| 1 | /* PAM Make Home Dir module |
| 2 | |
| 3 | This module will create a users home directory if it does not exist |
| 4 | when the session begins. This allows users to be present in central |
| 5 | database (such as nis, kerb or ldap) without using a distributed |
| 6 | file system or pre-creating a large number of directories. |
| 7 | |
| 8 | Here is a sample /etc/pam.d/login file for Debian GNU/Linux |
| 9 | 2.1: |
| 10 | |
| 11 | auth requisite pam_securetty.so |
| 12 | auth sufficient pam_ldap.so |
| 13 | auth required pam_pwdb.so |
| 14 | auth optional pam_group.so |
| 15 | auth optional pam_mail.so |
| 16 | account requisite pam_time.so |
| 17 | account sufficient pam_ldap.so |
| 18 | account required pam_pwdb.so |
| 19 | session required pam_mkhomedir.so skel=/etc/skel/ umask=0022 |
| 20 | session required pam_pwdb.so |
| 21 | session optional pam_lastlog.so |
| 22 | password required pam_pwdb.so |
| 23 | |
| 24 | Released under the GNU LGPL version 2 or later |
| 25 | Originally written by Jason Gunthorpe <jgg@debian.org> Feb 1999 |
| 26 | Structure taken from pam_lastlogin by Andrew Morgan |
| 27 | <morgan@parc.power.net> 1996 |
| 28 | * $FreeBSD: src/contrib/libpam/modules/pam_mkhomedir/pam_mkhomedir.c,v 1.1.1.1.2.2 2001/06/11 15:28:20 markm Exp $ |
| 29 | * $DragonFly: src/contrib/libpam/modules/pam_mkhomedir/Attic/pam_mkhomedir.c,v 1.2 2003/06/17 04:24:03 dillon Exp $ |
| 30 | */ |
| 31 | |
| 32 | /* I want snprintf dammit */ |
| 33 | #define _GNU_SOURCE 1 |
| 34 | #include <stdarg.h> |
| 35 | #include <sys/types.h> |
| 36 | #include <sys/stat.h> |
| 37 | #include <fcntl.h> |
| 38 | #include <unistd.h> |
| 39 | #include <pwd.h> |
| 40 | #include <stdlib.h> |
| 41 | #include <stdio.h> |
| 42 | #include <string.h> |
| 43 | #include <dirent.h> |
| 44 | |
| 45 | /* |
| 46 | * here, we make a definition for the externally accessible function |
| 47 | * in this file (this definition is required for static a module |
| 48 | * but strongly encouraged generally) it is used to instruct the |
| 49 | * modules include file to define the function prototypes. |
| 50 | */ |
| 51 | |
| 52 | #define PAM_SM_SESSION |
| 53 | |
| 54 | #include <security/pam_modules.h> |
| 55 | #include <security/_pam_macros.h> |
| 56 | |
| 57 | /* argument parsing */ |
| 58 | #define MKHOMEDIR_DEBUG 020 /* keep quiet about things */ |
| 59 | #define MKHOMEDIR_QUIET 040 /* keep quiet about things */ |
| 60 | |
| 61 | static unsigned int UMask = 0022; |
| 62 | static char SkelDir[BUFSIZ] = "/etc/skel"; |
| 63 | |
| 64 | /* some syslogging */ |
| 65 | static void _log_err(int err, const char *format, ...) |
| 66 | { |
| 67 | va_list args; |
| 68 | |
| 69 | va_start(args, format); |
| 70 | openlog("PAM-mkhomedir", LOG_CONS|LOG_PID, LOG_AUTH); |
| 71 | vsyslog(err, format, args); |
| 72 | va_end(args); |
| 73 | closelog(); |
| 74 | } |
| 75 | |
| 76 | static int _pam_parse(int flags, int argc, const char **argv) |
| 77 | { |
| 78 | int ctrl = 0; |
| 79 | |
| 80 | /* does the appliction require quiet? */ |
| 81 | if ((flags & PAM_SILENT) == PAM_SILENT) |
| 82 | ctrl |= MKHOMEDIR_QUIET; |
| 83 | |
| 84 | /* step through arguments */ |
| 85 | for (; argc-- > 0; ++argv) |
| 86 | { |
| 87 | if (!strcmp(*argv, "silent")) |
| 88 | { |
| 89 | ctrl |= MKHOMEDIR_QUIET; |
| 90 | } |
| 91 | else if (!strncmp(*argv,"umask=",6)) |
| 92 | UMask = strtol(*argv+6,0,0); |
| 93 | else if (!strncmp(*argv,"skel=",5)) |
| 94 | strcpy(SkelDir,*argv+5); |
| 95 | else |
| 96 | { |
| 97 | _log_err(LOG_ERR, "unknown option; %s", *argv); |
| 98 | } |
| 99 | } |
| 100 | |
| 101 | D(("ctrl = %o", ctrl)); |
| 102 | return ctrl; |
| 103 | } |
| 104 | |
| 105 | /* This common function is used to send a message to the applications |
| 106 | conversion function. Our only use is to ask the application to print |
| 107 | an informative message that we are creating a home directory */ |
| 108 | static int converse(pam_handle_t * pamh, int ctrl, int nargs |
| 109 | ,struct pam_message **message |
| 110 | ,struct pam_response **response) |
| 111 | { |
| 112 | int retval; |
| 113 | struct pam_conv *conv; |
| 114 | |
| 115 | D(("begin to converse")); |
| 116 | |
| 117 | retval = pam_get_item(pamh, PAM_CONV, (const void **) &conv); |
| 118 | if (retval == PAM_SUCCESS) |
| 119 | { |
| 120 | |
| 121 | retval = conv->conv(nargs, (const struct pam_message **) message |
| 122 | ,response, conv->appdata_ptr); |
| 123 | |
| 124 | D(("returned from application's conversation function")); |
| 125 | |
| 126 | if (retval != PAM_SUCCESS && (ctrl & MKHOMEDIR_DEBUG)) |
| 127 | { |
| 128 | _log_err(LOG_DEBUG, "conversation failure [%s]" |
| 129 | ,pam_strerror(pamh, retval)); |
| 130 | } |
| 131 | |
| 132 | } |
| 133 | else |
| 134 | { |
| 135 | _log_err(LOG_ERR, "couldn't obtain coversation function [%s]" |
| 136 | ,pam_strerror(pamh, retval)); |
| 137 | } |
| 138 | |
| 139 | D(("ready to return from module conversation")); |
| 140 | |
| 141 | return retval; /* propagate error status */ |
| 142 | } |
| 143 | |
| 144 | /* Ask the application to display a short text string for us. */ |
| 145 | static int make_remark(pam_handle_t * pamh, int ctrl, const char *remark) |
| 146 | { |
| 147 | int retval; |
| 148 | |
| 149 | if ((ctrl & MKHOMEDIR_QUIET) != MKHOMEDIR_QUIET) |
| 150 | { |
| 151 | struct pam_message msg[1], *mesg[1]; |
| 152 | struct pam_response *resp = NULL; |
| 153 | |
| 154 | mesg[0] = &msg[0]; |
| 155 | msg[0].msg_style = PAM_TEXT_INFO; |
| 156 | msg[0].msg = remark; |
| 157 | |
| 158 | retval = converse(pamh, ctrl, 1, mesg, &resp); |
| 159 | |
| 160 | msg[0].msg = NULL; |
| 161 | if (resp) |
| 162 | { |
| 163 | _pam_drop_reply(resp, 1); |
| 164 | } |
| 165 | } |
| 166 | else |
| 167 | { |
| 168 | D(("keeping quiet")); |
| 169 | retval = PAM_SUCCESS; |
| 170 | } |
| 171 | |
| 172 | D(("returning %s", pam_strerror(pamh, retval))); |
| 173 | return retval; |
| 174 | } |
| 175 | |
| 176 | /* Do the actual work of creating a home dir */ |
| 177 | static int create_homedir(pam_handle_t * pamh, int ctrl, |
| 178 | const struct passwd *pwd) |
| 179 | { |
| 180 | char *remark; |
| 181 | DIR *D; |
| 182 | struct dirent *Dir; |
| 183 | |
| 184 | /* Some scratch space */ |
| 185 | remark = malloc(BUFSIZ); |
| 186 | if (remark == NULL) |
| 187 | { |
| 188 | D(("no memory for last login remark")); |
| 189 | return PAM_BUF_ERR; |
| 190 | } |
| 191 | |
| 192 | /* Mention what is happening, if the notification fails that is OK */ |
| 193 | if (snprintf(remark,BUFSIZ,"Creating home directory '%s'.", |
| 194 | pwd->pw_dir) == -1) |
| 195 | return PAM_PERM_DENIED; |
| 196 | |
| 197 | make_remark(pamh, ctrl, remark); |
| 198 | |
| 199 | /* Crete the home directory */ |
| 200 | if (mkdir(pwd->pw_dir,0700) != 0) |
| 201 | { |
| 202 | free(remark); |
| 203 | _log_err(LOG_DEBUG, "unable to create home directory %s",pwd->pw_dir); |
| 204 | return PAM_PERM_DENIED; |
| 205 | } |
| 206 | if (chmod(pwd->pw_dir,0777 & (~UMask)) != 0 || |
| 207 | chown(pwd->pw_dir,pwd->pw_uid,pwd->pw_gid) != 0) |
| 208 | { |
| 209 | free(remark); |
| 210 | _log_err(LOG_DEBUG, "unable to chance perms on home directory %s",pwd->pw_dir); |
| 211 | return PAM_PERM_DENIED; |
| 212 | } |
| 213 | |
| 214 | /* See if we need to copy the skel dir over. */ |
| 215 | if (SkelDir[0] == 0) |
| 216 | { |
| 217 | free(remark); |
| 218 | return PAM_SUCCESS; |
| 219 | } |
| 220 | |
| 221 | /* Scan the directory */ |
| 222 | D = opendir(SkelDir); |
| 223 | if (D == 0) |
| 224 | { |
| 225 | free(remark); |
| 226 | _log_err(LOG_DEBUG, "unable to read directory %s",SkelDir); |
| 227 | return PAM_PERM_DENIED; |
| 228 | } |
| 229 | |
| 230 | for (Dir = readdir(D); Dir != 0; Dir = readdir(D)) |
| 231 | { |
| 232 | int SrcFd; |
| 233 | int DestFd; |
| 234 | int Res; |
| 235 | struct stat St; |
| 236 | |
| 237 | /* Skip some files.. */ |
| 238 | if (strcmp(Dir->d_name,".") == 0 || |
| 239 | strcmp(Dir->d_name,"..") == 0) |
| 240 | continue; |
| 241 | |
| 242 | /* Check if it is a directory */ |
| 243 | snprintf(remark,BUFSIZ,"%s/%s",SkelDir,Dir->d_name); |
| 244 | if (stat(remark,&St) != 0) |
| 245 | continue; |
| 246 | if (S_ISDIR(St.st_mode)) |
| 247 | { |
| 248 | snprintf(remark,BUFSIZ,"%s/%s",pwd->pw_dir,Dir->d_name); |
| 249 | if (mkdir(remark,(St.st_mode | 0222) & (~UMask)) != 0 || |
| 250 | chmod(remark,(St.st_mode | 0222) & (~UMask)) != 0 || |
| 251 | chown(remark,pwd->pw_uid,pwd->pw_gid) != 0) |
| 252 | { |
| 253 | free(remark); |
| 254 | _log_err(LOG_DEBUG, "unable to change perms on copy %s",remark); |
| 255 | return PAM_PERM_DENIED; |
| 256 | } |
| 257 | continue; |
| 258 | } |
| 259 | |
| 260 | /* Open the source file */ |
| 261 | if ((SrcFd = open(remark,O_RDONLY)) < 0 || fstat(SrcFd,&St) != 0) |
| 262 | { |
| 263 | free(remark); |
| 264 | _log_err(LOG_DEBUG, "unable to open src file %s",remark); |
| 265 | return PAM_PERM_DENIED; |
| 266 | } |
| 267 | stat(remark,&St); |
| 268 | |
| 269 | /* Open the dest file */ |
| 270 | snprintf(remark,BUFSIZ,"%s/%s",pwd->pw_dir,Dir->d_name); |
| 271 | if ((DestFd = open(remark,O_WRONLY | O_TRUNC | O_CREAT,0600)) < 0) |
| 272 | { |
| 273 | close(SrcFd); |
| 274 | free(remark); |
| 275 | _log_err(LOG_DEBUG, "unable to open dest file %s",remark); |
| 276 | return PAM_PERM_DENIED; |
| 277 | } |
| 278 | |
| 279 | /* Set the proper ownership and permissions for the module. We make |
| 280 | the file a+w and then mask it with the set mask. This preseves |
| 281 | execute bits */ |
| 282 | if (fchmod(DestFd,(St.st_mode | 0222) & (~UMask)) != 0 || |
| 283 | fchown(DestFd,pwd->pw_uid,pwd->pw_gid) != 0) |
| 284 | { |
| 285 | free(remark); |
| 286 | _log_err(LOG_DEBUG, "unable to chang perms on copy %s",remark); |
| 287 | return PAM_PERM_DENIED; |
| 288 | } |
| 289 | |
| 290 | /* Copy the file */ |
| 291 | do |
| 292 | { |
| 293 | Res = read(SrcFd,remark,BUFSIZ); |
| 294 | if (Res < 0 || write(DestFd,remark,Res) != Res) |
| 295 | { |
| 296 | close(SrcFd); |
| 297 | close(DestFd); |
| 298 | free(remark); |
| 299 | _log_err(LOG_DEBUG, "unable to perform IO"); |
| 300 | return PAM_PERM_DENIED; |
| 301 | } |
| 302 | } |
| 303 | while (Res != 0); |
| 304 | close(SrcFd); |
| 305 | close(DestFd); |
| 306 | } |
| 307 | |
| 308 | free(remark); |
| 309 | return PAM_SUCCESS; |
| 310 | } |
| 311 | |
| 312 | /* --- authentication management functions (only) --- */ |
| 313 | |
| 314 | PAM_EXTERN |
| 315 | int pam_sm_open_session(pam_handle_t * pamh, int flags, int argc |
| 316 | ,const char **argv) |
| 317 | { |
| 318 | int retval, ctrl; |
| 319 | const char *user; |
| 320 | const struct passwd *pwd; |
| 321 | struct stat St; |
| 322 | |
| 323 | /* Parse the flag values */ |
| 324 | ctrl = _pam_parse(flags, argc, argv); |
| 325 | |
| 326 | /* Determine the user name so we can get the home directory */ |
| 327 | retval = pam_get_item(pamh, PAM_USER, (const void **) &user); |
| 328 | if (retval != PAM_SUCCESS || user == NULL || *user == '\0') |
| 329 | { |
| 330 | _log_err(LOG_NOTICE, "user unknown"); |
| 331 | return PAM_USER_UNKNOWN; |
| 332 | } |
| 333 | |
| 334 | /* Get the password entry */ |
| 335 | pwd = getpwnam(user); |
| 336 | if (pwd == NULL) |
| 337 | { |
| 338 | D(("couldn't identify user %s", user)); |
| 339 | return PAM_CRED_INSUFFICIENT; |
| 340 | } |
| 341 | |
| 342 | /* Stat the home directory, if something exists then we assume it is |
| 343 | correct and return a success*/ |
| 344 | if (stat(pwd->pw_dir,&St) == 0) |
| 345 | return PAM_SUCCESS; |
| 346 | |
| 347 | return create_homedir(pamh,ctrl,pwd); |
| 348 | } |
| 349 | |
| 350 | /* Ignore */ |
| 351 | PAM_EXTERN |
| 352 | int pam_sm_close_session(pam_handle_t * pamh, int flags, int argc |
| 353 | ,const char **argv) |
| 354 | { |
| 355 | return PAM_SUCCESS; |
| 356 | } |
| 357 | |
| 358 | #ifdef PAM_STATIC |
| 359 | |
| 360 | /* static module data */ |
| 361 | struct pam_module _pam_mkhomedir_modstruct = |
| 362 | { |
| 363 | "pam_mkhomedir", |
| 364 | NULL, |
| 365 | NULL, |
| 366 | NULL, |
| 367 | pam_sm_open_session, |
| 368 | pam_sm_close_session, |
| 369 | NULL, |
| 370 | }; |
| 371 | |
| 372 | #endif |