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" |
Damien Miller | e4340be | 2000-09-16 13:29:08 +1100 | [diff] [blame^] | 17 | RCSID("$OpenBSD: auth-options.c,v 1.4 2000/09/07 21:13:36 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 | |
| 36 | /* return 1 if access is granted, 0 if not. side effect: sets key option flags */ |
| 37 | int |
| 38 | auth_parse_options(struct passwd *pw, char *options, unsigned long linenum) |
| 39 | { |
| 40 | const char *cp; |
| 41 | if (!options) |
| 42 | return 1; |
| 43 | while (*options && *options != ' ' && *options != '\t') { |
| 44 | cp = "no-port-forwarding"; |
| 45 | if (strncmp(options, cp, strlen(cp)) == 0) { |
| 46 | packet_send_debug("Port forwarding disabled."); |
| 47 | no_port_forwarding_flag = 1; |
| 48 | options += strlen(cp); |
| 49 | goto next_option; |
| 50 | } |
| 51 | cp = "no-agent-forwarding"; |
| 52 | if (strncmp(options, cp, strlen(cp)) == 0) { |
| 53 | packet_send_debug("Agent forwarding disabled."); |
| 54 | no_agent_forwarding_flag = 1; |
| 55 | options += strlen(cp); |
| 56 | goto next_option; |
| 57 | } |
| 58 | cp = "no-X11-forwarding"; |
| 59 | if (strncmp(options, cp, strlen(cp)) == 0) { |
| 60 | packet_send_debug("X11 forwarding disabled."); |
| 61 | no_x11_forwarding_flag = 1; |
| 62 | options += strlen(cp); |
| 63 | goto next_option; |
| 64 | } |
| 65 | cp = "no-pty"; |
| 66 | if (strncmp(options, cp, strlen(cp)) == 0) { |
| 67 | packet_send_debug("Pty allocation disabled."); |
| 68 | no_pty_flag = 1; |
| 69 | options += strlen(cp); |
| 70 | goto next_option; |
| 71 | } |
| 72 | cp = "command=\""; |
| 73 | if (strncmp(options, cp, strlen(cp)) == 0) { |
| 74 | int i; |
| 75 | options += strlen(cp); |
| 76 | forced_command = xmalloc(strlen(options) + 1); |
| 77 | i = 0; |
| 78 | while (*options) { |
| 79 | if (*options == '"') |
| 80 | break; |
| 81 | if (*options == '\\' && options[1] == '"') { |
| 82 | options += 2; |
| 83 | forced_command[i++] = '"'; |
| 84 | continue; |
| 85 | } |
| 86 | forced_command[i++] = *options++; |
| 87 | } |
| 88 | if (!*options) { |
| 89 | debug("%.100s, line %lu: missing end quote", |
| 90 | SSH_USER_PERMITTED_KEYS, linenum); |
| 91 | packet_send_debug("%.100s, line %lu: missing end quote", |
| 92 | SSH_USER_PERMITTED_KEYS, linenum); |
| 93 | continue; |
| 94 | } |
| 95 | forced_command[i] = 0; |
| 96 | packet_send_debug("Forced command: %.900s", forced_command); |
| 97 | options++; |
| 98 | goto next_option; |
| 99 | } |
| 100 | cp = "environment=\""; |
| 101 | if (strncmp(options, cp, strlen(cp)) == 0) { |
| 102 | int i; |
| 103 | char *s; |
| 104 | struct envstring *new_envstring; |
| 105 | options += strlen(cp); |
| 106 | s = xmalloc(strlen(options) + 1); |
| 107 | i = 0; |
| 108 | while (*options) { |
| 109 | if (*options == '"') |
| 110 | break; |
| 111 | if (*options == '\\' && options[1] == '"') { |
| 112 | options += 2; |
| 113 | s[i++] = '"'; |
| 114 | continue; |
| 115 | } |
| 116 | s[i++] = *options++; |
| 117 | } |
| 118 | if (!*options) { |
| 119 | debug("%.100s, line %lu: missing end quote", |
| 120 | SSH_USER_PERMITTED_KEYS, linenum); |
| 121 | packet_send_debug("%.100s, line %lu: missing end quote", |
| 122 | SSH_USER_PERMITTED_KEYS, linenum); |
| 123 | continue; |
| 124 | } |
| 125 | s[i] = 0; |
| 126 | packet_send_debug("Adding to environment: %.900s", s); |
| 127 | debug("Adding to environment: %.900s", s); |
| 128 | options++; |
| 129 | new_envstring = xmalloc(sizeof(struct envstring)); |
| 130 | new_envstring->s = s; |
| 131 | new_envstring->next = custom_environment; |
| 132 | custom_environment = new_envstring; |
| 133 | goto next_option; |
| 134 | } |
| 135 | cp = "from=\""; |
| 136 | if (strncmp(options, cp, strlen(cp)) == 0) { |
| 137 | int mname, mip; |
| 138 | char *patterns = xmalloc(strlen(options) + 1); |
| 139 | int i; |
| 140 | options += strlen(cp); |
| 141 | i = 0; |
| 142 | while (*options) { |
| 143 | if (*options == '"') |
| 144 | break; |
| 145 | if (*options == '\\' && options[1] == '"') { |
| 146 | options += 2; |
| 147 | patterns[i++] = '"'; |
| 148 | continue; |
| 149 | } |
| 150 | patterns[i++] = *options++; |
| 151 | } |
| 152 | if (!*options) { |
| 153 | debug("%.100s, line %lu: missing end quote", |
| 154 | SSH_USER_PERMITTED_KEYS, linenum); |
| 155 | packet_send_debug("%.100s, line %lu: missing end quote", |
| 156 | SSH_USER_PERMITTED_KEYS, linenum); |
| 157 | continue; |
| 158 | } |
| 159 | patterns[i] = 0; |
| 160 | options++; |
| 161 | /* |
| 162 | * Deny access if we get a negative |
| 163 | * match for the hostname or the ip |
| 164 | * or if we get not match at all |
| 165 | */ |
| 166 | mname = match_hostname(get_canonical_hostname(), |
| 167 | patterns, strlen(patterns)); |
| 168 | mip = match_hostname(get_remote_ipaddr(), |
| 169 | patterns, strlen(patterns)); |
| 170 | xfree(patterns); |
| 171 | if (mname == -1 || mip == -1 || |
| 172 | (mname != 1 && mip != 1)) { |
| 173 | log("Authentication tried for %.100s with correct key but not from a permitted host (host=%.200s, ip=%.200s).", |
| 174 | pw->pw_name, get_canonical_hostname(), |
| 175 | get_remote_ipaddr()); |
| 176 | packet_send_debug("Your host '%.200s' is not permitted to use this key for login.", |
| 177 | get_canonical_hostname()); |
| 178 | /* key invalid for this host, reset flags */ |
| 179 | no_agent_forwarding_flag = 0; |
| 180 | no_port_forwarding_flag = 0; |
| 181 | no_pty_flag = 0; |
| 182 | no_x11_forwarding_flag = 0; |
| 183 | while (custom_environment) { |
| 184 | struct envstring *ce = custom_environment; |
| 185 | custom_environment = ce->next; |
| 186 | xfree(ce->s); |
| 187 | xfree(ce); |
| 188 | } |
| 189 | if (forced_command) { |
| 190 | xfree(forced_command); |
| 191 | forced_command = NULL; |
| 192 | } |
| 193 | /* deny access */ |
| 194 | return 0; |
| 195 | } |
| 196 | /* Host name matches. */ |
| 197 | goto next_option; |
| 198 | } |
| 199 | next_option: |
| 200 | /* |
| 201 | * Skip the comma, and move to the next option |
| 202 | * (or break out if there are no more). |
| 203 | */ |
| 204 | if (!*options) |
| 205 | fatal("Bugs in auth-options.c option processing."); |
| 206 | if (*options == ' ' || *options == '\t') |
| 207 | break; /* End of options. */ |
| 208 | if (*options != ',') |
| 209 | goto bad_option; |
| 210 | options++; |
| 211 | /* Process the next option. */ |
| 212 | } |
| 213 | /* grant access */ |
| 214 | return 1; |
| 215 | |
| 216 | bad_option: |
| 217 | log("Bad options in %.100s file, line %lu: %.50s", |
| 218 | SSH_USER_PERMITTED_KEYS, linenum, options); |
| 219 | packet_send_debug("Bad options in %.100s file, line %lu: %.50s", |
| 220 | SSH_USER_PERMITTED_KEYS, linenum, options); |
| 221 | /* deny access */ |
| 222 | return 0; |
| 223 | } |