Damien Miller | e4340be | 2000-09-16 13:29:08 +1100 | [diff] [blame] | 1 | /* |
| 2 | * Author: Tatu Ylonen <ylo@cs.hut.fi> |
| 3 | * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland |
| 4 | * All rights reserved |
| 5 | * RSA-based authentication. This code determines whether to admit a login |
| 6 | * based on RSA authentication. This file also contains functions to check |
| 7 | * validity of the host key. |
| 8 | * |
| 9 | * As far as I am concerned, the code I have written for this software |
| 10 | * can be used freely for any purpose. Any derived versions of this |
| 11 | * software must be clearly marked as such, and if the derived work is |
| 12 | * incompatible with the protocol description in the RFC file, it must be |
| 13 | * called by a name other than "ssh" or "Secure Shell". |
| 14 | */ |
| 15 | |
Damien Miller | f6d9e22 | 2000-06-18 14:50:44 +1000 | [diff] [blame] | 16 | #include "includes.h" |
Ben Lindstrom | 46c1622 | 2000-12-22 01:43:59 +0000 | [diff] [blame] | 17 | RCSID("$OpenBSD: auth-options.c,v 1.7 2000/12/19 23:17:54 markus Exp $"); |
Damien Miller | f6d9e22 | 2000-06-18 14:50:44 +1000 | [diff] [blame] | 18 | |
| 19 | #include "ssh.h" |
| 20 | #include "packet.h" |
| 21 | #include "xmalloc.h" |
| 22 | #include "match.h" |
| 23 | |
| 24 | /* Flags set authorized_keys flags */ |
| 25 | int no_port_forwarding_flag = 0; |
| 26 | int no_agent_forwarding_flag = 0; |
| 27 | int no_x11_forwarding_flag = 0; |
| 28 | int no_pty_flag = 0; |
| 29 | |
| 30 | /* "command=" option. */ |
| 31 | char *forced_command = NULL; |
| 32 | |
| 33 | /* "environment=" options. */ |
| 34 | struct envstring *custom_environment = NULL; |
| 35 | |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 36 | void |
| 37 | auth_clear_options(void) |
| 38 | { |
| 39 | no_agent_forwarding_flag = 0; |
| 40 | no_port_forwarding_flag = 0; |
| 41 | no_pty_flag = 0; |
| 42 | no_x11_forwarding_flag = 0; |
| 43 | while (custom_environment) { |
| 44 | struct envstring *ce = custom_environment; |
| 45 | custom_environment = ce->next; |
| 46 | xfree(ce->s); |
| 47 | xfree(ce); |
| 48 | } |
| 49 | if (forced_command) { |
| 50 | xfree(forced_command); |
| 51 | forced_command = NULL; |
| 52 | } |
| 53 | } |
| 54 | |
Damien Miller | f6d9e22 | 2000-06-18 14:50:44 +1000 | [diff] [blame] | 55 | /* return 1 if access is granted, 0 if not. side effect: sets key option flags */ |
| 56 | int |
Ben Lindstrom | 46c1622 | 2000-12-22 01:43:59 +0000 | [diff] [blame] | 57 | auth_parse_options(struct passwd *pw, char *options, u_long linenum) |
Damien Miller | f6d9e22 | 2000-06-18 14:50:44 +1000 | [diff] [blame] | 58 | { |
| 59 | const char *cp; |
| 60 | if (!options) |
| 61 | return 1; |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 62 | |
| 63 | /* reset options */ |
| 64 | auth_clear_options(); |
| 65 | |
Damien Miller | f6d9e22 | 2000-06-18 14:50:44 +1000 | [diff] [blame] | 66 | while (*options && *options != ' ' && *options != '\t') { |
| 67 | cp = "no-port-forwarding"; |
Ben Lindstrom | 1492029 | 2000-11-21 21:24:55 +0000 | [diff] [blame] | 68 | if (strncasecmp(options, cp, strlen(cp)) == 0) { |
Damien Miller | f6d9e22 | 2000-06-18 14:50:44 +1000 | [diff] [blame] | 69 | packet_send_debug("Port forwarding disabled."); |
| 70 | no_port_forwarding_flag = 1; |
| 71 | options += strlen(cp); |
| 72 | goto next_option; |
| 73 | } |
| 74 | cp = "no-agent-forwarding"; |
Ben Lindstrom | 1492029 | 2000-11-21 21:24:55 +0000 | [diff] [blame] | 75 | if (strncasecmp(options, cp, strlen(cp)) == 0) { |
Damien Miller | f6d9e22 | 2000-06-18 14:50:44 +1000 | [diff] [blame] | 76 | packet_send_debug("Agent forwarding disabled."); |
| 77 | no_agent_forwarding_flag = 1; |
| 78 | options += strlen(cp); |
| 79 | goto next_option; |
| 80 | } |
| 81 | cp = "no-X11-forwarding"; |
Ben Lindstrom | 1492029 | 2000-11-21 21:24:55 +0000 | [diff] [blame] | 82 | if (strncasecmp(options, cp, strlen(cp)) == 0) { |
Damien Miller | f6d9e22 | 2000-06-18 14:50:44 +1000 | [diff] [blame] | 83 | packet_send_debug("X11 forwarding disabled."); |
| 84 | no_x11_forwarding_flag = 1; |
| 85 | options += strlen(cp); |
| 86 | goto next_option; |
| 87 | } |
| 88 | cp = "no-pty"; |
Ben Lindstrom | 1492029 | 2000-11-21 21:24:55 +0000 | [diff] [blame] | 89 | if (strncasecmp(options, cp, strlen(cp)) == 0) { |
Damien Miller | f6d9e22 | 2000-06-18 14:50:44 +1000 | [diff] [blame] | 90 | packet_send_debug("Pty allocation disabled."); |
| 91 | no_pty_flag = 1; |
| 92 | options += strlen(cp); |
| 93 | goto next_option; |
| 94 | } |
| 95 | cp = "command=\""; |
Ben Lindstrom | 1492029 | 2000-11-21 21:24:55 +0000 | [diff] [blame] | 96 | if (strncasecmp(options, cp, strlen(cp)) == 0) { |
Damien Miller | f6d9e22 | 2000-06-18 14:50:44 +1000 | [diff] [blame] | 97 | int i; |
| 98 | options += strlen(cp); |
| 99 | forced_command = xmalloc(strlen(options) + 1); |
| 100 | i = 0; |
| 101 | while (*options) { |
| 102 | if (*options == '"') |
| 103 | break; |
| 104 | if (*options == '\\' && options[1] == '"') { |
| 105 | options += 2; |
| 106 | forced_command[i++] = '"'; |
| 107 | continue; |
| 108 | } |
| 109 | forced_command[i++] = *options++; |
| 110 | } |
| 111 | if (!*options) { |
| 112 | debug("%.100s, line %lu: missing end quote", |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 113 | SSH_USER_PERMITTED_KEYS, linenum); |
Damien Miller | f6d9e22 | 2000-06-18 14:50:44 +1000 | [diff] [blame] | 114 | packet_send_debug("%.100s, line %lu: missing end quote", |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 115 | SSH_USER_PERMITTED_KEYS, linenum); |
Damien Miller | f6d9e22 | 2000-06-18 14:50:44 +1000 | [diff] [blame] | 116 | continue; |
| 117 | } |
| 118 | forced_command[i] = 0; |
| 119 | packet_send_debug("Forced command: %.900s", forced_command); |
| 120 | options++; |
| 121 | goto next_option; |
| 122 | } |
| 123 | cp = "environment=\""; |
Ben Lindstrom | 1492029 | 2000-11-21 21:24:55 +0000 | [diff] [blame] | 124 | if (strncasecmp(options, cp, strlen(cp)) == 0) { |
Damien Miller | f6d9e22 | 2000-06-18 14:50:44 +1000 | [diff] [blame] | 125 | int i; |
| 126 | char *s; |
| 127 | struct envstring *new_envstring; |
| 128 | options += strlen(cp); |
| 129 | s = xmalloc(strlen(options) + 1); |
| 130 | i = 0; |
| 131 | while (*options) { |
| 132 | if (*options == '"') |
| 133 | break; |
| 134 | if (*options == '\\' && options[1] == '"') { |
| 135 | options += 2; |
| 136 | s[i++] = '"'; |
| 137 | continue; |
| 138 | } |
| 139 | s[i++] = *options++; |
| 140 | } |
| 141 | if (!*options) { |
| 142 | debug("%.100s, line %lu: missing end quote", |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 143 | SSH_USER_PERMITTED_KEYS, linenum); |
Damien Miller | f6d9e22 | 2000-06-18 14:50:44 +1000 | [diff] [blame] | 144 | packet_send_debug("%.100s, line %lu: missing end quote", |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 145 | SSH_USER_PERMITTED_KEYS, linenum); |
Damien Miller | f6d9e22 | 2000-06-18 14:50:44 +1000 | [diff] [blame] | 146 | continue; |
| 147 | } |
| 148 | s[i] = 0; |
| 149 | packet_send_debug("Adding to environment: %.900s", s); |
| 150 | debug("Adding to environment: %.900s", s); |
| 151 | options++; |
| 152 | new_envstring = xmalloc(sizeof(struct envstring)); |
| 153 | new_envstring->s = s; |
| 154 | new_envstring->next = custom_environment; |
| 155 | custom_environment = new_envstring; |
| 156 | goto next_option; |
| 157 | } |
| 158 | cp = "from=\""; |
Ben Lindstrom | 1492029 | 2000-11-21 21:24:55 +0000 | [diff] [blame] | 159 | if (strncasecmp(options, cp, strlen(cp)) == 0) { |
Damien Miller | f6d9e22 | 2000-06-18 14:50:44 +1000 | [diff] [blame] | 160 | int mname, mip; |
| 161 | char *patterns = xmalloc(strlen(options) + 1); |
| 162 | int i; |
| 163 | options += strlen(cp); |
| 164 | i = 0; |
| 165 | while (*options) { |
| 166 | if (*options == '"') |
| 167 | break; |
| 168 | if (*options == '\\' && options[1] == '"') { |
| 169 | options += 2; |
| 170 | patterns[i++] = '"'; |
| 171 | continue; |
| 172 | } |
| 173 | patterns[i++] = *options++; |
| 174 | } |
| 175 | if (!*options) { |
| 176 | debug("%.100s, line %lu: missing end quote", |
| 177 | SSH_USER_PERMITTED_KEYS, linenum); |
| 178 | packet_send_debug("%.100s, line %lu: missing end quote", |
| 179 | SSH_USER_PERMITTED_KEYS, linenum); |
| 180 | continue; |
| 181 | } |
| 182 | patterns[i] = 0; |
| 183 | options++; |
| 184 | /* |
| 185 | * Deny access if we get a negative |
| 186 | * match for the hostname or the ip |
| 187 | * or if we get not match at all |
| 188 | */ |
| 189 | mname = match_hostname(get_canonical_hostname(), |
| 190 | patterns, strlen(patterns)); |
| 191 | mip = match_hostname(get_remote_ipaddr(), |
| 192 | patterns, strlen(patterns)); |
| 193 | xfree(patterns); |
| 194 | if (mname == -1 || mip == -1 || |
| 195 | (mname != 1 && mip != 1)) { |
| 196 | log("Authentication tried for %.100s with correct key but not from a permitted host (host=%.200s, ip=%.200s).", |
| 197 | pw->pw_name, get_canonical_hostname(), |
| 198 | get_remote_ipaddr()); |
| 199 | packet_send_debug("Your host '%.200s' is not permitted to use this key for login.", |
| 200 | get_canonical_hostname()); |
Damien Miller | f6d9e22 | 2000-06-18 14:50:44 +1000 | [diff] [blame] | 201 | /* deny access */ |
| 202 | return 0; |
| 203 | } |
| 204 | /* Host name matches. */ |
| 205 | goto next_option; |
| 206 | } |
| 207 | next_option: |
| 208 | /* |
| 209 | * Skip the comma, and move to the next option |
| 210 | * (or break out if there are no more). |
| 211 | */ |
| 212 | if (!*options) |
| 213 | fatal("Bugs in auth-options.c option processing."); |
| 214 | if (*options == ' ' || *options == '\t') |
| 215 | break; /* End of options. */ |
| 216 | if (*options != ',') |
| 217 | goto bad_option; |
| 218 | options++; |
| 219 | /* Process the next option. */ |
| 220 | } |
| 221 | /* grant access */ |
| 222 | return 1; |
| 223 | |
| 224 | bad_option: |
| 225 | log("Bad options in %.100s file, line %lu: %.50s", |
| 226 | SSH_USER_PERMITTED_KEYS, linenum, options); |
| 227 | packet_send_debug("Bad options in %.100s file, line %lu: %.50s", |
| 228 | SSH_USER_PERMITTED_KEYS, linenum, options); |
| 229 | /* deny access */ |
| 230 | return 0; |
| 231 | } |