/source3/lib/access.c
C | 343 lines | 227 code | 48 blank | 68 comment | 96 complexity | d428134ae1b07ba2d6cb39f9d5208990 MD5 | raw file
Possible License(s): LGPL-2.1, LGPL-3.0, GPL-3.0
- /*
- This module is an adaption of code from the tcpd-1.4 package written
- by Wietse Venema, Eindhoven University of Technology, The Netherlands.
- The code is used here with permission.
- The code has been considerably changed from the original. Bug reports
- should be sent to samba@samba.org
- Updated for IPv6 by Jeremy Allison (C) 2007.
- */
- #include "includes.h"
- #include "../lib/util/memcache.h"
- #include "lib/socket/interfaces.h"
- #define NAME_INDEX 0
- #define ADDR_INDEX 1
- /* masked_match - match address against netnumber/netmask */
- static bool masked_match(const char *tok, const char *slash, const char *s)
- {
- struct sockaddr_storage ss_mask;
- struct sockaddr_storage ss_tok;
- struct sockaddr_storage ss_host;
- char *tok_copy = NULL;
- if (!interpret_string_addr(&ss_host, s, 0)) {
- return false;
- }
- if (*tok == '[') {
- /* IPv6 address - remove braces. */
- tok_copy = SMB_STRDUP(tok+1);
- if (!tok_copy) {
- return false;
- }
- /* Remove the terminating ']' */
- tok_copy[PTR_DIFF(slash,tok)-1] = '\0';
- } else {
- tok_copy = SMB_STRDUP(tok);
- if (!tok_copy) {
- return false;
- }
- /* Remove the terminating '/' */
- tok_copy[PTR_DIFF(slash,tok)] = '\0';
- }
- if (!interpret_string_addr(&ss_tok, tok_copy, 0)) {
- SAFE_FREE(tok_copy);
- return false;
- }
- SAFE_FREE(tok_copy);
- if (strlen(slash + 1) > 2) {
- if (!interpret_string_addr(&ss_mask, slash+1, 0)) {
- return false;
- }
- } else {
- char *endp = NULL;
- unsigned long val = strtoul(slash+1, &endp, 0);
- if (slash+1 == endp || (endp && *endp != '\0')) {
- return false;
- }
- if (!make_netmask(&ss_mask, &ss_tok, val)) {
- return false;
- }
- }
- return same_net((struct sockaddr *)(void *)&ss_host,
- (struct sockaddr *)(void *)&ss_tok,
- (struct sockaddr *)(void *)&ss_mask);
- }
- /* string_match - match string s against token tok */
- static bool string_match(const char *tok,const char *s)
- {
- size_t tok_len;
- size_t str_len;
- const char *cut;
- /* Return true if a token has the magic value "ALL". Return
- * true if the token is "FAIL". If the token starts with a "."
- * (domain name), return true if it matches the last fields of
- * the string. If the token has the magic value "LOCAL",
- * return true if the string does not contain a "."
- * character. If the token ends on a "." (network number),
- * return true if it matches the first fields of the
- * string. If the token begins with a "@" (netgroup name),
- * return true if the string is a (host) member of the
- * netgroup. Return true if the token fully matches the
- * string. If the token is a netnumber/netmask pair, return
- * true if the address is a member of the specified subnet.
- */
- if (tok[0] == '.') { /* domain: match last fields */
- if ((str_len = strlen(s)) > (tok_len = strlen(tok))
- && strequal(tok, s + str_len - tok_len)) {
- return true;
- }
- } else if (tok[0] == '@') { /* netgroup: look it up */
- #ifdef HAVE_NETGROUP
- DATA_BLOB tmp;
- char *mydomain = NULL;
- char *hostname = NULL;
- bool netgroup_ok = false;
- if (memcache_lookup(
- NULL, SINGLETON_CACHE,
- data_blob_string_const_null("yp_default_domain"),
- &tmp)) {
- SMB_ASSERT(tmp.length > 0);
- mydomain = (tmp.data[0] == '\0')
- ? NULL : (char *)tmp.data;
- }
- else {
- yp_get_default_domain(&mydomain);
- memcache_add(
- NULL, SINGLETON_CACHE,
- data_blob_string_const_null("yp_default_domain"),
- data_blob_string_const_null(mydomain?mydomain:""));
- }
- if (!mydomain) {
- DEBUG(0,("Unable to get default yp domain. "
- "Try without it.\n"));
- }
- if (!(hostname = SMB_STRDUP(s))) {
- DEBUG(1,("out of memory for strdup!\n"));
- return false;
- }
- netgroup_ok = innetgr(tok + 1, hostname, (char *) 0, mydomain);
- DEBUG(5,("looking for %s of domain %s in netgroup %s gave %s\n",
- hostname,
- mydomain?mydomain:"(ANY)",
- tok+1,
- BOOLSTR(netgroup_ok)));
- SAFE_FREE(hostname);
- if (netgroup_ok)
- return true;
- #else
- DEBUG(0,("access: netgroup support is not configured\n"));
- return false;
- #endif
- } else if (strequal(tok, "ALL")) { /* all: match any */
- return true;
- } else if (strequal(tok, "FAIL")) { /* fail: match any */
- return true;
- } else if (strequal(tok, "LOCAL")) { /* local: no dots */
- if (strchr_m(s, '.') == 0 && !strequal(s, "unknown")) {
- return true;
- }
- } else if (strequal(tok, s)) { /* match host name or address */
- return true;
- } else if (tok[(tok_len = strlen(tok)) - 1] == '.') { /* network */
- if (strncmp(tok, s, tok_len) == 0) {
- return true;
- }
- } else if ((cut = strchr_m(tok, '/')) != 0) { /* netnumber/netmask */
- if ((isdigit(s[0]) && strchr_m(tok, '.') != NULL) ||
- (tok[0] == '[' && cut > tok && cut[-1] == ']') ||
- ((isxdigit(s[0]) || s[0] == ':') &&
- strchr_m(tok, ':') != NULL)) {
- /* IPv4/netmask or
- * [IPv6:addr]/netmask or IPv6:addr/netmask */
- return masked_match(tok, cut, s);
- }
- } else if (strchr_m(tok, '*') != 0 || strchr_m(tok, '?')) {
- return unix_wild_match(tok, s);
- }
- return false;
- }
- /* client_match - match host name and address against token */
- bool client_match(const char *tok, const void *item)
- {
- const char **client = discard_const_p(const char *, item);
- const char *tok_addr = tok;
- const char *cli_addr = client[ADDR_INDEX];
- /*
- * tok and client[ADDR_INDEX] can be an IPv4 mapped to IPv6,
- * we try and match the IPv4 part of address only.
- * Bug #5311 and #7383.
- */
- if (strnequal(tok_addr, "::ffff:",7)) {
- tok_addr += 7;
- }
- if (strnequal(cli_addr,"::ffff:",7)) {
- cli_addr += 7;
- }
- /*
- * Try to match the address first. If that fails, try to match the host
- * name if available.
- */
- if (string_match(tok_addr, cli_addr)) {
- return true;
- }
- if (client[NAME_INDEX][0] != 0) {
- if (string_match(tok, client[NAME_INDEX])) {
- return true;
- }
- }
- return false;
- }
- /* list_match - match an item against a list of tokens with exceptions */
- bool list_match(const char **list,const void *item,
- bool (*match_fn)(const char *, const void *))
- {
- bool match = false;
- if (!list) {
- return false;
- }
- /*
- * Process tokens one at a time. We have exhausted all possible matches
- * when we reach an "EXCEPT" token or the end of the list. If we do find
- * a match, look for an "EXCEPT" list and recurse to determine whether
- * the match is affected by any exceptions.
- */
- for (; *list ; list++) {
- if (strequal(*list, "EXCEPT")) {
- /* EXCEPT: give up */
- break;
- }
- if ((match = (*match_fn) (*list, item))) {
- /* true or FAIL */
- break;
- }
- }
- /* Process exceptions to true or FAIL matches. */
- if (match != false) {
- while (*list && !strequal(*list, "EXCEPT")) {
- list++;
- }
- for (; *list; list++) {
- if ((*match_fn) (*list, item)) {
- /* Exception Found */
- return false;
- }
- }
- }
- return match;
- }
- /* return true if access should be allowed */
- static bool allow_access_internal(const char **deny_list,
- const char **allow_list,
- const char *cname,
- const char *caddr)
- {
- const char *client[2];
- client[NAME_INDEX] = cname;
- client[ADDR_INDEX] = caddr;
- /* if it is loopback then always allow unless specifically denied */
- if (strcmp(caddr, "127.0.0.1") == 0 || strcmp(caddr, "::1") == 0) {
- /*
- * If 127.0.0.1 matches both allow and deny then allow.
- * Patch from Steve Langasek vorlon@netexpress.net.
- */
- if (deny_list &&
- list_match(deny_list,client,client_match) &&
- (!allow_list ||
- !list_match(allow_list,client, client_match))) {
- return false;
- }
- return true;
- }
- /* if theres no deny list and no allow list then allow access */
- if ((!deny_list || *deny_list == 0) &&
- (!allow_list || *allow_list == 0)) {
- return true;
- }
- /* if there is an allow list but no deny list then allow only hosts
- on the allow list */
- if (!deny_list || *deny_list == 0) {
- return(list_match(allow_list,client,client_match));
- }
- /* if theres a deny list but no allow list then allow
- all hosts not on the deny list */
- if (!allow_list || *allow_list == 0) {
- return(!list_match(deny_list,client,client_match));
- }
- /* if there are both types of list then allow all hosts on the
- allow list */
- if (list_match(allow_list,(const char *)client,client_match)) {
- return true;
- }
- /* if there are both types of list and it's not on the allow then
- allow it if its not on the deny */
- if (list_match(deny_list,(const char *)client,client_match)) {
- return false;
- }
- return true;
- }
- /* return true if access should be allowed */
- bool allow_access(const char **deny_list,
- const char **allow_list,
- const char *cname,
- const char *caddr)
- {
- bool ret;
- char *nc_cname = smb_xstrdup(cname);
- char *nc_caddr = smb_xstrdup(caddr);
- ret = allow_access_internal(deny_list, allow_list, nc_cname, nc_caddr);
- DEBUG(ret ? 3 : 0,
- ("%s connection from %s (%s)\n",
- ret ? "Allowed" : "Denied", nc_cname, nc_caddr));
- SAFE_FREE(nc_cname);
- SAFE_FREE(nc_caddr);
- return ret;
- }