ipsec_rcv.c

来自「FREESWAN VPN源代码包」· C语言 代码 · 共 2,240 行 · 第 1/5 页

					    sa_len ? sa : " (error)");
			} else {
				KLIPS_PRINT(debug_rcv,
					    "klips_debug:ipsec_rcv: "
					    "SA:%s First SA in group.\n",
					    sa_len ? sa : " (error)");
			}
			
			if(tdbp->tdb_onext) {
				if(tdbprev != tdbp->tdb_onext) {
					spin_unlock(&tdb_lock);
					KLIPS_PRINT(debug_rcv,
						    "klips_debug:ipsec_rcv: "
						    "unexpected SA:%s: does not agree with tdb->onext policy, dropped.\n",
						    sa_len ? sa : " (error)");
					if(stats) {
						stats->rx_dropped++;
					}
					goto rcvleave;
				} else {
					KLIPS_PRINT(debug_rcv,
						    "klips_debug:ipsec_rcv: "
						    "SA:%s grouping to previous SA is OK.\n",
						    sa_len ? sa : " (error)");
				}
			} else {
				KLIPS_PRINT(debug_rcv,
					    "klips_debug:ipsec_rcv: "
					    "SA:%s No previous backlink in group.\n",
					    sa_len ? sa : " (error)");
			}
#ifdef CONFIG_IPSEC_NAT_TRAVERSAL
			KLIPS_PRINT(debug_rcv,
				"klips_debug:ipsec_rcv: "
				"natt_type=%u tdbp->ips_natt_type=%u : %s\n",
				natt_type, tdbp->ips_natt_type,
				(natt_type==tdbp->ips_natt_type)?"ok":"bad");
			if (natt_type != tdbp->ips_natt_type) {
				spin_unlock(&tdb_lock);
				KLIPS_PRINT(debug_rcv,
					    "klips_debug:ipsec_rcv: "
					    "SA:%s does not agree with expected NAT-T policy.\n",
					    sa_len ? sa : " (error)");
				if(stats) {
					stats->rx_dropped++;
				}
				goto rcvleave;
			}
#endif
		}
		
		/* If it is in larval state, drop the packet, we cannot process yet. */
		if(tdbp->tdb_state == SADB_SASTATE_LARVAL) {
			spin_unlock(&tdb_lock);
			KLIPS_PRINT(debug_rcv,
				    "klips_debug:ipsec_rcv: "
				    "TDB in larval state, cannot be used yet, dropping packet.\n");
			if(stats) {
				stats->rx_dropped++;
			}
			goto rcvleave;
		}
		
		if(tdbp->tdb_state == SADB_SASTATE_DEAD) {
			spin_unlock(&tdb_lock);
			KLIPS_PRINT(debug_rcv,
				    "klips_debug:ipsec_rcv: "
				    "TDB in dead state, cannot be used any more, dropping packet.\n");
			if(stats) {
				stats->rx_dropped++;
			}
			goto rcvleave;
		}
		
		if(ipsec_lifetime_check(&tdbp->ips_life.ipl_bytes,   "bytes", sa,
					ipsec_life_countbased, ipsec_incoming, tdbp) == ipsec_life_harddied ||
		   ipsec_lifetime_check(&tdbp->ips_life.ipl_addtime, "addtime",sa,
					ipsec_life_timebased,  ipsec_incoming, tdbp) == ipsec_life_harddied ||
		   ipsec_lifetime_check(&tdbp->ips_life.ipl_addtime, "usetime",sa,
					ipsec_life_timebased,  ipsec_incoming, tdbp) == ipsec_life_harddied ||
		   ipsec_lifetime_check(&tdbp->ips_life.ipl_packets, "packets",sa, 
					ipsec_life_countbased, ipsec_incoming, tdbp) == ipsec_life_harddied) {
			ipsec_sa_delchain(tdbp);
			spin_unlock(&tdb_lock);
			if(stats) {
				stats->rx_dropped++;
			}
			goto rcvleave;
		}

		/* authenticate, if required */
		idat = dat + iphlen;
#ifdef CONFIG_IPSEC_ALG
		if ((ixt_a=IPSEC_ALG_SA_ESP_AUTH(tdbp))) {
			authlen = AHHMAC_HASHLEN;
			KLIPS_PRINT(debug_rcv,
					"klips_debug:ipsec_rcv: "
					"authalg=%d authlen=%d\n",
					tdbp->tdb_authalg, authlen);
		} else
#endif /* CONFIG_IPSEC_ALG */
		switch(tdbp->tdb_authalg) {
#ifdef CONFIG_IPSEC_AUTH_HMAC_MD5
		case AH_MD5:
			authlen = AHHMAC_HASHLEN;
			break;
#endif /* CONFIG_IPSEC_AUTH_HMAC_MD5 */
#ifdef CONFIG_IPSEC_AUTH_HMAC_SHA1
		case AH_SHA:
			authlen = AHHMAC_HASHLEN;
			break;
#endif /* CONFIG_IPSEC_AUTH_HMAC_SHA1 */
		case AH_NONE:
			authlen = 0;
			break;
		default:
			tdbp->tdb_alg_errs += 1;
			spin_unlock(&tdb_lock);
			if(stats) {
				stats->rx_errors++;
			}
			goto rcvleave;
		}
		ilen = len - iphlen - authlen;
		if(ilen <= 0) {
			spin_unlock(&tdb_lock);
			KLIPS_PRINT(debug_rcv,
				    "klips_debug:ipsec_rcv: "
				    "runt AH packet with no data, dropping.\n");
			if(stats) {
				stats->rx_dropped++;
			}
			goto rcvleave;
		}
		
#ifdef CONFIG_IPSEC_ESP
		KLIPS_PRINT(proto == IPPROTO_ESP && debug_rcv, 
			    "klips_debug:ipsec_rcv: "
			    "packet from %s received with seq=%d (iv)=0x%08x%08x iplen=%d esplen=%d sa=%s\n",
			    ipaddr_txt,
			    (__u32)ntohl(espp->esp_rpl),
			    (__u32)ntohl(*((__u32 *)(espp->esp_iv)    )),
			    (__u32)ntohl(*((__u32 *)(espp->esp_iv) + 1)),
			    len,
			    ilen,
			    sa_len ? sa : " (error)");
#endif /* !CONFIG_IPSEC_ESP */
		
		switch(proto) {
#ifdef CONFIG_IPSEC_ESP
		case IPPROTO_ESP:
			replay = ntohl(espp->esp_rpl);
			authenticator = &(dat[len - authlen]);
			break;
#endif /* !CONFIG_IPSEC_ESP */
#ifdef CONFIG_IPSEC_AH
		case IPPROTO_AH:
			replay = ntohl(ahp->ah_rpl);
			authenticator = ahp->ah_data;
			break;
#endif /* CONFIG_IPSEC_AH */
		}

		if (!ipsec_checkreplaywindow(tdbp, replay)) {
			tdbp->tdb_replaywin_errs += 1;
			spin_unlock(&tdb_lock);
			KLIPS_PRINT(debug_rcv & DB_RX_REPLAY,
				    "klips_debug:ipsec_rcv: "
				    "duplicate frame from %s, packet dropped\n",
				    ipaddr_txt);
			if(stats) {
				stats->rx_dropped++;
			}
			goto rcvleave;
		}
		
		/*
		 * verify authenticator
		 */
		
		KLIPS_PRINT(debug_rcv,
			    "klips_debug:ipsec_rcv: "
			    "encalg = %d, authalg = %d.\n",
			    tdbp->tdb_encalg,
			    tdbp->tdb_authalg);
		
#ifdef CONFIG_IPSEC_ALG
		if (ixt_a) {
			KLIPS_PRINT(debug_rcv,
					"klips_debug:ipsec_rcv: "
					"ipsec_alg hashing ... ");
			if(proto == IPPROTO_ESP) {
				ipsec_alg_sa_esp_hash(tdbp,
						(caddr_t)espp, ilen,
						hash, AHHMAC_HASHLEN);
#ifdef CONFIG_IPSEC_AH
#ifdef IPSEC_ALG_WHEN_AH_IS_READY
			} else {
				ipo = *ipp;
				ipo.tos = 0;
				ipo.frag_off = 0;
				ipo.ttl = 0;
				ipo.check = 0;

				ipsec_alg_hmac_update(tdbp->tdb_key_a,
						(caddr_t)&ipo, 
						sizeof(struct iphdr));
				ipsec_alg_hmac_update(tdbp->tdb_key_a,
						(caddr_t)ahp,
						ahhlen - AHHMAC_HASHLEN);
				ipsec_alg_hmac_update(tdbp->tdb_key_a,
						(caddr_t)zeroes,
						AHHMAC_HASHLEN);
				ipsec_alg_hmac_hash(tdbp->tdb_key_a,
						(caddr_t)dat + iphlen + ahhlen,
						len - iphlen - ahhlen,
						hash, AHHMAC_HASHLEN);
#endif
#endif /* CONFIG_IPSEC_AH */
			}
		} else
#endif /* CONFIG_IPSEC_ALG */
		if(tdbp->tdb_authalg) {
			switch(tdbp->tdb_authalg) {
#ifdef CONFIG_IPSEC_AUTH_HMAC_MD5
			case AH_MD5:
				tctx.md5 = ((struct md5_ctx*)(tdbp->tdb_key_a))->ictx;
				if(proto == IPPROTO_ESP) {
					MD5Update(&tctx.md5, (caddr_t)espp, ilen);
#ifdef CONFIG_IPSEC_AH
				} else {
					ipo = *ipp;
					ipo.tos = 0;	/* mutable RFC 2402 3.3.3.1.1.1 */
					ipo.frag_off = 0;
					ipo.ttl = 0;
					ipo.check = 0;
					
					MD5Update(&tctx.md5, (caddr_t)&ipo,
						  sizeof(struct iphdr));
					MD5Update(&tctx.md5, (caddr_t)ahp,
						  ahhlen - AHHMAC_HASHLEN);
					MD5Update(&tctx.md5, (caddr_t)zeroes,
						  AHHMAC_HASHLEN);
					MD5Update(&tctx.md5,
						  (caddr_t)dat + iphlen + ahhlen,
						  len - iphlen - ahhlen);
#endif /* CONFIG_IPSEC_AH */
				}
				MD5Final(hash, &tctx.md5);
				tctx.md5 = ((struct md5_ctx*)(tdbp->tdb_key_a))->octx;
				MD5Update(&tctx.md5, hash, AHMD596_ALEN);
				MD5Final(hash, &tctx.md5);
				break;
#endif /* CONFIG_IPSEC_AUTH_HMAC_MD5 */
#ifdef CONFIG_IPSEC_AUTH_HMAC_SHA1
			case AH_SHA:
				tctx.sha1 = ((struct sha1_ctx*)(tdbp->tdb_key_a))->ictx;
				if(proto == IPPROTO_ESP) {
					SHA1Update(&tctx.sha1, (caddr_t)espp, ilen);
#ifdef CONFIG_IPSEC_AH
				} else {
					ipo = *ipp;
					ipo.tos = 0;
					ipo.frag_off = 0;
					ipo.ttl = 0;
					ipo.check = 0;
					
					SHA1Update(&tctx.sha1, (caddr_t)&ipo,
						   sizeof(struct iphdr));
					SHA1Update(&tctx.sha1, (caddr_t)ahp,
						   ahhlen - AHHMAC_HASHLEN);
					SHA1Update(&tctx.sha1, (caddr_t)zeroes,
						   AHHMAC_HASHLEN);
					SHA1Update(&tctx.sha1,
						   (caddr_t)dat + iphlen + ahhlen,
						   len - iphlen - ahhlen);
#endif /* CONFIG_IPSEC_AH */
				}
				SHA1Final(hash, &tctx.sha1);
				tctx.sha1 = ((struct sha1_ctx*)(tdbp->tdb_key_a))->octx;
				SHA1Update(&tctx.sha1, hash, AHSHA196_ALEN);
				SHA1Final(hash, &tctx.sha1);
				break;
#endif /* CONFIG_IPSEC_AUTH_HMAC_SHA1 */
			case AH_NONE:
				break;
			}
		
			if(!authenticator) {
				tdbp->tdb_auth_errs += 1;
				spin_unlock(&tdb_lock);
				if(stats) {
					stats->rx_dropped++;
				}
				goto rcvleave;
			}

			if (memcmp(hash, authenticator, authlen)) {
				tdbp->tdb_auth_errs += 1;
				spin_unlock(&tdb_lock);
				KLIPS_PRINT(debug_rcv & DB_RX_INAU,
					    "klips_debug:ipsec_rcv: "
					    "auth failed on incoming packet from %s: hash=%08x%08x%08x auth=%08x%08x%08x, dropped\n",
					    ipaddr_txt,
					    *(__u32*)&hash[0],
					    *(__u32*)&hash[4],
					    *(__u32*)&hash[8],
					    *(__u32*)authenticator,
					    *((__u32*)authenticator + 1),
					    *((__u32*)authenticator + 2));
				if(stats) {
					stats->rx_dropped++;
				}
				goto rcvleave;
			} else {
				KLIPS_PRINT(debug_rcv,
					    "klips_debug:ipsec_rcv: "
					    "authentication successful.\n");
			}
			
			memset((caddr_t)&tctx, 0, sizeof(tctx));
			memset(hash, 0, sizeof(hash));
		}

		/* If the sequence number == 0, expire SA, it had rolled */
		if(tdbp->tdb_replaywin && !replay /* !tdbp->tdb_replaywin_lastseq */) {
			ipsec_sa_delchain(tdbp);
			spin_unlock(&tdb_lock);
			KLIPS_PRINT(debug_rcv,
				    "klips_debug:ipsec_rcv: "
				    "replay window counter rolled, expiring SA.\n");
			if(stats) {
				stats->rx_dropped++;
			}
			goto rcvleave;
		}

		if (!ipsec_updatereplaywindow(tdbp, replay)) {
			tdbp->tdb_replaywin_errs += 1;
			spin_unlock(&tdb_lock);
			KLIPS_PRINT(debug_rcv & DB_RX_REPLAY,
				    "klips_debug:ipsec_rcv: "
				    "duplicate frame from %s, packet dropped\n",
				    ipaddr_txt);
			if(stats) {
				stats->rx_dropped++;
			}
			goto rcvleave;
		}
		
		switch(proto) {
#ifdef CONFIG_IPSEC_ESP
		case IPPROTO_ESP:
#ifdef CONFIG_IPSEC_ALG
			if ((ixt_e=IPSEC_ALG_SA_ESP_ENC(tdbp))) {
				esphlen = ESP_HEADER_LEN + ixt_e->ixt_ivlen/8;
				KLIPS_PRINT(debug_rcv,
						"klips_debug:ipsec_rcv: "
						"encalg=%d esphlen=%d\n",
						tdbp->tdb_encalg, esphlen);
			} else
#endif /* CONFIG_IPSEC_ALG */
			switch(tdbp->tdb_encalg) {
#ifdef CONFIG_IPSEC_ENC_3DES
			case ESP_3DES:
				iv[0] = *((__u32 *)(espp->esp_iv)    );
				iv[1] = *((__u32 *)(espp->esp_iv) + 1);
				esphlen = sizeof(struct esp);
				break;
#endif /* CONFIG_IPSEC_ENC_3DES */
			default:
				tdbp->tdb_alg_errs += 1;
				spin_unlock(&tdb_lock);
				if(stats) {
					stats->rx_errors++;
				}
				goto rcvleave;
			}
			idat += esphlen;
			ilen -= esphlen;
			
#ifdef CONFIG_IPSEC_ALG
			if (ixt_e)
			{
				if (ipsec_alg_esp_encrypt(tdbp, 
					idat, ilen, espp->esp_iv, 
					IPSEC_ALG_DECRYPT) <= 0)
				{
					spin_unlock(&tdb_lock);
					printk("klips_error:ipsec_rcv: "
						"got packet with esplen = %d "
						"from %s -- should be on "
						"ENC(%d) octet boundary, "
						"packet dropped\n",
							ilen,
							ipaddr_txt,
							tdbp->tdb_encalg);
					stats->rx_errors++;
					goto rcvleave;
				}
			} else
#endif /* CONFIG_IPSEC_ALG */
			switch(tdbp->tdb_encalg) {
#ifdef CONFIG_IPSEC_ENC_3DES
			case ESP_3DES:
				if ((ilen) % 8) {
					tdbp->tdb_encsize_errs += 1;
					spin_unlock(&tdb_lock);
					printk("klips_error:ipsec_rcv: "
					       "got packet with esplen = %d from %s -- should be on 8 octet boundary, packet dropped\n",
					       ilen,
					       ipaddr_txt);
					if(stats) {
						stats->rx_errors++;
					}
					goto rcvleave;
				}
				des_ede3_cbc_encrypt((des_cblock *)idat,
						     (des_cblock *)idat,
						     ilen,
						     ((struct des_eks *)(tdbp->tdb_key_e))[0].ks,
						     ((struct des_eks *)(tdbp->tdb_key_e))[1].ks,
						     ((struct des_eks *)(tdbp->tdb_key_e))[2].ks,
						     (des_cblock *)iv, 0);
				break;
#endif /* CONFIG_IPSEC_ENC_3DES */
			default:
			}
			next_header = idat[ilen - 1];
			padlen = idat[ilen - 2];
			pad = padlen + 2 + authlen;
			{
			        int badpad = 0;
				
				KLIPS_PRINT(debug_rcv & DB_RX_IPAD,
					    "klips_debug:ipsec_rcv: "
					    "padlen=%d, contents: 0x<offset>: 0x<value> 0x<value> ...\n",
					    padlen);
				
				for (i = 1; i <= padlen; i++) {
					if((i % 16) == 1) {
						KLIPS_PRINT(debug_rcv & DB_RX_IPAD,
							    "klips_debug:           %02x:",
							    i - 1);
					}
					KLIPS_PRINTMORE(debug_rcv & DB_RX_IPAD,
						    " %02x",
						    idat[ilen - 2 - padlen + i - 1]);