| 1 | |
| 2 | /***************************************************************************** |
| 3 | * libnss-afs (nss_afs.c) |
| 4 | * |
| 5 | * Copyright 2008, licensed under GNU Library General Public License (LGPL) |
| 6 | * see COPYING file for details |
| 7 | * |
| 8 | * by Adam Megacz <megacz@hcoop.net> |
| 9 | * derived from Frank Burkhardt's libnss_ptdb, |
| 10 | * which was derived from Todd M. Lewis' libnss_pts |
| 11 | *****************************************************************************/ |
| 12 | |
| 13 | /* |
| 14 | * If you are reading this code for the first time, read the rest of |
| 15 | * this comment block, then start at the bottom of the file and work |
| 16 | * your way upwards. |
| 17 | * |
| 18 | * All functions which return an int use zero to signal success -- |
| 19 | * except cpstr(), which returns zero on *failure*. This should be |
| 20 | * fixed. |
| 21 | * |
| 22 | * A note about memory allocation: |
| 23 | * |
| 24 | * NSS plugins generally ought to work without attempting to call |
| 25 | * malloc() (which may fail). Therefore, glibc allocates a buffer |
| 26 | * before calling NSS library functions, and passes that buffer to |
| 27 | * the NSS library; library functions store their results in the |
| 28 | * buffer and return pointers into that buffer. |
| 29 | * |
| 30 | * The convention used throughout this library is to pass around a |
| 31 | * char** which points to a pointer to the first unused byte in the |
| 32 | * provided buffer, and a size_t* which points to an int indicating |
| 33 | * how many bytes are left between the char** and the end of the |
| 34 | * available region. |
| 35 | */ |
| 36 | |
| 37 | #include <ctype.h> |
| 38 | #include <err.h> |
| 39 | #include <errno.h> |
| 40 | #include <fcntl.h> |
| 41 | #include <getopt.h> |
| 42 | #include <grp.h> |
| 43 | #include <limits.h> |
| 44 | #include <netinet/in.h> |
| 45 | #include <nss.h> |
| 46 | #include <pthread.h> |
| 47 | #include <pwd.h> |
| 48 | #include <rx/rx.h> |
| 49 | #include <rx/xdr.h> |
| 50 | #include <signal.h> |
| 51 | #include <stdio.h> |
| 52 | #include <stdlib.h> |
| 53 | #include <string.h> |
| 54 | #include <sys/select.h> |
| 55 | #include <sys/socket.h> |
| 56 | #include <sys/stat.h> |
| 57 | #include <sys/time.h> |
| 58 | #include <sys/types.h> |
| 59 | #include <unistd.h> |
| 60 | #include <afs/afsutil.h> |
| 61 | #include <afs/cellconfig.h> |
| 62 | #include <afs/com_err.h> |
| 63 | #include <afs/param.h> |
| 64 | #include <afs/ptclient.h> |
| 65 | #include <afs/pterror.h> |
| 66 | #include <afs/ptuser.h> |
| 67 | #include <afs/stds.h> |
| 68 | |
| 69 | #define HOMEDIR_AUTO 0 |
| 70 | #define HOMEDIR_ADMINLINK 1 |
| 71 | #define HOMEDIR_PREFIX 2 |
| 72 | #define SHELL_BASH 0 |
| 73 | #define SHELL_ADMINLINK 1 |
| 74 | #define SHELL_USERLINK 2 |
| 75 | |
| 76 | #define AFS_MAGIC_ANONYMOUS_USERID 32766 |
| 77 | #define MIN_PAG_GID 0x41000000L |
| 78 | #define MAX_PAG_GID 0x41FFFFFFL |
| 79 | #define MIN_OLDPAG_GID 0x3f00 |
| 80 | #define MAX_OLDPAG_GID 0xff00 |
| 81 | |
| 82 | #define MAXCELLNAMELEN 256 |
| 83 | #define MAXUSERNAMELEN 256 |
| 84 | |
| 85 | static pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER; |
| 86 | |
| 87 | extern struct ubik_client *pruclient; |
| 88 | |
| 89 | int afs_initialized = 0; |
| 90 | char cellname[MAXCELLNAMELEN]; |
| 91 | char homedir_prefix[PATH_MAX]; |
| 92 | char cell_root[PATH_MAX]; |
| 93 | int homedir_prefix_len=0; |
| 94 | char homedirs_method=0; |
| 95 | char shells_method=0; |
| 96 | |
| 97 | int init_afs (); |
| 98 | |
| 99 | /** |
| 100 | * The cpstr() function copies a null-terminated string from str* |
| 101 | * (the first argument) into buf and updates both buf and buflen. If |
| 102 | * the string would overflow the buffer, no action is taken. The |
| 103 | * number of bytes copied is returned (zero indicates failure). |
| 104 | */ |
| 105 | int cpstr( char *str, char **buf, size_t *buflen) { |
| 106 | int len = strlen(str); |
| 107 | if ( len >= *buflen-1 ) return 0; |
| 108 | strcpy(*buf,str); |
| 109 | *buflen -= len + 1; |
| 110 | *buf += len + 1; |
| 111 | return len; |
| 112 | } |
| 113 | |
| 114 | /** |
| 115 | * Look up the name corresponding to uid, store in buffer. |
| 116 | */ |
| 117 | enum nss_status ptsid2name(int uid, char **buffer, size_t *buflen) { |
| 118 | int ret, i; |
| 119 | idlist lid; |
| 120 | namelist lnames; |
| 121 | |
| 122 | if (init_afs()) return NSS_STATUS_UNAVAIL; |
| 123 | |
| 124 | if (uid==AFS_MAGIC_ANONYMOUS_USERID) { |
| 125 | if (!cpstr("anonymous", buffer, buflen)) return NSS_STATUS_UNAVAIL; |
| 126 | return NSS_STATUS_SUCCESS; |
| 127 | } |
| 128 | |
| 129 | if (pthread_mutex_lock(&mutex)) return NSS_STATUS_UNAVAIL; |
| 130 | |
| 131 | lid.idlist_val = (afs_int32*)&uid; |
| 132 | lid.idlist_len = 1; |
| 133 | lnames.namelist_val = 0; |
| 134 | lnames.namelist_len = 0; |
| 135 | |
| 136 | if (ubik_PR_IDToName(pruclient,0,&lid,&lnames) != PRSUCCESS) { |
| 137 | perror("ubik_Call() in ptsid2name() failed\n"); |
| 138 | pthread_mutex_unlock(&mutex); |
| 139 | return NSS_STATUS_UNAVAIL; |
| 140 | } |
| 141 | |
| 142 | ret = NSS_STATUS_NOTFOUND; |
| 143 | for (i=0;i<lnames.namelist_len;i++) { |
| 144 | int delta = strlen(lnames.namelist_val[i]); |
| 145 | if ( (delta < *buflen) && islower(*(lnames.namelist_val[i])) ) { |
| 146 | cpstr(lnames.namelist_val[i], buffer, buflen); |
| 147 | ret = NSS_STATUS_SUCCESS; |
| 148 | } |
| 149 | } |
| 150 | free(lnames.namelist_val); |
| 151 | /* free(lid.idlist_val); */ |
| 152 | lid.idlist_val = 0; |
| 153 | lid.idlist_len = 0; |
| 154 | |
| 155 | pthread_mutex_unlock(&mutex); |
| 156 | return ret; |
| 157 | } |
| 158 | |
| 159 | /** |
| 160 | * Look up the uid corresponding to name in ptserver. |
| 161 | */ |
| 162 | enum nss_status ptsname2id(char *name, uid_t* uid) { |
| 163 | int res; |
| 164 | idlist lid; |
| 165 | namelist lnames; |
| 166 | char uname[MAXUSERNAMELEN]; |
| 167 | |
| 168 | if (init_afs()) return NSS_STATUS_UNAVAIL; |
| 169 | |
| 170 | if (!strcmp(name,"anonymous")) { |
| 171 | *uid = AFS_MAGIC_ANONYMOUS_USERID; |
| 172 | return NSS_STATUS_SUCCESS; |
| 173 | } |
| 174 | |
| 175 | if (pthread_mutex_lock(&mutex)) return NSS_STATUS_UNAVAIL; |
| 176 | |
| 177 | lid.idlist_val = 0; |
| 178 | lid.idlist_len = 0; |
| 179 | lnames.namelist_val = (prname*)uname; |
| 180 | // apparently ubik expects to be able to modify this? |
| 181 | strncpy(uname, name, MAXUSERNAMELEN); |
| 182 | lnames.namelist_len = 1; |
| 183 | |
| 184 | if (ubik_PR_NameToID(pruclient,0,&lnames,&lid) != PRSUCCESS) { |
| 185 | perror("ubik_Call() in ptsname2id() failed\n"); |
| 186 | pthread_mutex_unlock(&mutex); |
| 187 | return NSS_STATUS_UNAVAIL; |
| 188 | } |
| 189 | pthread_mutex_unlock(&mutex); |
| 190 | |
| 191 | res = (uid_t)lid.idlist_val[0]; |
| 192 | if (res == AFS_MAGIC_ANONYMOUS_USERID) return NSS_STATUS_NOTFOUND; |
| 193 | *uid = res; |
| 194 | return NSS_STATUS_SUCCESS; |
| 195 | } |
| 196 | |
| 197 | /** |
| 198 | * Initialize the library; returns zero on success |
| 199 | */ |
| 200 | int init_afs() { |
| 201 | FILE *thiscell; |
| 202 | int len; |
| 203 | struct stat statbuf; |
| 204 | |
| 205 | char buf[6]; |
| 206 | int fd; |
| 207 | int pos; |
| 208 | |
| 209 | if (afs_initialized) { |
| 210 | /* wait until /afs/@cell/ appears as a proxy for "the network is up" */ |
| 211 | if (stat(cell_root, &statbuf)) return -1; |
| 212 | return 0; |
| 213 | } |
| 214 | |
| 215 | // check to make sure that we are running inside nscd |
| 216 | pos = 0; |
| 217 | fd = open("/proc/self/cmdline", O_RDONLY); |
| 218 | if (fd==-1) return -1; |
| 219 | while(1) { |
| 220 | int numread; |
| 221 | numread = read(fd, buf+pos, 1); |
| 222 | if (buf[ (pos+5)%6 ] == 'd' && |
| 223 | buf[ (pos+4)%6 ] == 'c' && |
| 224 | buf[ (pos+3)%6 ] == 's' && |
| 225 | buf[ (pos+2)%6 ] == 'n' && |
| 226 | (buf[(pos+1)%6 ] == '/' || pos==4) && |
| 227 | (buf[(pos+0)%6 ] == 0 || numread==-1) |
| 228 | ) |
| 229 | break; |
| 230 | pos = (pos+1)%6; |
| 231 | if (numread==0) { close(fd); return -1; } |
| 232 | } |
| 233 | close(fd); |
| 234 | |
| 235 | if (pthread_mutex_lock(&mutex)) return -1; |
| 236 | do { |
| 237 | homedirs_method=HOMEDIR_PREFIX; |
| 238 | shells_method=SHELL_USERLINK; |
| 239 | |
| 240 | len = snprintf(cellname, MAXCELLNAMELEN, |
| 241 | "%s/ThisCell", AFSDIR_CLIENT_ETC_DIRPATH); |
| 242 | if (len < 0 || len >= MAXCELLNAMELEN) return -1; |
| 243 | |
| 244 | thiscell=fopen(cellname,"r"); |
| 245 | if (thiscell == NULL) break; |
| 246 | len=fread(cellname,1,MAXCELLNAMELEN,thiscell); |
| 247 | if (!feof(thiscell)) { |
| 248 | // Cellname too long |
| 249 | fclose(thiscell); |
| 250 | strcpy(homedir_prefix,"/tmp/\0"); |
| 251 | homedir_prefix_len=5; |
| 252 | break; |
| 253 | } |
| 254 | fclose(thiscell); |
| 255 | |
| 256 | if (cellname[len-1] == '\n') len--; |
| 257 | cellname[len]='\0'; |
| 258 | |
| 259 | /* wait until /afs/@cell/ appears as a proxy for "the network is up" */ |
| 260 | sprintf(cell_root,"/afs/%s/",cellname); |
| 261 | if (stat(cell_root, &statbuf)) break; |
| 262 | |
| 263 | sprintf(homedir_prefix,"/afs/%s/user/",cellname); |
| 264 | homedir_prefix_len=strlen(homedir_prefix); |
| 265 | |
| 266 | /* time out requests after 5 seconds to avoid hanging things */ |
| 267 | rx_SetRxDeadTime(5); |
| 268 | |
| 269 | if (pr_Initialize(0L,AFSDIR_CLIENT_ETC_DIRPATH, 0)) { |
| 270 | perror("pr_Initialize() failed\n"); |
| 271 | break; |
| 272 | } |
| 273 | |
| 274 | afs_initialized = 1; |
| 275 | pthread_mutex_unlock(&mutex); |
| 276 | return 0; |
| 277 | |
| 278 | } while(0); |
| 279 | pthread_mutex_unlock(&mutex); |
| 280 | return -1; |
| 281 | } |
| 282 | |
| 283 | |
| 284 | /** |
| 285 | * Retrieves the homedir for a given user; returns 0 on success. |
| 286 | */ |
| 287 | int get_homedir(char *name, char **buffer, size_t *buflen) { |
| 288 | char buf[256]; |
| 289 | int temp; |
| 290 | char *b; |
| 291 | b=*buffer; |
| 292 | switch (homedirs_method) { |
| 293 | case HOMEDIR_PREFIX: |
| 294 | homedir_prefix[homedir_prefix_len+0]=name[0]; |
| 295 | homedir_prefix[homedir_prefix_len+1]='/'; |
| 296 | homedir_prefix[homedir_prefix_len+2]=name[0]; |
| 297 | homedir_prefix[homedir_prefix_len+3]=name[1]; |
| 298 | homedir_prefix[homedir_prefix_len+4]='/'; |
| 299 | homedir_prefix[homedir_prefix_len+5]=0; |
| 300 | strncpy(&homedir_prefix[homedir_prefix_len+5],name,40); |
| 301 | if (! cpstr(homedir_prefix,buffer,buflen) ) return -1; |
| 302 | break; |
| 303 | case HOMEDIR_AUTO: |
| 304 | homedir_prefix[homedir_prefix_len]=0; |
| 305 | strncpy(&homedir_prefix[homedir_prefix_len],name,40); |
| 306 | if (! cpstr(homedir_prefix,buffer,buflen) ) return -1; |
| 307 | break; |
| 308 | case HOMEDIR_ADMINLINK: |
| 309 | if ( snprintf(buf,256,"/afs/%s/admin/homedirs/%s",cellname,name) > 0 ) { |
| 310 | temp=readlink(buf,*buffer,*buflen); |
| 311 | if ( temp > -1) { |
| 312 | b[temp]=0; |
| 313 | *buflen = *buflen - temp - 1; |
| 314 | return -1; |
| 315 | } |
| 316 | } |
| 317 | if (! cpstr("/tmp",buffer,buflen) ) return -1; |
| 318 | break; |
| 319 | } |
| 320 | return 0; |
| 321 | } |
| 322 | |
| 323 | /** |
| 324 | * Retrieves the shell for a given user; returns 0 on success. |
| 325 | */ |
| 326 | int get_shell(char *name, char **buffer, size_t *buflen) { |
| 327 | char buf[256]; |
| 328 | int temp; |
| 329 | char *b; |
| 330 | char* bufx = buf; |
| 331 | size_t bufxlen = 256; |
| 332 | b=*buffer; |
| 333 | |
| 334 | switch (shells_method) { |
| 335 | case SHELL_BASH: |
| 336 | break; |
| 337 | |
| 338 | case SHELL_ADMINLINK: |
| 339 | if (snprintf(buf,256,"/afs/%s/admin/shells/%s",cellname,name)<=0) break; |
| 340 | temp = readlink(buf,*buffer,*buflen); |
| 341 | if (temp < 0) break; |
| 342 | b[temp]=0; |
| 343 | *buflen = *buflen - temp - 1; |
| 344 | return 0; |
| 345 | |
| 346 | case SHELL_USERLINK: |
| 347 | if (get_homedir(name, &bufx, &bufxlen)) break; |
| 348 | if (strncpy(buf+strlen(buf),"/.loginshell",bufxlen)<=0) break; |
| 349 | temp = readlink(buf,*buffer,*buflen); |
| 350 | if (temp < 0) break; |
| 351 | b[temp]=0; |
| 352 | *buflen = *buflen - temp - 1; |
| 353 | return 0; |
| 354 | } |
| 355 | if (! cpstr("/bin/bash",buffer,buflen) ) |
| 356 | return -1; |
| 357 | return 0; |
| 358 | } |
| 359 | |
| 360 | |
| 361 | /* |
| 362 | * This function is exported; glibc will invoke it in order to find |
| 363 | * the name and list of members of a group specified by a numerical |
| 364 | * groupid. |
| 365 | */ |
| 366 | enum nss_status _nss_afs_getgrgid_r (gid_t gid, |
| 367 | struct group *result, |
| 368 | char *buffer, |
| 369 | size_t buflen, |
| 370 | int *errnop) { |
| 371 | int length; |
| 372 | int showgid = 0; |
| 373 | if (gid >= MIN_PAG_GID && gid <= MAX_PAG_GID) { |
| 374 | showgid = gid-MIN_PAG_GID; |
| 375 | } else if (gid >= MIN_OLDPAG_GID && gid <= MAX_OLDPAG_GID) { |
| 376 | showgid = gid-MIN_OLDPAG_GID; |
| 377 | } else { |
| 378 | *errnop=ENOENT; |
| 379 | return NSS_STATUS_NOTFOUND; |
| 380 | } |
| 381 | do { |
| 382 | result->gr_gid=gid; |
| 383 | |
| 384 | result->gr_name=buffer; |
| 385 | length=snprintf(buffer,buflen,"AfsPag-%x",showgid); |
| 386 | |
| 387 | if (length < 0) break; |
| 388 | length += 1; |
| 389 | buflen -= length; |
| 390 | buffer += length; |
| 391 | |
| 392 | result->gr_passwd=buffer; |
| 393 | |
| 394 | if (!cpstr("z",&buffer,&buflen)) break; |
| 395 | |
| 396 | if (buflen < sizeof(char*)) break; |
| 397 | result->gr_mem=&buffer; |
| 398 | result->gr_mem[0] = NULL; |
| 399 | |
| 400 | *errnop=errno; |
| 401 | return NSS_STATUS_SUCCESS; |
| 402 | |
| 403 | } while(0); |
| 404 | *errnop=ENOENT; |
| 405 | return NSS_STATUS_UNAVAIL; |
| 406 | } |
| 407 | |
| 408 | /** |
| 409 | * A helper function to fill in the fields of "struct passwd"; used by |
| 410 | * both _nss_afs_getpwuid_r() and _nss_afs_getpwnam_r(). |
| 411 | */ |
| 412 | enum nss_status fill_result_buf(uid_t uid, |
| 413 | char* name, |
| 414 | struct passwd *result_buf, |
| 415 | char *buffer, |
| 416 | size_t buflen, |
| 417 | int *errnop) { |
| 418 | result_buf->pw_name = name; |
| 419 | do { |
| 420 | /* set the password to "z"; we can't use "x" because of pam_unix.so */ |
| 421 | result_buf->pw_passwd = buffer; |
| 422 | if ( ! cpstr("z",&buffer, &buflen) ) break; |
| 423 | |
| 424 | /* the uid and gid are both the uid passed in */ |
| 425 | result_buf->pw_uid = uid; |
| 426 | result_buf->pw_gid = 65534; |
| 427 | |
| 428 | /* make the gecos the same as the PTS name */ |
| 429 | result_buf->pw_gecos = buffer; |
| 430 | if ( ! cpstr(result_buf->pw_name, &buffer, &buflen ) ) break; |
| 431 | |
| 432 | // Set the homedirectory |
| 433 | result_buf->pw_dir = buffer; |
| 434 | if ( get_homedir(result_buf->pw_name,&buffer,&buflen) ) break; |
| 435 | |
| 436 | // Set the login shell |
| 437 | result_buf->pw_shell = buffer; |
| 438 | if ( get_shell(result_buf->pw_name,&buffer,&buflen) ) break; |
| 439 | |
| 440 | #ifdef LIMIT_USERNAME_CHARS |
| 441 | if ( strlen(result_buf->pw_name) > LIMIT_USERNAME_CHARS ) { |
| 442 | result_buf->pw_name[LIMIT_USERNAME_CHARS] = '\0'; |
| 443 | buflen = buflen + ( buffer - &result_buf->pw_name[LIMIT_USERNAME_CHARS+1] ); |
| 444 | buffer = &result_buf->pw_name[LIMIT_USERNAME_CHARS+1]; |
| 445 | } |
| 446 | #endif |
| 447 | |
| 448 | *errnop = errno; |
| 449 | return NSS_STATUS_SUCCESS; |
| 450 | } while(0); |
| 451 | |
| 452 | *errnop = ERANGE; |
| 453 | return NSS_STATUS_UNAVAIL; |
| 454 | } |
| 455 | |
| 456 | |
| 457 | /** |
| 458 | * This function is exported; glibc will invoke it in order to gather |
| 459 | * the user information (userid, homedir, shell) associated with a |
| 460 | * numerical userid. |
| 461 | */ |
| 462 | enum nss_status _nss_afs_getpwuid_r (uid_t uid, |
| 463 | struct passwd *result_buf, |
| 464 | char *buffer, |
| 465 | size_t buflen, |
| 466 | int *errnop) { |
| 467 | int temp; |
| 468 | char* name; |
| 469 | |
| 470 | if (init_afs()) return NSS_STATUS_UNAVAIL; |
| 471 | |
| 472 | name = buffer; |
| 473 | temp = ptsid2name( uid, &buffer, &buflen); |
| 474 | if (temp != NSS_STATUS_SUCCESS) { |
| 475 | *errnop = ENOENT; |
| 476 | return temp; |
| 477 | } |
| 478 | |
| 479 | return fill_result_buf(uid, name, result_buf, buffer, buflen, errnop); |
| 480 | } |
| 481 | |
| 482 | /** |
| 483 | * This function is exported; glibc will invoke it in order to gather |
| 484 | * the user information (userid, homedir, shell) associated with a |
| 485 | * username. |
| 486 | */ |
| 487 | enum nss_status _nss_afs_getpwnam_r (char *name, |
| 488 | struct passwd *result_buf, |
| 489 | char *buffer, |
| 490 | size_t buflen, |
| 491 | int *errnop) { |
| 492 | uid_t uid; |
| 493 | int temp; |
| 494 | |
| 495 | if (init_afs()) return NSS_STATUS_UNAVAIL; |
| 496 | |
| 497 | temp = ptsname2id(name,&uid); |
| 498 | if (temp != NSS_STATUS_SUCCESS) { |
| 499 | *errnop = ENOENT; |
| 500 | return temp; |
| 501 | } |
| 502 | |
| 503 | return fill_result_buf(uid, name, result_buf, buffer, buflen, errnop); |
| 504 | } |
| 505 | |