 286                }
 287        }
 288
 289cow:
 290        nfrags = skb_cow_data(skb, tailen, &trailer);
 291        if (nfrags < 0)
 292                goto out;
 293        tail = skb_tail_pointer(trailer);
 294
 295skip_cow:
 296        esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto);
 297        pskb_put(skb, trailer, tailen);
 298
 299out:
 300        return nfrags;
 301}
 302EXPORT_SYMBOL_GPL(esp6_output_head);
 303
 304int esp6_output_tail(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp)
 305{
 306        u8 *iv;
 307        int alen;
 308        void *tmp;
 309        int ivlen;
 310        int assoclen;
 311        int seqhilen;
 312        __be32 *seqhi;
 313        struct page *page;
 314        struct ip_esp_hdr *esph;
 315        struct aead_request *req;
 316        struct crypto_aead *aead;
 317        struct scatterlist *sg, *dsg;
 318        int err = -ENOMEM;
 319
 320        assoclen = sizeof(struct ip_esp_hdr);
 321        seqhilen = 0;
 322
 323        if (x->props.flags & XFRM_STATE_ESN) {
 324                seqhilen += sizeof(__be32);
 325                assoclen += sizeof(__be32);
 326        }
 327
 328        aead = x->data;
 329        alen = crypto_aead_authsize(aead);
 330        ivlen = crypto_aead_ivsize(aead);
 331
 332        tmp = esp_alloc_tmp(aead, esp->nfrags + 2, seqhilen);
 333        if (!tmp)
 334                goto error;
 335
 336        seqhi = esp_tmp_seqhi(tmp);
 337        iv = esp_tmp_iv(aead, tmp, seqhilen);
 338        req = esp_tmp_req(aead, iv);
 339        sg = esp_req_sg(aead, req);
 340
 341        if (esp->inplace)
 342                dsg = sg;
 343        else
 344                dsg = &sg[esp->nfrags];
 345
 346        esph = esp_output_set_esn(skb, x, ip_esp_hdr(skb), seqhi);
 347
 348        sg_init_table(sg, esp->nfrags);
 349        skb_to_sgvec(skb, sg,
 350                     (unsigned char *)esph - skb->data,
 351                     assoclen + ivlen + esp->clen + alen);
 352
 353        if (!esp->inplace) {
 354                int allocsize;
 355                struct page_frag *pfrag = &x->xfrag;
 356
 357                allocsize = ALIGN(skb->data_len, L1_CACHE_BYTES);
 358
 359                spin_lock_bh(&x->lock);
 360                if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) {
 361                        spin_unlock_bh(&x->lock);
 362                        goto error;
 363                }
 364
 365                skb_shinfo(skb)->nr_frags = 1;
 366
 367                page = pfrag->page;
 368                get_page(page);
 369                /* replace page frags in skb with new page */
 370                __skb_fill_page_desc(skb, 0, page, pfrag->offset, skb->data_len);
 371                pfrag->offset = pfrag->offset + allocsize;
 372                spin_unlock_bh(&x->lock);
 373
 374                sg_init_table(dsg, skb_shinfo(skb)->nr_frags + 1);
 375                skb_to_sgvec(skb, dsg,
 376                             (unsigned char *)esph - skb->data,
 377                             assoclen + ivlen + esp->clen + alen);
 378        }
 379
 380        if ((x->props.flags & XFRM_STATE_ESN))
 381                aead_request_set_callback(req, 0, esp_output_done_esn, skb);
 382        else
 383                aead_request_set_callback(req, 0, esp_output_done, skb);
 384
 385        aead_request_set_crypt(req, sg, dsg, ivlen + esp->clen, iv);
 386        aead_request_set_ad(req, assoclen);
 387
 388        memset(iv, 0, ivlen);
 389        memcpy(iv + ivlen - min(ivlen, 8), (u8 *)&esp->seqno + 8 - min(ivlen, 8),
 390               min(ivlen, 8));
 391
 392        ESP_SKB_CB(skb)->tmp = tmp;
 393        err = crypto_aead_encrypt(req);
 394
 395        switch (err) {
 396        case -EINPROGRESS:
 397                goto error;
 398
 399        case -EBUSY:
 400                err = NET_XMIT_DROP;
 401                break;
 402
 403        case 0:
 404                if ((x->props.flags & XFRM_STATE_ESN))
 405                        esp_output_restore_header(skb);
 406        }
 407
 408        if (sg != dsg)
 409                esp_ssg_unref(x, tmp);
 410        kfree(tmp);
 411
 412error:
 413        return err;
 414}
 415EXPORT_SYMBOL_GPL(esp6_output_tail);
 416
 417static int esp6_output(struct xfrm_state *x, struct sk_buff *skb)
 418{
 419        int alen;
 420        int blksize;
 421        struct ip_esp_hdr *esph;
 422        struct crypto_aead *aead;
 423        struct esp_info esp;
 424
 425        esp.inplace = true;
 426
 427        esp.proto = *skb_mac_header(skb);
 428        *skb_mac_header(skb) = IPPROTO_ESP;
 429
 430        /* skb is pure payload to encrypt */
 431
 432        aead = x->data;
 433        alen = crypto_aead_authsize(aead);
 434
 435        esp.tfclen = 0;
 436        if (x->tfcpad) {
 437                struct xfrm_dst *dst = (struct xfrm_dst *)skb_dst(skb);
 438                u32 padto;
 439
 440                padto = min(x->tfcpad, esp6_get_mtu(x, dst->child_mtu_cached));
 441                if (skb->len < padto)
 442                        esp.tfclen = padto - skb->len;
 443        }
 444        blksize = ALIGN(crypto_aead_blocksize(aead), 4);
 445        esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize);
 446        esp.plen = esp.clen - skb->len - esp.tfclen;
 447        esp.tailen = esp.tfclen + esp.plen + alen;
 448
 449        esp.nfrags = esp6_output_head(x, skb, &esp);
 450        if (esp.nfrags < 0)
 451                return esp.nfrags;
 452
 453        esph = ip_esp_hdr(skb);
 454        esph->spi = x->id.spi;
 455
 456        esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
 457        esp.seqno = cpu_to_be64(XFRM_SKB_CB(skb)->seq.output.low +
 458                            ((u64)XFRM_SKB_CB(skb)->seq.output.hi << 32));
 459
 460        skb_push(skb, -skb_network_offset(skb));
 461
 462        return esp6_output_tail(x, skb, &esp);
 463}
 464
 465int esp6_input_done2(struct sk_buff *skb, int err)
 466{
 467        struct xfrm_state *x = xfrm_input_state(skb);
 468        struct xfrm_offload *xo = xfrm_offload(skb);
 469        struct crypto_aead *aead = x->data;
 470        int alen = crypto_aead_authsize(aead);
 471        int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
 472        int elen = skb->len - hlen;
 473        int hdr_len = skb_network_header_len(skb);
 474        int padlen;
 475        u8 nexthdr[2];
 476
 477        if (!xo || (xo && !(xo->flags & CRYPTO_DONE)))
 478                kfree(ESP_SKB_CB(skb)->tmp);
 479
 480        if (unlikely(err))
 481                goto out;
 482
 483        if (skb_copy_bits(skb, skb->len - alen - 2, nexthdr, 2))
 484                BUG();
 485
 486        err = -EINVAL;
 487        padlen = nexthdr[0];
 488        if (padlen + 2 + alen >= elen) {
 489                net_dbg_ratelimited("ipsec esp packet is garbage padlen=%d, elen=%d\n",
 490                                    padlen + 2, elen - alen);
 491                goto out;
 492        }
 493
 494        /* ... check padding bits here. Silly. :-) */
 495
 496        pskb_trim(skb, skb->len - alen - padlen - 2);
 497        __skb_pull(skb, hlen);
 498        if (x->props.mode == XFRM_MODE_TUNNEL)
 499                skb_reset_transport_header(skb);
 500        else
 501                skb_set_transport_header(skb, -hdr_len);
 502
 503        err = nexthdr[1];
 504
 505        /* RFC4303: Drop dummy packets without any error */
 506        if (err == IPPROTO_NONE)
 507                err = -EINVAL;
 508
 509out:
 510        return err;
 511}
 512EXPORT_SYMBOL_GPL(esp6_input_done2);
 513
 514static void esp_input_done(struct crypto_async_request *base, int err)
 515{
 516        struct sk_buff *skb = base->data;
 517
 518        xfrm_input_resume(skb, esp6_input_done2(skb, err));
 519}
 520
 521static void esp_input_restore_header(struct sk_buff *skb)
 522{
 523        esp_restore_header(skb, 0);
 524        __skb_pull(skb, 4);
 525}
 526
 527static void esp_input_set_header(struct sk_buff *skb, __be32 *seqhi)
 528{
 529        struct xfrm_state *x = xfrm_input_state(skb);
 530        struct ip_esp_hdr *esph = (struct ip_esp_hdr *)skb->data;
 531
 532        /* For ESN we move the header forward by 4 bytes to
 533         * accomodate the high bits.  We will move it back after
 534         * decryption.
 535         */
 536        if ((x->props.flags & XFRM_STATE_ESN)) {
 537                esph = (void *)skb_push(skb, 4);
 538                *seqhi = esph->spi;
 539                esph->spi = esph->seq_no;
 540                esph->seq_no = XFRM_SKB_CB(skb)->seq.input.hi;
 541        }
 542}
 543
 544static void esp_input_done_esn(struct crypto_async_request *base, int err)
 545{
 546        struct sk_buff *skb = base->data;
 547
 548        esp_input_restore_header(skb);
 549        esp_input_done(base, err);
 550}
 551
 552static int esp6_input(struct xfrm_state *x, struct sk_buff *skb)
 553{
 554        struct ip_esp_hdr *esph;
 555        struct crypto_aead *aead = x->data;
 556        struct aead_request *req;
 557        struct sk_buff *trailer;
 558        int ivlen = crypto_aead_ivsize(aead);
 559        int elen = skb->len - sizeof(*esph) - ivlen;
 560        int nfrags;
 561        int assoclen;
 562        int seqhilen;
 563        int ret = 0;
 564        void *tmp;
 565        __be32 *seqhi;
 566        u8 *iv;
 567        struct scatterlist *sg;
 568
 569        if (!pskb_may_pull(skb, sizeof(*esph) + ivlen)) {
 570                ret = -EINVAL;
 571                goto out;
 572        }
 573
 574        if (elen <= 0) {
 575                ret = -EINVAL;
 576                goto out;
 577        }
 578
 579        assoclen = sizeof(*esph);
 580        seqhilen = 0;
 581
 582        if (x->props.flags & XFRM_STATE_ESN) {
 583                seqhilen += sizeof(__be32);
 584                assoclen += seqhilen;
 585        }
 586
 587        if (!skb_cloned(skb)) {
 588                if (!skb_is_nonlinear(skb)) {
 589                        nfrags = 1;
 590
 591                        goto skip_cow;
 592                } else if (!skb_has_frag_list(skb)) {
 593                        nfrags = skb_shinfo(skb)->nr_frags;
 594                        nfrags++;
 595
 596                        goto skip_cow;
 597                }
 598        }
 599
 600        nfrags = skb_cow_data(skb, 0, &trailer);
 601        if (nfrags < 0) {
 602                ret = -EINVAL;
 603                goto out;
 604        }
 605
 606skip_cow:
 607        ret = -ENOMEM;
 608        tmp = esp_alloc_tmp(aead, nfrags, seqhilen);
 609        if (!tmp)
 610                goto out;
 611
 612        ESP_SKB_CB(skb)->tmp = tmp;
 613        seqhi = esp_tmp_seqhi(tmp);
 614        iv = esp_tmp_iv(aead, tmp, seqhilen);
 615        req = esp_tmp_req(aead, iv);
 616        sg = esp_req_sg(aead, req);
 617
 618        esp_input_set_header(skb, seqhi);
 619
 620        sg_init_table(sg, nfrags);
 621        skb_to_sgvec(skb, sg, 0, skb->len);
 622
 623        skb->ip_summed = CHECKSUM_NONE;
 624
 625        if ((x->props.flags & XFRM_STATE_ESN))
 626                aead_request_set_callback(req, 0, esp_input_done_esn, skb);
 627        else
 628                aead_request_set_callback(req, 0, esp_input_done, skb);
 629
 630        aead_request_set_crypt(req, sg, sg, elen + ivlen, iv);
 631        aead_request_set_ad(req, assoclen);
 632
 633        ret = crypto_aead_decrypt(req);
 634        if (ret == -EINPROGRESS)
 635                goto out;
 636
 637        if ((x->props.flags & XFRM_STATE_ESN))
 638                esp_input_restore_header(skb);
 639
 640        ret = esp6_input_done2(skb, ret);
 641
 642out:
 643        return ret;
 644}
 645
 646static u32 esp6_get_mtu(struct xfrm_state *x, int mtu)
 647{
 648        struct crypto_aead *aead = x->data;
 649        u32 blksize = ALIGN(crypto_aead_blocksize(aead), 4);
 650        unsigned int net_adj;
 651
 652        if (x->props.mode != XFRM_MODE_TUNNEL)
 653                net_adj = sizeof(struct ipv6hdr);
 654        else
 655                net_adj = 0;
 656
 657        return ((mtu - x->props.header_len - crypto_aead_authsize(aead) -
 658                 net_adj) & ~(blksize - 1)) + net_adj - 2;
 659}
 660
 661static int esp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 662                    u8 type, u8 code, int offset, __be32 info)
 663{
 664        struct net *net = dev_net(skb->dev);
 665        const struct ipv6hdr *iph = (const struct ipv6hdr *)skb->data;
 666        struct ip_esp_hdr *esph = (struct ip_esp_hdr *)(skb->data + offset);
 667        struct xfrm_state *x;
 668
 669        if (type != ICMPV6_PKT_TOOBIG &&
 670            type != NDISC_REDIRECT)
 671                return 0;
 672
 673        x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr,
 674                              esph->spi, IPPROTO_ESP, AF_INET6);
 675        if (!x)
 676                return 0;
 677
 678        if (type == NDISC_REDIRECT)
 679                ip6_redirect(skb, net, skb->dev->ifindex, 0,
 680                             sock_net_uid(net, NULL));
 681        else
 682                ip6_update_pmtu(skb, net, info, 0, 0, sock_net_uid(net, NULL));
 683        xfrm_state_put(x);
 684
 685        return 0;
 686}
 687
 688static void esp6_destroy(struct xfrm_state *x)
 689{
 690        struct crypto_aead *aead = x->data;
 691
 692        if (!aead)
 693                return;
 694
 695        crypto_free_aead(aead);
 696}
 697
 698static int esp_init_aead(struct xfrm_state *x)
 699{
 700        char aead_name[CRYPTO_MAX_ALG_NAME];
 701        struct crypto_aead *aead;
 702        int err;
 703        u32 mask = 0;
 704
 705        err = -ENAMETOOLONG;
 706        if (snprintf(aead_name, CRYPTO_MAX_ALG_NAME, "%s(%s)",
 707                     x->geniv, x->aead->alg_name) >= CRYPTO_MAX_ALG_NAME)
 708                goto error;
 709
 710        if (x->xso.offload_handle)
 711                mask |= CRYPTO_ALG_ASYNC;
 712
 713        aead = crypto_alloc_aead(aead_name, 0, mask);
 714        err = PTR_ERR(aead);
 715        if (IS_ERR(aead))
 716                goto error;
 717
 718        x->data = aead;
 719
 720        err = crypto_aead_setkey(aead, x->aead->alg_key,
 721                                 (x->aead->alg_key_len + 7) / 8);
 722        if (err)
 723                goto error;
 724
 725        err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8);
 726        if (err)
 727                goto error;
 728
 729error:
 730        return err;
 731}
 732
 733static int esp_init_authenc(struct xfrm_state *x)
 734{
 735        struct crypto_aead *aead;
 736        struct crypto_authenc_key_param *param;
 737        struct rtattr *rta;
 738        char *key;
 739        char *p;
 740        char authenc_name[CRYPTO_MAX_ALG_NAME];
 741        unsigned int keylen;
 742        int err;
 743        u32 mask = 0;
 744
 745        err = -EINVAL;
 746        if (!x->ealg)
 747                goto error;
 748
 749        err = -ENAMETOOLONG;
 750
 751        if ((x->props.flags & XFRM_STATE_ESN)) {
 752                if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
 753                             "%s%sauthencesn(%s,%s)%s",
 754                             x->geniv ?: "", x->geniv ? "(" : "",
 755                             x->aalg ? x->aalg->alg_name : "digest_null",
 756                             x->ealg->alg_name,
 757                             x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME)
 758                        goto error;
 759        } else {
 760                if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
 761                             "%s%sauthenc(%s,%s)%s",
 762                             x->geniv ?: "", x->geniv ? "(" : "",
 763                             x->aalg ? x->aalg->alg_name : "digest_null",
 764                             x->ealg->alg_name,
 765                             x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME)
 766                        goto error;
 767        }
 768
 769        if (x->xso.offload_handle)
 770                mask |= CRYPTO_ALG_ASYNC;
 771
 772        aead = crypto_alloc_aead(authenc_name, 0, mask);
 773        err = PTR_ERR(aead);
 774        if (IS_ERR(aead))
 775                goto error;
 776
 777        x->data = aead;
 778
 779        keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) +
 780                 (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param));
 781        err = -ENOMEM;
 782        key = kmalloc(keylen, GFP_KERNEL);
 783        if (!key)
 784                goto error;
 785
 786        p = key;
 787        rta = (void *)p;
 788        rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM;
 789        rta->rta_len = RTA_LENGTH(sizeof(*param));
 790        param = RTA_DATA(rta);
 791        p += RTA_SPACE(sizeof(*param));
 792
 793        if (x->aalg) {
 794                struct xfrm_algo_desc *aalg_desc;
 795
 796                memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8);
 797                p += (x->aalg->alg_key_len + 7) / 8;
 798
 799                aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
 800                BUG_ON(!aalg_desc);
 801
 802                err = -EINVAL;
 803                if (aalg_desc->uinfo.auth.icv_fullbits / 8 !=
 804                    crypto_aead_authsize(aead)) {
 805                        pr_info("ESP: %s digestsize %u != %hu\n",
 806                                x->aalg->alg_name,
 807                                crypto_aead_authsize(aead),
 808                                aalg_desc->uinfo.auth.icv_fullbits / 8);
 809                        goto free_key;
 810                }
 811
 812                err = crypto_aead_setauthsize(
 813                        aead, x->aalg->alg_trunc_len / 8);
 814                if (err)
 815                        goto free_key;
 816        }
 817
 818        param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8);
 819        memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8);
 820
 821        err = crypto_aead_setkey(aead, key, keylen);
 822
 823free_key:
 824        kfree(key);
 825
 826error:
 827        return err;
 828}
 829
 830static int esp6_init_state(struct xfrm_state *x)
 831{
 832        struct crypto_aead *aead;
 833        u32 align;
 834        int err;
 835
 836        if (x->encap)
 837                return -EINVAL;
 838
 839        x->data = NULL;
 840
 841        if (x->aead)
 842                err = esp_init_aead(x);
 843        else
 844                err = esp_init_authenc(x);
 845
 846        if (err)
 847                goto error;
 848
 849        aead = x->data;
 850
 851        x->props.header_len = sizeof(struct ip_esp_hdr) +
 852                              crypto_aead_ivsize(aead);
 853        switch (x->props.mode) {
 854        case XFRM_MODE_BEET:
 855                if (x->sel.family != AF_INET6)
 856                        x->props.header_len += IPV4_BEET_PHMAXLEN +
 857                                               (sizeof(struct ipv6hdr) - sizeof(struct iphdr));
 858                break;
 859        case XFRM_MODE_TRANSPORT:
 860                break;
 861        case XFRM_MODE_TUNNEL:
 862                x->props.header_len += sizeof(struct ipv6hdr);
 863                break;
 864        default:
 865                goto error;
 866        }
 867
 868        align = ALIGN(crypto_aead_blocksize(aead), 4);
 869        x->props.trailer_len = align + 1 + crypto_aead_authsize(aead);
 870
 871error:
 872        return err;
 873}
 874
 875static int esp6_rcv_cb(struct sk_buff *skb, int err)
 876{
 877        return 0;
 878}
 879
 880static const struct xfrm_type esp6_type = {
 881        .description    = "ESP6",
 882        .owner          = THIS_MODULE,
 883        .proto          = IPPROTO_ESP,
 884        .flags          = XFRM_TYPE_REPLAY_PROT,
 885        .init_state     = esp6_init_state,
 886        .destructor     = esp6_destroy,
 887        .get_mtu        = esp6_get_mtu,
 888        .input          = esp6_input,
 889        .output         = esp6_output,
 890        .hdr_offset     = xfrm6_find_1stfragopt,
 891};
 892
 893static struct xfrm6_protocol esp6_protocol = {
 894        .handler        =       xfrm6_rcv,
 895        .cb_handler     =       esp6_rcv_cb,
 896        .err_handler    =       esp6_err,
 897        .priority       =       0,
 898};
 899
 900static int __init esp6_init(void)
 901{
 902        if (xfrm_register_type(&esp6_type, AF_INET6) < 0) {
 903                pr_info("%s: can't add xfrm type\n", __func__);
 904                return -EAGAIN;
 905        }
 906        if (xfrm6_protocol_register(&esp6_protocol, IPPROTO_ESP) < 0) {
 907                pr_info("%s: can't add protocol\n", __func__);
 908                xfrm_unregister_type(&esp6_type, AF_INET6);
 909                return -EAGAIN;
 910        }
 911
 912        return 0;
 913}
 914
 915static void __exit esp6_fini(void)
 916{
 917        if (xfrm6_protocol_deregister(&esp6_protocol, IPPROTO_ESP) < 0)
 918                pr_info("%s: can't remove protocol\n", __func__);
 919        if (xfrm_unregister_type(&esp6_type, AF_INET6) < 0)
 920                pr_info("%s: can't remove xfrm type\n", __func__);
 921}
 922
 923module_init(esp6_init);
 924module_exit(esp6_fini);
 925
 926MODULE_LICENSE("GPL");
 927MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_ESP);
 928