[NET]: Conversions from kmalloc+memset to k(z|c)alloc.
[linux-3.10.git] / net / ipv4 / ah4.c
1 #include <linux/module.h>
2 #include <net/ip.h>
3 #include <net/xfrm.h>
4 #include <net/ah.h>
5 #include <linux/crypto.h>
6 #include <linux/pfkeyv2.h>
7 #include <net/icmp.h>
8 #include <net/protocol.h>
9 #include <asm/scatterlist.h>
10
11
12 /* Clear mutable options and find final destination to substitute
13  * into IP header for icv calculation. Options are already checked
14  * for validity, so paranoia is not required. */
15
16 static int ip_clear_mutable_options(struct iphdr *iph, u32 *daddr)
17 {
18         unsigned char * optptr = (unsigned char*)(iph+1);
19         int  l = iph->ihl*4 - sizeof(struct iphdr);
20         int  optlen;
21
22         while (l > 0) {
23                 switch (*optptr) {
24                 case IPOPT_END:
25                         return 0;
26                 case IPOPT_NOOP:
27                         l--;
28                         optptr++;
29                         continue;
30                 }
31                 optlen = optptr[1];
32                 if (optlen<2 || optlen>l)
33                         return -EINVAL;
34                 switch (*optptr) {
35                 case IPOPT_SEC:
36                 case 0x85:      /* Some "Extended Security" crap. */
37                 case 0x86:      /* Another "Commercial Security" crap. */
38                 case IPOPT_RA:
39                 case 0x80|21:   /* RFC1770 */
40                         break;
41                 case IPOPT_LSRR:
42                 case IPOPT_SSRR:
43                         if (optlen < 6)
44                                 return -EINVAL;
45                         memcpy(daddr, optptr+optlen-4, 4);
46                         /* Fall through */
47                 default:
48                         memset(optptr+2, 0, optlen-2);
49                 }
50                 l -= optlen;
51                 optptr += optlen;
52         }
53         return 0;
54 }
55
56 static int ah_output(struct xfrm_state *x, struct sk_buff *skb)
57 {
58         int err;
59         struct iphdr *iph, *top_iph;
60         struct ip_auth_hdr *ah;
61         struct ah_data *ahp;
62         union {
63                 struct iphdr    iph;
64                 char            buf[60];
65         } tmp_iph;
66
67         top_iph = skb->nh.iph;
68         iph = &tmp_iph.iph;
69
70         iph->tos = top_iph->tos;
71         iph->ttl = top_iph->ttl;
72         iph->frag_off = top_iph->frag_off;
73
74         if (top_iph->ihl != 5) {
75                 iph->daddr = top_iph->daddr;
76                 memcpy(iph+1, top_iph+1, top_iph->ihl*4 - sizeof(struct iphdr));
77                 err = ip_clear_mutable_options(top_iph, &top_iph->daddr);
78                 if (err)
79                         goto error;
80         }
81
82         ah = (struct ip_auth_hdr *)((char *)top_iph+top_iph->ihl*4);
83         ah->nexthdr = top_iph->protocol;
84
85         top_iph->tos = 0;
86         top_iph->tot_len = htons(skb->len);
87         top_iph->frag_off = 0;
88         top_iph->ttl = 0;
89         top_iph->protocol = IPPROTO_AH;
90         top_iph->check = 0;
91
92         ahp = x->data;
93         ah->hdrlen  = (XFRM_ALIGN8(sizeof(struct ip_auth_hdr) + 
94                                    ahp->icv_trunc_len) >> 2) - 2;
95
96         ah->reserved = 0;
97         ah->spi = x->id.spi;
98         ah->seq_no = htonl(++x->replay.oseq);
99         xfrm_aevent_doreplay(x);
100         ahp->icv(ahp, skb, ah->auth_data);
101
102         top_iph->tos = iph->tos;
103         top_iph->ttl = iph->ttl;
104         top_iph->frag_off = iph->frag_off;
105         if (top_iph->ihl != 5) {
106                 top_iph->daddr = iph->daddr;
107                 memcpy(top_iph+1, iph+1, top_iph->ihl*4 - sizeof(struct iphdr));
108         }
109
110         ip_send_check(top_iph);
111
112         err = 0;
113
114 error:
115         return err;
116 }
117
118 static int ah_input(struct xfrm_state *x, struct sk_buff *skb)
119 {
120         int ah_hlen;
121         int ihl;
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         ihl = skb->data - skb->nh.raw;
153         memcpy(work_buf, iph, ihl);
154
155         iph->ttl = 0;
156         iph->tos = 0;
157         iph->frag_off = 0;
158         iph->check = 0;
159         if (ihl > sizeof(*iph)) {
160                 u32 dummy;
161                 if (ip_clear_mutable_options(iph, &dummy))
162                         goto out;
163         }
164         {
165                 u8 auth_data[MAX_AH_AUTH_LEN];
166                 
167                 memcpy(auth_data, ah->auth_data, ahp->icv_trunc_len);
168                 skb_push(skb, ihl);
169                 ahp->icv(ahp, skb, ah->auth_data);
170                 if (memcmp(ah->auth_data, auth_data, ahp->icv_trunc_len)) {
171                         x->stats.integrity_failed++;
172                         goto out;
173                 }
174         }
175         ((struct iphdr*)work_buf)->protocol = ah->nexthdr;
176         skb->h.raw = memcpy(skb->nh.raw += ah_hlen, work_buf, ihl);
177         __skb_pull(skb, ah_hlen + ihl);
178
179         return 0;
180
181 out:
182         return -EINVAL;
183 }
184
185 static void ah4_err(struct sk_buff *skb, u32 info)
186 {
187         struct iphdr *iph = (struct iphdr*)skb->data;
188         struct ip_auth_hdr *ah = (struct ip_auth_hdr*)(skb->data+(iph->ihl<<2));
189         struct xfrm_state *x;
190
191         if (skb->h.icmph->type != ICMP_DEST_UNREACH ||
192             skb->h.icmph->code != ICMP_FRAG_NEEDED)
193                 return;
194
195         x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, ah->spi, IPPROTO_AH, AF_INET);
196         if (!x)
197                 return;
198         printk(KERN_DEBUG "pmtu discovery on SA AH/%08x/%08x\n",
199                ntohl(ah->spi), ntohl(iph->daddr));
200         xfrm_state_put(x);
201 }
202
203 static int ah_init_state(struct xfrm_state *x)
204 {
205         struct ah_data *ahp = NULL;
206         struct xfrm_algo_desc *aalg_desc;
207
208         if (!x->aalg)
209                 goto error;
210
211         /* null auth can use a zero length key */
212         if (x->aalg->alg_key_len > 512)
213                 goto error;
214
215         if (x->encap)
216                 goto error;
217
218         ahp = kzalloc(sizeof(*ahp), GFP_KERNEL);
219         if (ahp == NULL)
220                 return -ENOMEM;
221
222         ahp->key = x->aalg->alg_key;
223         ahp->key_len = (x->aalg->alg_key_len+7)/8;
224         ahp->tfm = crypto_alloc_tfm(x->aalg->alg_name, 0);
225         if (!ahp->tfm)
226                 goto error;
227         ahp->icv = ah_hmac_digest;
228         
229         /*
230          * Lookup the algorithm description maintained by xfrm_algo,
231          * verify crypto transform properties, and store information
232          * we need for AH processing.  This lookup cannot fail here
233          * after a successful crypto_alloc_tfm().
234          */
235         aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
236         BUG_ON(!aalg_desc);
237
238         if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
239             crypto_tfm_alg_digestsize(ahp->tfm)) {
240                 printk(KERN_INFO "AH: %s digestsize %u != %hu\n",
241                        x->aalg->alg_name, crypto_tfm_alg_digestsize(ahp->tfm),
242                        aalg_desc->uinfo.auth.icv_fullbits/8);
243                 goto error;
244         }
245         
246         ahp->icv_full_len = aalg_desc->uinfo.auth.icv_fullbits/8;
247         ahp->icv_trunc_len = aalg_desc->uinfo.auth.icv_truncbits/8;
248         
249         BUG_ON(ahp->icv_trunc_len > MAX_AH_AUTH_LEN);
250         
251         ahp->work_icv = kmalloc(ahp->icv_full_len, GFP_KERNEL);
252         if (!ahp->work_icv)
253                 goto error;
254         
255         x->props.header_len = XFRM_ALIGN8(sizeof(struct ip_auth_hdr) + ahp->icv_trunc_len);
256         if (x->props.mode)
257                 x->props.header_len += sizeof(struct iphdr);
258         x->data = ahp;
259
260         return 0;
261
262 error:
263         if (ahp) {
264                 kfree(ahp->work_icv);
265                 crypto_free_tfm(ahp->tfm);
266                 kfree(ahp);
267         }
268         return -EINVAL;
269 }
270
271 static void ah_destroy(struct xfrm_state *x)
272 {
273         struct ah_data *ahp = x->data;
274
275         if (!ahp)
276                 return;
277
278         kfree(ahp->work_icv);
279         ahp->work_icv = NULL;
280         crypto_free_tfm(ahp->tfm);
281         ahp->tfm = NULL;
282         kfree(ahp);
283 }
284
285
286 static struct xfrm_type ah_type =
287 {
288         .description    = "AH4",
289         .owner          = THIS_MODULE,
290         .proto          = IPPROTO_AH,
291         .init_state     = ah_init_state,
292         .destructor     = ah_destroy,
293         .input          = ah_input,
294         .output         = ah_output
295 };
296
297 static struct net_protocol ah4_protocol = {
298         .handler        =       xfrm4_rcv,
299         .err_handler    =       ah4_err,
300         .no_policy      =       1,
301 };
302
303 static int __init ah4_init(void)
304 {
305         if (xfrm_register_type(&ah_type, AF_INET) < 0) {
306                 printk(KERN_INFO "ip ah init: can't add xfrm type\n");
307                 return -EAGAIN;
308         }
309         if (inet_add_protocol(&ah4_protocol, IPPROTO_AH) < 0) {
310                 printk(KERN_INFO "ip ah init: can't add protocol\n");
311                 xfrm_unregister_type(&ah_type, AF_INET);
312                 return -EAGAIN;
313         }
314         return 0;
315 }
316
317 static void __exit ah4_fini(void)
318 {
319         if (inet_del_protocol(&ah4_protocol, IPPROTO_AH) < 0)
320                 printk(KERN_INFO "ip ah close: can't remove protocol\n");
321         if (xfrm_unregister_type(&ah_type, AF_INET) < 0)
322                 printk(KERN_INFO "ip ah close: can't remove xfrm type\n");
323 }
324
325 module_init(ah4_init);
326 module_exit(ah4_fini);
327 MODULE_LICENSE("GPL");