2 * This module implements a simple but effective form of login access
3 * control based on login names and on host (or domain) names, internet
4 * addresses (or network numbers), or on terminal line names in case of
5 * non-networked logins. Diagnostics are reported through syslog(3).
7 * Author: Wietse Venema, Eindhoven University of Technology, The Netherlands.
13 static char sccsid[] = "%Z% %M% %I% %E% %U%";
17 #include <sys/cdefs.h>
18 __FBSDID("$FreeBSD$");
20 #include <sys/types.h>
31 #include "pathnames.h"
33 /* Delimiters for fields and for lists of users, ttys or hosts. */
35 static char fs[] = ":"; /* field separator */
36 static char sep[] = ", \t"; /* list-element separator */
38 /* Constants to be used in assignments only, not in comparisons... */
43 static int from_match(const char *, const char *);
44 static int list_match(char *, const char *,
45 int (*)(const char *, const char *));
46 static int netgroup_match(const char *, const char *, const char *);
47 static int string_match(const char *, const char *);
48 static int user_match(const char *, const char *);
50 /* login_access - match username/group and host/tty with access control file */
53 login_access(user, from)
59 char *perm; /* becomes permission field */
60 char *users; /* becomes list of login names */
61 char *froms; /* becomes list of terminals or hosts */
64 int lineno = 0; /* for diagnostics */
67 * Process the table one line at a time and stop at the first match.
68 * Blank lines and lines that begin with a '#' character are ignored.
69 * Non-comment lines are broken at the ':' character. All fields are
70 * mandatory. The first field should be a "+" or "-" character. A
71 * non-existing table means no access control.
74 if ((fp = fopen(_PATH_LOGACCESS, "r")) != NULL) {
75 while (!match && fgets(line, sizeof(line), fp)) {
77 if (line[end = strlen(line) - 1] != '\n') {
78 syslog(LOG_ERR, "%s: line %d: missing newline or line too long",
79 _PATH_LOGACCESS, lineno);
83 continue; /* comment line */
84 while (end > 0 && isspace(line[end - 1]))
86 line[end] = 0; /* strip trailing whitespace */
87 if (line[0] == 0) /* skip blank lines */
89 if (!(perm = strtok(line, fs))
90 || !(users = strtok((char *) 0, fs))
91 || !(froms = strtok((char *) 0, fs))
92 || strtok((char *) 0, fs)) {
93 syslog(LOG_ERR, "%s: line %d: bad field count", _PATH_LOGACCESS,
97 if (perm[0] != '+' && perm[0] != '-') {
98 syslog(LOG_ERR, "%s: line %d: bad first field", _PATH_LOGACCESS,
102 match = (list_match(froms, from, from_match)
103 && list_match(users, user, user_match));
106 } else if (errno != ENOENT) {
107 syslog(LOG_ERR, "cannot open %s: %m", _PATH_LOGACCESS);
109 return (match == 0 || (line[0] == '+'));
112 /* list_match - match an item against a list of tokens with exceptions */
114 static int list_match(list, item, match_fn)
117 int (*match_fn)(const char *, const char *);
123 * Process tokens one at a time. We have exhausted all possible matches
124 * when we reach an "EXCEPT" token or the end of the list. If we do find
125 * a match, look for an "EXCEPT" list and recurse to determine whether
126 * the match is affected by any exceptions.
129 for (tok = strtok(list, sep); tok != 0; tok = strtok((char *) 0, sep)) {
130 if (strcasecmp(tok, "EXCEPT") == 0) /* EXCEPT: give up */
132 if ((match = (*match_fn)(tok, item)) != NULL) /* YES */
135 /* Process exceptions to matches. */
138 while ((tok = strtok((char *) 0, sep)) && strcasecmp(tok, "EXCEPT"))
140 if (tok == 0 || list_match((char *) 0, item, match_fn) == NO)
146 /* netgroup_match - match group against machine or user */
148 static int netgroup_match(group, machine, user)
149 const char *group __unused;
150 const char *machine __unused;
151 const char *user __unused;
153 syslog(LOG_ERR, "NIS netgroup support not configured");
157 /* user_match - match a username against one token */
159 static int user_match(tok, string)
167 * If a token has the magic value "ALL" the match always succeeds.
168 * Otherwise, return YES if the token fully matches the username, or if
169 * the token is a group that contains the username.
172 if (tok[0] == '@') { /* netgroup */
173 return (netgroup_match(tok + 1, (char *) 0, string));
174 } else if (string_match(tok, string)) { /* ALL or exact match */
176 } else if ((group = getgrnam(tok)) != NULL) {/* try group membership */
177 for (i = 0; group->gr_mem[i]; i++)
178 if (strcasecmp(string, group->gr_mem[i]) == 0)
184 /* from_match - match a host or tty against a list of tokens */
186 static int from_match(tok, string)
194 * If a token has the magic value "ALL" the match always succeeds. Return
195 * YES if the token fully matches the string. If the token is a domain
196 * name, return YES if it matches the last fields of the string. If the
197 * token has the magic value "LOCAL", return YES if the string does not
198 * contain a "." character. If the token is a network number, return YES
199 * if it matches the head of the string.
202 if (tok[0] == '@') { /* netgroup */
203 return (netgroup_match(tok + 1, string, (char *) 0));
204 } else if (string_match(tok, string)) { /* ALL or exact match */
206 } else if (tok[0] == '.') { /* domain: match last fields */
207 if ((str_len = strlen(string)) > (tok_len = strlen(tok))
208 && strcasecmp(tok, string + str_len - tok_len) == 0)
210 } else if (strcasecmp(tok, "LOCAL") == 0) { /* local: no dots */
211 if (strchr(string, '.') == 0)
213 } else if (tok[(tok_len = strlen(tok)) - 1] == '.' /* network */
214 && strncmp(tok, string, tok_len) == 0) {
220 /* string_match - match a string against one token */
222 static int string_match(tok, string)
228 * If the token has the magic value "ALL" the match always succeeds.
229 * Otherwise, return YES if the token fully matches the string.
232 if (strcasecmp(tok, "ALL") == 0) { /* all: always matches */
234 } else if (strcasecmp(tok, string) == 0) { /* try exact match */
239 #endif /* LOGIN_ACCES */