Back to home page

OSCL-LXR
 
 

     

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 #define pr_fmt(fmt) "IPsec: " fmt
0003 
0004 #include <crypto/aead.h>
0005 #include <crypto/authenc.h>
0006 #include <linux/err.h>
0007 #include <linux/module.h>
0008 #include <net/ip.h>
0009 #include <net/xfrm.h>
0010 #include <net/esp.h>
0011 #include <linux/scatterlist.h>
0012 #include <linux/kernel.h>
0013 #include <linux/pfkeyv2.h>
0014 #include <linux/rtnetlink.h>
0015 #include <linux/slab.h>
0016 #include <linux/spinlock.h>
0017 #include <linux/in6.h>
0018 #include <net/icmp.h>
0019 #include <net/protocol.h>
0020 #include <net/udp.h>
0021 #include <net/tcp.h>
0022 #include <net/espintcp.h>
0023 
0024 #include <linux/highmem.h>
0025 
0026 struct esp_skb_cb {
0027     struct xfrm_skb_cb xfrm;
0028     void *tmp;
0029 };
0030 
0031 struct esp_output_extra {
0032     __be32 seqhi;
0033     u32 esphoff;
0034 };
0035 
0036 #define ESP_SKB_CB(__skb) ((struct esp_skb_cb *)&((__skb)->cb[0]))
0037 
0038 /*
0039  * Allocate an AEAD request structure with extra space for SG and IV.
0040  *
0041  * For alignment considerations the IV is placed at the front, followed
0042  * by the request and finally the SG list.
0043  *
0044  * TODO: Use spare space in skb for this where possible.
0045  */
0046 static void *esp_alloc_tmp(struct crypto_aead *aead, int nfrags, int extralen)
0047 {
0048     unsigned int len;
0049 
0050     len = extralen;
0051 
0052     len += crypto_aead_ivsize(aead);
0053 
0054     if (len) {
0055         len += crypto_aead_alignmask(aead) &
0056                ~(crypto_tfm_ctx_alignment() - 1);
0057         len = ALIGN(len, crypto_tfm_ctx_alignment());
0058     }
0059 
0060     len += sizeof(struct aead_request) + crypto_aead_reqsize(aead);
0061     len = ALIGN(len, __alignof__(struct scatterlist));
0062 
0063     len += sizeof(struct scatterlist) * nfrags;
0064 
0065     return kmalloc(len, GFP_ATOMIC);
0066 }
0067 
0068 static inline void *esp_tmp_extra(void *tmp)
0069 {
0070     return PTR_ALIGN(tmp, __alignof__(struct esp_output_extra));
0071 }
0072 
0073 static inline u8 *esp_tmp_iv(struct crypto_aead *aead, void *tmp, int extralen)
0074 {
0075     return crypto_aead_ivsize(aead) ?
0076            PTR_ALIGN((u8 *)tmp + extralen,
0077              crypto_aead_alignmask(aead) + 1) : tmp + extralen;
0078 }
0079 
0080 static inline struct aead_request *esp_tmp_req(struct crypto_aead *aead, u8 *iv)
0081 {
0082     struct aead_request *req;
0083 
0084     req = (void *)PTR_ALIGN(iv + crypto_aead_ivsize(aead),
0085                 crypto_tfm_ctx_alignment());
0086     aead_request_set_tfm(req, aead);
0087     return req;
0088 }
0089 
0090 static inline struct scatterlist *esp_req_sg(struct crypto_aead *aead,
0091                          struct aead_request *req)
0092 {
0093     return (void *)ALIGN((unsigned long)(req + 1) +
0094                  crypto_aead_reqsize(aead),
0095                  __alignof__(struct scatterlist));
0096 }
0097 
0098 static void esp_ssg_unref(struct xfrm_state *x, void *tmp)
0099 {
0100     struct crypto_aead *aead = x->data;
0101     int extralen = 0;
0102     u8 *iv;
0103     struct aead_request *req;
0104     struct scatterlist *sg;
0105 
0106     if (x->props.flags & XFRM_STATE_ESN)
0107         extralen += sizeof(struct esp_output_extra);
0108 
0109     iv = esp_tmp_iv(aead, tmp, extralen);
0110     req = esp_tmp_req(aead, iv);
0111 
0112     /* Unref skb_frag_pages in the src scatterlist if necessary.
0113      * Skip the first sg which comes from skb->data.
0114      */
0115     if (req->src != req->dst)
0116         for (sg = sg_next(req->src); sg; sg = sg_next(sg))
0117             put_page(sg_page(sg));
0118 }
0119 
0120 #ifdef CONFIG_INET_ESPINTCP
0121 struct esp_tcp_sk {
0122     struct sock *sk;
0123     struct rcu_head rcu;
0124 };
0125 
0126 static void esp_free_tcp_sk(struct rcu_head *head)
0127 {
0128     struct esp_tcp_sk *esk = container_of(head, struct esp_tcp_sk, rcu);
0129 
0130     sock_put(esk->sk);
0131     kfree(esk);
0132 }
0133 
0134 static struct sock *esp_find_tcp_sk(struct xfrm_state *x)
0135 {
0136     struct xfrm_encap_tmpl *encap = x->encap;
0137     struct esp_tcp_sk *esk;
0138     __be16 sport, dport;
0139     struct sock *nsk;
0140     struct sock *sk;
0141 
0142     sk = rcu_dereference(x->encap_sk);
0143     if (sk && sk->sk_state == TCP_ESTABLISHED)
0144         return sk;
0145 
0146     spin_lock_bh(&x->lock);
0147     sport = encap->encap_sport;
0148     dport = encap->encap_dport;
0149     nsk = rcu_dereference_protected(x->encap_sk,
0150                     lockdep_is_held(&x->lock));
0151     if (sk && sk == nsk) {
0152         esk = kmalloc(sizeof(*esk), GFP_ATOMIC);
0153         if (!esk) {
0154             spin_unlock_bh(&x->lock);
0155             return ERR_PTR(-ENOMEM);
0156         }
0157         RCU_INIT_POINTER(x->encap_sk, NULL);
0158         esk->sk = sk;
0159         call_rcu(&esk->rcu, esp_free_tcp_sk);
0160     }
0161     spin_unlock_bh(&x->lock);
0162 
0163     sk = inet_lookup_established(xs_net(x), &tcp_hashinfo, x->id.daddr.a4,
0164                      dport, x->props.saddr.a4, sport, 0);
0165     if (!sk)
0166         return ERR_PTR(-ENOENT);
0167 
0168     if (!tcp_is_ulp_esp(sk)) {
0169         sock_put(sk);
0170         return ERR_PTR(-EINVAL);
0171     }
0172 
0173     spin_lock_bh(&x->lock);
0174     nsk = rcu_dereference_protected(x->encap_sk,
0175                     lockdep_is_held(&x->lock));
0176     if (encap->encap_sport != sport ||
0177         encap->encap_dport != dport) {
0178         sock_put(sk);
0179         sk = nsk ?: ERR_PTR(-EREMCHG);
0180     } else if (sk == nsk) {
0181         sock_put(sk);
0182     } else {
0183         rcu_assign_pointer(x->encap_sk, sk);
0184     }
0185     spin_unlock_bh(&x->lock);
0186 
0187     return sk;
0188 }
0189 
0190 static int esp_output_tcp_finish(struct xfrm_state *x, struct sk_buff *skb)
0191 {
0192     struct sock *sk;
0193     int err;
0194 
0195     rcu_read_lock();
0196 
0197     sk = esp_find_tcp_sk(x);
0198     err = PTR_ERR_OR_ZERO(sk);
0199     if (err)
0200         goto out;
0201 
0202     bh_lock_sock(sk);
0203     if (sock_owned_by_user(sk))
0204         err = espintcp_queue_out(sk, skb);
0205     else
0206         err = espintcp_push_skb(sk, skb);
0207     bh_unlock_sock(sk);
0208 
0209 out:
0210     rcu_read_unlock();
0211     return err;
0212 }
0213 
0214 static int esp_output_tcp_encap_cb(struct net *net, struct sock *sk,
0215                    struct sk_buff *skb)
0216 {
0217     struct dst_entry *dst = skb_dst(skb);
0218     struct xfrm_state *x = dst->xfrm;
0219 
0220     return esp_output_tcp_finish(x, skb);
0221 }
0222 
0223 static int esp_output_tail_tcp(struct xfrm_state *x, struct sk_buff *skb)
0224 {
0225     int err;
0226 
0227     local_bh_disable();
0228     err = xfrm_trans_queue_net(xs_net(x), skb, esp_output_tcp_encap_cb);
0229     local_bh_enable();
0230 
0231     /* EINPROGRESS just happens to do the right thing.  It
0232      * actually means that the skb has been consumed and
0233      * isn't coming back.
0234      */
0235     return err ?: -EINPROGRESS;
0236 }
0237 #else
0238 static int esp_output_tail_tcp(struct xfrm_state *x, struct sk_buff *skb)
0239 {
0240     kfree_skb(skb);
0241 
0242     return -EOPNOTSUPP;
0243 }
0244 #endif
0245 
0246 static void esp_output_done(struct crypto_async_request *base, int err)
0247 {
0248     struct sk_buff *skb = base->data;
0249     struct xfrm_offload *xo = xfrm_offload(skb);
0250     void *tmp;
0251     struct xfrm_state *x;
0252 
0253     if (xo && (xo->flags & XFRM_DEV_RESUME)) {
0254         struct sec_path *sp = skb_sec_path(skb);
0255 
0256         x = sp->xvec[sp->len - 1];
0257     } else {
0258         x = skb_dst(skb)->xfrm;
0259     }
0260 
0261     tmp = ESP_SKB_CB(skb)->tmp;
0262     esp_ssg_unref(x, tmp);
0263     kfree(tmp);
0264 
0265     if (xo && (xo->flags & XFRM_DEV_RESUME)) {
0266         if (err) {
0267             XFRM_INC_STATS(xs_net(x), LINUX_MIB_XFRMOUTSTATEPROTOERROR);
0268             kfree_skb(skb);
0269             return;
0270         }
0271 
0272         skb_push(skb, skb->data - skb_mac_header(skb));
0273         secpath_reset(skb);
0274         xfrm_dev_resume(skb);
0275     } else {
0276         if (!err &&
0277             x->encap && x->encap->encap_type == TCP_ENCAP_ESPINTCP)
0278             esp_output_tail_tcp(x, skb);
0279         else
0280             xfrm_output_resume(skb->sk, skb, err);
0281     }
0282 }
0283 
0284 /* Move ESP header back into place. */
0285 static void esp_restore_header(struct sk_buff *skb, unsigned int offset)
0286 {
0287     struct ip_esp_hdr *esph = (void *)(skb->data + offset);
0288     void *tmp = ESP_SKB_CB(skb)->tmp;
0289     __be32 *seqhi = esp_tmp_extra(tmp);
0290 
0291     esph->seq_no = esph->spi;
0292     esph->spi = *seqhi;
0293 }
0294 
0295 static void esp_output_restore_header(struct sk_buff *skb)
0296 {
0297     void *tmp = ESP_SKB_CB(skb)->tmp;
0298     struct esp_output_extra *extra = esp_tmp_extra(tmp);
0299 
0300     esp_restore_header(skb, skb_transport_offset(skb) + extra->esphoff -
0301                 sizeof(__be32));
0302 }
0303 
0304 static struct ip_esp_hdr *esp_output_set_extra(struct sk_buff *skb,
0305                            struct xfrm_state *x,
0306                            struct ip_esp_hdr *esph,
0307                            struct esp_output_extra *extra)
0308 {
0309     /* For ESN we move the header forward by 4 bytes to
0310      * accommodate the high bits.  We will move it back after
0311      * encryption.
0312      */
0313     if ((x->props.flags & XFRM_STATE_ESN)) {
0314         __u32 seqhi;
0315         struct xfrm_offload *xo = xfrm_offload(skb);
0316 
0317         if (xo)
0318             seqhi = xo->seq.hi;
0319         else
0320             seqhi = XFRM_SKB_CB(skb)->seq.output.hi;
0321 
0322         extra->esphoff = (unsigned char *)esph -
0323                  skb_transport_header(skb);
0324         esph = (struct ip_esp_hdr *)((unsigned char *)esph - 4);
0325         extra->seqhi = esph->spi;
0326         esph->seq_no = htonl(seqhi);
0327     }
0328 
0329     esph->spi = x->id.spi;
0330 
0331     return esph;
0332 }
0333 
0334 static void esp_output_done_esn(struct crypto_async_request *base, int err)
0335 {
0336     struct sk_buff *skb = base->data;
0337 
0338     esp_output_restore_header(skb);
0339     esp_output_done(base, err);
0340 }
0341 
0342 static struct ip_esp_hdr *esp_output_udp_encap(struct sk_buff *skb,
0343                            int encap_type,
0344                            struct esp_info *esp,
0345                            __be16 sport,
0346                            __be16 dport)
0347 {
0348     struct udphdr *uh;
0349     __be32 *udpdata32;
0350     unsigned int len;
0351 
0352     len = skb->len + esp->tailen - skb_transport_offset(skb);
0353     if (len + sizeof(struct iphdr) > IP_MAX_MTU)
0354         return ERR_PTR(-EMSGSIZE);
0355 
0356     uh = (struct udphdr *)esp->esph;
0357     uh->source = sport;
0358     uh->dest = dport;
0359     uh->len = htons(len);
0360     uh->check = 0;
0361 
0362     *skb_mac_header(skb) = IPPROTO_UDP;
0363 
0364     if (encap_type == UDP_ENCAP_ESPINUDP_NON_IKE) {
0365         udpdata32 = (__be32 *)(uh + 1);
0366         udpdata32[0] = udpdata32[1] = 0;
0367         return (struct ip_esp_hdr *)(udpdata32 + 2);
0368     }
0369 
0370     return (struct ip_esp_hdr *)(uh + 1);
0371 }
0372 
0373 #ifdef CONFIG_INET_ESPINTCP
0374 static struct ip_esp_hdr *esp_output_tcp_encap(struct xfrm_state *x,
0375                             struct sk_buff *skb,
0376                             struct esp_info *esp)
0377 {
0378     __be16 *lenp = (void *)esp->esph;
0379     struct ip_esp_hdr *esph;
0380     unsigned int len;
0381     struct sock *sk;
0382 
0383     len = skb->len + esp->tailen - skb_transport_offset(skb);
0384     if (len > IP_MAX_MTU)
0385         return ERR_PTR(-EMSGSIZE);
0386 
0387     rcu_read_lock();
0388     sk = esp_find_tcp_sk(x);
0389     rcu_read_unlock();
0390 
0391     if (IS_ERR(sk))
0392         return ERR_CAST(sk);
0393 
0394     *lenp = htons(len);
0395     esph = (struct ip_esp_hdr *)(lenp + 1);
0396 
0397     return esph;
0398 }
0399 #else
0400 static struct ip_esp_hdr *esp_output_tcp_encap(struct xfrm_state *x,
0401                             struct sk_buff *skb,
0402                             struct esp_info *esp)
0403 {
0404     return ERR_PTR(-EOPNOTSUPP);
0405 }
0406 #endif
0407 
0408 static int esp_output_encap(struct xfrm_state *x, struct sk_buff *skb,
0409                 struct esp_info *esp)
0410 {
0411     struct xfrm_encap_tmpl *encap = x->encap;
0412     struct ip_esp_hdr *esph;
0413     __be16 sport, dport;
0414     int encap_type;
0415 
0416     spin_lock_bh(&x->lock);
0417     sport = encap->encap_sport;
0418     dport = encap->encap_dport;
0419     encap_type = encap->encap_type;
0420     spin_unlock_bh(&x->lock);
0421 
0422     switch (encap_type) {
0423     default:
0424     case UDP_ENCAP_ESPINUDP:
0425     case UDP_ENCAP_ESPINUDP_NON_IKE:
0426         esph = esp_output_udp_encap(skb, encap_type, esp, sport, dport);
0427         break;
0428     case TCP_ENCAP_ESPINTCP:
0429         esph = esp_output_tcp_encap(x, skb, esp);
0430         break;
0431     }
0432 
0433     if (IS_ERR(esph))
0434         return PTR_ERR(esph);
0435 
0436     esp->esph = esph;
0437 
0438     return 0;
0439 }
0440 
0441 int esp_output_head(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp)
0442 {
0443     u8 *tail;
0444     int nfrags;
0445     int esph_offset;
0446     struct page *page;
0447     struct sk_buff *trailer;
0448     int tailen = esp->tailen;
0449 
0450     /* this is non-NULL only with TCP/UDP Encapsulation */
0451     if (x->encap) {
0452         int err = esp_output_encap(x, skb, esp);
0453 
0454         if (err < 0)
0455             return err;
0456     }
0457 
0458     if (ALIGN(tailen, L1_CACHE_BYTES) > PAGE_SIZE ||
0459         ALIGN(skb->data_len, L1_CACHE_BYTES) > PAGE_SIZE)
0460         goto cow;
0461 
0462     if (!skb_cloned(skb)) {
0463         if (tailen <= skb_tailroom(skb)) {
0464             nfrags = 1;
0465             trailer = skb;
0466             tail = skb_tail_pointer(trailer);
0467 
0468             goto skip_cow;
0469         } else if ((skb_shinfo(skb)->nr_frags < MAX_SKB_FRAGS)
0470                && !skb_has_frag_list(skb)) {
0471             int allocsize;
0472             struct sock *sk = skb->sk;
0473             struct page_frag *pfrag = &x->xfrag;
0474 
0475             esp->inplace = false;
0476 
0477             allocsize = ALIGN(tailen, L1_CACHE_BYTES);
0478 
0479             spin_lock_bh(&x->lock);
0480 
0481             if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) {
0482                 spin_unlock_bh(&x->lock);
0483                 goto cow;
0484             }
0485 
0486             page = pfrag->page;
0487             get_page(page);
0488 
0489             tail = page_address(page) + pfrag->offset;
0490 
0491             esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto);
0492 
0493             nfrags = skb_shinfo(skb)->nr_frags;
0494 
0495             __skb_fill_page_desc(skb, nfrags, page, pfrag->offset,
0496                          tailen);
0497             skb_shinfo(skb)->nr_frags = ++nfrags;
0498 
0499             pfrag->offset = pfrag->offset + allocsize;
0500 
0501             spin_unlock_bh(&x->lock);
0502 
0503             nfrags++;
0504 
0505             skb_len_add(skb, tailen);
0506             if (sk && sk_fullsock(sk))
0507                 refcount_add(tailen, &sk->sk_wmem_alloc);
0508 
0509             goto out;
0510         }
0511     }
0512 
0513 cow:
0514     esph_offset = (unsigned char *)esp->esph - skb_transport_header(skb);
0515 
0516     nfrags = skb_cow_data(skb, tailen, &trailer);
0517     if (nfrags < 0)
0518         goto out;
0519     tail = skb_tail_pointer(trailer);
0520     esp->esph = (struct ip_esp_hdr *)(skb_transport_header(skb) + esph_offset);
0521 
0522 skip_cow:
0523     esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto);
0524     pskb_put(skb, trailer, tailen);
0525 
0526 out:
0527     return nfrags;
0528 }
0529 EXPORT_SYMBOL_GPL(esp_output_head);
0530 
0531 int esp_output_tail(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp)
0532 {
0533     u8 *iv;
0534     int alen;
0535     void *tmp;
0536     int ivlen;
0537     int assoclen;
0538     int extralen;
0539     struct page *page;
0540     struct ip_esp_hdr *esph;
0541     struct crypto_aead *aead;
0542     struct aead_request *req;
0543     struct scatterlist *sg, *dsg;
0544     struct esp_output_extra *extra;
0545     int err = -ENOMEM;
0546 
0547     assoclen = sizeof(struct ip_esp_hdr);
0548     extralen = 0;
0549 
0550     if (x->props.flags & XFRM_STATE_ESN) {
0551         extralen += sizeof(*extra);
0552         assoclen += sizeof(__be32);
0553     }
0554 
0555     aead = x->data;
0556     alen = crypto_aead_authsize(aead);
0557     ivlen = crypto_aead_ivsize(aead);
0558 
0559     tmp = esp_alloc_tmp(aead, esp->nfrags + 2, extralen);
0560     if (!tmp)
0561         goto error;
0562 
0563     extra = esp_tmp_extra(tmp);
0564     iv = esp_tmp_iv(aead, tmp, extralen);
0565     req = esp_tmp_req(aead, iv);
0566     sg = esp_req_sg(aead, req);
0567 
0568     if (esp->inplace)
0569         dsg = sg;
0570     else
0571         dsg = &sg[esp->nfrags];
0572 
0573     esph = esp_output_set_extra(skb, x, esp->esph, extra);
0574     esp->esph = esph;
0575 
0576     sg_init_table(sg, esp->nfrags);
0577     err = skb_to_sgvec(skb, sg,
0578                    (unsigned char *)esph - skb->data,
0579                    assoclen + ivlen + esp->clen + alen);
0580     if (unlikely(err < 0))
0581         goto error_free;
0582 
0583     if (!esp->inplace) {
0584         int allocsize;
0585         struct page_frag *pfrag = &x->xfrag;
0586 
0587         allocsize = ALIGN(skb->data_len, L1_CACHE_BYTES);
0588 
0589         spin_lock_bh(&x->lock);
0590         if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) {
0591             spin_unlock_bh(&x->lock);
0592             goto error_free;
0593         }
0594 
0595         skb_shinfo(skb)->nr_frags = 1;
0596 
0597         page = pfrag->page;
0598         get_page(page);
0599         /* replace page frags in skb with new page */
0600         __skb_fill_page_desc(skb, 0, page, pfrag->offset, skb->data_len);
0601         pfrag->offset = pfrag->offset + allocsize;
0602         spin_unlock_bh(&x->lock);
0603 
0604         sg_init_table(dsg, skb_shinfo(skb)->nr_frags + 1);
0605         err = skb_to_sgvec(skb, dsg,
0606                        (unsigned char *)esph - skb->data,
0607                        assoclen + ivlen + esp->clen + alen);
0608         if (unlikely(err < 0))
0609             goto error_free;
0610     }
0611 
0612     if ((x->props.flags & XFRM_STATE_ESN))
0613         aead_request_set_callback(req, 0, esp_output_done_esn, skb);
0614     else
0615         aead_request_set_callback(req, 0, esp_output_done, skb);
0616 
0617     aead_request_set_crypt(req, sg, dsg, ivlen + esp->clen, iv);
0618     aead_request_set_ad(req, assoclen);
0619 
0620     memset(iv, 0, ivlen);
0621     memcpy(iv + ivlen - min(ivlen, 8), (u8 *)&esp->seqno + 8 - min(ivlen, 8),
0622            min(ivlen, 8));
0623 
0624     ESP_SKB_CB(skb)->tmp = tmp;
0625     err = crypto_aead_encrypt(req);
0626 
0627     switch (err) {
0628     case -EINPROGRESS:
0629         goto error;
0630 
0631     case -ENOSPC:
0632         err = NET_XMIT_DROP;
0633         break;
0634 
0635     case 0:
0636         if ((x->props.flags & XFRM_STATE_ESN))
0637             esp_output_restore_header(skb);
0638     }
0639 
0640     if (sg != dsg)
0641         esp_ssg_unref(x, tmp);
0642 
0643     if (!err && x->encap && x->encap->encap_type == TCP_ENCAP_ESPINTCP)
0644         err = esp_output_tail_tcp(x, skb);
0645 
0646 error_free:
0647     kfree(tmp);
0648 error:
0649     return err;
0650 }
0651 EXPORT_SYMBOL_GPL(esp_output_tail);
0652 
0653 static int esp_output(struct xfrm_state *x, struct sk_buff *skb)
0654 {
0655     int alen;
0656     int blksize;
0657     struct ip_esp_hdr *esph;
0658     struct crypto_aead *aead;
0659     struct esp_info esp;
0660 
0661     esp.inplace = true;
0662 
0663     esp.proto = *skb_mac_header(skb);
0664     *skb_mac_header(skb) = IPPROTO_ESP;
0665 
0666     /* skb is pure payload to encrypt */
0667 
0668     aead = x->data;
0669     alen = crypto_aead_authsize(aead);
0670 
0671     esp.tfclen = 0;
0672     if (x->tfcpad) {
0673         struct xfrm_dst *dst = (struct xfrm_dst *)skb_dst(skb);
0674         u32 padto;
0675 
0676         padto = min(x->tfcpad, xfrm_state_mtu(x, dst->child_mtu_cached));
0677         if (skb->len < padto)
0678             esp.tfclen = padto - skb->len;
0679     }
0680     blksize = ALIGN(crypto_aead_blocksize(aead), 4);
0681     esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize);
0682     esp.plen = esp.clen - skb->len - esp.tfclen;
0683     esp.tailen = esp.tfclen + esp.plen + alen;
0684 
0685     esp.esph = ip_esp_hdr(skb);
0686 
0687     esp.nfrags = esp_output_head(x, skb, &esp);
0688     if (esp.nfrags < 0)
0689         return esp.nfrags;
0690 
0691     esph = esp.esph;
0692     esph->spi = x->id.spi;
0693 
0694     esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
0695     esp.seqno = cpu_to_be64(XFRM_SKB_CB(skb)->seq.output.low +
0696                  ((u64)XFRM_SKB_CB(skb)->seq.output.hi << 32));
0697 
0698     skb_push(skb, -skb_network_offset(skb));
0699 
0700     return esp_output_tail(x, skb, &esp);
0701 }
0702 
0703 static inline int esp_remove_trailer(struct sk_buff *skb)
0704 {
0705     struct xfrm_state *x = xfrm_input_state(skb);
0706     struct crypto_aead *aead = x->data;
0707     int alen, hlen, elen;
0708     int padlen, trimlen;
0709     __wsum csumdiff;
0710     u8 nexthdr[2];
0711     int ret;
0712 
0713     alen = crypto_aead_authsize(aead);
0714     hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
0715     elen = skb->len - hlen;
0716 
0717     if (skb_copy_bits(skb, skb->len - alen - 2, nexthdr, 2))
0718         BUG();
0719 
0720     ret = -EINVAL;
0721     padlen = nexthdr[0];
0722     if (padlen + 2 + alen >= elen) {
0723         net_dbg_ratelimited("ipsec esp packet is garbage padlen=%d, elen=%d\n",
0724                     padlen + 2, elen - alen);
0725         goto out;
0726     }
0727 
0728     trimlen = alen + padlen + 2;
0729     if (skb->ip_summed == CHECKSUM_COMPLETE) {
0730         csumdiff = skb_checksum(skb, skb->len - trimlen, trimlen, 0);
0731         skb->csum = csum_block_sub(skb->csum, csumdiff,
0732                        skb->len - trimlen);
0733     }
0734     pskb_trim(skb, skb->len - trimlen);
0735 
0736     ret = nexthdr[1];
0737 
0738 out:
0739     return ret;
0740 }
0741 
0742 int esp_input_done2(struct sk_buff *skb, int err)
0743 {
0744     const struct iphdr *iph;
0745     struct xfrm_state *x = xfrm_input_state(skb);
0746     struct xfrm_offload *xo = xfrm_offload(skb);
0747     struct crypto_aead *aead = x->data;
0748     int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
0749     int ihl;
0750 
0751     if (!xo || !(xo->flags & CRYPTO_DONE))
0752         kfree(ESP_SKB_CB(skb)->tmp);
0753 
0754     if (unlikely(err))
0755         goto out;
0756 
0757     err = esp_remove_trailer(skb);
0758     if (unlikely(err < 0))
0759         goto out;
0760 
0761     iph = ip_hdr(skb);
0762     ihl = iph->ihl * 4;
0763 
0764     if (x->encap) {
0765         struct xfrm_encap_tmpl *encap = x->encap;
0766         struct tcphdr *th = (void *)(skb_network_header(skb) + ihl);
0767         struct udphdr *uh = (void *)(skb_network_header(skb) + ihl);
0768         __be16 source;
0769 
0770         switch (x->encap->encap_type) {
0771         case TCP_ENCAP_ESPINTCP:
0772             source = th->source;
0773             break;
0774         case UDP_ENCAP_ESPINUDP:
0775         case UDP_ENCAP_ESPINUDP_NON_IKE:
0776             source = uh->source;
0777             break;
0778         default:
0779             WARN_ON_ONCE(1);
0780             err = -EINVAL;
0781             goto out;
0782         }
0783 
0784         /*
0785          * 1) if the NAT-T peer's IP or port changed then
0786          *    advertize the change to the keying daemon.
0787          *    This is an inbound SA, so just compare
0788          *    SRC ports.
0789          */
0790         if (iph->saddr != x->props.saddr.a4 ||
0791             source != encap->encap_sport) {
0792             xfrm_address_t ipaddr;
0793 
0794             ipaddr.a4 = iph->saddr;
0795             km_new_mapping(x, &ipaddr, source);
0796 
0797             /* XXX: perhaps add an extra
0798              * policy check here, to see
0799              * if we should allow or
0800              * reject a packet from a
0801              * different source
0802              * address/port.
0803              */
0804         }
0805 
0806         /*
0807          * 2) ignore UDP/TCP checksums in case
0808          *    of NAT-T in Transport Mode, or
0809          *    perform other post-processing fixes
0810          *    as per draft-ietf-ipsec-udp-encaps-06,
0811          *    section 3.1.2
0812          */
0813         if (x->props.mode == XFRM_MODE_TRANSPORT)
0814             skb->ip_summed = CHECKSUM_UNNECESSARY;
0815     }
0816 
0817     skb_pull_rcsum(skb, hlen);
0818     if (x->props.mode == XFRM_MODE_TUNNEL)
0819         skb_reset_transport_header(skb);
0820     else
0821         skb_set_transport_header(skb, -ihl);
0822 
0823     /* RFC4303: Drop dummy packets without any error */
0824     if (err == IPPROTO_NONE)
0825         err = -EINVAL;
0826 
0827 out:
0828     return err;
0829 }
0830 EXPORT_SYMBOL_GPL(esp_input_done2);
0831 
0832 static void esp_input_done(struct crypto_async_request *base, int err)
0833 {
0834     struct sk_buff *skb = base->data;
0835 
0836     xfrm_input_resume(skb, esp_input_done2(skb, err));
0837 }
0838 
0839 static void esp_input_restore_header(struct sk_buff *skb)
0840 {
0841     esp_restore_header(skb, 0);
0842     __skb_pull(skb, 4);
0843 }
0844 
0845 static void esp_input_set_header(struct sk_buff *skb, __be32 *seqhi)
0846 {
0847     struct xfrm_state *x = xfrm_input_state(skb);
0848     struct ip_esp_hdr *esph;
0849 
0850     /* For ESN we move the header forward by 4 bytes to
0851      * accommodate the high bits.  We will move it back after
0852      * decryption.
0853      */
0854     if ((x->props.flags & XFRM_STATE_ESN)) {
0855         esph = skb_push(skb, 4);
0856         *seqhi = esph->spi;
0857         esph->spi = esph->seq_no;
0858         esph->seq_no = XFRM_SKB_CB(skb)->seq.input.hi;
0859     }
0860 }
0861 
0862 static void esp_input_done_esn(struct crypto_async_request *base, int err)
0863 {
0864     struct sk_buff *skb = base->data;
0865 
0866     esp_input_restore_header(skb);
0867     esp_input_done(base, err);
0868 }
0869 
0870 /*
0871  * Note: detecting truncated vs. non-truncated authentication data is very
0872  * expensive, so we only support truncated data, which is the recommended
0873  * and common case.
0874  */
0875 static int esp_input(struct xfrm_state *x, struct sk_buff *skb)
0876 {
0877     struct crypto_aead *aead = x->data;
0878     struct aead_request *req;
0879     struct sk_buff *trailer;
0880     int ivlen = crypto_aead_ivsize(aead);
0881     int elen = skb->len - sizeof(struct ip_esp_hdr) - ivlen;
0882     int nfrags;
0883     int assoclen;
0884     int seqhilen;
0885     __be32 *seqhi;
0886     void *tmp;
0887     u8 *iv;
0888     struct scatterlist *sg;
0889     int err = -EINVAL;
0890 
0891     if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + ivlen))
0892         goto out;
0893 
0894     if (elen <= 0)
0895         goto out;
0896 
0897     assoclen = sizeof(struct ip_esp_hdr);
0898     seqhilen = 0;
0899 
0900     if (x->props.flags & XFRM_STATE_ESN) {
0901         seqhilen += sizeof(__be32);
0902         assoclen += seqhilen;
0903     }
0904 
0905     if (!skb_cloned(skb)) {
0906         if (!skb_is_nonlinear(skb)) {
0907             nfrags = 1;
0908 
0909             goto skip_cow;
0910         } else if (!skb_has_frag_list(skb)) {
0911             nfrags = skb_shinfo(skb)->nr_frags;
0912             nfrags++;
0913 
0914             goto skip_cow;
0915         }
0916     }
0917 
0918     err = skb_cow_data(skb, 0, &trailer);
0919     if (err < 0)
0920         goto out;
0921 
0922     nfrags = err;
0923 
0924 skip_cow:
0925     err = -ENOMEM;
0926     tmp = esp_alloc_tmp(aead, nfrags, seqhilen);
0927     if (!tmp)
0928         goto out;
0929 
0930     ESP_SKB_CB(skb)->tmp = tmp;
0931     seqhi = esp_tmp_extra(tmp);
0932     iv = esp_tmp_iv(aead, tmp, seqhilen);
0933     req = esp_tmp_req(aead, iv);
0934     sg = esp_req_sg(aead, req);
0935 
0936     esp_input_set_header(skb, seqhi);
0937 
0938     sg_init_table(sg, nfrags);
0939     err = skb_to_sgvec(skb, sg, 0, skb->len);
0940     if (unlikely(err < 0)) {
0941         kfree(tmp);
0942         goto out;
0943     }
0944 
0945     skb->ip_summed = CHECKSUM_NONE;
0946 
0947     if ((x->props.flags & XFRM_STATE_ESN))
0948         aead_request_set_callback(req, 0, esp_input_done_esn, skb);
0949     else
0950         aead_request_set_callback(req, 0, esp_input_done, skb);
0951 
0952     aead_request_set_crypt(req, sg, sg, elen + ivlen, iv);
0953     aead_request_set_ad(req, assoclen);
0954 
0955     err = crypto_aead_decrypt(req);
0956     if (err == -EINPROGRESS)
0957         goto out;
0958 
0959     if ((x->props.flags & XFRM_STATE_ESN))
0960         esp_input_restore_header(skb);
0961 
0962     err = esp_input_done2(skb, err);
0963 
0964 out:
0965     return err;
0966 }
0967 
0968 static int esp4_err(struct sk_buff *skb, u32 info)
0969 {
0970     struct net *net = dev_net(skb->dev);
0971     const struct iphdr *iph = (const struct iphdr *)skb->data;
0972     struct ip_esp_hdr *esph = (struct ip_esp_hdr *)(skb->data+(iph->ihl<<2));
0973     struct xfrm_state *x;
0974 
0975     switch (icmp_hdr(skb)->type) {
0976     case ICMP_DEST_UNREACH:
0977         if (icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
0978             return 0;
0979         break;
0980     case ICMP_REDIRECT:
0981         break;
0982     default:
0983         return 0;
0984     }
0985 
0986     x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr,
0987                   esph->spi, IPPROTO_ESP, AF_INET);
0988     if (!x)
0989         return 0;
0990 
0991     if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH)
0992         ipv4_update_pmtu(skb, net, info, 0, IPPROTO_ESP);
0993     else
0994         ipv4_redirect(skb, net, 0, IPPROTO_ESP);
0995     xfrm_state_put(x);
0996 
0997     return 0;
0998 }
0999 
1000 static void esp_destroy(struct xfrm_state *x)
1001 {
1002     struct crypto_aead *aead = x->data;
1003 
1004     if (!aead)
1005         return;
1006 
1007     crypto_free_aead(aead);
1008 }
1009 
1010 static int esp_init_aead(struct xfrm_state *x)
1011 {
1012     char aead_name[CRYPTO_MAX_ALG_NAME];
1013     struct crypto_aead *aead;
1014     int err;
1015 
1016     err = -ENAMETOOLONG;
1017     if (snprintf(aead_name, CRYPTO_MAX_ALG_NAME, "%s(%s)",
1018              x->geniv, x->aead->alg_name) >= CRYPTO_MAX_ALG_NAME)
1019         goto error;
1020 
1021     aead = crypto_alloc_aead(aead_name, 0, 0);
1022     err = PTR_ERR(aead);
1023     if (IS_ERR(aead))
1024         goto error;
1025 
1026     x->data = aead;
1027 
1028     err = crypto_aead_setkey(aead, x->aead->alg_key,
1029                  (x->aead->alg_key_len + 7) / 8);
1030     if (err)
1031         goto error;
1032 
1033     err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8);
1034     if (err)
1035         goto error;
1036 
1037 error:
1038     return err;
1039 }
1040 
1041 static int esp_init_authenc(struct xfrm_state *x)
1042 {
1043     struct crypto_aead *aead;
1044     struct crypto_authenc_key_param *param;
1045     struct rtattr *rta;
1046     char *key;
1047     char *p;
1048     char authenc_name[CRYPTO_MAX_ALG_NAME];
1049     unsigned int keylen;
1050     int err;
1051 
1052     err = -EINVAL;
1053     if (!x->ealg)
1054         goto error;
1055 
1056     err = -ENAMETOOLONG;
1057 
1058     if ((x->props.flags & XFRM_STATE_ESN)) {
1059         if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
1060                  "%s%sauthencesn(%s,%s)%s",
1061                  x->geniv ?: "", x->geniv ? "(" : "",
1062                  x->aalg ? x->aalg->alg_name : "digest_null",
1063                  x->ealg->alg_name,
1064                  x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME)
1065             goto error;
1066     } else {
1067         if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
1068                  "%s%sauthenc(%s,%s)%s",
1069                  x->geniv ?: "", x->geniv ? "(" : "",
1070                  x->aalg ? x->aalg->alg_name : "digest_null",
1071                  x->ealg->alg_name,
1072                  x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME)
1073             goto error;
1074     }
1075 
1076     aead = crypto_alloc_aead(authenc_name, 0, 0);
1077     err = PTR_ERR(aead);
1078     if (IS_ERR(aead))
1079         goto error;
1080 
1081     x->data = aead;
1082 
1083     keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) +
1084          (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param));
1085     err = -ENOMEM;
1086     key = kmalloc(keylen, GFP_KERNEL);
1087     if (!key)
1088         goto error;
1089 
1090     p = key;
1091     rta = (void *)p;
1092     rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM;
1093     rta->rta_len = RTA_LENGTH(sizeof(*param));
1094     param = RTA_DATA(rta);
1095     p += RTA_SPACE(sizeof(*param));
1096 
1097     if (x->aalg) {
1098         struct xfrm_algo_desc *aalg_desc;
1099 
1100         memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8);
1101         p += (x->aalg->alg_key_len + 7) / 8;
1102 
1103         aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
1104         BUG_ON(!aalg_desc);
1105 
1106         err = -EINVAL;
1107         if (aalg_desc->uinfo.auth.icv_fullbits / 8 !=
1108             crypto_aead_authsize(aead)) {
1109             pr_info("ESP: %s digestsize %u != %u\n",
1110                 x->aalg->alg_name,
1111                 crypto_aead_authsize(aead),
1112                 aalg_desc->uinfo.auth.icv_fullbits / 8);
1113             goto free_key;
1114         }
1115 
1116         err = crypto_aead_setauthsize(
1117             aead, x->aalg->alg_trunc_len / 8);
1118         if (err)
1119             goto free_key;
1120     }
1121 
1122     param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8);
1123     memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8);
1124 
1125     err = crypto_aead_setkey(aead, key, keylen);
1126 
1127 free_key:
1128     kfree(key);
1129 
1130 error:
1131     return err;
1132 }
1133 
1134 static int esp_init_state(struct xfrm_state *x)
1135 {
1136     struct crypto_aead *aead;
1137     u32 align;
1138     int err;
1139 
1140     x->data = NULL;
1141 
1142     if (x->aead)
1143         err = esp_init_aead(x);
1144     else
1145         err = esp_init_authenc(x);
1146 
1147     if (err)
1148         goto error;
1149 
1150     aead = x->data;
1151 
1152     x->props.header_len = sizeof(struct ip_esp_hdr) +
1153                   crypto_aead_ivsize(aead);
1154     if (x->props.mode == XFRM_MODE_TUNNEL)
1155         x->props.header_len += sizeof(struct iphdr);
1156     else if (x->props.mode == XFRM_MODE_BEET && x->sel.family != AF_INET6)
1157         x->props.header_len += IPV4_BEET_PHMAXLEN;
1158     if (x->encap) {
1159         struct xfrm_encap_tmpl *encap = x->encap;
1160 
1161         switch (encap->encap_type) {
1162         default:
1163             err = -EINVAL;
1164             goto error;
1165         case UDP_ENCAP_ESPINUDP:
1166             x->props.header_len += sizeof(struct udphdr);
1167             break;
1168         case UDP_ENCAP_ESPINUDP_NON_IKE:
1169             x->props.header_len += sizeof(struct udphdr) + 2 * sizeof(u32);
1170             break;
1171 #ifdef CONFIG_INET_ESPINTCP
1172         case TCP_ENCAP_ESPINTCP:
1173             /* only the length field, TCP encap is done by
1174              * the socket
1175              */
1176             x->props.header_len += 2;
1177             break;
1178 #endif
1179         }
1180     }
1181 
1182     align = ALIGN(crypto_aead_blocksize(aead), 4);
1183     x->props.trailer_len = align + 1 + crypto_aead_authsize(aead);
1184 
1185 error:
1186     return err;
1187 }
1188 
1189 static int esp4_rcv_cb(struct sk_buff *skb, int err)
1190 {
1191     return 0;
1192 }
1193 
1194 static const struct xfrm_type esp_type =
1195 {
1196     .owner      = THIS_MODULE,
1197     .proto          = IPPROTO_ESP,
1198     .flags      = XFRM_TYPE_REPLAY_PROT,
1199     .init_state = esp_init_state,
1200     .destructor = esp_destroy,
1201     .input      = esp_input,
1202     .output     = esp_output,
1203 };
1204 
1205 static struct xfrm4_protocol esp4_protocol = {
1206     .handler    =   xfrm4_rcv,
1207     .input_handler  =   xfrm_input,
1208     .cb_handler =   esp4_rcv_cb,
1209     .err_handler    =   esp4_err,
1210     .priority   =   0,
1211 };
1212 
1213 static int __init esp4_init(void)
1214 {
1215     if (xfrm_register_type(&esp_type, AF_INET) < 0) {
1216         pr_info("%s: can't add xfrm type\n", __func__);
1217         return -EAGAIN;
1218     }
1219     if (xfrm4_protocol_register(&esp4_protocol, IPPROTO_ESP) < 0) {
1220         pr_info("%s: can't add protocol\n", __func__);
1221         xfrm_unregister_type(&esp_type, AF_INET);
1222         return -EAGAIN;
1223     }
1224     return 0;
1225 }
1226 
1227 static void __exit esp4_fini(void)
1228 {
1229     if (xfrm4_protocol_deregister(&esp4_protocol, IPPROTO_ESP) < 0)
1230         pr_info("%s: can't remove protocol\n", __func__);
1231     xfrm_unregister_type(&esp_type, AF_INET);
1232 }
1233 
1234 module_init(esp4_init);
1235 module_exit(esp4_fini);
1236 MODULE_LICENSE("GPL");
1237 MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_ESP);
[ Source navigation ] [ Diff markup ] [ Identifier search ] [ general search ]

This page was automatically generated by the 2.1.0 LXR engine.

The LXR team
Valid CSS 2.1! Valid HTML 4.01!