cregit-Linux how code gets into the kernel

Release 4.11 net/ipv6/esp6.c

Directory: net/ipv6
/*
 * Copyright (C)2002 USAGI/WIDE Project
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, see <http://www.gnu.org/licenses/>.
 *
 * Authors
 *
 *      Mitsuru KANDA @USAGI       : IPv6 Support
 *      Kazunori MIYAZAWA @USAGI   :
 *      Kunihiro Ishiguro <kunihiro@ipinfusion.com>
 *
 *      This file is derived from net/ipv4/esp.c
 */


#define pr_fmt(fmt) "IPv6: " fmt

#include <crypto/aead.h>
#include <crypto/authenc.h>
#include <linux/err.h>
#include <linux/module.h>
#include <net/ip.h>
#include <net/xfrm.h>
#include <net/esp.h>
#include <linux/scatterlist.h>
#include <linux/kernel.h>
#include <linux/pfkeyv2.h>
#include <linux/random.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <net/ip6_route.h>
#include <net/icmp.h>
#include <net/ipv6.h>
#include <net/protocol.h>
#include <linux/icmpv6.h>

#include <linux/highmem.h>


struct esp_skb_cb {
	
struct xfrm_skb_cb xfrm;
	
void *tmp;
};


#define ESP_SKB_CB(__skb) ((struct esp_skb_cb *)&((__skb)->cb[0]))

static u32 esp6_get_mtu(struct xfrm_state *x, int mtu);

/*
 * Allocate an AEAD request structure with extra space for SG and IV.
 *
 * For alignment considerations the upper 32 bits of the sequence number are
 * placed at the front, if present. Followed by the IV, the request and finally
 * the SG list.
 *
 * TODO: Use spare space in skb for this where possible.
 */

static void *esp_alloc_tmp(struct crypto_aead *aead, int nfrags, int seqihlen) { unsigned int len; len = seqihlen; len += crypto_aead_ivsize(aead); if (len) { len += crypto_aead_alignmask(aead) & ~(crypto_tfm_ctx_alignment() - 1); len = ALIGN(len, crypto_tfm_ctx_alignment()); } len += sizeof(struct aead_request) + crypto_aead_reqsize(aead); len = ALIGN(len, __alignof__(struct scatterlist)); len += sizeof(struct scatterlist) * nfrags; return kmalloc(len, GFP_ATOMIC); }

Contributors

PersonTokensPropCommitsCommitProp
Herbert Xu8477.78%466.67%
Kazunori Miyazawa1715.74%116.67%
Steffen Klassert76.48%116.67%
Total108100.00%6100.00%


static inline __be32 *esp_tmp_seqhi(void *tmp) { return PTR_ALIGN((__be32 *)tmp, __alignof__(__be32)); }

Contributors

PersonTokensPropCommitsCommitProp
Steffen Klassert27100.00%1100.00%
Total27100.00%1100.00%


static inline u8 *esp_tmp_iv(struct crypto_aead *aead, void *tmp, int seqhilen) { return crypto_aead_ivsize(aead) ? PTR_ALIGN((u8 *)tmp + seqhilen, crypto_aead_alignmask(aead) + 1) : tmp + seqhilen; }

Contributors

PersonTokensPropCommitsCommitProp
Herbert Xu3981.25%133.33%
Steffen Klassert714.58%133.33%
Arnaldo Carvalho de Melo24.17%133.33%
Total48100.00%3100.00%


static inline struct aead_request *esp_tmp_req(struct crypto_aead *aead, u8 *iv) { struct aead_request *req; req = (void *)PTR_ALIGN(iv + crypto_aead_ivsize(aead), crypto_tfm_ctx_alignment()); aead_request_set_tfm(req, aead); return req; }

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PersonTokensPropCommitsCommitProp
Herbert Xu52100.00%1100.00%
Total52100.00%1100.00%


static inline struct scatterlist *esp_req_sg(struct crypto_aead *aead, struct aead_request *req) { return (void *)ALIGN((unsigned long)(req + 1) + crypto_aead_reqsize(aead), __alignof__(struct scatterlist)); }

Contributors

PersonTokensPropCommitsCommitProp
Herbert Xu48100.00%1100.00%
Total48100.00%1100.00%


static void esp_ssg_unref(struct xfrm_state *x, void *tmp) { __be32 *seqhi; struct crypto_aead *aead = x->data; int seqhilen = 0; u8 *iv; struct aead_request *req; struct scatterlist *sg; if (x->props.flags & XFRM_STATE_ESN) seqhilen += sizeof(__be32); seqhi = esp_tmp_seqhi(tmp); iv = esp_tmp_iv(aead, tmp, seqhilen); req = esp_tmp_req(aead, iv); /* Unref skb_frag_pages in the src scatterlist if necessary. * Skip the first sg which comes from skb->data. */ if (req->src != req->dst) for (sg = sg_next(req->src); sg; sg = sg_next(sg)) put_page(sg_page(sg)); }

Contributors

PersonTokensPropCommitsCommitProp
Steffen Klassert130100.00%1100.00%
Total130100.00%1100.00%


static void esp_output_done(struct crypto_async_request *base, int err) { struct sk_buff *skb = base->data; void *tmp; struct dst_entry *dst = skb_dst(skb); struct xfrm_state *x = dst->xfrm; tmp = ESP_SKB_CB(skb)->tmp; esp_ssg_unref(x, tmp); kfree(tmp); xfrm_output_resume(skb, err); }

Contributors

PersonTokensPropCommitsCommitProp
Herbert Xu3952.70%266.67%
Steffen Klassert3547.30%133.33%
Total74100.00%3100.00%

/* Move ESP header back into place. */
static void esp_restore_header(struct sk_buff *skb, unsigned int offset) { struct ip_esp_hdr *esph = (void *)(skb->data + offset); void *tmp = ESP_SKB_CB(skb)->tmp; __be32 *seqhi = esp_tmp_seqhi(tmp); esph->seq_no = esph->spi; esph->spi = *seqhi; }

Contributors

PersonTokensPropCommitsCommitProp
Herbert Xu67100.00%2100.00%
Total67100.00%2100.00%


static void esp_output_restore_header(struct sk_buff *skb) { esp_restore_header(skb, skb_transport_offset(skb) - sizeof(__be32)); }

Contributors

PersonTokensPropCommitsCommitProp
Herbert Xu26100.00%2100.00%
Total26100.00%2100.00%


static struct ip_esp_hdr *esp_output_set_esn(struct sk_buff *skb, struct ip_esp_hdr *esph, __be32 *seqhi) { struct xfrm_state *x = skb_dst(skb)->xfrm; /* For ESN we move the header forward by 4 bytes to * accomodate the high bits. We will move it back after * encryption. */ if ((x->props.flags & XFRM_STATE_ESN)) { esph = (void *)(skb_transport_header(skb) - sizeof(__be32)); *seqhi = esph->spi; esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.hi); } esph->spi = x->id.spi; return esph; }

Contributors

PersonTokensPropCommitsCommitProp
Steffen Klassert8580.95%150.00%
Herbert Xu2019.05%150.00%
Total105100.00%2100.00%


static void esp_output_done_esn(struct crypto_async_request *base, int err) { struct sk_buff *skb = base->data; esp_output_restore_header(skb); esp_output_done(base, err); }

Contributors

PersonTokensPropCommitsCommitProp
Steffen Klassert35100.00%1100.00%
Total35100.00%1100.00%


static void esp_output_fill_trailer(u8 *tail, int tfclen, int plen, __u8 proto) { /* Fill padding... */ if (tfclen) { memset(tail, 0, tfclen); tail += tfclen; } do { int i; for (i = 0; i < plen - 2; i++) tail[i] = i + 1; } while (0); tail[plen - 2] = plen - 2; tail[plen - 1] = proto; }

Contributors

PersonTokensPropCommitsCommitProp
Steffen Klassert94100.00%1100.00%
Total94100.00%1100.00%


static int esp6_output(struct xfrm_state *x, struct sk_buff *skb) { int err; struct ip_esp_hdr *esph; struct crypto_aead *aead; struct aead_request *req; struct scatterlist *sg, *dsg; struct sk_buff *trailer; struct page *page; void *tmp; int blksize; int clen; int alen; int plen; int ivlen; int tfclen; int nfrags; int assoclen; int seqhilen; int tailen; u8 *iv; u8 *tail; u8 *vaddr; __be32 *seqhi; __be64 seqno; __u8 proto = *skb_mac_header(skb); /* skb is pure payload to encrypt */ aead = x->data; alen = crypto_aead_authsize(aead); ivlen = crypto_aead_ivsize(aead); tfclen = 0; if (x->tfcpad) { struct xfrm_dst *dst = (struct xfrm_dst *)skb_dst(skb); u32 padto; padto = min(x->tfcpad, esp6_get_mtu(x, dst->child_mtu_cached)); if (skb->len < padto) tfclen = padto - skb->len; } blksize = ALIGN(crypto_aead_blocksize(aead), 4); clen = ALIGN(skb->len + 2 + tfclen, blksize); plen = clen - skb->len - tfclen; tailen = tfclen + plen + alen; assoclen = sizeof(*esph); seqhilen = 0; if (x->props.flags & XFRM_STATE_ESN) { seqhilen += sizeof(__be32); assoclen += seqhilen; } *skb_mac_header(skb) = IPPROTO_ESP; esph = ip_esp_hdr(skb); if (!skb_cloned(skb)) { if (tailen <= skb_availroom(skb)) { nfrags = 1; trailer = skb; tail = skb_tail_pointer(trailer); goto skip_cow; } else if ((skb_shinfo(skb)->nr_frags < MAX_SKB_FRAGS) && !skb_has_frag_list(skb)) { int allocsize; struct sock *sk = skb->sk; struct page_frag *pfrag = &x->xfrag; allocsize = ALIGN(tailen, L1_CACHE_BYTES); spin_lock_bh(&x->lock); if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) { spin_unlock_bh(&x->lock); goto cow; } page = pfrag->page; get_page(page); vaddr = kmap_atomic(page); tail = vaddr + pfrag->offset; esp_output_fill_trailer(tail, tfclen, plen, proto); kunmap_atomic(vaddr); nfrags = skb_shinfo(skb)->nr_frags; __skb_fill_page_desc(skb, nfrags, page, pfrag->offset, tailen); skb_shinfo(skb)->nr_frags = ++nfrags; pfrag->offset = pfrag->offset + allocsize; nfrags++; skb->len += tailen; skb->data_len += tailen; skb->truesize += tailen; if (sk) atomic_add(tailen, &sk->sk_wmem_alloc); skb_push(skb, -skb_network_offset(skb)); esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low); esph->spi = x->id.spi; tmp = esp_alloc_tmp(aead, nfrags + 2, seqhilen); if (!tmp) { spin_unlock_bh(&x->lock); err = -ENOMEM; goto error; } seqhi = esp_tmp_seqhi(tmp); iv = esp_tmp_iv(aead, tmp, seqhilen); req = esp_tmp_req(aead, iv); sg = esp_req_sg(aead, req); dsg = &sg[nfrags]; esph = esp_output_set_esn(skb, esph, seqhi); sg_init_table(sg, nfrags); skb_to_sgvec(skb, sg, (unsigned char *)esph - skb->data, assoclen + ivlen + clen + alen); allocsize = ALIGN(skb->data_len, L1_CACHE_BYTES); if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) { spin_unlock_bh(&x->lock); err = -ENOMEM; goto error; } skb_shinfo(skb)->nr_frags = 1; page = pfrag->page; get_page(page); /* replace page frags in skb with new page */ __skb_fill_page_desc(skb, 0, page, pfrag->offset, skb->data_len); pfrag->offset = pfrag->offset + allocsize; sg_init_table(dsg, skb_shinfo(skb)->nr_frags + 1); skb_to_sgvec(skb, dsg, (unsigned char *)esph - skb->data, assoclen + ivlen + clen + alen); spin_unlock_bh(&x->lock); goto skip_cow2; } } cow: err = skb_cow_data(skb, tailen, &trailer); if (err < 0) goto error; nfrags = err; tail = skb_tail_pointer(trailer); esph = ip_esp_hdr(skb); skip_cow: esp_output_fill_trailer(tail, tfclen, plen, proto); pskb_put(skb, trailer, clen - skb->len + alen); skb_push(skb, -skb_network_offset(skb)); esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low); esph->spi = x->id.spi; tmp = esp_alloc_tmp(aead, nfrags, seqhilen); if (!tmp) { err = -ENOMEM; goto error; } seqhi = esp_tmp_seqhi(tmp); iv = esp_tmp_iv(aead, tmp, seqhilen); req = esp_tmp_req(aead, iv); sg = esp_req_sg(aead, req); dsg = sg; esph = esp_output_set_esn(skb, esph, seqhi); sg_init_table(sg, nfrags); skb_to_sgvec(skb, sg, (unsigned char *)esph - skb->data, assoclen + ivlen + clen + alen); skip_cow2: if ((x->props.flags & XFRM_STATE_ESN)) aead_request_set_callback(req, 0, esp_output_done_esn, skb); else aead_request_set_callback(req, 0, esp_output_done, skb); aead_request_set_crypt(req, sg, dsg, ivlen + clen, iv); aead_request_set_ad(req, assoclen); seqno = cpu_to_be64(XFRM_SKB_CB(skb)->seq.output.low + ((u64)XFRM_SKB_CB(skb)->seq.output.hi << 32)); memset(iv, 0, ivlen); memcpy(iv + ivlen - min(ivlen, 8), (u8 *)&seqno + 8 - min(ivlen, 8), min(ivlen, 8)); ESP_SKB_CB(skb)->tmp = tmp; err = crypto_aead_encrypt(req); switch (err) { case -EINPROGRESS: goto error; case -EBUSY: err = NET_XMIT_DROP; break; case 0: if ((x->props.flags & XFRM_STATE_ESN)) esp_output_restore_header(skb); } if (sg != dsg) esp_ssg_unref(x, tmp); kfree(tmp); error: return err; }

Contributors

PersonTokensPropCommitsCommitProp
Steffen Klassert80062.16%421.05%
Herbert Xu36128.05%736.84%
Martin Willi886.84%15.26%
Kazunori Miyazawa171.32%15.26%
David S. Miller90.70%15.26%
Julia Lawall40.31%15.26%
Jamal Hadi Salim30.23%15.26%
Arnaldo Carvalho de Melo30.23%210.53%
Mathias Krause20.16%15.26%
Total1287100.00%19100.00%


static int esp_input_done2(struct sk_buff *skb, int err) { struct xfrm_state *x = xfrm_input_state(skb); struct crypto_aead *aead = x->data; int alen = crypto_aead_authsize(aead); int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead); int elen = skb->len - hlen; int hdr_len = skb_network_header_len(skb); int padlen; u8 nexthdr[2]; kfree(ESP_SKB_CB(skb)->tmp); if (unlikely(err)) goto out; if (skb_copy_bits(skb, skb->len - alen - 2, nexthdr, 2)) BUG(); err = -EINVAL; padlen = nexthdr[0]; if (padlen + 2 + alen >= elen) { net_dbg_ratelimited("ipsec esp packet is garbage padlen=%d, elen=%d\n", padlen + 2, elen - alen); goto out; } /* ... check padding bits here. Silly. :-) */ pskb_trim(skb, skb->len - alen - padlen - 2); __skb_pull(skb, hlen); if (x->props.mode == XFRM_MODE_TUNNEL) skb_reset_transport_header(skb); else skb_set_transport_header(skb, -hdr_len); err = nexthdr[1]; /* RFC4303: Drop dummy packets without any error */ if (err == IPPROTO_NONE) err = -EINVAL; out: return err; }

Contributors

PersonTokensPropCommitsCommitProp
Herbert Xu16972.22%650.00%
Kazunori Miyazawa4117.52%18.33%
Li RongQing166.84%18.33%
David S. Miller41.71%216.67%
Joe Perches20.85%18.33%
Mathias Krause20.85%18.33%
Total234100.00%12100.00%


static void esp_input_done(struct crypto_async_request *base, int err) { struct sk_buff *skb = base->data; xfrm_input_resume(skb, esp_input_done2(skb, err)); }

Contributors

PersonTokensPropCommitsCommitProp
Herbert Xu35100.00%1100.00%
Total35100.00%1100.00%


static void esp_input_restore_header(struct sk_buff *skb) { esp_restore_header(skb, 0); __skb_pull(skb, 4); }

Contributors

PersonTokensPropCommitsCommitProp
Steffen Klassert1560.00%150.00%
Herbert Xu1040.00%150.00%
Total25100.00%2100.00%


static void esp_input_set_header(struct sk_buff *skb, __be32 *seqhi) { struct xfrm_state *x = xfrm_input_state(skb); struct ip_esp_hdr *esph = (struct ip_esp_hdr *)skb->data; /* For ESN we move the header forward by 4 bytes to * accomodate the high bits. We will move it back after * decryption. */ if ((x->props.flags & XFRM_STATE_ESN)) { esph = (void *)skb_push(skb, 4); *seqhi = esph->spi; esph->spi = esph->seq_no; esph->seq_no = XFRM_SKB_CB(skb)->seq.input.hi; } }

Contributors

PersonTokensPropCommitsCommitProp
Steffen Klassert8789.69%133.33%
Herbert Xu99.28%133.33%
Kazunori Miyazawa11.03%133.33%
Total97100.00%3100.00%


static void esp_input_done_esn(struct crypto_async_request *base, int err) { struct sk_buff *skb = base->data; esp_input_restore_header(skb); esp_input_done(base, err); }

Contributors

PersonTokensPropCommitsCommitProp
Herbert Xu35100.00%2100.00%
Total35100.00%2100.00%


static int esp6_input(struct xfrm_state *x, struct sk_buff *skb) { struct ip_esp_hdr *esph; struct crypto_aead *aead = x->data; struct aead_request *req; struct sk_buff *trailer; int ivlen = crypto_aead_ivsize(aead); int elen = skb->len - sizeof(*esph) - ivlen; int nfrags; int assoclen; int seqhilen; int ret = 0; void *tmp; __be32 *seqhi; u8 *iv; struct scatterlist *sg; if (!pskb_may_pull(skb, sizeof(*esph) + ivlen)) { ret = -EINVAL; goto out; } if (elen <= 0) { ret = -EINVAL; goto out; } assoclen = sizeof(*esph); seqhilen = 0; if (x->props.flags & XFRM_STATE_ESN) { seqhilen += sizeof(__be32); assoclen += seqhilen; } if (!skb_cloned(skb)) { if (!skb_is_nonlinear(skb)) { nfrags = 1; goto skip_cow; } else if (!skb_has_frag_list(skb)) { nfrags = skb_shinfo(skb)->nr_frags; nfrags++; goto skip_cow; } } nfrags = skb_cow_data(skb, 0, &trailer); if (nfrags < 0) { ret = -EINVAL; goto out; } skip_cow: ret = -ENOMEM; tmp = esp_alloc_tmp(aead, nfrags, seqhilen); if (!tmp) goto out; ESP_SKB_CB(skb)->tmp = tmp; seqhi = esp_tmp_seqhi(tmp); iv = esp_tmp_iv(aead, tmp, seqhilen); req = esp_tmp_req(aead, iv); sg = esp_req_sg(aead, req); esp_input_set_header(skb, seqhi); sg_init_table(sg, nfrags); skb_to_sgvec(skb, sg, 0, skb->len); skb->ip_summed = CHECKSUM_NONE; if ((x->props.flags & XFRM_STATE_ESN)) aead_request_set_callback(req, 0, esp_input_done_esn, skb); else aead_request_set_callback(req, 0, esp_input_done, skb); aead_request_set_crypt(req, sg, sg, elen + ivlen, iv); aead_request_set_ad(req, assoclen); ret = crypto_aead_decrypt(req); if (ret == -EINPROGRESS) goto out; if ((x->props.flags & XFRM_STATE_ESN)) esp_input_restore_header(