[INET]: Fix typo in Arnaldo's connection sock compat fixups.
[linux-2.6.git] / net / ipv4 / ah4.c
1 #include <linux/config.h>
2 #include <linux/module.h>
3 #include <net/ip.h>
4 #include <net/xfrm.h>
5 #include <net/ah.h>
6 #include <linux/crypto.h>
7 #include <linux/pfkeyv2.h>
8 #include <net/icmp.h>
9 #include <net/protocol.h>
10 #include <asm/scatterlist.h>
11
12
13 /* Clear mutable options and find final destination to substitute
14  * into IP header for icv calculation. Options are already checked
15  * for validity, so paranoia is not required. */
16
17 static int ip_clear_mutable_options(struct iphdr *iph, u32 *daddr)
18 {
19         unsigned char * optptr = (unsigned char*)(iph+1);
20         int  l = iph->ihl*4 - sizeof(struct iphdr);
21         int  optlen;
22
23         while (l > 0) {
24                 switch (*optptr) {
25                 case IPOPT_END:
26                         return 0;
27                 case IPOPT_NOOP:
28                         l--;
29                         optptr++;
30                         continue;
31                 }
32                 optlen = optptr[1];
33                 if (optlen<2 || optlen>l)
34                         return -EINVAL;
35                 switch (*optptr) {
36                 case IPOPT_SEC:
37                 case 0x85:      /* Some "Extended Security" crap. */
38                 case 0x86:      /* Another "Commercial Security" crap. */
39                 case IPOPT_RA:
40                 case 0x80|21:   /* RFC1770 */
41                         break;
42                 case IPOPT_LSRR:
43                 case IPOPT_SSRR:
44                         if (optlen < 6)
45                                 return -EINVAL;
46                         memcpy(daddr, optptr+optlen-4, 4);
47                         /* Fall through */
48                 default:
49                         memset(optptr+2, 0, optlen-2);
50                 }
51                 l -= optlen;
52                 optptr += optlen;
53         }
54         return 0;
55 }
56
57 static int ah_output(struct xfrm_state *x, struct sk_buff *skb)
58 {
59         int err;
60         struct iphdr *iph, *top_iph;
61         struct ip_auth_hdr *ah;
62         struct ah_data *ahp;
63         union {
64                 struct iphdr    iph;
65                 char            buf[60];
66         } tmp_iph;
67
68         top_iph = skb->nh.iph;
69         iph = &tmp_iph.iph;
70
71         iph->tos = top_iph->tos;
72         iph->ttl = top_iph->ttl;
73         iph->frag_off = top_iph->frag_off;
74
75         if (top_iph->ihl != 5) {
76                 iph->daddr = top_iph->daddr;
77                 memcpy(iph+1, top_iph+1, top_iph->ihl*4 - sizeof(struct iphdr));
78                 err = ip_clear_mutable_options(top_iph, &top_iph->daddr);
79                 if (err)
80                         goto error;
81         }
82
83         ah = (struct ip_auth_hdr *)((char *)top_iph+top_iph->ihl*4);
84         ah->nexthdr = top_iph->protocol;
85
86         top_iph->tos = 0;
87         top_iph->tot_len = htons(skb->len);
88         top_iph->frag_off = 0;
89         top_iph->ttl = 0;
90         top_iph->protocol = IPPROTO_AH;
91         top_iph->check = 0;
92
93         ahp = x->data;
94         ah->hdrlen  = (XFRM_ALIGN8(sizeof(struct ip_auth_hdr) + 
95                                    ahp->icv_trunc_len) >> 2) - 2;
96
97         ah->reserved = 0;
98         ah->spi = x->id.spi;
99         ah->seq_no = htonl(++x->replay.oseq);
100         xfrm_aevent_doreplay(x);
101         ahp->icv(ahp, skb, ah->auth_data);
102
103         top_iph->tos = iph->tos;
104         top_iph->ttl = iph->ttl;
105         top_iph->frag_off = iph->frag_off;
106         if (top_iph->ihl != 5) {
107                 top_iph->daddr = iph->daddr;
108                 memcpy(top_iph+1, iph+1, top_iph->ihl*4 - sizeof(struct iphdr));
109         }
110
111         ip_send_check(top_iph);
112
113         err = 0;
114
115 error:
116         return err;
117 }
118
119 static int ah_input(struct xfrm_state *x, struct xfrm_decap_state *decap, struct sk_buff *skb)
120 {
121         int ah_hlen;
122         struct iphdr *iph;
123         struct ip_auth_hdr *ah;
124         struct ah_data *ahp;
125         char work_buf[60];
126
127         if (!pskb_may_pull(skb, sizeof(struct ip_auth_hdr)))
128                 goto out;
129
130         ah = (struct ip_auth_hdr*)skb->data;
131         ahp = x->data;
132         ah_hlen = (ah->hdrlen + 2) << 2;
133         
134         if (ah_hlen != XFRM_ALIGN8(sizeof(struct ip_auth_hdr) + ahp->icv_full_len) &&
135             ah_hlen != XFRM_ALIGN8(sizeof(struct ip_auth_hdr) + ahp->icv_trunc_len)) 
136                 goto out;
137
138         if (!pskb_may_pull(skb, ah_hlen))
139                 goto out;
140
141         /* We are going to _remove_ AH header to keep sockets happy,
142          * so... Later this can change. */
143         if (skb_cloned(skb) &&
144             pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
145                 goto out;
146
147         skb->ip_summed = CHECKSUM_NONE;
148
149         ah = (struct ip_auth_hdr*)skb->data;
150         iph = skb->nh.iph;
151
152         memcpy(work_buf, iph, iph->ihl*4);
153
154         iph->ttl = 0;
155         iph->tos = 0;
156         iph->frag_off = 0;
157         iph->check = 0;
158         if (iph->ihl != 5) {
159                 u32 dummy;
160                 if (ip_clear_mutable_options(iph, &dummy))
161                         goto out;
162         }
163         {
164                 u8 auth_data[MAX_AH_AUTH_LEN];
165                 
166                 memcpy(auth_data, ah->auth_data, ahp->icv_trunc_len);
167                 skb_push(skb, skb->data - skb->nh.raw);
168                 ahp->icv(ahp, skb, ah->auth_data);
169                 if (memcmp(ah->auth_data, auth_data, ahp->icv_trunc_len)) {
170                         x->stats.integrity_failed++;
171                         goto out;
172                 }
173         }
174         ((struct iphdr*)work_buf)->protocol = ah->nexthdr;
175         skb->nh.raw = skb_pull(skb, ah_hlen);
176         memcpy(skb->nh.raw, work_buf, iph->ihl*4);
177         skb->nh.iph->tot_len = htons(skb->len);
178         skb_pull(skb, skb->nh.iph->ihl*4);
179         skb->h.raw = skb->data;
180
181         return 0;
182
183 out:
184         return -EINVAL;
185 }
186
187 static void ah4_err(struct sk_buff *skb, u32 info)
188 {
189         struct iphdr *iph = (struct iphdr*)skb->data;
190         struct ip_auth_hdr *ah = (struct ip_auth_hdr*)(skb->data+(iph->ihl<<2));
191         struct xfrm_state *x;
192
193         if (skb->h.icmph->type != ICMP_DEST_UNREACH ||
194             skb->h.icmph->code != ICMP_FRAG_NEEDED)
195                 return;
196
197         x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, ah->spi, IPPROTO_AH, AF_INET);
198         if (!x)
199                 return;
200         printk(KERN_DEBUG "pmtu discovery on SA AH/%08x/%08x\n",
201                ntohl(ah->spi), ntohl(iph->daddr));
202         xfrm_state_put(x);
203 }
204
205 static int ah_init_state(struct xfrm_state *x)
206 {
207         struct ah_data *ahp = NULL;
208         struct xfrm_algo_desc *aalg_desc;
209
210         if (!x->aalg)
211                 goto error;
212
213         /* null auth can use a zero length key */
214         if (x->aalg->alg_key_len > 512)
215                 goto error;
216
217         if (x->encap)
218                 goto error;
219
220         ahp = kmalloc(sizeof(*ahp), GFP_KERNEL);
221         if (ahp == NULL)
222                 return -ENOMEM;
223
224         memset(ahp, 0, sizeof(*ahp));
225
226         ahp->key = x->aalg->alg_key;
227         ahp->key_len = (x->aalg->alg_key_len+7)/8;
228         ahp->tfm = crypto_alloc_tfm(x->aalg->alg_name, 0);
229         if (!ahp->tfm)
230                 goto error;
231         ahp->icv = ah_hmac_digest;
232         
233         /*
234          * Lookup the algorithm description maintained by xfrm_algo,
235          * verify crypto transform properties, and store information
236          * we need for AH processing.  This lookup cannot fail here
237          * after a successful crypto_alloc_tfm().
238          */
239         aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
240         BUG_ON(!aalg_desc);
241
242         if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
243             crypto_tfm_alg_digestsize(ahp->tfm)) {
244                 printk(KERN_INFO "AH: %s digestsize %u != %hu\n",
245                        x->aalg->alg_name, crypto_tfm_alg_digestsize(ahp->tfm),
246                        aalg_desc->uinfo.auth.icv_fullbits/8);
247                 goto error;
248         }
249         
250         ahp->icv_full_len = aalg_desc->uinfo.auth.icv_fullbits/8;
251         ahp->icv_trunc_len = aalg_desc->uinfo.auth.icv_truncbits/8;
252         
253         BUG_ON(ahp->icv_trunc_len > MAX_AH_AUTH_LEN);
254         
255         ahp->work_icv = kmalloc(ahp->icv_full_len, GFP_KERNEL);
256         if (!ahp->work_icv)
257                 goto error;
258         
259         x->props.header_len = XFRM_ALIGN8(sizeof(struct ip_auth_hdr) + ahp->icv_trunc_len);
260         if (x->props.mode)
261                 x->props.header_len += sizeof(struct iphdr);
262         x->data = ahp;
263
264         return 0;
265
266 error:
267         if (ahp) {
268                 kfree(ahp->work_icv);
269                 crypto_free_tfm(ahp->tfm);
270                 kfree(ahp);
271         }
272         return -EINVAL;
273 }
274
275 static void ah_destroy(struct xfrm_state *x)
276 {
277         struct ah_data *ahp = x->data;
278
279         if (!ahp)
280                 return;
281
282         kfree(ahp->work_icv);
283         ahp->work_icv = NULL;
284         crypto_free_tfm(ahp->tfm);
285         ahp->tfm = NULL;
286         kfree(ahp);
287 }
288
289
290 static struct xfrm_type ah_type =
291 {
292         .description    = "AH4",
293         .owner          = THIS_MODULE,
294         .proto          = IPPROTO_AH,
295         .init_state     = ah_init_state,
296         .destructor     = ah_destroy,
297         .input          = ah_input,
298         .output         = ah_output
299 };
300
301 static struct net_protocol ah4_protocol = {
302         .handler        =       xfrm4_rcv,
303         .err_handler    =       ah4_err,
304         .no_policy      =       1,
305 };
306
307 static int __init ah4_init(void)
308 {
309         if (xfrm_register_type(&ah_type, AF_INET) < 0) {
310                 printk(KERN_INFO "ip ah init: can't add xfrm type\n");
311                 return -EAGAIN;
312         }
313         if (inet_add_protocol(&ah4_protocol, IPPROTO_AH) < 0) {
314                 printk(KERN_INFO "ip ah init: can't add protocol\n");
315                 xfrm_unregister_type(&ah_type, AF_INET);
316                 return -EAGAIN;
317         }
318         return 0;
319 }
320
321 static void __exit ah4_fini(void)
322 {
323         if (inet_del_protocol(&ah4_protocol, IPPROTO_AH) < 0)
324                 printk(KERN_INFO "ip ah close: can't remove protocol\n");
325         if (xfrm_unregister_type(&ah_type, AF_INET) < 0)
326                 printk(KERN_INFO "ip ah close: can't remove xfrm type\n");
327 }
328
329 module_init(ah4_init);
330 module_exit(ah4_fini);
331 MODULE_LICENSE("GPL");