/* $OpenBSD: addrmatch.c,v 1.14 2018/07/31 03:07:24 djm Exp $ */
/*
* Copyright (c) 2004-2008 Damien Miller <djm@mindrot.org>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include "includes.h"
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include <stdarg.h>
#include "match.h"
#include "log.h"
struct xaddr {
sa_family_t af;
union {
struct in_addr v4;
struct in6_addr v6;
u_int8_t addr8[16];
u_int32_t addr32[4];
} xa; /* 128-bit address */
u_int32_t scope_id; /* iface scope id for v6 */
#define v4 xa.v4
#define v6 xa.v6
#define addr8 xa.addr8
#define addr32 xa.addr32
};
static int
addr_unicast_masklen(int af)
{
switch (af) {
case AF_INET:
return 32;
case AF_INET6:
return 128;
default:
return -1;
}
}
static inline int
masklen_valid(int af, u_int masklen)
{
switch (af) {
case AF_INET:
return masklen <= 32 ? 0 : -1;
case AF_INET6:
return masklen <= 128 ? 0 : -1;
default:
return -1;
}
}
/*
* Convert struct sockaddr to struct xaddr
* Returns 0 on success, -1 on failure.
*/
static int
addr_sa_to_xaddr(struct sockaddr *sa, socklen_t slen, struct xaddr *xa)
{
struct sockaddr_in *in4 = (struct sockaddr_in *)sa;
struct sockaddr_in6 *in6 = (struct sockaddr_in6 *)sa;
memset(xa, '\0', sizeof(*xa));
switch (sa->sa_family) {
case AF_INET:
if (slen < (socklen_t)sizeof(*in4))
return -1;
xa->af = AF_INET;
memcpy(&xa->v4, &in4->sin_addr, sizeof(xa->v4));
break;
case AF_INET6:
if (slen < (socklen_t)sizeof(*in6))
return -1;
xa->af = AF_INET6;
memcpy(&xa->v6, &in6->sin6_addr, sizeof(xa->v6));
#ifdef HAVE_STRUCT_SOCKADDR_IN6_SIN6_SCOPE_ID
xa->scope_id = in6->sin6_scope_id;
#endif
break;
default:
return -1;
}
return 0;
}
/*
* Calculate a netmask of length 'l' for address family 'af' and
* store it in 'n'.
* Returns 0 on success, -1 on failure.
*/
static int
addr_netmask(int af, u_int l, struct xaddr *n)
{
int i;
if (masklen_valid(af, l) != 0 || n == NULL)
return -1;
memset(n, '\0', sizeof(*n));
switch (af) {
case AF_INET:
n->af = AF_INET;
if (l == 0)
return 0;
n->v4.s_addr = htonl((0xffffffff << (32 - l)) & 0xffffffff);
return 0;
case AF_INET6:
n->af = AF_INET6;
for (i = 0; i < 4 && l >= 32; i++, l -= 32)
n->addr32[i] = 0xffffffffU;
if (i < 4 && l != 0)
n->addr32[i] = htonl((0xffffffff << (32 - l)) &
0xffffffff);
return 0;
default:
return -1;
}
}
/*
* Perform logical AND of addresses 'a' and 'b', storing result in 'dst'.
* Returns 0 on success, -1 on failure.
*/
static int
addr_and(struct xaddr *dst, const struct xaddr *a, const struct xaddr *b)
{
int i;
if (dst == NULL || a == NULL || b == NULL || a->af != b->af)
return -1;
memcpy(dst, a, sizeof(*dst));
switch (a->af) {
case AF_INET:
dst->v4.s_addr &= b->v4.s_addr;
return 0;
case AF_INET6:
dst->scope_id = a->scope_id;
for (i = 0; i < 4; i++)
dst->addr32[i] &= b->addr32[i];
return 0;
default:
return -1;
}
}
/*
* Compare addresses 'a' and 'b'
* Return 0 if addresses are identical, -1 if (a < b) or 1 if (a > b)
*/
static int
addr_cmp(const struct xaddr *a, const struct xaddr *b)
{
int i;
if (a->af != b->af)
return a->af == AF_INET6 ? 1 : -1;
switch (a->af) {
case AF_INET:
if (a->v4.s_addr == b->v4.s_addr)
return 0;
return ntohl(a->v4.s_addr) > ntohl(b->v4.s_addr) ? 1 : -1;
case AF_INET6:
for (i = 0; i < 16; i++)
if (a->addr8[i] - b->addr8[i] != 0)
return a->addr8[i] > b->addr8[i] ? 1 : -1;
if (a->scope_id == b->scope_id)
return 0;
return a->scope_id > b->scope_id ? 1 : -1;
default:
return -1;
}
}
/*
* Parse string address 'p' into 'n'
* Returns 0 on success, -1 on failure.
*/
static int
addr_pton(const char *p, struct xaddr *n)
{
struct addrinfo hints, *ai = NULL;
int ret = -1;
memset(&hints, '\0', sizeof(hints));
hints.ai_flags = AI_NUMERICHOST;
if (p == NULL || getaddrinfo(p, NULL, &hints, &ai) != 0)
goto out;
if (ai == NULL || ai->ai_addr == NULL)
goto out;
if (n != NULL && addr_sa_to_xaddr(ai->ai_addr, ai->ai_addrlen, n) == -1)
goto out;
/* success */
ret = 0;
out:
if (ai != NULL)
freeaddrinfo(ai);
return ret;
}
/*
* Perform bitwise negation of address
* Returns 0 on success, -1 on failure.
*/
static int
addr_invert(struct xaddr *n)
{
int i;
if (n == NULL)
return (-1);
switch (n->af) {
case AF_INET:
n->v4.s_addr = ~n->v4.s_addr;
return (0);
case AF_INET6:
for (i = 0; i < 4; i++)
n->addr32[i] = ~n->addr32[i];
return (0);
default:
return (-1);
}
}
/*
* Calculate a netmask of length 'l' for address family 'af' and
* store it in 'n'.
* Returns 0 on success, -1 on failure.
*/
static int
addr_hostmask(int af, u_int l, struct xaddr *n)
{
if (addr_netmask(af, l, n) == -1 || addr_invert(n) == -1)
return (-1);
return (0);
}
/*
* Test whether address 'a' is all zeros (i.e. 0.0.0.0 or ::)
* Returns 0 on if address is all-zeros, -1 if not all zeros or on failure.
*/
static int
addr_is_all0s(const struct xaddr *a)
{
int i;
switch (a->af) {
case AF_INET:
return (a->v4.s_addr == 0 ? 0 : -1);
case AF_INET6:;
for (i = 0; i < 4; i++)
if (a->addr32[i] != 0)
return (-1);
return (0);
default:
return (-1);
}
}
/*
* Test whether host portion of address 'a', as determined by 'masklen'
* is all zeros.
* Returns 0 on if host portion of address is all-zeros,
* -1 if not all zeros or on failure.
*/
static int
addr_host_is_all0s(const struct xaddr *a, u_int masklen)
{
struct xaddr tmp_addr, tmp_mask, tmp_result;
memcpy(&tmp_addr, a, sizeof(tmp_addr));
if (addr_hostmask(a->af, masklen, &tmp_mask) == -1)
return (-1);
if (addr_and(&tmp_result, &tmp_addr, &tmp_mask) == -1)
return (-1);
return (addr_is_all0s(&tmp_result));
}
/*
* Parse a CIDR address (x.x.x.x/y or xxxx:yyyy::/z).
* Return -1 on parse error, -2 on inconsistency or 0 on success.
*/
static int
addr_pton_cidr(const char *p, struct xaddr *n, u_int *l)
{
struct xaddr tmp;
long unsigned int masklen = 999;
char addrbuf[64], *mp, *cp;
/* Don't modify argument */
if (p == NULL || strlcpy(addrbuf, p, sizeof(addrbuf)) >= sizeof(addrbuf))
return -1;
if ((mp = strchr(addrbuf, '/')) != NULL) {
*mp = '\0';
mp++;
masklen = strtoul(mp, &cp, 10);
if (*mp == '\0' || *cp != '\0' || masklen > 128)
return -1;
}
if (addr_pton(addrbuf, &tmp) == -1)
return -1;
if (mp == NULL)
masklen = addr_unicast_masklen(tmp.af);
if (masklen_valid(tmp.af, masklen) == -1)
return -2;
if (addr_host_is_all0s(&tmp, masklen) != 0)
return -2;
if (n != NULL)
memcpy(n, &tmp, sizeof(*n));
if (l != NULL)
*l = masklen;
return 0;
}
static int
addr_netmatch(const struct xaddr *host, const struct xaddr *net, u_int masklen)
{
struct xaddr tmp_mask, tmp_result;
if (host->af != net->af)
return -1;
if (addr_netmask(host->af, masklen, &tmp_mask) == -1)
return -1;
if (addr_and(&tmp_result, host, &tmp_mask) == -1)
return -1;
return addr_cmp(&tmp_result, net);
}
/*
* Match "addr" against list pattern list "_list", which may contain a
* mix of CIDR addresses and old-school wildcards.
*
* If addr is NULL, then no matching is performed, but _list is parsed
* and checked for well-formedness.
*
* Returns 1 on match found (never returned when addr == NULL).
* Returns 0 on if no match found, or no errors found when addr == NULL.
* Returns -1 on negated match found (never returned when addr == NULL).
* Returns -2 on invalid list entry.
*/
int
addr_match_list(const char *addr, const char *_list)
{
char *list, *cp, *o;
struct xaddr try_addr, match_addr;
u_int masklen, neg;
int ret = 0, r;
if (addr != NULL && addr_pton(addr, &try_addr) != 0) {
debug2("%s: couldn't parse address %.100s", __func__, addr);
return 0;
}
if ((o = list = strdup(_list)) == NULL)
return -1;
while ((cp = strsep(&list, ",")) != NULL) {
neg = *cp == '!';
if (neg)
cp++;
if (*cp == '\0') {
ret = -2;
break;
}
/* Prefer CIDR address matching */
r = addr_pton_cidr(cp, &match_addr, &masklen);
if (r == -2) {
debug2("%s: inconsistent mask length for "
"match network \"%.100s\"", __func__, cp);
ret = -2;
break;
} else if (r == 0) {
if (addr != NULL && addr_netmatch(&try_addr,
&match_addr, masklen) == 0) {
foundit:
if (neg) {
ret = -1;
break;
}
ret = 1;
}
continue;
} else {
/* If CIDR parse failed, try wildcard string match */
if (addr != NULL && match_pattern(addr, cp) == 1)
goto foundit;
}
}
free(o);
return ret;
}
/*
* Match "addr" against list CIDR list "_list". Lexical wildcards and
* negation are not supported. If "addr" == NULL, will verify structure
* of "_list".
*
* Returns 1 on match found (never returned when addr == NULL).
* Returns 0 on if no match found, or no errors found when addr == NULL.
* Returns -1 on error
*/
int
addr_match_cidr_list(const char *addr, const char *_list)
{
char *list, *cp, *o;
struct xaddr try_addr, match_addr;
u_int masklen;
int ret = 0, r;
if (addr != NULL && addr_pton(addr, &try_addr) != 0) {
debug2("%s: couldn't parse address %.100s", __func__, addr);
return 0;
}
if ((o = list = strdup(_list)) == NULL)
return -1;
while ((cp = strsep(&list, ",")) != NULL) {
if (*cp == '\0') {
error("%s: empty entry in list \"%.100s\"",
__func__, o);
ret = -1;
break;
}
/*
* NB. This function is called in pre-auth with untrusted data,
* so be extra paranoid about junk reaching getaddrino (via
* addr_pton_cidr).
*/
/* Stop junk from reaching getaddrinfo. +3 is for masklen */
if (strlen(cp) > INET6_ADDRSTRLEN + 3) {
error("%s: list entry \"%.100s\" too long",
__func__, cp);
ret = -1;
break;
}
#define VALID_CIDR_CHARS "0123456789abcdefABCDEF.:/"
if (strspn(cp, VALID_CIDR_CHARS) != strlen(cp)) {
error("%s: list entry \"%.100s\" contains invalid "
"characters", __func__, cp);
ret = -1;
}
/* Prefer CIDR address matching */
r = addr_pton_cidr(cp, &match_addr, &masklen);
if (r == -1) {
error("Invalid network entry \"%.100s\"", cp);
ret = -1;
break;
} else if (r == -2) {
error("Inconsistent mask length for "
"network \"%.100s\"", cp);
ret = -1;
break;
} else if (r == 0 && addr != NULL) {
if (addr_netmatch(&try_addr, &match_addr,
masklen) == 0)
ret = 1;
continue;
}
}
free(o);
return ret;
}
