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Diffstat (limited to 'addrmatch.c')
| -rw-r--r-- | addrmatch.c | 498 |
1 files changed, 498 insertions, 0 deletions
diff --git a/addrmatch.c b/addrmatch.c new file mode 100644 index 0000000..5a402d0 --- /dev/null +++ b/addrmatch.c @@ -0,0 +1,498 @@ +/* $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; +} |