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This module is an adaption of code from the tcpd-1.4 package written
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by Wietse Venema, Eindhoven University of Technology, The Netherlands.
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The code is used here with permission.
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The code has been considerably changed from the original. Bug reports
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should be sent to samba@samba.org
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#define ALLONES ((uint32)0xFFFFFFFF)
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/* masked_match - match address against netnumber/netmask */
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static BOOL masked_match(const char *tok, const char *slash, const char *s)
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if ((addr = interpret_addr(s)) == INADDR_NONE)
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fstrcpy(tok_cpy, tok);
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tok_cpy[PTR_DIFF(slash,tok)] = '\0';
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net = interpret_addr(tok_cpy);
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tok_cpy[PTR_DIFF(slash,tok)] = '/';
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if (strlen(slash + 1) > 2) {
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mask = interpret_addr(slash + 1);
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mask = (uint32)((ALLONES >> atoi(slash + 1)) ^ ALLONES);
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/* convert to network byte order */
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if (net == INADDR_NONE || mask == INADDR_NONE) {
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DEBUG(0,("access: bad net/mask access control: %s\n", tok));
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return ((addr & mask) == (net & mask));
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/* string_match - match string against token */
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static BOOL string_match(const char *tok,const char *s, char *invalid_char)
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/* Return True if a token has the magic value "ALL". Return
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* FAIL if the token is "FAIL". If the token starts with a "."
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* (domain name), return True if it matches the last fields of
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* the string. If the token has the magic value "LOCAL",
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* return True if the string does not contain a "."
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* character. If the token ends on a "." (network number),
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* return True if it matches the first fields of the
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* string. If the token begins with a "@" (netgroup name),
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* return True if the string is a (host) member of the
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* netgroup. Return True if the token fully matches the
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* string. If the token is a netnumber/netmask pair, return
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* True if the address is a member of the specified subnet.
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if (tok[0] == '.') { /* domain: match last fields */
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if ((str_len = strlen(s)) > (tok_len = strlen(tok))
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&& strequal(tok, s + str_len - tok_len))
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} else if (tok[0] == '@') { /* netgroup: look it up */
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static char *mydomain = NULL;
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char *hostname = NULL;
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BOOL netgroup_ok = False;
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yp_get_default_domain(&mydomain);
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DEBUG(0,("Unable to get default yp domain.\n"));
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if (!(hostname = strdup(s))) {
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DEBUG(1,("out of memory for strdup!\n"));
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netgroup_ok = innetgr(tok + 1, hostname, (char *) 0, mydomain);
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DEBUG(5,("looking for %s of domain %s in netgroup %s gave %s\n",
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BOOLSTR(netgroup_ok)));
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DEBUG(0,("access: netgroup support is not configured\n"));
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} else if (strequal(tok, "ALL")) { /* all: match any */
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} else if (strequal(tok, "FAIL")) { /* fail: match any */
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} else if (strequal(tok, "LOCAL")) { /* local: no dots */
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if (strchr_m(s, '.') == 0 && !strequal(s, "unknown"))
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} else if (strequal(tok, s)) { /* match host name or address */
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} else if (tok[(tok_len = strlen(tok)) - 1] == '.') { /* network */
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if (strncmp(tok, s, tok_len) == 0)
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} else if ((cut = strchr_m(tok, '/')) != 0) { /* netnumber/netmask */
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if (isdigit((int)s[0]) && masked_match(tok, cut, s))
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} else if (strchr_m(tok, '*') != 0) {
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} else if (strchr_m(tok, '?') != 0) {
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/* client_match - match host name and address against token */
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static BOOL client_match(const char *tok, const char *item)
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const char **client = (const char **)item;
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char invalid_char = '\0';
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* Try to match the address first. If that fails, try to match the host
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if ((match = string_match(tok, client[1], &invalid_char)) == 0) {
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DEBUG(0,("client_match: address match failing due to invalid character '%c' found in \
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token '%s' in an allow/deny hosts line.\n", invalid_char, tok ));
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if (client[0][0] != 0)
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match = string_match(tok, client[0], &invalid_char);
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DEBUG(0,("client_match: address match failing due to invalid character '%c' found in \
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token '%s' in an allow/deny hosts line.\n", invalid_char, tok ));
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/* list_match - match an item against a list of tokens with exceptions */
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static BOOL list_match(const char **list,const char *item,
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BOOL (*match_fn)(const char *, const char *))
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* Process tokens one at a time. We have exhausted all possible matches
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* when we reach an "EXCEPT" token or the end of the list. If we do find
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* a match, look for an "EXCEPT" list and recurse to determine whether
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* the match is affected by any exceptions.
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for (; *list ; list++) {
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if (strequal(*list, "EXCEPT")) /* EXCEPT: give up */
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if ((match = (*match_fn) (*list, item))) /* True or FAIL */
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/* Process exceptions to True or FAIL matches. */
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if (match != False) {
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while (*list && !strequal(*list, "EXCEPT"))
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for (; *list; list++) {
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if ((*match_fn) (*list, item)) /* Exception Found */
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/* return true if access should be allowed */
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static BOOL allow_access_internal(const char **deny_list,const char **allow_list,
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const char *cname, const char *caddr)
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const char *client[2];
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/* if it is loopback then always allow unless specifically denied */
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if (strcmp(caddr, "127.0.0.1") == 0) {
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* If 127.0.0.1 matches both allow and deny then allow.
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* Patch from Steve Langasek vorlon@netexpress.net.
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list_match(deny_list,(const char *)client,client_match) &&
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!list_match(allow_list,(const char *)client, client_match))) {
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/* if theres no deny list and no allow list then allow access */
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if ((!deny_list || *deny_list == 0) &&
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(!allow_list || *allow_list == 0)) {
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/* if there is an allow list but no deny list then allow only hosts
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if (!deny_list || *deny_list == 0)
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return(list_match(allow_list,(const char *)client,client_match));
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/* if theres a deny list but no allow list then allow
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all hosts not on the deny list */
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if (!allow_list || *allow_list == 0)
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return(!list_match(deny_list,(const char *)client,client_match));
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/* if there are both types of list then allow all hosts on the
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if (list_match(allow_list,(const char *)client,client_match))
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/* if there are both types of list and it's not on the allow then
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allow it if its not on the deny */
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if (list_match(deny_list,(const char *)client,client_match))
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/* return true if access should be allowed */
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BOOL allow_access(const char **deny_list, const char **allow_list,
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const char *cname, const char *caddr)
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char *nc_cname = smb_xstrdup(cname);
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char *nc_caddr = smb_xstrdup(caddr);
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ret = allow_access_internal(deny_list, allow_list, nc_cname, nc_caddr);
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/* return true if the char* contains ip addrs only. Used to avoid
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gethostbyaddr() calls */
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static BOOL only_ipaddrs_in_list(const char** list)
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for (; *list ; list++) {
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/* factor out the special strings */
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if (strequal(*list, "ALL") || strequal(*list, "FAIL") ||
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strequal(*list, "EXCEPT")) {
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if (!is_ipaddress(*list)) {
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* if we failed, make sure that it was not because the token
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* was a network/netmask pair. Only network/netmask pairs
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if ((strchr_m(*list, '/')) == NULL) {
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DEBUG(3,("only_ipaddrs_in_list: list has non-ip address (%s)\n", *list));
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/* return true if access should be allowed to a service for a socket */
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BOOL check_access(int sock, const char **allow_list, const char **deny_list)
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BOOL only_ip = False;
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if ((!deny_list || *deny_list==0) && (!allow_list || *allow_list==0))
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/* bypass gethostbyaddr() calls if the lists only contain IP addrs */
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if (only_ipaddrs_in_list(allow_list) && only_ipaddrs_in_list(deny_list)) {
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DEBUG (3, ("check_access: no hostnames in host allow/deny list.\n"));
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ret = allow_access(deny_list,allow_list, "", get_peer_addr(sock));
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DEBUG (3, ("check_access: hostnames in host allow/deny list.\n"));
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ret = allow_access(deny_list,allow_list, get_peer_name(sock,True),
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get_peer_addr(sock));
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DEBUG(2,("Allowed connection from %s (%s)\n",
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only_ip ? "" : get_peer_name(sock,True),
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get_peer_addr(sock)));
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DEBUG(0,("Denied connection from %s (%s)\n",
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only_ip ? "" : get_peer_name(sock,True),
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get_peer_addr(sock)));