Damien Miller | e72b7af | 1999-12-30 15:08:44 +1100 | [diff] [blame] | 1 | /* |
| 2 | * Author: Damien Miller |
| 3 | * Copyright (c) 1999 Damien Miller <djm@mindrot.org> |
| 4 | * All rights reserved |
| 5 | * Created: Thursday December 30 1999 |
| 6 | * PAM authentication and session management code. |
| 7 | */ |
| 8 | |
| 9 | #include "includes.h" |
| 10 | |
| 11 | #ifdef USE_PAM |
| 12 | #include "ssh.h" |
| 13 | #include "xmalloc.h" |
| 14 | #include "servconf.h" |
| 15 | |
Damien Miller | 2f6a0ad | 2000-05-31 11:20:11 +1000 | [diff] [blame^] | 16 | RCSID("$Id: auth-pam.c,v 1.5 2000/05/31 01:20:12 damien Exp $"); |
| 17 | |
| 18 | #define NEW_AUTHTOK_MSG \ |
| 19 | "Warning: You password has expired, please change it now" |
Damien Miller | e72b7af | 1999-12-30 15:08:44 +1100 | [diff] [blame] | 20 | |
| 21 | /* Callbacks */ |
| 22 | static int pamconv(int num_msg, const struct pam_message **msg, |
| 23 | struct pam_response **resp, void *appdata_ptr); |
| 24 | void pam_cleanup_proc(void *context); |
Damien Miller | 2f6a0ad | 2000-05-31 11:20:11 +1000 | [diff] [blame^] | 25 | void pam_msg_cat(const char *msg); |
Damien Miller | e72b7af | 1999-12-30 15:08:44 +1100 | [diff] [blame] | 26 | |
| 27 | /* module-local variables */ |
| 28 | static struct pam_conv conv = { |
| 29 | pamconv, |
| 30 | NULL |
| 31 | }; |
| 32 | static struct pam_handle_t *pamh = NULL; |
| 33 | static const char *pampasswd = NULL; |
Damien Miller | 2f6a0ad | 2000-05-31 11:20:11 +1000 | [diff] [blame^] | 34 | static char *pam_msg = NULL; |
Damien Miller | e72b7af | 1999-12-30 15:08:44 +1100 | [diff] [blame] | 35 | |
| 36 | /* PAM conversation function. This is really a kludge to get the password */ |
| 37 | /* into PAM and to pick up any messages generated by PAM into pamconv_msg */ |
| 38 | static int pamconv(int num_msg, const struct pam_message **msg, |
| 39 | struct pam_response **resp, void *appdata_ptr) |
| 40 | { |
| 41 | struct pam_response *reply; |
| 42 | int count; |
Damien Miller | e72b7af | 1999-12-30 15:08:44 +1100 | [diff] [blame] | 43 | |
| 44 | /* PAM will free this later */ |
| 45 | reply = malloc(num_msg * sizeof(*reply)); |
| 46 | if (reply == NULL) |
| 47 | return PAM_CONV_ERR; |
| 48 | |
| 49 | for(count = 0; count < num_msg; count++) { |
| 50 | switch (msg[count]->msg_style) { |
| 51 | case PAM_PROMPT_ECHO_OFF: |
| 52 | if (pampasswd == NULL) { |
| 53 | free(reply); |
| 54 | return PAM_CONV_ERR; |
| 55 | } |
| 56 | reply[count].resp_retcode = PAM_SUCCESS; |
| 57 | reply[count].resp = xstrdup(pampasswd); |
| 58 | break; |
Damien Miller | e72b7af | 1999-12-30 15:08:44 +1100 | [diff] [blame] | 59 | case PAM_TEXT_INFO: |
| 60 | reply[count].resp_retcode = PAM_SUCCESS; |
| 61 | reply[count].resp = xstrdup(""); |
| 62 | |
Damien Miller | 2f6a0ad | 2000-05-31 11:20:11 +1000 | [diff] [blame^] | 63 | if (msg[count]->msg != NULL) |
| 64 | pam_msg_cat(msg[count]->msg); |
Damien Miller | e72b7af | 1999-12-30 15:08:44 +1100 | [diff] [blame] | 65 | |
Damien Miller | e72b7af | 1999-12-30 15:08:44 +1100 | [diff] [blame] | 66 | break; |
Damien Miller | e72b7af | 1999-12-30 15:08:44 +1100 | [diff] [blame] | 67 | default: |
| 68 | free(reply); |
| 69 | return PAM_CONV_ERR; |
| 70 | } |
| 71 | } |
| 72 | |
| 73 | *resp = reply; |
| 74 | |
| 75 | return PAM_SUCCESS; |
| 76 | } |
| 77 | |
| 78 | /* Called at exit to cleanly shutdown PAM */ |
| 79 | void pam_cleanup_proc(void *context) |
| 80 | { |
| 81 | int pam_retval; |
| 82 | |
| 83 | if (pamh != NULL) |
| 84 | { |
| 85 | pam_retval = pam_close_session((pam_handle_t *)pamh, 0); |
| 86 | if (pam_retval != PAM_SUCCESS) { |
| 87 | log("Cannot close PAM session: %.200s", |
Damien Miller | 2f6a0ad | 2000-05-31 11:20:11 +1000 | [diff] [blame^] | 88 | PAM_STRERROR((pam_handle_t *)pamh, pam_retval)); |
Damien Miller | e72b7af | 1999-12-30 15:08:44 +1100 | [diff] [blame] | 89 | } |
| 90 | |
| 91 | pam_retval = pam_setcred((pam_handle_t *)pamh, PAM_DELETE_CRED); |
| 92 | if (pam_retval != PAM_SUCCESS) { |
| 93 | log("Cannot delete credentials: %.200s", |
Damien Miller | 2f6a0ad | 2000-05-31 11:20:11 +1000 | [diff] [blame^] | 94 | PAM_STRERROR((pam_handle_t *)pamh, pam_retval)); |
Damien Miller | e72b7af | 1999-12-30 15:08:44 +1100 | [diff] [blame] | 95 | } |
| 96 | |
| 97 | pam_retval = pam_end((pam_handle_t *)pamh, pam_retval); |
| 98 | if (pam_retval != PAM_SUCCESS) { |
| 99 | log("Cannot release PAM authentication: %.200s", |
Damien Miller | 2f6a0ad | 2000-05-31 11:20:11 +1000 | [diff] [blame^] | 100 | PAM_STRERROR((pam_handle_t *)pamh, pam_retval)); |
Damien Miller | e72b7af | 1999-12-30 15:08:44 +1100 | [diff] [blame] | 101 | } |
| 102 | } |
| 103 | } |
| 104 | |
| 105 | /* Attempt password authentation using PAM */ |
| 106 | int auth_pam_password(struct passwd *pw, const char *password) |
| 107 | { |
| 108 | extern ServerOptions options; |
| 109 | int pam_retval; |
| 110 | |
| 111 | /* deny if no user. */ |
| 112 | if (pw == NULL) |
| 113 | return 0; |
| 114 | if (pw->pw_uid == 0 && options.permit_root_login == 2) |
| 115 | return 0; |
| 116 | if (*password == '\0' && options.permit_empty_passwd == 0) |
| 117 | return 0; |
| 118 | |
| 119 | pampasswd = password; |
| 120 | |
| 121 | pam_retval = pam_authenticate((pam_handle_t *)pamh, 0); |
| 122 | if (pam_retval == PAM_SUCCESS) { |
Damien Miller | 2f6a0ad | 2000-05-31 11:20:11 +1000 | [diff] [blame^] | 123 | debug("PAM Password authentication accepted for user \"%.100s\"", |
| 124 | pw->pw_name); |
Damien Miller | e72b7af | 1999-12-30 15:08:44 +1100 | [diff] [blame] | 125 | return 1; |
| 126 | } else { |
| 127 | debug("PAM Password authentication for \"%.100s\" failed: %s", |
| 128 | pw->pw_name, PAM_STRERROR((pam_handle_t *)pamh, pam_retval)); |
| 129 | return 0; |
| 130 | } |
| 131 | } |
| 132 | |
| 133 | /* Do account management using PAM */ |
| 134 | int do_pam_account(char *username, char *remote_user) |
| 135 | { |
| 136 | int pam_retval; |
Damien Miller | 2f6a0ad | 2000-05-31 11:20:11 +1000 | [diff] [blame^] | 137 | |
Damien Miller | e72b7af | 1999-12-30 15:08:44 +1100 | [diff] [blame] | 138 | debug("PAM setting rhost to \"%.200s\"", get_canonical_hostname()); |
| 139 | pam_retval = pam_set_item((pam_handle_t *)pamh, PAM_RHOST, |
| 140 | get_canonical_hostname()); |
| 141 | if (pam_retval != PAM_SUCCESS) { |
Damien Miller | 2f6a0ad | 2000-05-31 11:20:11 +1000 | [diff] [blame^] | 142 | fatal("PAM set rhost failed: %.200s", |
| 143 | PAM_STRERROR((pam_handle_t *)pamh, pam_retval)); |
Damien Miller | e72b7af | 1999-12-30 15:08:44 +1100 | [diff] [blame] | 144 | } |
| 145 | |
| 146 | if (remote_user != NULL) { |
| 147 | debug("PAM setting ruser to \"%.200s\"", remote_user); |
| 148 | pam_retval = pam_set_item((pam_handle_t *)pamh, PAM_RUSER, remote_user); |
| 149 | if (pam_retval != PAM_SUCCESS) { |
Damien Miller | 2f6a0ad | 2000-05-31 11:20:11 +1000 | [diff] [blame^] | 150 | fatal("PAM set ruser failed: %.200s", |
| 151 | PAM_STRERROR((pam_handle_t *)pamh, pam_retval)); |
Damien Miller | e72b7af | 1999-12-30 15:08:44 +1100 | [diff] [blame] | 152 | } |
| 153 | } |
| 154 | |
| 155 | pam_retval = pam_acct_mgmt((pam_handle_t *)pamh, 0); |
Damien Miller | 2f6a0ad | 2000-05-31 11:20:11 +1000 | [diff] [blame^] | 156 | switch (pam_retval) { |
| 157 | case PAM_SUCCESS: |
| 158 | /* This is what we want */ |
| 159 | break; |
| 160 | case PAM_NEW_AUTHTOK_REQD: |
| 161 | pam_msg_cat(NEW_AUTHTOK_MSG); |
| 162 | break; |
| 163 | default: |
| 164 | log("PAM rejected by account configuration: %.200s", |
| 165 | PAM_STRERROR((pam_handle_t *)pamh, pam_retval)); |
| 166 | return(0); |
Damien Miller | e72b7af | 1999-12-30 15:08:44 +1100 | [diff] [blame] | 167 | } |
| 168 | |
| 169 | return(1); |
| 170 | } |
| 171 | |
| 172 | /* Do PAM-specific session initialisation */ |
Damien Miller | 3e955e7 | 2000-01-27 10:55:38 +1100 | [diff] [blame] | 173 | void do_pam_session(char *username, const char *ttyname) |
Damien Miller | e72b7af | 1999-12-30 15:08:44 +1100 | [diff] [blame] | 174 | { |
| 175 | int pam_retval; |
| 176 | |
| 177 | if (ttyname != NULL) { |
| 178 | debug("PAM setting tty to \"%.200s\"", ttyname); |
| 179 | pam_retval = pam_set_item((pam_handle_t *)pamh, PAM_TTY, ttyname); |
Damien Miller | 2f6a0ad | 2000-05-31 11:20:11 +1000 | [diff] [blame^] | 180 | if (pam_retval != PAM_SUCCESS) { |
| 181 | fatal("PAM set tty failed: %.200s", |
| 182 | PAM_STRERROR((pam_handle_t *)pamh, pam_retval)); |
| 183 | } |
Damien Miller | e72b7af | 1999-12-30 15:08:44 +1100 | [diff] [blame] | 184 | } |
| 185 | |
| 186 | pam_retval = pam_open_session((pam_handle_t *)pamh, 0); |
Damien Miller | 2f6a0ad | 2000-05-31 11:20:11 +1000 | [diff] [blame^] | 187 | if (pam_retval != PAM_SUCCESS) { |
| 188 | fatal("PAM session setup failed: %.200s", |
| 189 | PAM_STRERROR((pam_handle_t *)pamh, pam_retval)); |
| 190 | } |
Damien Miller | e72b7af | 1999-12-30 15:08:44 +1100 | [diff] [blame] | 191 | } |
| 192 | |
| 193 | /* Set PAM credentials */ |
| 194 | void do_pam_setcred() |
| 195 | { |
| 196 | int pam_retval; |
| 197 | |
| 198 | debug("PAM establishing creds"); |
| 199 | pam_retval = pam_setcred((pam_handle_t *)pamh, PAM_ESTABLISH_CRED); |
Damien Miller | 2f6a0ad | 2000-05-31 11:20:11 +1000 | [diff] [blame^] | 200 | if (pam_retval != PAM_SUCCESS) { |
| 201 | fatal("PAM setcred failed: %.200s", |
| 202 | PAM_STRERROR((pam_handle_t *)pamh, pam_retval)); |
| 203 | } |
Damien Miller | e72b7af | 1999-12-30 15:08:44 +1100 | [diff] [blame] | 204 | } |
| 205 | |
| 206 | /* Cleanly shutdown PAM */ |
| 207 | void finish_pam(void) |
| 208 | { |
| 209 | pam_cleanup_proc(NULL); |
| 210 | fatal_remove_cleanup(&pam_cleanup_proc, NULL); |
| 211 | } |
| 212 | |
| 213 | /* Start PAM authentication for specified account */ |
| 214 | void start_pam(struct passwd *pw) |
| 215 | { |
| 216 | int pam_retval; |
| 217 | |
| 218 | debug("Starting up PAM with username \"%.200s\"", pw->pw_name); |
| 219 | |
Damien Miller | d0cff3e | 2000-04-20 23:12:58 +1000 | [diff] [blame] | 220 | pam_retval = pam_start(SSHD_PAM_SERVICE, pw->pw_name, &conv, |
| 221 | (pam_handle_t**)&pamh); |
Damien Miller | e72b7af | 1999-12-30 15:08:44 +1100 | [diff] [blame] | 222 | |
Damien Miller | 2f6a0ad | 2000-05-31 11:20:11 +1000 | [diff] [blame^] | 223 | if (pam_retval != PAM_SUCCESS) { |
| 224 | fatal("PAM initialisation failed: %.200s", |
| 225 | PAM_STRERROR((pam_handle_t *)pamh, pam_retval)); |
| 226 | } |
| 227 | |
Damien Miller | e72b7af | 1999-12-30 15:08:44 +1100 | [diff] [blame] | 228 | fatal_add_cleanup(&pam_cleanup_proc, NULL); |
| 229 | } |
| 230 | |
| 231 | /* Return list of PAM enviornment strings */ |
| 232 | char **fetch_pam_environment(void) |
| 233 | { |
Damien Miller | 1bead33 | 2000-04-30 00:47:29 +1000 | [diff] [blame] | 234 | #ifdef HAVE_PAM_GETENVLIST |
Damien Miller | e72b7af | 1999-12-30 15:08:44 +1100 | [diff] [blame] | 235 | return(pam_getenvlist((pam_handle_t *)pamh)); |
Damien Miller | 1bead33 | 2000-04-30 00:47:29 +1000 | [diff] [blame] | 236 | #else /* HAVE_PAM_GETENVLIST */ |
| 237 | return(NULL); |
| 238 | #endif /* HAVE_PAM_GETENVLIST */ |
Damien Miller | e72b7af | 1999-12-30 15:08:44 +1100 | [diff] [blame] | 239 | } |
| 240 | |
| 241 | /* Print any messages that have been generated during authentication */ |
| 242 | /* or account checking to stderr */ |
| 243 | void print_pam_messages(void) |
| 244 | { |
Damien Miller | 2f6a0ad | 2000-05-31 11:20:11 +1000 | [diff] [blame^] | 245 | if (pam_msg != NULL) |
| 246 | fprintf(stderr, pam_msg); |
| 247 | } |
| 248 | |
| 249 | /* Append a message to the PAM message buffer */ |
| 250 | void pam_msg_cat(const char *msg) |
| 251 | { |
| 252 | char *p; |
| 253 | size_t new_msg_len; |
| 254 | size_t pam_msg_len; |
| 255 | |
| 256 | new_msg_len = strlen(msg); |
| 257 | |
| 258 | if (pam_msg) { |
| 259 | pam_msg_len = strlen(pam_msg); |
| 260 | pam_msg = xrealloc(pam_msg, new_msg_len + pam_msg_len + 2); |
| 261 | p = pam_msg + pam_msg_len; |
| 262 | } else { |
| 263 | pam_msg = p = xmalloc(new_msg_len + 2); |
| 264 | } |
| 265 | |
| 266 | memcpy(p, msg, new_msg_len); |
| 267 | p[new_msg_len] = '\n'; |
| 268 | p[new_msg_len + 1] = '\0'; |
Damien Miller | e72b7af | 1999-12-30 15:08:44 +1100 | [diff] [blame] | 269 | } |
| 270 | |
| 271 | #endif /* USE_PAM */ |