Annotation of src/usr.bin/ssh/auth.c, Revision 1.10
1.1 markus 1: /*
2: * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
3: * All rights reserved
1.9 deraadt 4: *
5: * As far as I am concerned, the code I have written for this software
6: * can be used freely for any purpose. Any derived versions of this
7: * software must be clearly marked as such, and if the derived work is
8: * incompatible with the protocol description in the RFC file, it must be
9: * called by a name other than "ssh" or "Secure Shell".
10: *
11: *
1.2 markus 12: * Copyright (c) 2000 Markus Friedl. All rights reserved.
1.9 deraadt 13: *
14: * Redistribution and use in source and binary forms, with or without
15: * modification, are permitted provided that the following conditions
16: * are met:
17: * 1. Redistributions of source code must retain the above copyright
18: * notice, this list of conditions and the following disclaimer.
19: * 2. Redistributions in binary form must reproduce the above copyright
20: * notice, this list of conditions and the following disclaimer in the
21: * documentation and/or other materials provided with the distribution.
22: *
23: * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
24: * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
25: * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
26: * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
27: * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
28: * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
29: * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
30: * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
31: * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
32: * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
1.1 markus 33: */
34:
35: #include "includes.h"
1.10 ! markus 36: RCSID("$OpenBSD: auth.c,v 1.9 2000/09/07 20:27:49 deraadt Exp $");
1.1 markus 37:
38: #include "xmalloc.h"
39: #include "rsa.h"
40: #include "ssh.h"
41: #include "pty.h"
42: #include "packet.h"
43: #include "buffer.h"
44: #include "cipher.h"
45: #include "mpaux.h"
46: #include "servconf.h"
1.2 markus 47: #include "compat.h"
1.1 markus 48: #include "channels.h"
49: #include "match.h"
1.6 markus 50:
1.2 markus 51: #include "bufaux.h"
52: #include "ssh2.h"
53: #include "auth.h"
1.1 markus 54: #include "session.h"
1.2 markus 55:
1.1 markus 56: /* import */
57: extern ServerOptions options;
58:
59: /*
60: * Check if the user is allowed to log in via ssh. If user is listed in
61: * DenyUsers or user's primary group is listed in DenyGroups, false will
62: * be returned. If AllowUsers isn't empty and user isn't listed there, or
63: * if AllowGroups isn't empty and user isn't listed there, false will be
1.4 markus 64: * returned.
1.1 markus 65: * If the user's shell is not executable, false will be returned.
1.4 markus 66: * Otherwise true is returned.
1.1 markus 67: */
1.5 markus 68: int
1.1 markus 69: allowed_user(struct passwd * pw)
70: {
71: struct stat st;
72: struct group *grp;
1.7 deraadt 73: char *shell;
1.1 markus 74: int i;
75:
76: /* Shouldn't be called if pw is NULL, but better safe than sorry... */
77: if (!pw)
78: return 0;
79:
1.7 deraadt 80: /*
81: * Get the shell from the password data. An empty shell field is
82: * legal, and means /bin/sh.
83: */
84: shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
85:
1.1 markus 86: /* deny if shell does not exists or is not executable */
1.7 deraadt 87: if (stat(shell, &st) != 0)
1.1 markus 88: return 0;
89: if (!((st.st_mode & S_IFREG) && (st.st_mode & (S_IXOTH|S_IXUSR|S_IXGRP))))
90: return 0;
91:
92: /* Return false if user is listed in DenyUsers */
93: if (options.num_deny_users > 0) {
94: if (!pw->pw_name)
95: return 0;
96: for (i = 0; i < options.num_deny_users; i++)
97: if (match_pattern(pw->pw_name, options.deny_users[i]))
98: return 0;
99: }
100: /* Return false if AllowUsers isn't empty and user isn't listed there */
101: if (options.num_allow_users > 0) {
102: if (!pw->pw_name)
103: return 0;
104: for (i = 0; i < options.num_allow_users; i++)
105: if (match_pattern(pw->pw_name, options.allow_users[i]))
106: break;
107: /* i < options.num_allow_users iff we break for loop */
108: if (i >= options.num_allow_users)
109: return 0;
110: }
111: /* Get the primary group name if we need it. Return false if it fails */
112: if (options.num_deny_groups > 0 || options.num_allow_groups > 0) {
113: grp = getgrgid(pw->pw_gid);
114: if (!grp)
115: return 0;
116:
117: /* Return false if user's group is listed in DenyGroups */
118: if (options.num_deny_groups > 0) {
119: if (!grp->gr_name)
120: return 0;
121: for (i = 0; i < options.num_deny_groups; i++)
122: if (match_pattern(grp->gr_name, options.deny_groups[i]))
123: return 0;
124: }
125: /*
126: * Return false if AllowGroups isn't empty and user's group
127: * isn't listed there
128: */
129: if (options.num_allow_groups > 0) {
130: if (!grp->gr_name)
131: return 0;
132: for (i = 0; i < options.num_allow_groups; i++)
133: if (match_pattern(grp->gr_name, options.allow_groups[i]))
134: break;
135: /* i < options.num_allow_groups iff we break for
136: loop */
137: if (i >= options.num_allow_groups)
138: return 0;
139: }
140: }
141: /* We found no reason not to let this user try to log on... */
142: return 1;
143: }
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