/* $OpenBSD: addrmatch.c,v 1.12 2016/08/23 08:17:42 djm Exp $ */ /* * Copyright (c) 2004-2008 Damien Miller * * 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 #include #include #include #include #include #include #include #include #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)); 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; 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; 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 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; } else if (neg) 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; }