1 /*
2  * ProFTPD - FTP server daemon
3  * Copyright (c) 2004-2020 The ProFTPD Project team
4  *
5  * This program is free software; you can redistribute it and/or modify
6  * it under the terms of the GNU General Public License as published by
7  * the Free Software Foundation; either version 2 of the License, or
8  * (at your option) any later version.
9  *
10  * This program is distributed in the hope that it will be useful,
11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13  * GNU General Public License for more details.
14  *
15  * You should have received a copy of the GNU General Public License
16  * along with this program; if not, write to the Free Software
17  * Foundation, Inc., 51 Franklin Street, Suite 500, Boston, MA 02110-1335, USA.
18  *
19  * As a special exemption, the ProFTPD Project and other respective copyright
20  * holders give permission to link this program with OpenSSL, and distribute
21  * the resulting executable, without including the source code for OpenSSL in
22  * the source distribution.
23  */
24 
25 /* ProFTPD Auth API */
26 
27 #ifndef PR_AUTH_H
28 #define PR_AUTH_H
29 
30 /* Possible return codes for auth handlers
31  */
32 
33 /* Account authenticated by means other than PASS (e.g. RFC2228 modules).
34  * This value is more generic than PR_AUTH_RFC2228_OK.
35  */
36 #define PR_AUTH_OK_NO_PASS		3
37 
38 /* Account authenticated by RFC2228 security data exchange */
39 #define PR_AUTH_RFC2228_OK		2
40 
41 /* Account authenticated normally */
42 #define PR_AUTH_OK			0
43 
44 /* Error occurred in auth handler */
45 #define PR_AUTH_ERROR			-1
46 
47 /* Account does not exist */
48 #define PR_AUTH_NOPWD			-2
49 
50 /* Password mismatch */
51 #define PR_AUTH_BADPWD			-3
52 
53 /* Password hasn't been changed recently enough */
54 #define PR_AUTH_AGEPWD			-4
55 
56 /* Account has been disabled */
57 #define PR_AUTH_DISABLEDPWD		-5
58 
59 /* Insufficient credentials. */
60 #define PR_AUTH_CRED_INSUFFICIENT	-6
61 
62 /* Unavailable credentials. */
63 #define PR_AUTH_CRED_UNAVAIL		-7
64 
65 /* Failure setting/using credentials. */
66 #define PR_AUTH_CRED_ERROR		-8
67 
68 /* Unavailable credential/authentication service. */
69 #define PR_AUTH_INFO_UNAVAIL		-9
70 
71 /* Max authentication attempts reached. */
72 #define PR_AUTH_MAX_ATTEMPTS_EXCEEDED	-10
73 
74 /* Authentication service initialization failure. */
75 #define PR_AUTH_INIT_ERROR		-11
76 
77 /* New authentication token/credentials needed. */
78 #define PR_AUTH_NEW_TOKEN_REQUIRED	-12
79 
80 void pr_auth_setpwent(pool *);
81 void pr_auth_endpwent(pool *);
82 void pr_auth_setgrent(pool *);
83 void pr_auth_endgrent(pool *);
84 struct passwd *pr_auth_getpwent(pool *);
85 struct group *pr_auth_getgrent(pool *);
86 struct passwd *pr_auth_getpwnam(pool *, const char *);
87 struct passwd *pr_auth_getpwuid(pool *, uid_t);
88 struct group *pr_auth_getgrnam(pool *, const char *);
89 struct group *pr_auth_getgrgid(pool *, gid_t);
90 int pr_auth_authenticate(pool *, const char *, const char *);
91 int pr_auth_authorize(pool *, const char *);
92 int pr_auth_check(pool *, const char *, const char *, const char *);
93 const char *pr_auth_uid2name(pool *, uid_t);
94 const char *pr_auth_gid2name(pool *, gid_t);
95 uid_t pr_auth_name2uid(pool *, const char *);
96 gid_t pr_auth_name2gid(pool *, const char *);
97 int pr_auth_getgroups(pool *, const char *, array_header **, array_header **);
98 int pr_auth_requires_pass(pool *, const char *);
99 
100 /* This is a convenience function used by mod_auth as part of the
101  * authentication process.  Given a user name, retrieve the <Anonymous>
102  * configuration for that user.  If the user name is not be handled as
103  * an anonymous login, NULL is returned.
104  */
105 config_rec *pr_auth_get_anon_config(pool *p, const char **login_user,
106   char **real_user, char **anon_user);
107 
108 /* Wrapper function around the chroot(2) system call, handles setting of
109  * appropriate environment variables if necessary.
110  */
111 int pr_auth_chroot(const char *);
112 
113 /* Check the /etc/ftpusers file, as per the UseFtpUsers directive, to see
114  * if the given user is allowed.  Returns TRUE if the user is banned by
115  * /etc/ftpusers, FALSE if not banned, and -1 if there was an error.
116  */
117 int pr_auth_banned_by_ftpusers(xaset_t *, const char *);
118 
119 /* Check the /etc/shells file, as per the RequireValidShell directive, to
120  * ensure that the given shell is valid.  Returns TRUE if the user has
121  * a valid shell, FALSE if an invalid shell, and -1 if there was an error.
122  */
123 int pr_auth_is_valid_shell(xaset_t *, const char *);
124 
125 /* Add to the list of authenticating-only modules (e.g. PAM). */
126 int pr_auth_add_auth_only_module(const char *);
127 
128 /* Remove the named module from the list of authenticating-only modules. */
129 int pr_auth_remove_auth_only_module(const char *);
130 
131 /* Clear the authenticating-only module list, e.g. when authentication has
132  * completed.
133  */
134 int pr_auth_clear_auth_only_modules(void);
135 
136 /* Clears any cached IDs/names. */
137 void pr_auth_cache_clear(void);
138 
139 /* Enable caching of certain data within the Auth API. */
140 int pr_auth_cache_set(int enable, unsigned int flags);
141 #define PR_AUTH_CACHE_FL_UID2NAME	0x00001
142 #define PR_AUTH_CACHE_FL_GID2NAME	0x00002
143 #define PR_AUTH_CACHE_FL_AUTH_MODULE	0x00004
144 #define PR_AUTH_CACHE_FL_NAME2UID	0x00008
145 #define PR_AUTH_CACHE_FL_NAME2GID	0x00010
146 #define PR_AUTH_CACHE_FL_BAD_UID2NAME	0x00020
147 #define PR_AUTH_CACHE_FL_BAD_GID2NAME	0x00040
148 #define PR_AUTH_CACHE_FL_BAD_NAME2UID	0x00080
149 #define PR_AUTH_CACHE_FL_BAD_NAME2GID	0x00100
150 
151 /* Default Auth API cache flags/settings. */
152 #define PR_AUTH_CACHE_FL_DEFAULT \
153   (PR_AUTH_CACHE_FL_UID2NAME|\
154    PR_AUTH_CACHE_FL_GID2NAME|\
155    PR_AUTH_CACHE_FL_AUTH_MODULE|\
156    PR_AUTH_CACHE_FL_NAME2UID|\
157    PR_AUTH_CACHE_FL_NAME2GID|\
158    PR_AUTH_CACHE_FL_BAD_UID2NAME|\
159    PR_AUTH_CACHE_FL_BAD_GID2NAME|\
160    PR_AUTH_CACHE_FL_BAD_NAME2UID|\
161    PR_AUTH_CACHE_FL_BAD_NAME2GID)
162 
163 /* Wrapper function for retrieving the user's home directory.  This handles
164  * any possible RewriteHome configuration.
165  */
166 const char *pr_auth_get_home(pool *, const char *pw_dir);
167 
168 /* Policy setting for the maximum allowable password length.  This is
169  * supported for mitigating potential resource consumption attack via the
170  * crypt(3) function.
171  */
172 size_t pr_auth_set_max_password_len(pool *p, size_t len);
173 
174 /* Pool-using convenience wrapper for the bcrypt() function. */
175 char *pr_auth_bcrypt(pool *p, const char *key, const char *salt,
176   size_t *hashed_len);
177 
178 /* For internal use only. */
179 int init_auth(void);
180 int set_groups(pool *, gid_t, array_header *);
181 
182 #endif /* PR_MODULES_H */
183