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|
/* $OpenBSD: ip_esp3des.c,v 1.4 1997/06/24 12:15:22 provos Exp $ */
/*
* The author of this code is John Ioannidis, ji@tla.org,
* (except when noted otherwise).
*
* This code was written for BSD/OS in Athens, Greece, in November 1995.
*
* Ported to OpenBSD and NetBSD, with additional transforms, in December 1996,
* by Angelos D. Keromytis, kermit@forthnet.gr.
*
* Copyright (C) 1995, 1996, 1997 by John Ioannidis and Angelos D. Keromytis.
*
* Permission to use, copy, and modify this software without fee
* is hereby granted, provided that this entire notice is included in
* all copies of any software which is or includes a copy or
* modification of this software.
*
* THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR
* IMPLIED WARRANTY. IN PARTICULAR, NEITHER AUTHOR MAKES ANY
* REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE
* MERCHANTABILITY OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR
* PURPOSE.
*/
/*
* 3DES-CBC
* Per RFC1851 (Metzger & Simpson, 1995)
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/domain.h>
#include <sys/protosw.h>
#include <sys/socket.h>
#include <sys/errno.h>
#include <sys/time.h>
#include <sys/kernel.h>
#include <machine/cpu.h>
#include <net/if.h>
#include <net/route.h>
#include <net/netisr.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/in_pcb.h>
#include <netinet/in_var.h>
#include <netinet/ip_var.h>
#include <sys/socketvar.h>
#include <net/raw_cb.h>
#include <net/encap.h>
#include <netinet/ip_icmp.h>
#include <netinet/ip_ipsp.h>
#include <netinet/ip_esp.h>
#include <dev/rndvar.h>
extern struct ifnet loif;
extern void des_ecb3_encrypt(caddr_t, caddr_t, caddr_t, caddr_t, caddr_t, int);
extern void des_set_key(caddr_t, caddr_t);
int
esp3des_attach()
{
return 0;
}
/*
* esp3des_init() is called when an SPI is being set up. It interprets the
* encap_msghdr present in m, and sets up the transformation data, in
* this case, the encryption and decryption key schedules
*/
int
esp3des_init(struct tdb *tdbp, struct xformsw *xsp, struct mbuf *m)
{
struct esp3des_xdata *xd;
struct encap_msghdr *em;
u_int32_t rk[2];
tdbp->tdb_xform = xsp;
m = m_pullup(m, ESP_ULENGTH);
if (m == NULL)
{
#ifdef ENCDEBUG
if (encdebug)
printf("esp3des_init: can't pull up %d bytes\n",
ESP_ULENGTH);
#endif ENCDEBUG
return ENOBUFS;
}
MALLOC(tdbp->tdb_xdata, caddr_t, sizeof (struct esp3des_xdata),
M_XDATA, M_WAITOK);
if (tdbp->tdb_xdata == NULL)
return ENOBUFS;
bzero(tdbp->tdb_xdata, sizeof (struct esp3des_xdata));
xd = (struct esp3des_xdata *)tdbp->tdb_xdata;
em = mtod(m, struct encap_msghdr *);
if (em->em_msglen - EMT_SETSPI_FLEN != ESP_ULENGTH)
{
free((caddr_t)tdbp->tdb_xdata, M_XDATA);
tdbp->tdb_xdata = NULL;
return EINVAL;
}
m_copydata(m, EMT_SETSPI_FLEN, ESP_ULENGTH, (caddr_t)xd);
rk[0] = xd->edx_eks[0][0][0]; /* some overloading doesn't hurt */
rk[1] = xd->edx_eks[0][0][1]; /* XXX -- raw-major order */
des_set_key((caddr_t)rk, (caddr_t)(xd->edx_eks[0]));
rk[0] = xd->edx_eks[1][0][0];
rk[1] = xd->edx_eks[1][0][1];
des_set_key((caddr_t)rk, (caddr_t)(xd->edx_eks[1]));
rk[0] = xd->edx_eks[2][0][0];
rk[1] = xd->edx_eks[2][0][1];
des_set_key((caddr_t)rk, (caddr_t)(xd->edx_eks[2]));
rk[0] = rk[1] = 0; /* zeroize! */
return 0;
}
int
esp3des_zeroize(struct tdb *tdbp)
{
FREE(tdbp->tdb_xdata, M_XDATA);
return 0;
}
struct mbuf *
esp3des_input(struct mbuf *m, struct tdb *tdb)
{
struct esp3des_xdata *xd;
struct ip *ip, ipo;
u_char iv[8], niv[8], blk[8];
u_char *idat, *odat;
struct esp *esp;
struct ifnet *rcvif;
int ohlen, plen, ilen, olen, i;
struct mbuf *mi, *mo;
xd = (struct esp3des_xdata *)tdb->tdb_xdata;
ohlen = sizeof (struct ip) + ESP_FLENGTH;
rcvif = m->m_pkthdr.rcvif;
if (rcvif == NULL)
{
#ifdef ENCDEBUG
if (encdebug)
printf("esp3des_input: receive interface is NULL!!!\n");
#endif ENCDEBUG
rcvif = &loif;
}
ip = mtod(m, struct ip *);
ipo = *ip;
esp = (struct esp *)(ip + 1);
plen = m->m_pkthdr.len - sizeof (struct ip) - sizeof (u_int32_t) -
xd->edx_ivlen;
if (plen & 07)
{
#ifdef ENCDEBUG
if (encdebug)
printf("esp3des_input: payload not a multiple of 8 octets\n");
#endif ENCDEBUG
espstat.esps_badilen++;
m_freem(m);
return NULL;
}
ilen = m->m_len - sizeof (struct ip) - 8;
idat = mtod(m, unsigned char *) + sizeof (struct ip) + 8;
iv[0] = esp->esp_iv[0];
iv[1] = esp->esp_iv[1];
iv[2] = esp->esp_iv[2];
iv[3] = esp->esp_iv[3];
if (xd->edx_ivlen == 4)
{
iv[4] = ~esp->esp_iv[0];
iv[5] = ~esp->esp_iv[1];
iv[6] = ~esp->esp_iv[2];
iv[7] = ~esp->esp_iv[3];
}
else
{
iv[4] = esp->esp_iv[4];
iv[5] = esp->esp_iv[5];
iv[6] = esp->esp_iv[6];
iv[7] = esp->esp_iv[7];
ilen -= 4;
idat += 4;
}
olen = ilen;
odat = idat;
mi = mo = m;
i = 0;
/*
* At this point:
* plen is # of encapsulated payload octets
* ilen is # of octets left in this mbuf
* idat is first encapsulated payload octed in this mbuf
* same for olen and odat
* iv contains the IV.
* mi and mo point to the first mbuf
*
* From now on until the end of the mbuf chain:
* . move the next eight octets of the chain into blk[]
* (ilen, idat, and mi are adjusted accordingly)
* and save it back into iv[]
* . decrypt blk[], xor with iv[], put back into chain
* (olen, odat, amd mo are adjusted accordingly)
* . repeat
*/
while (plen > 0) /* while not done */
{
while (ilen == 0) /* we exhausted previous mbuf */
{
mi = mi->m_next;
if (mi == NULL)
panic("esp3des_input: bad chain (i)\n");
ilen = mi->m_len;
idat = (u_char *)mi->m_data;
}
blk[i] = niv[i] = *idat++;
i++;
ilen--;
if (i == 8)
{
des_ecb3_encrypt(blk, blk, (caddr_t)(xd->edx_eks[2]),
(caddr_t)(xd->edx_eks[1]),
(caddr_t)(xd->edx_eks[0]), 0);
for (i=0; i<8; i++)
{
while (olen == 0)
{
mo = mo->m_next;
if (mo == NULL)
panic("esp3des_input: bad chain (o)\n");
olen = mo->m_len;
odat = (u_char *)mo->m_data;
}
*odat = blk[i] ^ iv[i];
iv[i] = niv[i];
blk[i] = *odat++; /* needed elsewhere */
olen--;
}
i = 0;
}
plen--;
}
/*
* Now, the entire chain has been decrypted. As a side effect,
* blk[7] contains the next protocol, and blk[6] contains the
* amount of padding the original chain had. Chop off the
* appropriate parts of the chain, and return.
*/
m_adj(m, -blk[6] - 2);
m_adj(m, 4 + xd->edx_ivlen);
if (m->m_len < sizeof (struct ip))
{
m = m_pullup(m, sizeof (struct ip));
if (m == NULL)
{
return NULL;
}
}
ip = mtod(m, struct ip *);
ipo.ip_p = blk[7];
ipo.ip_id = htons(ipo.ip_id);
ipo.ip_off = 0;
ipo.ip_len += sizeof (struct ip) - 4 - xd->edx_ivlen - blk[6] - 2;
ipo.ip_len = htons(ipo.ip_len);
ipo.ip_sum = 0;
*ip = ipo;
ip->ip_sum = in_cksum(m, sizeof (struct ip));
/* Update the counters */
tdb->tdb_packets++;
tdb->tdb_bytes += NTOHS(ip->ip_len) - (ip->ip_hl << 2) + blk[6] + 2;
return m;
}
int
esp3des_output(struct mbuf *m, struct sockaddr_encap *gw, struct tdb *tdb, struct mbuf **mp)
{
struct esp3des_xdata *xd;
struct ip *ip, ipo;
int i, ilen, olen, ohlen, nh, rlen, plen, padding;
u_int32_t spi;
struct mbuf *mi, *mo;
u_char *pad, *idat, *odat;
u_char iv[8], blk[8], opts[40];
int iphlen;
espstat.esps_output++;
m = m_pullup(m, sizeof (struct ip));
if (m == NULL)
return ENOBUFS;
ip = mtod(m, struct ip *);
spi = tdb->tdb_spi;
iphlen = ip->ip_hl << 2;
/*
* If options are present, pullup the IP header, the options
* and one DES block (8 bytes) of data.
*/
if (iphlen != sizeof(struct ip))
{
m = m_pullup(m, iphlen + 8);
if (m == NULL)
return ENOBUFS;
ip = mtod(m, struct ip *);
/* Keep the options */
bcopy(mtod(m, u_char *) + sizeof(struct ip), opts,
iphlen - sizeof(struct ip));
}
xd = (struct esp3des_xdata *)tdb->tdb_xdata;
ilen = ntohs(ip->ip_len);
ohlen = sizeof (u_int32_t) + xd->edx_ivlen;
ipo = *ip;
nh = ipo.ip_p;
rlen = ilen - iphlen; /* raw payload length */
padding = ((8 - ((rlen + 2) % 8)) % 8) + 2;
pad = (u_char *)m_pad(m, padding);
if (pad == NULL)
return ENOBUFS;
pad[padding-2] = padding - 2;
pad[padding-1] = nh;
plen = rlen + padding;
mi = mo = m;
ilen = olen = m->m_len - iphlen;
idat = odat = mtod(m, u_char *) + iphlen;
i = 0;
/*
* We are now ready to encrypt the payload.
*/
xd->edx_ivl++;
iv[0] = xd->edx_iv[0];
iv[1] = xd->edx_iv[1];
iv[2] = xd->edx_iv[2];
iv[3] = xd->edx_iv[3];
if (xd->edx_ivlen == 4)
{
iv[4] = ~xd->edx_iv[0];
iv[5] = ~xd->edx_iv[1];
iv[6] = ~xd->edx_iv[2];
iv[7] = ~xd->edx_iv[3];
}
else
{
iv[4] = xd->edx_iv[4];
iv[5] = xd->edx_iv[5];
iv[6] = xd->edx_iv[6];
iv[7] = xd->edx_iv[7];
}
while (plen > 0) /* while not done */
{
while (ilen == 0) /* we exhausted previous mbuf */
{
mi = mi->m_next;
if (mi == NULL)
panic("esp3des_output: bad chain (i)\n");
ilen = mi->m_len;
idat = (u_char *)mi->m_data;
}
blk[i] = *idat++ ^ iv[i];
i++;
ilen--;
if (i == 8)
{
des_ecb3_encrypt(blk, blk, (caddr_t)(xd->edx_eks[0]),
(caddr_t)(xd->edx_eks[1]),
(caddr_t)(xd->edx_eks[2]), 1);
for (i = 0; i < 8; i++)
{
while (olen == 0)
{
mo = mo->m_next;
if (mo == NULL)
panic("esp3des_output: bad chain (o)\n");
olen = mo->m_len;
odat = (u_char *)mo->m_data;
}
*odat++ = blk[i];
iv[i] = blk[i];
olen--;
}
i = 0;
}
plen--;
}
/*
* Done with encryption. Let's wedge in the ESP header
* and send it out.
*/
M_PREPEND(m, ohlen, M_DONTWAIT);
if (m == NULL)
return ENOBUFS;
m = m_pullup(m, iphlen + ohlen);
if (m == NULL)
return ENOBUFS;
ipo.ip_len = htons(iphlen + ohlen + rlen + padding);
ipo.ip_p = IPPROTO_ESP;
iv[0] = xd->edx_iv[0];
iv[1] = xd->edx_iv[1];
iv[2] = xd->edx_iv[2];
iv[3] = xd->edx_iv[3];
if (xd->edx_ivlen == 8)
{
iv[4] = xd->edx_iv[4];
iv[5] = xd->edx_iv[5];
iv[6] = xd->edx_iv[6];
iv[7] = xd->edx_iv[7];
}
bcopy((caddr_t)&ipo, mtod(m, caddr_t), sizeof (struct ip));
/* Copy options, if existing */
if (iphlen != sizeof(struct ip))
bcopy(opts, mtod(m, caddr_t) + sizeof(struct ip),
iphlen - sizeof(struct ip));
bcopy((caddr_t)&spi, mtod(m, caddr_t) + sizeof(struct ip),
sizeof (u_int32_t));
bcopy((caddr_t)iv, mtod(m, caddr_t) + sizeof(struct ip) +
sizeof (u_int32_t), xd->edx_ivlen);
*mp = m;
/* Update the counters */
tdb->tdb_packets++;
tdb->tdb_bytes += rlen + padding;
return 0;
}
|