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 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 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 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 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); 104 105 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 __be32 seq_hi; 111 struct xfrm_state *x; 112 xfrm_address_t *daddr; 113 struct xfrm_mode *inner_mode; 114 unsigned int family; 115 int decaps = 0; 116 int async = 0; 117 118 /* A negative encap_type indicates async resumption. */ 119 if (encap_type < 0) { 120 async = 1; 121 x = xfrm_input_state(skb); 122 seq = XFRM_SKB_CB(skb)->seq.input.low; 123 goto resume; 124 } 125 126 /* Allocate new secpath or COW existing one. */ 127 if (!skb->sp || atomic_read(&skb->sp->refcnt) != 1) { 128 struct sec_path *sp; 129 130 sp = secpath_dup(skb->sp); 131 if (!sp) { 132 XFRM_INC_STATS(net, LINUX_MIB_XFRMINERROR); 133 goto drop; 134 } 135 if (skb->sp) 136 secpath_put(skb->sp); 137 skb->sp = sp; 138 } 139 140 daddr = (xfrm_address_t *)(skb_network_header(skb) + 141 XFRM_SPI_SKB_CB(skb)->daddroff); 142 family = XFRM_SPI_SKB_CB(skb)->family; 143 144 seq = 0; 145 if (!spi && (err = xfrm_parse_spi(skb, nexthdr, &spi, &seq)) != 0) { 146 XFRM_INC_STATS(net, LINUX_MIB_XFRMINHDRERROR); 147 goto drop; 148 } 149 150 do { 151 if (skb->sp->len == XFRM_MAX_DEPTH) { 152 XFRM_INC_STATS(net, LINUX_MIB_XFRMINBUFFERERROR); 153 goto drop; 154 } 155 156 x = xfrm_state_lookup(net, skb->mark, daddr, spi, nexthdr, family); 157 if (x == NULL) { 158 XFRM_INC_STATS(net, LINUX_MIB_XFRMINNOSTATES); 159 xfrm_audit_state_notfound(skb, family, spi, seq); 160 goto drop; 161 } 162 163 skb->sp->xvec[skb->sp->len++] = x; 164 165 spin_lock(&x->lock); 166 if (unlikely(x->km.state != XFRM_STATE_VALID)) { 167 XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEINVALID); 168 goto drop_unlock; 169 } 170 171 if ((x->encap ? x->encap->encap_type : 0) != encap_type) { 172 XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEMISMATCH); 173 goto drop_unlock; 174 } 175 176 if (x->repl->check(x, skb, seq)) { 177 XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATESEQERROR); 178 goto drop_unlock; 179 } 180 181 if (xfrm_state_check_expire(x)) { 182 XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEEXPIRED); 183 goto drop_unlock; 184 } 185 186 spin_unlock(&x->lock); 187 188 seq_hi = htonl(xfrm_replay_seqhi(x, seq)); 189 190 XFRM_SKB_CB(skb)->seq.input.low = seq; 191 XFRM_SKB_CB(skb)->seq.input.hi = seq_hi; 192 193 skb_dst_force(skb); 194 195 nexthdr = x->type->input(x, skb); 196 197 if (nexthdr == -EINPROGRESS) 198 return 0; 199 200 resume: 201 spin_lock(&x->lock); 202 if (nexthdr <= 0) { 203 if (nexthdr == -EBADMSG) { 204 xfrm_audit_state_icvfail(x, skb, 205 x->type->proto); 206 x->stats.integrity_failed++; 207 } 208 XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEPROTOERROR); 209 goto drop_unlock; 210 } 211 212 /* only the first xfrm gets the encap type */ 213 encap_type = 0; 214 215 if (async && x->repl->recheck(x, skb, seq)) { 216 XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATESEQERROR); 217 goto drop_unlock; 218 } 219 220 x->repl->advance(x, seq); 221 222 x->curlft.bytes += skb->len; 223 x->curlft.packets++; 224 225 spin_unlock(&x->lock); 226 227 XFRM_MODE_SKB_CB(skb)->protocol = nexthdr; 228 229 inner_mode = x->inner_mode; 230 231 if (x->sel.family == AF_UNSPEC) { 232 inner_mode = xfrm_ip2inner_mode(x, XFRM_MODE_SKB_CB(skb)->protocol); 233 if (inner_mode == NULL) 234 goto drop; 235 } 236 237 if (inner_mode->input(x, skb)) { 238 XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEMODEERROR); 239 goto drop; 240 } 241 242 if (x->outer_mode->flags & XFRM_MODE_FLAG_TUNNEL) { 243 decaps = 1; 244 break; 245 } 246 247 /* 248 * We need the inner address. However, we only get here for 249 * transport mode so the outer address is identical. 250 */ 251 daddr = &x->id.daddr; 252 family = x->outer_mode->afinfo->family; 253 254 err = xfrm_parse_spi(skb, nexthdr, &spi, &seq); 255 if (err < 0) { 256 XFRM_INC_STATS(net, LINUX_MIB_XFRMINHDRERROR); 257 goto drop; 258 } 259 } while (!err); 260 261 nf_reset(skb); 262 263 if (decaps) { 264 skb_dst_drop(skb); 265 netif_rx(skb); 266 return 0; 267 } else { 268 return x->inner_mode->afinfo->transport_finish(skb, async); 269 } 270 271 drop_unlock: 272 spin_unlock(&x->lock); 273 drop: 274 kfree_skb(skb); 275 return 0; 276 } 277 EXPORT_SYMBOL(xfrm_input); 278 279 int xfrm_input_resume(struct sk_buff *skb, int nexthdr) 280 { 281 return xfrm_input(skb, nexthdr, 0, -1); 282 } 283 EXPORT_SYMBOL(xfrm_input_resume); 284 285 void __init xfrm_input_init(void) 286 { 287 secpath_cachep = kmem_cache_create("secpath_cache", 288 sizeof(struct sec_path), 289 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, 290 NULL); 291 } 292