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03b6b479 | 1 | |
908a6ebe | 2 | /***************************************************************************** |
3 | * libnss-afs (nss_afs.c) | |
03b6b479 | 4 | * |
5 | * Copyright 2008, licensed under GNU Library General Public License (LGPL) | |
6 | * see COPYING file for details | |
7 | * | |
908a6ebe | 8 | * by Adam Megacz <megacz@hcoop.net> |
03b6b479 | 9 | * derived from Frank Burkhardt's libnss_ptdb, |
10 | * which was derived from Todd M. Lewis' libnss_pts | |
908a6ebe | 11 | *****************************************************************************/ |
03b6b479 | 12 | |
13 | /* | |
908a6ebe | 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. | |
03b6b479 | 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 <netinet/in.h> | |
44 | #include <nss.h> | |
45 | #include <pthread.h> | |
46 | #include <pwd.h> | |
47 | #include <rx/rx.h> | |
48 | #include <rx/xdr.h> | |
49 | #include <signal.h> | |
50 | #include <stdio.h> | |
51 | #include <stdlib.h> | |
52 | #include <string.h> | |
53 | #include <sys/select.h> | |
54 | #include <sys/socket.h> | |
43d1801e | 55 | #include <sys/stat.h> |
03b6b479 | 56 | #include <sys/time.h> |
57 | #include <sys/types.h> | |
58 | #include <unistd.h> | |
59 | #include <afs/afs.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/stds.h> | |
67 | ||
908a6ebe | 68 | #define HOMEDIR_AUTO 0 |
03b6b479 | 69 | #define HOMEDIR_ADMINLINK 1 |
908a6ebe | 70 | #define HOMEDIR_PREFIX 2 |
71 | #define SHELL_BASH 0 | |
72 | #define SHELL_ADMINLINK 1 | |
73 | #define SHELL_USERLINK 2 | |
03b6b479 | 74 | |
75 | #define AFS_MAGIC_ANONYMOUS_USERID 32766 | |
908a6ebe | 76 | #define MIN_PAG_GID 0x41000000L |
77 | #define MAX_PAG_GID 0x41FFFFFFL | |
78 | #define MIN_OLDPAG_GID 0x3f00 | |
79 | #define MAX_OLDPAG_GID 0xff00 | |
03b6b479 | 80 | |
908a6ebe | 81 | #define MAXCELLNAMELEN 256 |
abfd757b | 82 | #define MAXUSERNAMELEN 256 |
91bb9ebc | 83 | |
03b6b479 | 84 | static pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER; |
85 | ||
03b6b479 | 86 | extern struct ubik_client *pruclient; |
87 | ||
88 | int afs_initialized = 0; | |
908a6ebe | 89 | char cellname[MAXCELLNAMELEN]; |
90 | char homedir_prefix[MAXPATHLEN]; | |
43d1801e | 91 | char cell_root[MAXPATHLEN]; |
03b6b479 | 92 | int homedir_prefix_len=0; |
93 | char homedirs_method=0; | |
94 | char shells_method=0; | |
95 | ||
908a6ebe | 96 | /** |
97 | * The cpstr() function copies a null-terminated string from str* | |
98 | * (the first argument) into buf and updates both buf and buflen. If | |
99 | * the string would overflow the buffer, no action is taken. The | |
100 | * number of bytes copied is returned (zero indicates failure). | |
101 | */ | |
03b6b479 | 102 | int cpstr( char *str, char **buf, size_t *buflen) { |
908a6ebe | 103 | int len = strlen(str); |
104 | if ( len >= *buflen-1 ) return 0; | |
105 | strcpy(*buf,str); | |
106 | *buflen -= len + 1; | |
107 | *buf += len + 1; | |
108 | return len; | |
03b6b479 | 109 | } |
110 | ||
908a6ebe | 111 | /** |
03b6b479 | 112 | * Look up the name corresponding to uid, store in buffer. |
03b6b479 | 113 | */ |
908a6ebe | 114 | enum nss_status ptsid2name(int uid, char **buffer, int *buflen) { |
03b6b479 | 115 | int ret, i; |
116 | idlist lid; | |
117 | namelist lnames; | |
118 | ||
b5f46b9e | 119 | if (init_afs()) return NSS_STATUS_UNAVAIL; |
03b6b479 | 120 | |
121 | if (uid==AFS_MAGIC_ANONYMOUS_USERID) { | |
122 | if (!cpstr("anonymous", buffer, buflen)) return NSS_STATUS_UNAVAIL; | |
123 | return NSS_STATUS_SUCCESS; | |
124 | } | |
125 | ||
126 | if (pthread_mutex_lock(&mutex)) return NSS_STATUS_UNAVAIL; | |
127 | ||
128 | lid.idlist_val = (afs_int32*)&uid; | |
129 | lid.idlist_len = 1; | |
130 | lnames.namelist_val = 0; | |
131 | lnames.namelist_len = 0; | |
132 | ||
133 | if (ubik_Call(PR_IDToName,pruclient,0,&lid,&lnames) != PRSUCCESS) { | |
be93aa7b | 134 | perror("ubik_Call() in ptsid2name() failed\n"); |
03b6b479 | 135 | pthread_mutex_unlock(&mutex); |
136 | return NSS_STATUS_UNAVAIL; | |
137 | } | |
138 | ||
139 | ret = NSS_STATUS_NOTFOUND; | |
140 | for (i=0;i<lnames.namelist_len;i++) { | |
141 | int delta = strlen(lnames.namelist_val[i]); | |
142 | if ( (delta < buflen) && islower(*(lnames.namelist_val[i])) ) { | |
143 | cpstr(lnames.namelist_val[i], buffer, buflen); | |
144 | ret = NSS_STATUS_SUCCESS; | |
145 | } | |
146 | } | |
147 | free(lnames.namelist_val); | |
148 | /* free(lid.idlist_val); */ | |
149 | lid.idlist_val = 0; | |
150 | lid.idlist_len = 0; | |
151 | ||
152 | pthread_mutex_unlock(&mutex); | |
153 | return ret; | |
154 | } | |
155 | ||
908a6ebe | 156 | /** |
157 | * Look up the uid corresponding to name in ptserver. | |
03b6b479 | 158 | */ |
908a6ebe | 159 | enum nss_status ptsname2id(char *name, uid_t* uid) { |
03b6b479 | 160 | int res; |
161 | idlist lid; | |
162 | namelist lnames; | |
abfd757b | 163 | char uname[MAXUSERNAMELEN]; |
03b6b479 | 164 | |
b5f46b9e | 165 | if (init_afs()) return NSS_STATUS_UNAVAIL; |
03b6b479 | 166 | |
167 | if (!strcmp(name,"anonymous")) { | |
168 | *uid = AFS_MAGIC_ANONYMOUS_USERID; | |
169 | return NSS_STATUS_SUCCESS; | |
170 | } | |
171 | ||
172 | if (pthread_mutex_lock(&mutex)) return NSS_STATUS_UNAVAIL; | |
173 | ||
174 | lid.idlist_val = 0; | |
175 | lid.idlist_len = 0; | |
be93aa7b | 176 | lnames.namelist_val = (prname*)uname; |
abfd757b | 177 | // apparently ubik expects to be able to modify this? |
178 | strncpy(uname, name, MAXUSERNAMELEN); | |
03b6b479 | 179 | lnames.namelist_len = 1; |
180 | ||
181 | if (ubik_Call(PR_NameToID,pruclient,0,&lnames,&lid) != PRSUCCESS) { | |
be93aa7b | 182 | perror("ubik_Call() in ptsname2id() failed\n"); |
03b6b479 | 183 | pthread_mutex_unlock(&mutex); |
184 | return NSS_STATUS_UNAVAIL; | |
185 | } | |
186 | pthread_mutex_unlock(&mutex); | |
187 | ||
188 | res = (uid_t)lid.idlist_val[0]; | |
189 | if (res == AFS_MAGIC_ANONYMOUS_USERID) return NSS_STATUS_NOTFOUND; | |
190 | *uid = res; | |
191 | return NSS_STATUS_SUCCESS; | |
192 | } | |
193 | ||
908a6ebe | 194 | /** |
195 | * Initialize the library; returns zero on success | |
03b6b479 | 196 | */ |
197 | int init_afs() { | |
198 | FILE *thiscell; | |
199 | int len; | |
43d1801e | 200 | struct stat statbuf; |
03b6b479 | 201 | |
b5f46b9e AM |
202 | char buf[6]; |
203 | int fd; | |
204 | int pos; | |
205 | ||
43d1801e | 206 | if (afs_initialized) { |
207 | /* wait until /afs/@cell/ appears as a proxy for "the network is up" */ | |
208 | if (stat(cell_root, &statbuf)) return -1; | |
209 | return 0; | |
210 | } | |
b5f46b9e AM |
211 | |
212 | // check to make sure that we are running inside nscd | |
213 | pos = 0; | |
214 | fd = open("/proc/self/cmdline", O_RDONLY); | |
215 | if (fd==-1) return -1; | |
216 | while(1) { | |
217 | int numread; | |
218 | numread = read(fd, buf+pos, 1); | |
219 | if (buf[ (pos+5)%6 ] == 'd' && | |
220 | buf[ (pos+4)%6 ] == 'c' && | |
221 | buf[ (pos+3)%6 ] == 's' && | |
222 | buf[ (pos+2)%6 ] == 'n' && | |
223 | (buf[(pos+1)%6 ] == '/' || pos==4) && | |
224 | (buf[(pos+0)%6 ] == 0 || numread==-1) | |
225 | ) | |
226 | break; | |
227 | pos = (pos+1)%6; | |
228 | if (numread==0) { close(fd); return -1; } | |
229 | } | |
230 | close(fd); | |
43d1801e | 231 | |
03b6b479 | 232 | if (pthread_mutex_lock(&mutex)) return -1; |
233 | do { | |
234 | homedirs_method=HOMEDIR_PREFIX; | |
235 | shells_method=SHELL_USERLINK; | |
91bb9ebc | 236 | |
908a6ebe | 237 | len = snprintf(cellname, MAXCELLNAMELEN, |
238 | "%s/ThisCell", AFSDIR_CLIENT_ETC_DIRPATH); | |
be93aa7b | 239 | if (len < 0 || len >= MAXCELLNAMELEN) return -1; |
91bb9ebc | 240 | |
241 | thiscell=fopen(cellname,"r"); | |
03b6b479 | 242 | if (thiscell == NULL) break; |
908a6ebe | 243 | len=fread(cellname,1,MAXCELLNAMELEN,thiscell); |
03b6b479 | 244 | if (!feof(thiscell)) { |
245 | // Cellname too long | |
246 | fclose(thiscell); | |
247 | strcpy(homedir_prefix,"/tmp/\0"); | |
248 | homedir_prefix_len=5; | |
249 | break; | |
250 | } | |
251 | fclose(thiscell); | |
91bb9ebc | 252 | |
03b6b479 | 253 | if (cellname[len-1] == '\n') len--; |
254 | cellname[len]='\0'; | |
43d1801e | 255 | |
256 | /* wait until /afs/@cell/ appears as a proxy for "the network is up" */ | |
257 | sprintf(cell_root,"/afs/%s/",cellname); | |
258 | if (stat(cell_root, &statbuf)) break; | |
259 | ||
03b6b479 | 260 | sprintf(homedir_prefix,"/afs/%s/user/",cellname); |
261 | homedir_prefix_len=strlen(homedir_prefix); | |
43d1801e | 262 | |
263 | /* time out requests after 5 seconds to avoid hanging things */ | |
264 | rx_SetRxDeadTime(5); | |
265 | ||
93d939f4 | 266 | if (pr_Initialize(0L,AFSDIR_CLIENT_ETC_DIRPATH, 0)) { |
be93aa7b | 267 | perror("pr_Initialize() failed\n"); |
93d939f4 | 268 | break; |
269 | } | |
03b6b479 | 270 | |
271 | afs_initialized = 1; | |
272 | pthread_mutex_unlock(&mutex); | |
273 | return 0; | |
274 | ||
275 | } while(0); | |
276 | pthread_mutex_unlock(&mutex); | |
277 | return -1; | |
278 | } | |
279 | ||
280 | ||
908a6ebe | 281 | /** |
282 | * Retrieves the homedir for a given user; returns 0 on success. | |
283 | */ | |
03b6b479 | 284 | int get_homedir(char *name, char **buffer, size_t *buflen) { |
285 | char buf[256]; | |
286 | int temp; | |
287 | char *b; | |
288 | b=*buffer; | |
289 | switch (homedirs_method) { | |
290 | case HOMEDIR_PREFIX: | |
291 | homedir_prefix[homedir_prefix_len+0]=name[0]; | |
292 | homedir_prefix[homedir_prefix_len+1]='/'; | |
293 | homedir_prefix[homedir_prefix_len+2]=name[0]; | |
294 | homedir_prefix[homedir_prefix_len+3]=name[1]; | |
295 | homedir_prefix[homedir_prefix_len+4]='/'; | |
296 | homedir_prefix[homedir_prefix_len+5]=0; | |
297 | strncpy(&homedir_prefix[homedir_prefix_len+5],name,40); | |
298 | if (! cpstr(homedir_prefix,buffer,buflen) ) return -1; | |
299 | break; | |
300 | case HOMEDIR_AUTO: | |
301 | homedir_prefix[homedir_prefix_len]=0; | |
302 | strncpy(&homedir_prefix[homedir_prefix_len],name,40); | |
303 | if (! cpstr(homedir_prefix,buffer,buflen) ) return -1; | |
304 | break; | |
305 | case HOMEDIR_ADMINLINK: | |
306 | if ( snprintf(buf,256,"/afs/%s/admin/homedirs/%s",cellname,name) > 0 ) { | |
307 | temp=readlink(buf,*buffer,*buflen); | |
308 | if ( temp > -1) { | |
309 | b[temp]=0; | |
310 | *buflen = *buflen - temp - 1; | |
311 | return -1; | |
312 | } | |
313 | } | |
314 | if (! cpstr("/tmp",buffer,buflen) ) return -1; | |
315 | break; | |
316 | } | |
317 | return 0; | |
318 | } | |
319 | ||
908a6ebe | 320 | /** |
321 | * Retrieves the shell for a given user; returns 0 on success. | |
322 | */ | |
03b6b479 | 323 | int get_shell(char *name, char **buffer, size_t *buflen) { |
324 | char buf[256]; | |
325 | int temp; | |
326 | char *b; | |
327 | char* bufx = buf; | |
328 | int bufxlen = 256; | |
329 | b=*buffer; | |
330 | ||
331 | switch (shells_method) { | |
332 | case SHELL_BASH: | |
03b6b479 | 333 | break; |
334 | ||
335 | case SHELL_ADMINLINK: | |
91bb9ebc | 336 | if (snprintf(buf,256,"/afs/%s/admin/shells/%s",cellname,name)<=0) break; |
337 | temp = readlink(buf,*buffer,*buflen); | |
338 | if (temp < 0) break; | |
339 | b[temp]=0; | |
340 | *buflen = *buflen - temp - 1; | |
341 | return 0; | |
03b6b479 | 342 | |
343 | case SHELL_USERLINK: | |
91bb9ebc | 344 | if (get_homedir(name, &bufx, &bufxlen)) break; |
345 | if (strncpy(buf+strlen(buf),"/.loginshell",bufxlen)<=0) break; | |
346 | temp = readlink(buf,*buffer,*buflen); | |
347 | if (temp < 0) break; | |
348 | b[temp]=0; | |
349 | *buflen = *buflen - temp - 1; | |
350 | return 0; | |
03b6b479 | 351 | } |
91bb9ebc | 352 | if (! cpstr("/bin/bash",buffer,buflen) ) |
353 | return -1; | |
03b6b479 | 354 | return 0; |
355 | } | |
356 | ||
357 | ||
908a6ebe | 358 | /* |
359 | * This function is exported; glibc will invoke it in order to find | |
360 | * the name and list of members of a group specified by a numerical | |
361 | * groupid. | |
03b6b479 | 362 | */ |
908a6ebe | 363 | enum nss_status _nss_afs_getgrgid_r (gid_t gid, |
364 | struct group *result, | |
365 | char *buffer, | |
366 | size_t buflen, | |
367 | int *errnop) { | |
03b6b479 | 368 | int length; |
582fb19e | 369 | int showgid = 0; |
370 | if (gid >= MIN_PAG_GID && gid <= MAX_PAG_GID) { | |
371 | showgid = gid-MIN_PAG_GID; | |
372 | } else if (gid >= MIN_OLDPAG_GID && gid <= MAX_OLDPAG_GID) { | |
373 | showgid = gid-MIN_OLDPAG_GID; | |
374 | } else { | |
03b6b479 | 375 | *errnop=ENOENT; |
376 | return NSS_STATUS_NOTFOUND; | |
377 | } | |
378 | do { | |
379 | result->gr_gid=gid; | |
380 | ||
381 | result->gr_name=buffer; | |
582fb19e | 382 | length=snprintf(buffer,buflen,"AfsPag-%x",showgid); |
03b6b479 | 383 | |
384 | if (length < 0) break; | |
385 | length += 1; | |
386 | buflen -= length; | |
387 | buffer += length; | |
388 | ||
389 | result->gr_passwd=buffer; | |
390 | ||
277abbf3 | 391 | if (!cpstr("z",&buffer,&buflen)) break; |
03b6b479 | 392 | |
393 | if (buflen < sizeof(char*)) break; | |
394 | result->gr_mem=buffer; | |
395 | result->gr_mem[0] = NULL; | |
396 | ||
397 | *errnop=errno; | |
398 | return NSS_STATUS_SUCCESS; | |
399 | ||
400 | } while(0); | |
401 | *errnop=ENOENT; | |
402 | return NSS_STATUS_UNAVAIL; | |
403 | } | |
404 | ||
908a6ebe | 405 | /** |
406 | * A helper function to fill in the fields of "struct passwd"; used by | |
407 | * both _nss_afs_getpwuid_r() and _nss_afs_getpwnam_r(). | |
408 | */ | |
409 | enum nss_status fill_result_buf(uid_t uid, | |
410 | char* name, | |
411 | struct passwd *result_buf, | |
412 | char *buffer, | |
413 | size_t buflen, | |
414 | int *errnop) { | |
415 | result_buf->pw_name = name; | |
03b6b479 | 416 | do { |
277abbf3 | 417 | /* set the password to "z"; we can't use "x" because of pam_unix.so */ |
03b6b479 | 418 | result_buf->pw_passwd = buffer; |
277abbf3 | 419 | if ( ! cpstr("z",&buffer, &buflen) ) break; |
908a6ebe | 420 | |
03b6b479 | 421 | /* the uid and gid are both the uid passed in */ |
422 | result_buf->pw_uid = uid; | |
423 | result_buf->pw_gid = 65534; | |
908a6ebe | 424 | |
03b6b479 | 425 | /* make the gecos the same as the PTS name */ |
426 | result_buf->pw_gecos = buffer; | |
427 | if ( ! cpstr(result_buf->pw_name, &buffer, &buflen ) ) break; | |
428 | ||
429 | // Set the homedirectory | |
430 | result_buf->pw_dir = buffer; | |
431 | if ( get_homedir(result_buf->pw_name,&buffer,&buflen) ) break; | |
432 | ||
433 | // Set the login shell | |
434 | result_buf->pw_shell = buffer; | |
435 | if ( get_shell(result_buf->pw_name,&buffer,&buflen) ) break; | |
436 | ||
e8c23dae | 437 | #ifdef LIMIT_USERNAME_CHARS |
438 | if ( strlen(result_buf->pw_name) > LIMIT_USERNAME_CHARS ) { | |
439 | result_buf->pw_name[LIMIT_USERNAME_CHARS] = '\0'; | |
440 | buflen = buflen + ( buffer - &result_buf->pw_name[LIMIT_USERNAME_CHARS+1] ); | |
441 | buffer = &result_buf->pw_name[LIMIT_USERNAME_CHARS+1]; | |
442 | } | |
443 | #endif | |
444 | ||
03b6b479 | 445 | *errnop = errno; |
446 | return NSS_STATUS_SUCCESS; | |
447 | } while(0); | |
448 | ||
449 | *errnop = ERANGE; | |
450 | return NSS_STATUS_UNAVAIL; | |
451 | } | |
452 | ||
453 | ||
908a6ebe | 454 | /** |
455 | * This function is exported; glibc will invoke it in order to gather | |
456 | * the user information (userid, homedir, shell) associated with a | |
457 | * numerical userid. | |
458 | */ | |
459 | enum nss_status _nss_afs_getpwuid_r (uid_t uid, | |
460 | struct passwd *result_buf, | |
461 | char *buffer, | |
462 | size_t buflen, | |
463 | int *errnop) { | |
464 | int temp; | |
465 | char* name; | |
466 | ||
467 | if (init_afs()) return NSS_STATUS_UNAVAIL; | |
468 | ||
469 | name = buffer; | |
470 | temp = ptsid2name( uid, &buffer, &buflen); | |
471 | if (temp != NSS_STATUS_SUCCESS) { | |
472 | *errnop = ENOENT; | |
473 | return temp; | |
474 | } | |
475 | ||
908a6ebe | 476 | return fill_result_buf(uid, name, result_buf, buffer, buflen, errnop); |
477 | } | |
478 | ||
479 | /** | |
480 | * This function is exported; glibc will invoke it in order to gather | |
481 | * the user information (userid, homedir, shell) associated with a | |
482 | * username. | |
03b6b479 | 483 | */ |
908a6ebe | 484 | enum nss_status _nss_afs_getpwnam_r (char *name, |
485 | struct passwd *result_buf, | |
486 | char *buffer, | |
487 | size_t buflen, | |
488 | int *errnop) { | |
03b6b479 | 489 | uid_t uid; |
490 | int temp; | |
491 | ||
492 | if (init_afs()) return NSS_STATUS_UNAVAIL; | |
493 | ||
494 | temp = ptsname2id(name,&uid); | |
495 | if (temp != NSS_STATUS_SUCCESS) { | |
496 | *errnop = ENOENT; | |
497 | return temp; | |
498 | } | |
499 | ||
908a6ebe | 500 | return fill_result_buf(uid, name, result_buf, buffer, buflen, errnop); |
03b6b479 | 501 | } |
502 |