1 /*
2 * xfrm_input.c
3 *
4 * Changes:
5 * YOSHIFUJI Hideaki @USAGI
6 * Split up af-specific portion
7 *
8 */
9
10 #include <linux/slab.h>
11 #include <linux/module.h>
12 #include <linux/netdevice.h>
13 #include <net/dst.h>
14 #include <net/ip.h>
15 #include <net/xfrm.h>
16
17 static struct kmem_cache *secpath_cachep __read_mostly;
18
__secpath_destroy(struct sec_path * sp)19 void __secpath_destroy(struct sec_path *sp)
20 {
21 int i;
22 for (i = 0; i < sp->len; i++)
23 xfrm_state_put(sp->xvec[i]);
24 kmem_cache_free(secpath_cachep, sp);
25 }
26 EXPORT_SYMBOL(__secpath_destroy);
27
secpath_dup(struct sec_path * src)28 struct sec_path *secpath_dup(struct sec_path *src)
29 {
30 struct sec_path *sp;
31
32 sp = kmem_cache_alloc(secpath_cachep, GFP_ATOMIC);
33 if (!sp)
34 return NULL;
35
36 sp->len = 0;
37 if (src) {
38 int i;
39
40 memcpy(sp, src, sizeof(*sp));
41 for (i = 0; i < sp->len; i++)
42 xfrm_state_hold(sp->xvec[i]);
43 }
44 atomic_set(&sp->refcnt, 1);
45 return sp;
46 }
47 EXPORT_SYMBOL(secpath_dup);
48
49 /* Fetch spi and seq from ipsec header */
50
xfrm_parse_spi(struct sk_buff * skb,u8 nexthdr,__be32 * spi,__be32 * seq)51 int xfrm_parse_spi(struct sk_buff *skb, u8 nexthdr, __be32 *spi, __be32 *seq)
52 {
53 int offset, offset_seq;
54 int hlen;
55
56 switch (nexthdr) {
57 case IPPROTO_AH:
58 hlen = sizeof(struct ip_auth_hdr);
59 offset = offsetof(struct ip_auth_hdr, spi);
60 offset_seq = offsetof(struct ip_auth_hdr, seq_no);
61 break;
62 case IPPROTO_ESP:
63 hlen = sizeof(struct ip_esp_hdr);
64 offset = offsetof(struct ip_esp_hdr, spi);
65 offset_seq = offsetof(struct ip_esp_hdr, seq_no);
66 break;
67 case IPPROTO_COMP:
68 if (!pskb_may_pull(skb, sizeof(struct ip_comp_hdr)))
69 return -EINVAL;
70 *spi = htonl(ntohs(*(__be16*)(skb_transport_header(skb) + 2)));
71 *seq = 0;
72 return 0;
73 default:
74 return 1;
75 }
76
77 if (!pskb_may_pull(skb, hlen))
78 return -EINVAL;
79
80 *spi = *(__be32*)(skb_transport_header(skb) + offset);
81 *seq = *(__be32*)(skb_transport_header(skb) + offset_seq);
82 return 0;
83 }
84
xfrm_prepare_input(struct xfrm_state * x,struct sk_buff * skb)85 int xfrm_prepare_input(struct xfrm_state *x, struct sk_buff *skb)
86 {
87 struct xfrm_mode *inner_mode = x->inner_mode;
88 int err;
89
90 err = x->outer_mode->afinfo->extract_input(x, skb);
91 if (err)
92 return err;
93
94 if (x->sel.family == AF_UNSPEC) {
95 inner_mode = xfrm_ip2inner_mode(x, XFRM_MODE_SKB_CB(skb)->protocol);
96 if (inner_mode == NULL)
97 return -EAFNOSUPPORT;
98 }
99
100 skb->protocol = inner_mode->afinfo->eth_proto;
101 return inner_mode->input2(x, skb);
102 }
103 EXPORT_SYMBOL(xfrm_prepare_input);
104
xfrm_input(struct sk_buff * skb,int nexthdr,__be32 spi,int encap_type)105 int xfrm_input(struct sk_buff *skb, int nexthdr, __be32 spi, int encap_type)
106 {
107 struct net *net = dev_net(skb->dev);
108 int err;
109 __be32 seq;
110 struct xfrm_state *x;
111 xfrm_address_t *daddr;
112 struct xfrm_mode *inner_mode;
113 unsigned int family;
114 int decaps = 0;
115 int async = 0;
116
117 /* A negative encap_type indicates async resumption. */
118 if (encap_type < 0) {
119 async = 1;
120 x = xfrm_input_state(skb);
121 seq = XFRM_SKB_CB(skb)->seq.input;
122 goto resume;
123 }
124
125 /* Allocate new secpath or COW existing one. */
126 if (!skb->sp || atomic_read(&skb->sp->refcnt) != 1) {
127 struct sec_path *sp;
128
129 sp = secpath_dup(skb->sp);
130 if (!sp) {
131 XFRM_INC_STATS(net, LINUX_MIB_XFRMINERROR);
132 goto drop;
133 }
134 if (skb->sp)
135 secpath_put(skb->sp);
136 skb->sp = sp;
137 }
138
139 daddr = (xfrm_address_t *)(skb_network_header(skb) +
140 XFRM_SPI_SKB_CB(skb)->daddroff);
141 family = XFRM_SPI_SKB_CB(skb)->family;
142
143 seq = 0;
144 if (!spi && (err = xfrm_parse_spi(skb, nexthdr, &spi, &seq)) != 0) {
145 XFRM_INC_STATS(net, LINUX_MIB_XFRMINHDRERROR);
146 goto drop;
147 }
148
149 do {
150 if (skb->sp->len == XFRM_MAX_DEPTH) {
151 XFRM_INC_STATS(net, LINUX_MIB_XFRMINBUFFERERROR);
152 goto drop;
153 }
154
155 x = xfrm_state_lookup(net, daddr, spi, nexthdr, family);
156 if (x == NULL) {
157 XFRM_INC_STATS(net, LINUX_MIB_XFRMINNOSTATES);
158 xfrm_audit_state_notfound(skb, family, spi, seq);
159 goto drop;
160 }
161
162 skb->sp->xvec[skb->sp->len++] = x;
163
164 spin_lock(&x->lock);
165 if (unlikely(x->km.state != XFRM_STATE_VALID)) {
166 XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEINVALID);
167 goto drop_unlock;
168 }
169
170 if ((x->encap ? x->encap->encap_type : 0) != encap_type) {
171 XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEMISMATCH);
172 goto drop_unlock;
173 }
174
175 if (x->props.replay_window && xfrm_replay_check(x, skb, seq)) {
176 XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATESEQERROR);
177 goto drop_unlock;
178 }
179
180 if (xfrm_state_check_expire(x)) {
181 XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEEXPIRED);
182 goto drop_unlock;
183 }
184
185 spin_unlock(&x->lock);
186
187 XFRM_SKB_CB(skb)->seq.input = seq;
188
189 nexthdr = x->type->input(x, skb);
190
191 if (nexthdr == -EINPROGRESS)
192 return 0;
193
194 resume:
195 spin_lock(&x->lock);
196 if (nexthdr <= 0) {
197 if (nexthdr == -EBADMSG) {
198 xfrm_audit_state_icvfail(x, skb,
199 x->type->proto);
200 x->stats.integrity_failed++;
201 }
202 XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEPROTOERROR);
203 goto drop_unlock;
204 }
205
206 /* only the first xfrm gets the encap type */
207 encap_type = 0;
208
209 if (x->props.replay_window)
210 xfrm_replay_advance(x, seq);
211
212 x->curlft.bytes += skb->len;
213 x->curlft.packets++;
214
215 spin_unlock(&x->lock);
216
217 XFRM_MODE_SKB_CB(skb)->protocol = nexthdr;
218
219 inner_mode = x->inner_mode;
220
221 if (x->sel.family == AF_UNSPEC) {
222 inner_mode = xfrm_ip2inner_mode(x, XFRM_MODE_SKB_CB(skb)->protocol);
223 if (inner_mode == NULL)
224 goto drop;
225 }
226
227 if (inner_mode->input(x, skb)) {
228 XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEMODEERROR);
229 goto drop;
230 }
231
232 if (x->outer_mode->flags & XFRM_MODE_FLAG_TUNNEL) {
233 decaps = 1;
234 break;
235 }
236
237 /*
238 * We need the inner address. However, we only get here for
239 * transport mode so the outer address is identical.
240 */
241 daddr = &x->id.daddr;
242 family = x->outer_mode->afinfo->family;
243
244 err = xfrm_parse_spi(skb, nexthdr, &spi, &seq);
245 if (err < 0) {
246 XFRM_INC_STATS(net, LINUX_MIB_XFRMINHDRERROR);
247 goto drop;
248 }
249 } while (!err);
250
251 nf_reset(skb);
252
253 if (decaps) {
254 dst_release(skb->dst);
255 skb->dst = NULL;
256 netif_rx(skb);
257 return 0;
258 } else {
259 return x->inner_mode->afinfo->transport_finish(skb, async);
260 }
261
262 drop_unlock:
263 spin_unlock(&x->lock);
264 drop:
265 kfree_skb(skb);
266 return 0;
267 }
268 EXPORT_SYMBOL(xfrm_input);
269
xfrm_input_resume(struct sk_buff * skb,int nexthdr)270 int xfrm_input_resume(struct sk_buff *skb, int nexthdr)
271 {
272 return xfrm_input(skb, nexthdr, 0, -1);
273 }
274 EXPORT_SYMBOL(xfrm_input_resume);
275
xfrm_input_init(void)276 void __init xfrm_input_init(void)
277 {
278 secpath_cachep = kmem_cache_create("secpath_cache",
279 sizeof(struct sec_path),
280 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC,
281 NULL);
282 }
283