Release 4.11 net/ipv4/esp4.c

#define pr_fmt(fmt) "IPsec: " 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/rtnetlink.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/in6.h>
#include <net/icmp.h>
#include <net/protocol.h>
#include <net/udp.h>

#include <linux/highmem.h>


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


struct esp_output_extra {
	
__be32 seqhi;
	
u32 esphoff;
};


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

static u32 esp4_get_mtu(struct xfrm_state *x, int mtu);

/*
 * Allocate an AEAD request structure with extra space for SG and IV.
 *
 * For alignment considerations the IV is placed at the front, followed
 * by 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 extralen)
{
	unsigned int len;

	len = extralen;

	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);
}

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15
13.89%
1
11.11%
Steffen Klassert
5
4.63%
1
11.11%
Arnaldo Carvalho de Melo
1
0.93%
1
11.11%
James Morris
1
0.93%
1
11.11%
Total
108
100.00%
9
100.00%



static inline void *esp_tmp_extra(void *tmp)
{
	return PTR_ALIGN(tmp, __alignof__(struct esp_output_extra));
}

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24
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100.00%



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

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2
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Steffen Klassert
4
8.33%
1
20.00%
Arnaldo Carvalho de Melo
2
4.17%
1
20.00%
Alexey Kuznetsov
2
4.17%
1
20.00%
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48
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5
100.00%



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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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));
}

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static void esp_ssg_unref(struct xfrm_state *x, void *tmp)
{
	struct esp_output_extra *extra = esp_tmp_extra(tmp);
	struct crypto_aead *aead = x->data;
	int extralen = 0;
	u8 *iv;
	struct aead_request *req;
	struct scatterlist *sg;

	if (x->props.flags & XFRM_STATE_ESN)
		extralen += sizeof(*extra);

	extra = esp_tmp_extra(tmp);
	iv = esp_tmp_iv(aead, tmp, extralen);
	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));
}

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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);
}

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1
33.33%
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74
100.00%
3
100.00%

/* 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_extra(tmp);

	esph->seq_no = esph->spi;
	esph->spi = *seqhi;
}

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static void esp_output_restore_header(struct sk_buff *skb)
{
	void *tmp = ESP_SKB_CB(skb)->tmp;
	struct esp_output_extra *extra = esp_tmp_extra(tmp);

	esp_restore_header(skb, skb_transport_offset(skb) + extra->esphoff -
				sizeof(__be32));
}

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static struct ip_esp_hdr *esp_output_set_extra(struct sk_buff *skb,
					       struct ip_esp_hdr *esph,
					       struct esp_output_extra *extra)
{
	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)) {
		extra->esphoff = (unsigned char *)esph -
				 skb_transport_header(skb);
		esph = (struct ip_esp_hdr *)((unsigned char *)esph - 4);
		extra->seqhi = esph->spi;
		esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.hi);
	}

	esph->spi = x->id.spi;

	return esph;
}

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123
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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);
}

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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;
}

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static int esp_output(struct xfrm_state *x, struct sk_buff *skb)
{
	struct esp_output_extra *extra;
	int err = -ENOMEM;
	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;
	u8 *iv;
	u8 *tail;
	u8 *vaddr;
	int blksize;
	int clen;
	int alen;
	int plen;
	int ivlen;
	int tfclen;
	int nfrags;
	int assoclen;
	int extralen;
	int tailen;
	__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, esp4_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);
	extralen = 0;

	if (x->props.flags & XFRM_STATE_ESN) {
		extralen += sizeof(*extra);
		assoclen += sizeof(__be32);
	}

	*skb_mac_header(skb) = IPPROTO_ESP;
	esph = ip_esp_hdr(skb);

	/* this is non-NULL only with UDP Encapsulation */
	if (x->encap) {
		struct xfrm_encap_tmpl *encap = x->encap;
		struct udphdr *uh;
		__be32 *udpdata32;
		__be16 sport, dport;
		int encap_type;

		spin_lock_bh(&x->lock);
		sport = encap->encap_sport;
		dport = encap->encap_dport;
		encap_type = encap->encap_type;
		spin_unlock_bh(&x->lock);

		uh = (struct udphdr *)esph;
		uh->source = sport;
		uh->dest = dport;
		uh->len = htons(skb->len + tailen
				- skb_transport_offset(skb));
		uh->check = 0;

		switch (encap_type) {
		default:
		case UDP_ENCAP_ESPINUDP:
			esph = (struct ip_esp_hdr *)(uh + 1);
			break;
		case UDP_ENCAP_ESPINUDP_NON_IKE:
			udpdata32 = (__be32 *)(uh + 1);
			udpdata32[0] = udpdata32[1] = 0;
			esph = (struct ip_esp_hdr *)(udpdata32 + 2);
			break;
		}

		*skb_mac_header(skb) = IPPROTO_UDP;
	}

	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, extralen);
			if (!tmp) {
				spin_unlock_bh(&x->lock);
				err = -ENOMEM;
				goto error;
			}

			extra = esp_tmp_extra(tmp);
			iv = esp_tmp_iv(aead, tmp, extralen);
			req = esp_tmp_req(aead, iv);
			sg = esp_req_sg(aead, req);
			dsg = &sg[nfrags];

			esph = esp_output_set_extra(skb, esph, extra);

			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, extralen);
	if (!tmp) {
		err = -ENOMEM;
		goto error;
	}

	extra = esp_tmp_extra(tmp);
	iv = esp_tmp_iv(aead, tmp, extralen);
	req = esp_tmp_req(aead, iv);
	sg = esp_req_sg(aead, req);
	dsg = sg;

	esph = esp_output_set_extra(skb, esph, extra);

	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;
}

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411
27.73%
10
45.45%
Martin Willi
83
5.60%
1
4.55%
Alexey Kuznetsov
37
2.50%
1
4.55%
Derek Atkins
27
1.82%
1
4.55%
David S. Miller
1
0.07%
1
4.55%
James Morris
1
0.07%
1
4.55%
Wei Yongjun
1
0.07%
1
4.55%
Al Viro
1
0.07%
1
4.55%
Mathias Krause
1
0.07%
1
4.55%
Total
1482
100.00%
22
100.00%



static int esp_input_done2(struct sk_buff *skb, int err)
{
	const struct iphdr *iph;
	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 ihl;
	u8 nexthdr[2];
	int padlen;

	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)
		goto out;

	/* ... check padding bits here. Silly. :-) */

	iph = ip_hdr(skb);
	ihl = iph->ihl * 4;

	if (x->encap) {
		struct xfrm_encap_tmpl *encap = x->encap;
		struct udphdr *uh = (void *)(skb_network_header(skb) + ihl);

		/*
                 * 1) if the NAT-T peer's IP or port changed then
                 *    advertize the change to the keying daemon.
                 *    This is an inbound SA, so just compare
                 *    SRC ports.
                 */
		if (iph->saddr != x->props.saddr.a4 ||
		    uh->source != encap->encap_sport) {
			xfrm_address_t ipaddr;

			ipaddr.a4 = iph->saddr;
			km_new_mapping(x, &ipaddr, uh->source);

			/* XXX: perhaps add an extra
                         * policy check here, to see
                         * if we should allow or
                         * reject a packet from a
                         * different source
                         * address/port.
                         */
		}

		/*
                 * 2) ignore UDP/TCP checksums in case
                 *    of NAT-T in Transport Mode, or
                 *    perform other post-processing fixes
                 *    as per draft-ietf-ipsec-udp-encaps-06,
                 *    section 3.1.2
                 */
		if (x->props.mode == XFRM_MODE_TRANSPORT)
			skb->ip_summed = CHECKSUM_UNNECESSARY;
	}

	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, -ihl);

	err = nexthdr[1];

	/* RFC4303: Drop dummy packets without any error */
	if (err == IPPROTO_NONE)
		err = -EINVAL;

out:
	return err;
}

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19.35%
1
5.88%
Li RongQing
16
4.76%
1
5.88%
Hideaki Yoshifuji / 吉藤英明
3
0.89%
1
5.88%
Derek Atkins
2
0.60%
1
5.88%
David S. Miller
2
0.60%
1
5.88%
Mathias Krause
2
0.60%
1
5.88%
Eric Dumazet
1
0.30%
1
5.88%
Patrick McHardy
1
0.30%
1
5.88%
Total
336
100.00%
17
100.00%



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));
}

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

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25
100.00%
2
100.00%



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;
	}
}

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10.31%
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66.67%
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97
100.00%
3
100.00%



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
Person
Tokens
Prop
Commits
CommitProp
Herbert Xu
31
88.57%
2
50.00%
David S. Miller
3
8.57%
1
25.00%
Alexey Kuznetsov
1
2.86%
1
25.00%
Total
35
100.00%
4
100.00%

/*
 * Note: detecting truncated vs. non-truncated authentication data is very
 * expensive, so we only support truncated data, which is the recommended
 * and common case.
 */


static int esp_input(struct xfrm_state *x, struct sk_buff *skb)
{
	struct ip_esp_hdr *esph;
	struct crypto_aead *aead = x->data;
	struct aead_request *req;