Small summary ------------- o Almost all IPsec releated code was moved into sys/netipsec. o New kernel modules added: ipsec.ko and tcpmd5.ko. New kernel option IPSEC_SUPPORT added. It enables support for loading and unloading of ipsec.ko and tcpmd5.ko kernel modules. o IPSEC_NAT_T option was removed. Now NAT-T support is enabled by default. The UDP_ENCAP_ESPINUDP_NON_IKE encapsulation type support was removed. Added TCP/UDP checksum handling for inbound packets that were decapsulated by transport mode SAs. setkey(8) modified to show run-time NAT-T configuration of SA. o New network pseudo interface if_ipsec(4) added. For now it is build as part of ipsec.ko module (or with IPSEC kernel). It implements IPsec virtual tunnels to create route-based VPNs. o The network stack now invokes IPsec functions using special methods. The only one header file <netipsec/ipsec_support.h> should be included to declare all the needed things to work with IPsec. o All IPsec protocols handlers (ESP/AH/IPCOMP protosw) were removed. Now these protocols are handled directly via IPsec methods. o TCP_SIGNATURE support was reworked to be more close to RFC. o PF_KEY SADB was reworked: - now all security associations stored in the single SPI namespace, and all SAs MUST have unique SPI. - several hash tables added to speed up lookups in SADB. - SADB now uses rmlock to protect access, and concurrent threads can do SA lookups in the same time. - many PF_KEY message handlers were reworked to reflect changes in SADB. - SADB_UPDATE message was extended to support new PF_KEY headers: SADB_X_EXT_NEW_ADDRESS_SRC and SADB_X_EXT_NEW_ADDRESS_DST. They can be used by IKE daemon to change SA addresses. o ipsecrequest and secpolicy structures were cardinally changed to avoid locking protection for ipsecrequest. Now we support only limited number (4) of bundled SAs, but they are supported for both INET and INET6. o INPCB security policy cache was introduced. Each PCB now caches used security policies to avoid SP lookup for each packet. o For inbound security policies added the mode, when the kernel does check for full history of applied IPsec transforms. o References counting rules for security policies and security associations were changed. The proper SA locking added into xform code. o xform code was also changed. Now it is possible to unregister xforms. tdb_xxx structures were changed and renamed to reflect changes in SADB/SPDB, and changed rules for locking and refcounting. Reviewed by: gnn, wblock Obtained from: Yandex LLC Relnotes: yes Sponsored by: Yandex LLC Differential Revision: https://reviews.freebsd.org/D9352
295 lines
7.5 KiB
C
295 lines
7.5 KiB
C
/*-
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* Copyright (c) 2016 Andrey V. Elsukov <ae@FreeBSD.org>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include "opt_inet.h"
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#include "opt_ipsec.h"
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/kernel.h>
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#include <sys/lock.h>
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#include <sys/mbuf.h>
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#include <sys/protosw.h>
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#include <sys/socket.h>
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#include <sys/sockopt.h>
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#include <sys/sysctl.h>
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#include <netinet/in.h>
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#include <netinet/in_pcb.h>
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#include <netinet/in_systm.h>
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#include <netinet/ip.h>
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#include <netinet/ip_var.h>
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#include <netinet/tcp.h>
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#include <netinet/udp.h>
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#include <netinet/udp_var.h>
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#include <net/vnet.h>
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#include <netipsec/ipsec.h>
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#include <netipsec/esp.h>
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#include <netipsec/esp_var.h>
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#include <netipsec/xform.h>
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#include <netipsec/key.h>
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#include <netipsec/key_debug.h>
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#include <netipsec/ipsec_support.h>
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#include <machine/in_cksum.h>
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/*
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* Handle UDP_ENCAP socket option. Always return with released INP_WLOCK.
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*/
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int
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udp_ipsec_pcbctl(struct inpcb *inp, struct sockopt *sopt)
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{
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struct udpcb *up;
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int error, optval;
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INP_WLOCK_ASSERT(inp);
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if (sopt->sopt_name != UDP_ENCAP) {
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INP_WUNLOCK(inp);
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return (ENOPROTOOPT);
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}
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up = intoudpcb(inp);
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if (sopt->sopt_dir == SOPT_GET) {
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if (up->u_flags & UF_ESPINUDP)
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optval = UDP_ENCAP_ESPINUDP;
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else
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optval = 0;
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INP_WUNLOCK(inp);
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return (sooptcopyout(sopt, &optval, sizeof(optval)));
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}
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INP_WUNLOCK(inp);
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error = sooptcopyin(sopt, &optval, sizeof(optval), sizeof(optval));
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if (error != 0)
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return (error);
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INP_WLOCK(inp);
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switch (optval) {
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case 0:
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up->u_flags &= ~UF_ESPINUDP;
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break;
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case UDP_ENCAP_ESPINUDP:
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up->u_flags |= UF_ESPINUDP;
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break;
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default:
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error = EINVAL;
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}
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INP_WUNLOCK(inp);
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return (error);
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}
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/*
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* Potentially decap ESP in UDP frame. Check for an ESP header.
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* If present, strip the UDP header and push the result through IPSec.
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*
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* Returns error if mbuf consumed and/or processed, otherwise 0.
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*/
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int
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udp_ipsec_input(struct mbuf *m, int off, int af)
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{
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union sockaddr_union dst;
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struct secasvar *sav;
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struct udphdr *udp;
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struct ip *ip;
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uint32_t spi;
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int error, hlen;
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/*
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* Just return if packet doesn't have enough data.
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* We need at least [IP header + UDP header + ESP header].
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* NAT-Keepalive packet has only one byte of payload, so it
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* by default will not be processed.
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*/
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if (m->m_pkthdr.len < off + sizeof(struct esp))
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return (0);
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m_copydata(m, off, sizeof(uint32_t), (caddr_t)&spi);
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if (spi == 0) /* Non-ESP marker. */
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return (0);
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/*
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* Find SA and check that it is configured for UDP
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* encapsulation.
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*/
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bzero(&dst, sizeof(dst));
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dst.sa.sa_family = af;
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switch (af) {
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#ifdef INET
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case AF_INET:
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dst.sin.sin_len = sizeof(struct sockaddr_in);
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ip = mtod(m, struct ip *);
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ip->ip_p = IPPROTO_ESP;
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off = offsetof(struct ip, ip_p);
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hlen = ip->ip_hl << 2;
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dst.sin.sin_addr = ip->ip_dst;
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break;
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#endif
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#ifdef INET6
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case AF_INET6:
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/* Not yet */
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/* FALLTHROUGH */
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#endif
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default:
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ESPSTAT_INC(esps_nopf);
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m_freem(m);
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return (EPFNOSUPPORT);
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}
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sav = key_allocsa(&dst, IPPROTO_ESP, spi);
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if (sav == NULL) {
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ESPSTAT_INC(esps_notdb);
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m_freem(m);
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return (ENOENT);
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}
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udp = mtodo(m, hlen);
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if (sav->natt == NULL ||
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sav->natt->sport != udp->uh_sport ||
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sav->natt->dport != udp->uh_dport) {
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/* XXXAE: should we check source address? */
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ESPSTAT_INC(esps_notdb);
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key_freesav(&sav);
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m_freem(m);
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return (ENOENT);
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}
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/*
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* Remove the UDP header
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* Before:
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* <--- off --->
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* +----+------+-----+
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* | IP | UDP | ESP |
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* +----+------+-----+
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* <-skip->
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* After:
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* +----+-----+
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* | IP | ESP |
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* +----+-----+
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* <-skip->
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*/
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m_striphdr(m, hlen, sizeof(*udp));
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/*
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* We cannot yet update the cksums so clear any h/w cksum flags
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* as they are no longer valid.
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*/
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if (m->m_pkthdr.csum_flags & CSUM_DATA_VALID)
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m->m_pkthdr.csum_flags &= ~(CSUM_DATA_VALID | CSUM_PSEUDO_HDR);
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/*
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* We can update ip_len and ip_sum here, but ipsec4_input_cb()
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* will do this anyway, so don't touch them here.
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*/
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ESPSTAT_INC(esps_input);
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error = (*sav->tdb_xform->xf_input)(m, sav, hlen, off);
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if (error != 0)
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key_freesav(&sav);
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return (EINPROGRESS); /* Consumed by IPsec. */
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}
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int
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udp_ipsec_output(struct mbuf *m, struct secasvar *sav)
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{
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struct udphdr *udp;
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struct mbuf *n;
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struct ip *ip;
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int hlen, off;
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IPSEC_ASSERT(sav->natt != NULL, ("UDP encapsulation isn't required."));
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if (sav->sah->saidx.dst.sa.sa_family == AF_INET6)
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return (EAFNOSUPPORT);
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ip = mtod(m, struct ip *);
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hlen = ip->ip_hl << 2;
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n = m_makespace(m, hlen, sizeof(*udp), &off);
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if (n == NULL) {
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DPRINTF(("%s: m_makespace for udphdr failed\n", __func__));
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return (ENOBUFS);
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}
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udp = mtodo(n, off);
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udp->uh_dport = sav->natt->dport;
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udp->uh_sport = sav->natt->sport;
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udp->uh_sum = 0;
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udp->uh_ulen = htons(m->m_pkthdr.len - hlen);
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ip = mtod(m, struct ip *);
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ip->ip_len = htons(m->m_pkthdr.len);
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ip->ip_p = IPPROTO_UDP;
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return (0);
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}
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void
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udp_ipsec_adjust_cksum(struct mbuf *m, struct secasvar *sav, int proto,
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int skip)
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{
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struct ip *ip;
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uint16_t cksum, off;
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IPSEC_ASSERT(sav->natt != NULL, ("NAT-T isn't required"));
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IPSEC_ASSERT(proto == IPPROTO_UDP || proto == IPPROTO_TCP,
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("unexpected protocol %u", proto));
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if (proto == IPPROTO_UDP)
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off = offsetof(struct udphdr, uh_sum);
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else
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off = offsetof(struct tcphdr, th_sum);
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if (V_natt_cksum_policy == 0) { /* auto */
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if (sav->natt->cksum != 0) {
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/* Incrementally recompute. */
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m_copydata(m, skip + off, sizeof(cksum),
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(caddr_t)&cksum);
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cksum = in_addword(cksum, sav->natt->cksum);
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} else {
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/* No OA from IKEd. */
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if (proto == IPPROTO_TCP) {
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/* Ignore for TCP. */
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m->m_pkthdr.csum_data = 0xffff;
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m->m_pkthdr.csum_flags |= (CSUM_DATA_VALID |
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CSUM_PSEUDO_HDR);
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return;
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}
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cksum = 0; /* Reset for UDP. */
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}
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m_copyback(m, skip + off, sizeof(cksum), (caddr_t)&cksum);
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} else { /* Fully recompute */
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ip = mtod(m, struct ip *);
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cksum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr,
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htons(m->m_pkthdr.len - skip + proto));
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m_copyback(m, skip + off, sizeof(cksum), (caddr_t)&cksum);
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m->m_pkthdr.csum_flags =
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(proto == IPPROTO_UDP) ? CSUM_UDP: CSUM_TCP;
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m->m_pkthdr.csum_data = off;
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in_delayed_cksum(m);
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m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
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}
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}
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