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NetBSD/dist/ipf/ip_scan.c

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/* $NetBSD: ip_scan.c,v 1.2 2007/06/16 10:52:25 martin Exp $ */
/*
* Copyright (C) 1995-2001 by Darren Reed.
*
* See the IPFILTER.LICENCE file for details on licencing.
*/
#if defined(KERNEL) || defined(_KERNEL)
# undef KERNEL
# undef _KERNEL
# define KERNEL 1
# define _KERNEL 1
#endif
#include <sys/param.h>
#if defined(__hpux) && (HPUXREV >= 1111) && !defined(_KERNEL)
# include <sys/kern_svcs.h>
#endif
#include <sys/types.h>
#include <sys/time.h>
#include <sys/errno.h>
#if !defined(_KERNEL)
# include <stdlib.h>
# include <string.h>
# define _KERNEL
# ifdef __OpenBSD__
struct file;
# endif
# include <sys/uio.h>
# undef _KERNEL
#else
# include <sys/systm.h>
# if !defined(__svr4__) && !defined(__SVR4)
# include <sys/mbuf.h>
# endif
#endif
#include <sys/socket.h>
#if !defined(__hpux) && !defined(__osf__) && !defined(linux) && !defined(AIX)
# include <sys/ioccom.h>
#endif
#ifdef __FreeBSD__
# include <sys/filio.h>
# include <sys/malloc.h>
#else
# include <sys/ioctl.h>
#endif
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/tcp.h>
#include <net/if.h>
#include "netinet/ip_compat.h"
#include "netinet/ip_fil.h"
#include "netinet/ip_state.h"
#include "netinet/ip_scan.h"
/* END OF INCLUDES */
#if !defined(lint)
static const char sccsid[] = "@(#)ip_state.c 1.8 6/5/96 (C) 1993-2000 Darren Reed";
static const char rcsid[] = "@(#)Id: ip_scan.c,v 2.40.2.9 2007/03/13 09:42:05 darrenr Exp";
#endif
#ifdef IPFILTER_SCAN /* endif at bottom of file */
ipscan_t *ipsc_list = NULL,
*ipsc_tail = NULL;
ipscanstat_t ipsc_stat;
# ifdef USE_MUTEXES
ipfrwlock_t ipsc_rwlock;
# endif
# ifndef isalpha
# define isalpha(x) (((x) >= 'A' && 'Z' >= (x)) || \
((x) >= 'a' && 'z' >= (x)))
# endif
int ipsc_add __P((caddr_t));
int ipsc_delete __P((caddr_t));
struct ipscan *ipsc_lookup __P((char *));
int ipsc_matchstr __P((sinfo_t *, char *, int));
int ipsc_matchisc __P((ipscan_t *, ipstate_t *, int, int, int *));
int ipsc_match __P((ipstate_t *));
static int ipsc_inited = 0;
int ipsc_init()
{
RWLOCK_INIT(&ipsc_rwlock, "ip scan rwlock");
ipsc_inited = 1;
return 0;
}
void fr_scanunload()
{
if (ipsc_inited == 1) {
RW_DESTROY(&ipsc_rwlock);
ipsc_inited = 0;
}
}
int ipsc_add(data)
caddr_t data;
{
ipscan_t *i, *isc;
int err;
KMALLOC(isc, ipscan_t *);
if (!isc)
return ENOMEM;
err = copyinptr(data, isc, sizeof(*isc));
if (err) {
KFREE(isc);
return err;
}
WRITE_ENTER(&ipsc_rwlock);
i = ipsc_lookup(isc->ipsc_tag);
if (i) {
RWLOCK_EXIT(&ipsc_rwlock);
KFREE(isc);
return EEXIST;
}
if (ipsc_tail) {
ipsc_tail->ipsc_next = isc;
isc->ipsc_pnext = &ipsc_tail->ipsc_next;
ipsc_tail = isc;
} else {
ipsc_list = isc;
ipsc_tail = isc;
isc->ipsc_pnext = &ipsc_list;
}
isc->ipsc_next = NULL;
isc->ipsc_hits = 0;
isc->ipsc_fref = 0;
isc->ipsc_sref = 0;
isc->ipsc_active = 0;
ipsc_stat.iscs_entries++;
RWLOCK_EXIT(&ipsc_rwlock);
return 0;
}
int ipsc_delete(data)
caddr_t data;
{
ipscan_t isc, *i;
int err;
err = copyinptr(data, &isc, sizeof(isc));
if (err)
return err;
WRITE_ENTER(&ipsc_rwlock);
i = ipsc_lookup(isc.ipsc_tag);
if (i == NULL)
err = ENOENT;
else {
if (i->ipsc_fref) {
RWLOCK_EXIT(&ipsc_rwlock);
return EBUSY;
}
*i->ipsc_pnext = i->ipsc_next;
if (i->ipsc_next)
i->ipsc_next->ipsc_pnext = i->ipsc_pnext;
else {
if (i->ipsc_pnext == &ipsc_list)
ipsc_tail = NULL;
else
ipsc_tail = *(*i->ipsc_pnext)->ipsc_pnext;
}
ipsc_stat.iscs_entries--;
KFREE(i);
}
RWLOCK_EXIT(&ipsc_rwlock);
return err;
}
struct ipscan *ipsc_lookup(tag)
char *tag;
{
ipscan_t *i;
for (i = ipsc_list; i; i = i->ipsc_next)
if (!strcmp(i->ipsc_tag, tag))
return i;
return NULL;
}
int ipsc_attachfr(fr)
struct frentry *fr;
{
ipscan_t *i;
if (fr->fr_isctag[0]) {
READ_ENTER(&ipsc_rwlock);
i = ipsc_lookup(fr->fr_isctag);
if (i != NULL) {
ATOMIC_INC32(i->ipsc_fref);
}
RWLOCK_EXIT(&ipsc_rwlock);
if (i == NULL)
return ENOENT;
fr->fr_isc = i;
}
return 0;
}
int ipsc_attachis(is)
struct ipstate *is;
{
frentry_t *fr;
ipscan_t *i;
READ_ENTER(&ipsc_rwlock);
fr = is->is_rule;
if (fr) {
i = fr->fr_isc;
if ((i != NULL) && (i != (ipscan_t *)-1)) {
is->is_isc = i;
ATOMIC_INC32(i->ipsc_sref);
if (i->ipsc_clen)
is->is_flags |= IS_SC_CLIENT;
else
is->is_flags |= IS_SC_MATCHC;
if (i->ipsc_slen)
is->is_flags |= IS_SC_SERVER;
else
is->is_flags |= IS_SC_MATCHS;
}
}
RWLOCK_EXIT(&ipsc_rwlock);
return 0;
}
int ipsc_detachfr(fr)
struct frentry *fr;
{
ipscan_t *i;
i = fr->fr_isc;
if (i != NULL) {
ATOMIC_DEC32(i->ipsc_fref);
}
return 0;
}
int ipsc_detachis(is)
struct ipstate *is;
{
ipscan_t *i;
READ_ENTER(&ipsc_rwlock);
if ((i = is->is_isc) && (i != (ipscan_t *)-1)) {
ATOMIC_DEC32(i->ipsc_sref);
is->is_isc = NULL;
is->is_flags &= ~(IS_SC_CLIENT|IS_SC_SERVER);
}
RWLOCK_EXIT(&ipsc_rwlock);
return 0;
}
/*
* 'string' compare for scanning
*/
int ipsc_matchstr(sp, str, n)
sinfo_t *sp;
char *str;
int n;
{
char *s, *t, *up;
int i = n;
if (i > sp->s_len)
i = sp->s_len;
up = str;
for (s = sp->s_txt, t = sp->s_msk; i; i--, s++, t++, up++)
switch ((int)*t)
{
case '.' :
if (*s != *up)
return 1;
break;
case '?' :
if (!ISALPHA(*up) || ((*s & 0x5f) != (*up & 0x5f)))
return 1;
break;
case '*' :
break;
}
return 0;
}
/*
* Returns 3 if both server and client match, 2 if just server,
* 1 if just client
*/
int ipsc_matchisc(isc, is, cl, sl, maxm)
ipscan_t *isc;
ipstate_t *is;
int cl, sl, maxm[2];
{
int i, j, k, n, ret = 0, flags;
flags = is->is_flags;
/*
* If we've already matched more than what is on offer, then
* assume we have a better match already and forget this one.
*/
if (maxm != NULL) {
if (isc->ipsc_clen < maxm[0])
return 0;
if (isc->ipsc_slen < maxm[1])
return 0;
j = maxm[0];
k = maxm[1];
} else {
j = 0;
k = 0;
}
if (!isc->ipsc_clen)
ret = 1;
else if (((flags & (IS_SC_MATCHC|IS_SC_CLIENT)) == IS_SC_CLIENT) &&
cl && isc->ipsc_clen) {
i = 0;
n = MIN(cl, isc->ipsc_clen);
if ((n > 0) && (!maxm || (n >= maxm[1]))) {
if (!ipsc_matchstr(&isc->ipsc_cl, is->is_sbuf[0], n)) {
i++;
ret |= 1;
if (n > j)
j = n;
}
}
}
if (!isc->ipsc_slen)
ret |= 2;
else if (((flags & (IS_SC_MATCHS|IS_SC_SERVER)) == IS_SC_SERVER) &&
sl && isc->ipsc_slen) {
i = 0;
n = MIN(cl, isc->ipsc_slen);
if ((n > 0) && (!maxm || (n >= maxm[1]))) {
if (!ipsc_matchstr(&isc->ipsc_sl, is->is_sbuf[1], n)) {
i++;
ret |= 2;
if (n > k)
k = n;
}
}
}
if (maxm && (ret == 3)) {
maxm[0] = j;
maxm[1] = k;
}
return ret;
}
int ipsc_match(is)
ipstate_t *is;
{
int i, j, k, n, cl, sl, maxm[2];
ipscan_t *isc, *lm;
tcpdata_t *t;
for (cl = 0, n = is->is_smsk[0]; n & 1; n >>= 1)
cl++;
for (sl = 0, n = is->is_smsk[1]; n & 1; n >>= 1)
sl++;
j = 0;
isc = is->is_isc;
if (isc != NULL) {
/*
* Known object to scan for.
*/
i = ipsc_matchisc(isc, is, cl, sl, NULL);
if (i & 1) {
is->is_flags |= IS_SC_MATCHC;
is->is_flags &= ~IS_SC_CLIENT;
} else if (cl >= isc->ipsc_clen)
is->is_flags &= ~IS_SC_CLIENT;
if (i & 2) {
is->is_flags |= IS_SC_MATCHS;
is->is_flags &= ~IS_SC_SERVER;
} else if (sl >= isc->ipsc_slen)
is->is_flags &= ~IS_SC_SERVER;
} else {
i = 0;
lm = NULL;
maxm[0] = 0;
maxm[1] = 0;
for (k = 0, isc = ipsc_list; isc; isc = isc->ipsc_next) {
i = ipsc_matchisc(isc, is, cl, sl, maxm);
if (i) {
/*
* We only want to remember the best match
* and the number of times we get a best
* match.
*/
if ((j == 3) && (i < 3))
continue;
if ((i == 3) && (j != 3))
k = 1;
else
k++;
j = i;
lm = isc;
}
}
if (k == 1)
isc = lm;
if (isc == NULL)
return 0;
/*
* No matches or partial matches, so reset the respective
* search flag.
*/
if (!(j & 1))
is->is_flags &= ~IS_SC_CLIENT;
if (!(j & 2))
is->is_flags &= ~IS_SC_SERVER;
/*
* If we found the best match, then set flags appropriately.
*/
if ((j == 3) && (k == 1)) {
is->is_flags &= ~(IS_SC_SERVER|IS_SC_CLIENT);
is->is_flags |= (IS_SC_MATCHS|IS_SC_MATCHC);
}
}
/*
* If the acknowledged side of a connection has moved past the data in
* which we are interested, then reset respective flag.
*/
t = &is->is_tcp.ts_data[0];
if (t->td_end > is->is_s0[0] + 15)
is->is_flags &= ~IS_SC_CLIENT;
t = &is->is_tcp.ts_data[1];
if (t->td_end > is->is_s0[1] + 15)
is->is_flags &= ~IS_SC_SERVER;
/*
* Matching complete ?
*/
j = ISC_A_NONE;
if ((is->is_flags & IS_SC_MATCHALL) == IS_SC_MATCHALL) {
j = isc->ipsc_action;
ipsc_stat.iscs_acted++;
} else if ((is->is_isc != NULL) &&
((is->is_flags & IS_SC_MATCHALL) != IS_SC_MATCHALL) &&
!(is->is_flags & (IS_SC_CLIENT|IS_SC_SERVER))) {
/*
* Matching failed...
*/
j = isc->ipsc_else;
ipsc_stat.iscs_else++;
}
switch (j)
{
case ISC_A_CLOSE :
/*
* If as a result of a successful match we are to
* close a connection, change the "keep state" info.
* to block packets and generate TCP RST's.
*/
is->is_pass &= ~FR_RETICMP;
is->is_pass |= FR_RETRST;
break;
default :
break;
}
return i;
}
/*
* check if a packet matches what we're scanning for
*/
int ipsc_packet(fin, is)
fr_info_t *fin;
ipstate_t *is;
{
int i, j, rv, dlen, off, thoff;
u_32_t seq, s0;
tcphdr_t *tcp;
rv = !IP6_EQ(&fin->fin_fi.fi_src, &is->is_src);
tcp = fin->fin_dp;
seq = ntohl(tcp->th_seq);
if (!is->is_s0[rv])
return 1;
/*
* check if this packet has more data that falls within the first
* 16 bytes sent in either direction.
*/
s0 = is->is_s0[rv];
off = seq - s0;
if ((off > 15) || (off < 0))
return 1;
thoff = TCP_OFF(tcp) << 2;
dlen = fin->fin_dlen - thoff;
if (dlen <= 0)
return 1;
if (dlen > 16)
dlen = 16;
if (off + dlen > 16)
dlen = 16 - off;
j = 0xffff >> (16 - dlen);
i = (0xffff & j) << off;
#ifdef _KERNEL
COPYDATA(*(mb_t **)fin->fin_mp, fin->fin_plen - fin->fin_dlen + thoff,
dlen, (caddr_t)is->is_sbuf[rv] + off);
#endif
is->is_smsk[rv] |= i;
for (j = 0, i = is->is_smsk[rv]; i & 1; i >>= 1)
j++;
if (j == 0)
return 1;
(void) ipsc_match(is);
#if 0
/*
* There is the potential here for plain text passwords to get
* buffered and stored for some time...
*/
if (!(is->is_flags & IS_SC_CLIENT))
bzero(is->is_sbuf[0], sizeof(is->is_sbuf[0]));
if (!(is->is_flags & IS_SC_SERVER))
bzero(is->is_sbuf[1], sizeof(is->is_sbuf[1]));
#endif
return 0;
}
int fr_scan_ioctl(data, cmd, mode, uid, ctx)
caddr_t data;
ioctlcmd_t cmd;
int mode, uid;
void *ctx;
{
ipscanstat_t ipscs;
int err;
switch (cmd)
{
case SIOCADSCA :
err = ipsc_add(data);
break;
case SIOCRMSCA :
err = ipsc_delete(data);
break;
case SIOCGSCST :
bcopy((char *)&ipsc_stat, (char *)&ipscs, sizeof(ipscs));
ipscs.iscs_list = ipsc_list;
err = BCOPYOUT(&ipscs, data, sizeof(ipscs));
break;
default :
err = EINVAL;
break;
}
return err;
}
#endif /* IPFILTER_SCAN */
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