1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
|
/*-
* Copyright (c) 1996 by
* Sean Eric Fagan <sef@kithrup.com>
* David Nugent <davidn@blaze.net.au>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, is permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice immediately at the beginning of the file, without modification,
* this list of conditions, and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. This work was done expressly for inclusion into FreeBSD. Other use
* is permitted provided this notation is included.
* 4. Absolutely no warranty of function or purpose is made by the authors.
* 5. Modifications may be freely made to this file providing the above
* conditions are met.
*
* High-level routines relating to use of the user capabilities database
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/types.h>
#include <sys/param.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <sys/cpuset.h>
#include <sys/mac.h>
#include <sys/rtprio.h>
#include <errno.h>
#include <fcntl.h>
#include <login_cap.h>
#include <paths.h>
#include <pwd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <syslog.h>
#include <unistd.h>
static struct login_res {
const char *what;
rlim_t (*who)(login_cap_t *, const char *, rlim_t, rlim_t);
int why;
} resources[] = {
{ "cputime", login_getcaptime, RLIMIT_CPU },
{ "filesize", login_getcapsize, RLIMIT_FSIZE },
{ "datasize", login_getcapsize, RLIMIT_DATA },
{ "stacksize", login_getcapsize, RLIMIT_STACK },
{ "memoryuse", login_getcapsize, RLIMIT_RSS },
{ "memorylocked", login_getcapsize, RLIMIT_MEMLOCK },
{ "maxproc", login_getcapnum, RLIMIT_NPROC },
{ "openfiles", login_getcapnum, RLIMIT_NOFILE },
{ "coredumpsize", login_getcapsize, RLIMIT_CORE },
{ "sbsize", login_getcapsize, RLIMIT_SBSIZE },
{ "vmemoryuse", login_getcapsize, RLIMIT_VMEM },
{ "pseudoterminals", login_getcapnum, RLIMIT_NPTS },
{ NULL, 0, 0 }
};
void
setclassresources(login_cap_t *lc)
{
struct login_res *lr;
if (lc == NULL)
return;
for (lr = resources; lr->what != NULL; ++lr) {
struct rlimit rlim;
/*
* The login.conf file can have <limit>, <limit>-max, and
* <limit>-cur entries.
* What we do is get the current current- and maximum- limits.
* Then, we try to get an entry for <limit> from the capability,
* using the current and max limits we just got as the
* default/error values.
* *Then*, we try looking for <limit>-cur and <limit>-max,
* again using the appropriate values as the default/error
* conditions.
*/
if (getrlimit(lr->why, &rlim) != 0)
syslog(LOG_ERR, "getting %s resource limit: %m", lr->what);
else {
char name_cur[40];
char name_max[40];
rlim_t rcur = rlim.rlim_cur;
rlim_t rmax = rlim.rlim_max;
sprintf(name_cur, "%s-cur", lr->what);
sprintf(name_max, "%s-max", lr->what);
rcur = (*lr->who)(lc, lr->what, rcur, rcur);
rmax = (*lr->who)(lc, lr->what, rmax, rmax);
rlim.rlim_cur = (*lr->who)(lc, name_cur, rcur, rcur);
rlim.rlim_max = (*lr->who)(lc, name_max, rmax, rmax);
if (setrlimit(lr->why, &rlim) == -1)
syslog(LOG_WARNING, "set class '%s' resource limit %s: %m", lc->lc_class, lr->what);
}
}
}
static struct login_vars {
const char *tag;
const char *var;
const char *def;
int overwrite;
} pathvars[] = {
{ "path", "PATH", NULL, 1},
{ "cdpath", "CDPATH", NULL, 1},
{ "manpath", "MANPATH", NULL, 1},
{ NULL, NULL, NULL, 0}
}, envars[] = {
{ "lang", "LANG", NULL, 1},
{ "charset", "MM_CHARSET", NULL, 1},
{ "timezone", "TZ", NULL, 1},
{ "term", "TERM", NULL, 0},
{ NULL, NULL, NULL, 0}
};
static char *
substvar(const char * var, const struct passwd * pwd, int hlen, int pch, int nlen)
{
char *np = NULL;
if (var != NULL) {
int tildes = 0;
int dollas = 0;
char *p;
if (pwd != NULL) {
/* Count the number of ~'s in var to substitute */
for (p = (char *)var; (p = strchr(p, '~')) != NULL; p++)
++tildes;
/* Count the number of $'s in var to substitute */
for (p = (char *)var; (p = strchr(p, '$')) != NULL; p++)
++dollas;
}
np = malloc(strlen(var) + (dollas * nlen)
- dollas + (tildes * (pch+hlen))
- tildes + 1);
if (np != NULL) {
p = strcpy(np, var);
if (pwd != NULL) {
/*
* This loop does user username and homedir substitutions
* for unescaped $ (username) and ~ (homedir)
*/
while (*(p += strcspn(p, "~$")) != '\0') {
int l = strlen(p);
if (p > np && *(p-1) == '\\') /* Escaped: */
memmove(p - 1, p, l + 1); /* Slide-out the backslash */
else if (*p == '~') {
int v = pch && *(p+1) != '/'; /* Avoid double // */
memmove(p + hlen + v, p + 1, l); /* Subst homedir */
memmove(p, pwd->pw_dir, hlen);
if (v)
p[hlen] = '/';
p += hlen + v;
}
else /* if (*p == '$') */ {
memmove(p + nlen, p + 1, l); /* Subst username */
memmove(p, pwd->pw_name, nlen);
p += nlen;
}
}
}
}
}
return np;
}
void
setclassenvironment(login_cap_t *lc, const struct passwd * pwd, int paths)
{
struct login_vars *vars = paths ? pathvars : envars;
int hlen = pwd ? strlen(pwd->pw_dir) : 0;
int nlen = pwd ? strlen(pwd->pw_name) : 0;
char pch = 0;
if (hlen && pwd->pw_dir[hlen-1] != '/')
++pch;
while (vars->tag != NULL) {
const char * var = paths ? login_getpath(lc, vars->tag, NULL)
: login_getcapstr(lc, vars->tag, NULL, NULL);
char * np = substvar(var, pwd, hlen, pch, nlen);
if (np != NULL) {
setenv(vars->var, np, vars->overwrite);
free(np);
} else if (vars->def != NULL) {
setenv(vars->var, vars->def, 0);
}
++vars;
}
/*
* If we're not processing paths, then see if there is a setenv list by
* which the admin and/or user may set an arbitrary set of env vars.
*/
if (!paths) {
const char **set_env = login_getcaplist(lc, "setenv", ",");
if (set_env != NULL) {
while (*set_env != NULL) {
char *p = strchr(*set_env, '=');
if (p != NULL) { /* Discard invalid entries */
char *np;
*p++ = '\0';
if ((np = substvar(p, pwd, hlen, pch, nlen)) != NULL) {
setenv(*set_env, np, 1);
free(np);
}
}
++set_env;
}
}
}
}
static int
list2cpuset(const char *list, cpuset_t *mask)
{
enum { NONE, NUM, DASH } state;
int lastnum;
int curnum;
const char *l;
state = NONE;
curnum = lastnum = 0;
for (l = list; *l != '\0';) {
if (isdigit(*l)) {
curnum = atoi(l);
if (curnum > CPU_SETSIZE)
errx(EXIT_FAILURE,
"Only %d cpus supported", CPU_SETSIZE);
while (isdigit(*l))
l++;
switch (state) {
case NONE:
lastnum = curnum;
state = NUM;
break;
case DASH:
for (; lastnum <= curnum; lastnum++)
CPU_SET(lastnum, mask);
state = NONE;
break;
case NUM:
default:
return (0);
}
continue;
}
switch (*l) {
case ',':
switch (state) {
case NONE:
break;
case NUM:
CPU_SET(curnum, mask);
state = NONE;
break;
case DASH:
return (0);
break;
}
break;
case '-':
if (state != NUM)
return (0);
state = DASH;
break;
default:
return (0);
}
l++;
}
switch (state) {
case NONE:
break;
case NUM:
CPU_SET(curnum, mask);
break;
case DASH:
return (0);
}
return 1;
}
void
setclasscpumask(login_cap_t *lc)
{
const char *maskstr;
cpuset_t maskset;
cpusetid_t setid;
maskstr = login_getcapstr(lc, "cpumask", NULL, NULL);
CPU_ZERO(&maskset);
if (maskstr == NULL)
return;
if (strcasecmp("default", maskstr) == 0)
return;
if (!list2cpuset(maskstr, &maskset)) {
syslog(LOG_WARNING,
"list2cpuset(%s) invalid mask specification", maskstr);
return;
}
if (cpuset(&setid) != 0) {
syslog(LOG_ERR, "cpuset(): %s", strerror(errno));
return;
}
if (cpuset_setaffinity(CPU_LEVEL_CPUSET, CPU_WHICH_PID, -1,
sizeof(maskset), &maskset) != 0)
syslog(LOG_ERR, "cpuset_setaffinity(%s): %s", maskstr,
strerror(errno));
}
/*
* setclasscontext()
*
* For the login class <class>, set various class context values
* (limits, mainly) to the values for that class. Which values are
* set are controlled by <flags> -- see <login_class.h> for the
* possible values.
*
* setclasscontext() can only set resources, priority, and umask.
*/
int
setclasscontext(const char *classname, unsigned int flags)
{
int rc;
login_cap_t *lc;
lc = login_getclassbyname(classname, NULL);
flags &= LOGIN_SETRESOURCES | LOGIN_SETPRIORITY |
LOGIN_SETUMASK | LOGIN_SETPATH;
rc = lc ? setusercontext(lc, NULL, 0, flags) : -1;
login_close(lc);
return rc;
}
/*
* Private function which takes care of processing
*/
static mode_t
setlogincontext(login_cap_t *lc, const struct passwd *pwd,
mode_t mymask, unsigned long flags)
{
if (lc) {
/* Set resources */
if (flags & LOGIN_SETRESOURCES)
setclassresources(lc);
/* See if there's a umask override */
if (flags & LOGIN_SETUMASK)
mymask = (mode_t)login_getcapnum(lc, "umask", mymask, mymask);
/* Set paths */
if (flags & LOGIN_SETPATH)
setclassenvironment(lc, pwd, 1);
/* Set environment */
if (flags & LOGIN_SETENV)
setclassenvironment(lc, pwd, 0);
/* Set cpu affinity */
if (flags & LOGIN_SETCPUMASK)
setclasscpumask(lc);
}
return mymask;
}
/*
* setusercontext()
*
* Given a login class <lc> and a user in <pwd>, with a uid <uid>,
* set the context as in setclasscontext(). <flags> controls which
* values are set.
*
* The difference between setclasscontext() and setusercontext() is
* that the former sets things up for an already-existing process,
* while the latter sets things up from a root context. Such as might
* be called from login(1).
*
*/
int
setusercontext(login_cap_t *lc, const struct passwd *pwd, uid_t uid, unsigned int flags)
{
quad_t p;
mode_t mymask;
login_cap_t *llc = NULL;
struct rtprio rtp;
int error;
if (lc == NULL) {
if (pwd != NULL && (lc = login_getpwclass(pwd)) != NULL)
llc = lc; /* free this when we're done */
}
if (flags & LOGIN_SETPATH)
pathvars[0].def = uid ? _PATH_DEFPATH : _PATH_STDPATH;
/* we need a passwd entry to set these */
if (pwd == NULL)
flags &= ~(LOGIN_SETGROUP | LOGIN_SETLOGIN | LOGIN_SETMAC);
/* Set the process priority */
if (flags & LOGIN_SETPRIORITY) {
p = login_getcapnum(lc, "priority", LOGIN_DEFPRI, LOGIN_DEFPRI);
if (p > PRIO_MAX) {
rtp.type = RTP_PRIO_IDLE;
rtp.prio = p - PRIO_MAX - 1;
p = (rtp.prio > RTP_PRIO_MAX) ? 31 : p;
if (rtprio(RTP_SET, 0, &rtp))
syslog(LOG_WARNING, "rtprio '%s' (%s): %m",
pwd->pw_name, lc ? lc->lc_class : LOGIN_DEFCLASS);
} else if (p < PRIO_MIN) {
rtp.type = RTP_PRIO_REALTIME;
rtp.prio = abs(p - PRIO_MIN + RTP_PRIO_MAX);
p = (rtp.prio > RTP_PRIO_MAX) ? 1 : p;
if (rtprio(RTP_SET, 0, &rtp))
syslog(LOG_WARNING, "rtprio '%s' (%s): %m",
pwd->pw_name, lc ? lc->lc_class : LOGIN_DEFCLASS);
} else {
if (setpriority(PRIO_PROCESS, 0, (int)p) != 0)
syslog(LOG_WARNING, "setpriority '%s' (%s): %m",
pwd->pw_name, lc ? lc->lc_class : LOGIN_DEFCLASS);
}
}
/* Setup the user's group permissions */
if (flags & LOGIN_SETGROUP) {
if (setgid(pwd->pw_gid) != 0) {
syslog(LOG_ERR, "setgid(%lu): %m", (u_long)pwd->pw_gid);
login_close(llc);
return -1;
}
if (initgroups(pwd->pw_name, pwd->pw_gid) == -1) {
syslog(LOG_ERR, "initgroups(%s,%lu): %m", pwd->pw_name,
(u_long)pwd->pw_gid);
login_close(llc);
return -1;
}
}
/* Set up the user's MAC label. */
if ((flags & LOGIN_SETMAC) && mac_is_present(NULL) == 1) {
const char *label_string;
mac_t label;
label_string = login_getcapstr(lc, "label", NULL, NULL);
if (label_string != NULL) {
if (mac_from_text(&label, label_string) == -1) {
syslog(LOG_ERR, "mac_from_text('%s') for %s: %m",
pwd->pw_name, label_string);
return -1;
}
if (mac_set_proc(label) == -1)
error = errno;
else
error = 0;
mac_free(label);
if (error != 0) {
syslog(LOG_ERR, "mac_set_proc('%s') for %s: %s",
label_string, pwd->pw_name, strerror(error));
return -1;
}
}
}
/* Set the sessions login */
if ((flags & LOGIN_SETLOGIN) && setlogin(pwd->pw_name) != 0) {
syslog(LOG_ERR, "setlogin(%s): %m", pwd->pw_name);
login_close(llc);
return -1;
}
mymask = (flags & LOGIN_SETUMASK) ? umask(LOGIN_DEFUMASK) : 0;
mymask = setlogincontext(lc, pwd, mymask, flags);
login_close(llc);
/* This needs to be done after anything that needs root privs */
if ((flags & LOGIN_SETUSER) && setuid(uid) != 0) {
syslog(LOG_ERR, "setuid(%lu): %m", (u_long)uid);
return -1; /* Paranoia again */
}
/*
* Now, we repeat some of the above for the user's private entries
*/
if ((lc = login_getuserclass(pwd)) != NULL) {
mymask = setlogincontext(lc, pwd, mymask, flags);
login_close(lc);
}
/* Finally, set any umask we've found */
if (flags & LOGIN_SETUMASK)
umask(mymask);
return 0;
}
|