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