- (dtucker) OpenBSD CVS Sync
- djm@cvs.openbsd.org 2008/06/10 03:57:27
[servconf.c match.h sshd_config.5]
support CIDR address matching in sshd_config "Match address" blocks, with
full support for negation and fall-back to classic wildcard matching.
For example:
Match address 192.0.2.0/24,3ffe:ffff::/32,!10.*
PasswordAuthentication yes
addrmatch.c code mostly lifted from flowd's addr.c
feedback and ok dtucker@
diff --git a/addrmatch.c b/addrmatch.c
new file mode 100644
index 0000000..a0559ef
--- /dev/null
+++ b/addrmatch.c
@@ -0,0 +1,420 @@
+/* $OpenBSD: addrmatch.c,v 1.2 2008/06/10 05:22:45 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 < sizeof(*in4))
+ return -1;
+ xa->af = AF_INET;
+ memcpy(&xa->v4, &in4->sin_addr, sizeof(xa->v4));
+ break;
+ case AF_INET6:
+ if (slen < sizeof(*in6))
+ return -1;
+ xa->af = AF_INET6;
+ memcpy(&xa->v6, &in6->sin6_addr, sizeof(xa->v6));
+ xa->scope_id = in6->sin6_scope_id;
+ 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;
+ 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;
+
+ memset(&hints, '\0', sizeof(hints));
+ hints.ai_flags = AI_NUMERICHOST;
+
+ if (p == NULL || getaddrinfo(p, NULL, &hints, &ai) != 0)
+ return -1;
+
+ if (ai == NULL || ai->ai_addr == NULL)
+ return -1;
+
+ if (n != NULL &&
+ addr_sa_to_xaddr(ai->ai_addr, ai->ai_addrlen, n) == -1) {
+ freeaddrinfo(ai);
+ return -1;
+ }
+
+ freeaddrinfo(ai);
+ return 0;
+}
+
+/*
+ * 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 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 = -1;
+ break;
+ }
+ /* Prefer CIDR address matching */
+ r = addr_pton_cidr(cp, &match_addr, &masklen);
+ if (r == -2) {
+ error("Inconsistent mask length for "
+ "network \"%.100s\"", cp);
+ ret = -1;
+ break;
+ } else if (r == 0) {
+ if (addr != NULL && addr_netmatch(&try_addr,
+ &match_addr, masklen) == 0) {
+ foundit:
+ if (neg) {
+ ret = 0;
+ 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;
+}