summaryrefslogtreecommitdiffstats
path: root/sys/kern/kern_prot.c
blob: 728e4306c76048881301a9a18c336a380cfce2a8 (plain)
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
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
/*
 * Copyright (c) 1982, 1986, 1989, 1990, 1991, 1993
 *	The Regents of the University of California.  All rights reserved.
 * (c) UNIX System Laboratories, Inc.
 * All or some portions of this file are derived from material licensed
 * to the University of California by American Telephone and Telegraph
 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
 * the permission of UNIX System Laboratories, Inc.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *	@(#)kern_prot.c	8.6 (Berkeley) 1/21/94
 * $Id: kern_prot.c,v 1.43 1998/12/13 07:07:51 truckman Exp $
 */

/*
 * System calls related to processes and protection
 */

#include "opt_compat.h"

#include <sys/param.h>
#include <sys/acct.h>
#include <sys/systm.h>
#include <sys/sysproto.h>
#include <sys/kernel.h>
#include <sys/proc.h>
#include <sys/malloc.h>
#include <sys/unistd.h>
#include <sys/pioctl.h>

static MALLOC_DEFINE(M_CRED, "cred", "credentials");

#ifndef _SYS_SYSPROTO_H_
struct getpid_args {
	int	dummy;
};
#endif

/* ARGSUSED */
int
getpid(p, uap)
	struct proc *p;
	struct getpid_args *uap;
{

	p->p_retval[0] = p->p_pid;
#if defined(COMPAT_43) || defined(COMPAT_SUNOS)
	p->p_retval[1] = p->p_pptr->p_pid;
#endif
	return (0);
}

#ifndef _SYS_SYSPROTO_H_
struct getppid_args {
        int     dummy;
};
#endif
/* ARGSUSED */
int
getppid(p, uap)
	struct proc *p;
	struct getppid_args *uap;
{

	p->p_retval[0] = p->p_pptr->p_pid;
	return (0);
}

/* Get process group ID; note that POSIX getpgrp takes no parameter */
#ifndef _SYS_SYSPROTO_H_
struct getpgrp_args {
        int     dummy;
};
#endif

int
getpgrp(p, uap)
	struct proc *p;
	struct getpgrp_args *uap;
{

	p->p_retval[0] = p->p_pgrp->pg_id;
	return (0);
}

/* Get an arbitary pid's process group id */
#ifndef _SYS_SYSPROTO_H_
struct getpgid_args {
	pid_t	pid;
};
#endif

int
getpgid(p, uap)
	struct proc *p;
	struct getpgid_args *uap;
{
	struct proc *pt;

	pt = p;
	if (uap->pid == 0)
		goto found;

	if ((pt = pfind(uap->pid)) == 0)
		return ESRCH;
found:
	p->p_retval[0] = pt->p_pgrp->pg_id;
	return 0;
}

/*
 * Get an arbitary pid's session id.
 */
#ifndef _SYS_SYSPROTO_H_
struct getsid_args {
	pid_t	pid;
};
#endif

int
getsid(p, uap)
	struct proc *p;
	struct getsid_args *uap;
{
	struct proc *pt;

	pt = p;
	if (uap->pid == 0)
		goto found;

	if ((pt == pfind(uap->pid)) == 0)
		return ESRCH;
found:
	p->p_retval[0] = pt->p_session->s_sid;
	return 0;
}


#ifndef _SYS_SYSPROTO_H_
struct getuid_args {
        int     dummy;
};
#endif

/* ARGSUSED */
int
getuid(p, uap)
	struct proc *p;
	struct getuid_args *uap;
{

	p->p_retval[0] = p->p_cred->p_ruid;
#if defined(COMPAT_43) || defined(COMPAT_SUNOS)
	p->p_retval[1] = p->p_ucred->cr_uid;
#endif
	return (0);
}

#ifndef _SYS_SYSPROTO_H_
struct geteuid_args {
        int     dummy;
};
#endif

/* ARGSUSED */
int
geteuid(p, uap)
	struct proc *p;
	struct geteuid_args *uap;
{

	p->p_retval[0] = p->p_ucred->cr_uid;
	return (0);
}

#ifndef _SYS_SYSPROTO_H_
struct getgid_args {
        int     dummy;
};
#endif

/* ARGSUSED */
int
getgid(p, uap)
	struct proc *p;
	struct getgid_args *uap;
{

	p->p_retval[0] = p->p_cred->p_rgid;
#if defined(COMPAT_43) || defined(COMPAT_SUNOS)
	p->p_retval[1] = p->p_ucred->cr_groups[0];
#endif
	return (0);
}

/*
 * Get effective group ID.  The "egid" is groups[0], and could be obtained
 * via getgroups.  This syscall exists because it is somewhat painful to do
 * correctly in a library function.
 */
#ifndef _SYS_SYSPROTO_H_
struct getegid_args {
        int     dummy;
};
#endif

/* ARGSUSED */
int
getegid(p, uap)
	struct proc *p;
	struct getegid_args *uap;
{

	p->p_retval[0] = p->p_ucred->cr_groups[0];
	return (0);
}

#ifndef _SYS_SYSPROTO_H_
struct getgroups_args {
	u_int	gidsetsize;
	gid_t	*gidset;
};
#endif
int
getgroups(p, uap)
	struct proc *p;
	register struct	getgroups_args *uap;
{
	register struct pcred *pc = p->p_cred;
	register u_int ngrp;
	int error;

	if ((ngrp = uap->gidsetsize) == 0) {
		p->p_retval[0] = pc->pc_ucred->cr_ngroups;
		return (0);
	}
	if (ngrp < pc->pc_ucred->cr_ngroups)
		return (EINVAL);
	ngrp = pc->pc_ucred->cr_ngroups;
	if ((error = copyout((caddr_t)pc->pc_ucred->cr_groups,
	    (caddr_t)uap->gidset, ngrp * sizeof(gid_t))))
		return (error);
	p->p_retval[0] = ngrp;
	return (0);
}

#ifndef _SYS_SYSPROTO_H_
struct setsid_args {
        int     dummy;
};
#endif

/* ARGSUSED */
int
setsid(p, uap)
	register struct proc *p;
	struct setsid_args *uap;
{

	if (p->p_pgid == p->p_pid || pgfind(p->p_pid)) {
		return (EPERM);
	} else {
		(void)enterpgrp(p, p->p_pid, 1);
		p->p_retval[0] = p->p_pid;
		return (0);
	}
}

/*
 * set process group (setpgid/old setpgrp)
 *
 * caller does setpgid(targpid, targpgid)
 *
 * pid must be caller or child of caller (ESRCH)
 * if a child
 *	pid must be in same session (EPERM)
 *	pid can't have done an exec (EACCES)
 * if pgid != pid
 * 	there must exist some pid in same session having pgid (EPERM)
 * pid must not be session leader (EPERM)
 */
#ifndef _SYS_SYSPROTO_H_
struct setpgid_args {
	int	pid;	/* target process id */
	int	pgid;	/* target pgrp id */
};
#endif
/* ARGSUSED */
int
setpgid(curp, uap)
	struct proc *curp;
	register struct setpgid_args *uap;
{
	register struct proc *targp;		/* target process */
	register struct pgrp *pgrp;		/* target pgrp */

	if (uap->pgid < 0)
		return (EINVAL);
	if (uap->pid != 0 && uap->pid != curp->p_pid) {
		if ((targp = pfind(uap->pid)) == 0 || !inferior(targp))
			return (ESRCH);
		if (targp->p_pgrp == NULL ||  targp->p_session != curp->p_session)
			return (EPERM);
		if (targp->p_flag & P_EXEC)
			return (EACCES);
	} else
		targp = curp;
	if (SESS_LEADER(targp))
		return (EPERM);
	if (uap->pgid == 0)
		uap->pgid = targp->p_pid;
	else if (uap->pgid != targp->p_pid)
		if ((pgrp = pgfind(uap->pgid)) == 0 ||
	            pgrp->pg_session != curp->p_session)
			return (EPERM);
	return (enterpgrp(targp, uap->pgid, 0));
}

/*
 * Use the clause in B.4.2.2 that allows setuid/setgid to be 4.2/4.3BSD
 * compatable.  It says that setting the uid/gid to euid/egid is a special
 * case of "appropriate privilege".  Once the rules are expanded out, this
 * basically means that setuid(nnn) sets all three id's, in all permitted
 * cases unless _POSIX_SAVED_IDS is enabled.  In that case, setuid(getuid())
 * does not set the saved id - this is dangerous for traditional BSD
 * programs.  For this reason, we *really* do not want to set
 * _POSIX_SAVED_IDS and do not want to clear POSIX_APPENDIX_B_4_2_2.
 */
#define POSIX_APPENDIX_B_4_2_2

#ifndef _SYS_SYSPROTO_H_
struct setuid_args {
	uid_t	uid;
};
#endif
/* ARGSUSED */
int
setuid(p, uap)
	struct proc *p;
	struct setuid_args *uap;
{
	register struct pcred *pc = p->p_cred;
	register uid_t uid;
	int error;

	/*
	 * See if we have "permission" by POSIX 1003.1 rules.
	 *
	 * Note that setuid(geteuid()) is a special case of 
	 * "appropriate privileges" in appendix B.4.2.2.  We need
	 * to use this clause to be compatable with traditional BSD
	 * semantics.  Basically, it means that "setuid(xx)" sets all
	 * three id's (assuming you have privs).
	 *
	 * Notes on the logic.  We do things in three steps.
	 * 1: We determine if the euid is going to change, and do EPERM
	 *    right away.  We unconditionally change the euid later if this
	 *    test is satisfied, simplifying that part of the logic.
	 * 2: We determine if the real and/or saved uid's are going to
	 *    change.  Determined by compile options.
	 * 3: Change euid last. (after tests in #2 for "appropriate privs")
	 */
	uid = uap->uid;
	if (uid != pc->p_ruid &&		/* allow setuid(getuid()) */
#ifdef _POSIX_SAVED_IDS
	    uid != pc->p_svuid &&		/* allow setuid(saved gid) */
#endif
#ifdef POSIX_APPENDIX_B_4_2_2	/* Use BSD-compat clause from B.4.2.2 */
	    uid != pc->pc_ucred->cr_uid &&	/* allow setuid(geteuid()) */
#endif
	    (error = suser(pc->pc_ucred, &p->p_acflag)))
		return (error);

#ifdef _POSIX_SAVED_IDS
	/*
	 * Do we have "appropriate privileges" (are we root or uid == euid)
	 * If so, we are changing the real uid and/or saved uid.
	 */
	if (
#ifdef POSIX_APPENDIX_B_4_2_2	/* Use the clause from B.4.2.2 */
	    uid == pc->pc_ucred->cr_uid ||
#endif
	    suser(pc->pc_ucred, &p->p_acflag) == 0) /* we are using privs */
#endif
	{
		/*
		 * Transfer proc count to new user.
		 */
		if (uid != pc->p_ruid) {
			(void)chgproccnt(pc->p_ruid, -1);
			(void)chgproccnt(uid, 1);
		}
		/*
		 * Set real uid
		 */
		if (uid != pc->p_ruid) {
			pc->p_ruid = uid;
			setsugid(p);
		}
		/*
		 * Set saved uid
		 *
		 * XXX always set saved uid even if not _POSIX_SAVED_IDS, as
		 * the security of seteuid() depends on it.  B.4.2.2 says it
		 * is important that we should do this.
		 */
		if (pc->p_svuid != uid) {
			pc->p_svuid = uid;
			setsugid(p);
		}
	}

	/*
	 * In all permitted cases, we are changing the euid.
	 * Copy credentials so other references do not see our changes.
	 */
	if (pc->pc_ucred->cr_uid != uid) {
		pc->pc_ucred = crcopy(pc->pc_ucred);
		pc->pc_ucred->cr_uid = uid;
		setsugid(p);
	}
	return (0);
}

#ifndef _SYS_SYSPROTO_H_
struct seteuid_args {
	uid_t	euid;
};
#endif
/* ARGSUSED */
int
seteuid(p, uap)
	struct proc *p;
	struct seteuid_args *uap;
{
	register struct pcred *pc = p->p_cred;
	register uid_t euid;
	int error;

	euid = uap->euid;
	if (euid != pc->p_ruid &&		/* allow seteuid(getuid()) */
	    euid != pc->p_svuid &&		/* allow seteuid(saved uid) */
	    (error = suser(pc->pc_ucred, &p->p_acflag)))
		return (error);
	/*
	 * Everything's okay, do it.  Copy credentials so other references do
	 * not see our changes.
	 */
	if (pc->pc_ucred->cr_uid != euid) {
		pc->pc_ucred = crcopy(pc->pc_ucred);
		pc->pc_ucred->cr_uid = euid;
		setsugid(p);
	}
	return (0);
}

#ifndef _SYS_SYSPROTO_H_
struct setgid_args {
	gid_t	gid;
};
#endif
/* ARGSUSED */
int
setgid(p, uap)
	struct proc *p;
	struct setgid_args *uap;
{
	register struct pcred *pc = p->p_cred;
	register gid_t gid;
	int error;

	/*
	 * See if we have "permission" by POSIX 1003.1 rules.
	 *
	 * Note that setgid(getegid()) is a special case of
	 * "appropriate privileges" in appendix B.4.2.2.  We need
	 * to use this clause to be compatable with traditional BSD
	 * semantics.  Basically, it means that "setgid(xx)" sets all
	 * three id's (assuming you have privs).
	 *
	 * For notes on the logic here, see setuid() above.
	 */
	gid = uap->gid;
	if (gid != pc->p_rgid &&		/* allow setgid(getgid()) */
#ifdef _POSIX_SAVED_IDS
	    gid != pc->p_svgid &&		/* allow setgid(saved gid) */
#endif
#ifdef POSIX_APPENDIX_B_4_2_2	/* Use BSD-compat clause from B.4.2.2 */
	    gid != pc->pc_ucred->cr_groups[0] && /* allow setgid(getegid()) */
#endif
	    (error = suser(pc->pc_ucred, &p->p_acflag)))
		return (error);

#ifdef _POSIX_SAVED_IDS
	/*
	 * Do we have "appropriate privileges" (are we root or gid == egid)
	 * If so, we are changing the real uid and saved gid.
	 */
	if (
#ifdef POSIX_APPENDIX_B_4_2_2	/* use the clause from B.4.2.2 */
	    gid == pc->pc_ucred->cr_groups[0] ||
#endif
	    suser(pc->pc_ucred, &p->p_acflag) == 0) /* we are using privs */
#endif
	{
		/*
		 * Set real gid
		 */
		if (pc->p_rgid != gid) {
			pc->p_rgid = gid;
			setsugid(p);
		}
		/*
		 * Set saved gid
		 *
		 * XXX always set saved gid even if not _POSIX_SAVED_IDS, as
		 * the security of setegid() depends on it.  B.4.2.2 says it
		 * is important that we should do this.
		 */
		if (pc->p_svgid != gid) {
			pc->p_svgid = gid;
			setsugid(p);
		}
	}
	/*
	 * In all cases permitted cases, we are changing the egid.
	 * Copy credentials so other references do not see our changes.
	 */
	if (pc->pc_ucred->cr_groups[0] != gid) {
		pc->pc_ucred = crcopy(pc->pc_ucred);
		pc->pc_ucred->cr_groups[0] = gid;
		setsugid(p);
	}
	return (0);
}

#ifndef _SYS_SYSPROTO_H_
struct setegid_args {
	gid_t	egid;
};
#endif
/* ARGSUSED */
int
setegid(p, uap)
	struct proc *p;
	struct setegid_args *uap;
{
	register struct pcred *pc = p->p_cred;
	register gid_t egid;
	int error;

	egid = uap->egid;
	if (egid != pc->p_rgid &&		/* allow setegid(getgid()) */
	    egid != pc->p_svgid &&		/* allow setegid(saved gid) */
	    (error = suser(pc->pc_ucred, &p->p_acflag)))
		return (error);
	if (pc->pc_ucred->cr_groups[0] != egid) {
		pc->pc_ucred = crcopy(pc->pc_ucred);
		pc->pc_ucred->cr_groups[0] = egid;
		setsugid(p);
	}
	return (0);
}

#ifndef _SYS_SYSPROTO_H_
struct setgroups_args {
	u_int	gidsetsize;
	gid_t	*gidset;
};
#endif
/* ARGSUSED */
int
setgroups(p, uap)
	struct proc *p;
	struct setgroups_args *uap;
{
	register struct pcred *pc = p->p_cred;
	register u_int ngrp;
	int error;

	if ((error = suser(pc->pc_ucred, &p->p_acflag)))
		return (error);
	ngrp = uap->gidsetsize;
	if (ngrp > NGROUPS)
		return (EINVAL);
	/*
	 * XXX A little bit lazy here.  We could test if anything has
	 * changed before crcopy() and setting P_SUGID.
	 */
	pc->pc_ucred = crcopy(pc->pc_ucred);
	if (ngrp < 1) {
		/*
		 * setgroups(0, NULL) is a legitimate way of clearing the
		 * groups vector on non-BSD systems (which generally do not
		 * have the egid in the groups[0]).  We risk security holes
		 * when running non-BSD software if we do not do the same.
		 */
		pc->pc_ucred->cr_ngroups = 1;
	} else {
		if ((error = copyin((caddr_t)uap->gidset,
		    (caddr_t)pc->pc_ucred->cr_groups, ngrp * sizeof(gid_t))))
			return (error);
		pc->pc_ucred->cr_ngroups = ngrp;
	}
	setsugid(p);
	return (0);
}

#ifndef _SYS_SYSPROTO_H_
struct setreuid_args {
	uid_t	ruid;
	uid_t	euid;
};
#endif
/* ARGSUSED */
int
setreuid(p, uap)
	register struct proc *p;
	struct setreuid_args *uap;
{
	register struct pcred *pc = p->p_cred;
	register uid_t ruid, euid;
	int error;

	ruid = uap->ruid;
	euid = uap->euid;
	if (((ruid != (uid_t)-1 && ruid != pc->p_ruid && ruid != pc->p_svuid) ||
	     (euid != (uid_t)-1 && euid != pc->pc_ucred->cr_uid &&
	     euid != pc->p_ruid && euid != pc->p_svuid)) &&
	    (error = suser(pc->pc_ucred, &p->p_acflag)) != 0)
		return (error);

	if (euid != (uid_t)-1 && pc->pc_ucred->cr_uid != euid) {
		pc->pc_ucred = crcopy(pc->pc_ucred);
		pc->pc_ucred->cr_uid = euid;
		setsugid(p);
	}
	if (ruid != (uid_t)-1 && pc->p_ruid != ruid) {
		(void)chgproccnt(pc->p_ruid, -1);
		(void)chgproccnt(ruid, 1);
		pc->p_ruid = ruid;
		setsugid(p);
	}
	if ((ruid != (uid_t)-1 || pc->pc_ucred->cr_uid != pc->p_ruid) &&
	    pc->p_svuid != pc->pc_ucred->cr_uid) {
		pc->p_svuid = pc->pc_ucred->cr_uid;
		setsugid(p);
	}
	return (0);
}

#ifndef _SYS_SYSPROTO_H_
struct setregid_args {
	gid_t	rgid;
	gid_t	egid;
};
#endif
/* ARGSUSED */
int
setregid(p, uap)
	register struct proc *p;
	struct setregid_args *uap;
{
	register struct pcred *pc = p->p_cred;
	register gid_t rgid, egid;
	int error;

	rgid = uap->rgid;
	egid = uap->egid;
	if (((rgid != (gid_t)-1 && rgid != pc->p_rgid && rgid != pc->p_svgid) ||
	     (egid != (gid_t)-1 && egid != pc->pc_ucred->cr_groups[0] &&
	     egid != pc->p_rgid && egid != pc->p_svgid)) &&
	    (error = suser(pc->pc_ucred, &p->p_acflag)) != 0)
		return (error);

	if (egid != (gid_t)-1 && pc->pc_ucred->cr_groups[0] != egid) {
		pc->pc_ucred = crcopy(pc->pc_ucred);
		pc->pc_ucred->cr_groups[0] = egid;
		setsugid(p);
	}
	if (rgid != (gid_t)-1 && pc->p_rgid != rgid) {
		pc->p_rgid = rgid;
		setsugid(p);
	}
	if ((rgid != (gid_t)-1 || pc->pc_ucred->cr_groups[0] != pc->p_rgid) &&
	    pc->p_svgid != pc->pc_ucred->cr_groups[0]) {
		pc->p_svgid = pc->pc_ucred->cr_groups[0];
		setsugid(p);
	}
	return (0);
}

#ifndef _SYS_SYSPROTO_H_
struct issetugid_args {
	int dummy;
};
#endif
/* ARGSUSED */
int
issetugid(p, uap)
	register struct proc *p;
	struct issetugid_args *uap;
{
	/*
	 * Note: OpenBSD sets a P_SUGIDEXEC flag set at execve() time,
	 * we use P_SUGID because we consider changing the owners as
	 * "tainting" as well.
	 * This is significant for procs that start as root and "become"
	 * a user without an exec - programs cannot know *everything*
	 * that libc *might* have put in their data segment.
	 */
	if (p->p_flag & P_SUGID)
		return (1);
	return (0);
}

/*
 * Check if gid is a member of the group set.
 */
int
groupmember(gid, cred)
	gid_t gid;
	register struct ucred *cred;
{
	register gid_t *gp;
	gid_t *egp;

	egp = &(cred->cr_groups[cred->cr_ngroups]);
	for (gp = cred->cr_groups; gp < egp; gp++)
		if (*gp == gid)
			return (1);
	return (0);
}

/*
 * Test whether the specified credentials imply "super-user"
 * privilege; if so, and we have accounting info, set the flag
 * indicating use of super-powers.
 * Returns 0 or error.
 */
int
suser(cred, acflag)
	struct ucred *cred;
	u_short *acflag;
{
	if (cred->cr_uid == 0) {
		if (acflag)
			*acflag |= ASU;
		return (0);
	}
	return (EPERM);
}

/*
 * Allocate a zeroed cred structure.
 */
struct ucred *
crget()
{
	register struct ucred *cr;

	MALLOC(cr, struct ucred *, sizeof(*cr), M_CRED, M_WAITOK);
	bzero((caddr_t)cr, sizeof(*cr));
	cr->cr_ref = 1;
	return (cr);
}

/*
 * Free a cred structure.
 * Throws away space when ref count gets to 0.
 */
void
crfree(cr)
	struct ucred *cr;
{
	if (--cr->cr_ref == 0)
		FREE((caddr_t)cr, M_CRED);
}

/*
 * Copy cred structure to a new one and free the old one.
 */
struct ucred *
crcopy(cr)
	struct ucred *cr;
{
	struct ucred *newcr;

	if (cr->cr_ref == 1)
		return (cr);
	newcr = crget();
	*newcr = *cr;
	crfree(cr);
	newcr->cr_ref = 1;
	return (newcr);
}

/*
 * Dup cred struct to a new held one.
 */
struct ucred *
crdup(cr)
	struct ucred *cr;
{
	struct ucred *newcr;

	newcr = crget();
	*newcr = *cr;
	newcr->cr_ref = 1;
	return (newcr);
}

/*
 * Get login name, if available.
 */
#ifndef _SYS_SYSPROTO_H_
struct getlogin_args {
	char	*namebuf;
	u_int	namelen;
};
#endif
/* ARGSUSED */
int
getlogin(p, uap)
	struct proc *p;
	struct getlogin_args *uap;
{

	if (uap->namelen > MAXLOGNAME)
		uap->namelen = MAXLOGNAME;
	return (copyout((caddr_t) p->p_pgrp->pg_session->s_login,
	    (caddr_t) uap->namebuf, uap->namelen));
}

/*
 * Set login name.
 */
#ifndef _SYS_SYSPROTO_H_
struct setlogin_args {
	char	*namebuf;
};
#endif
/* ARGSUSED */
int
setlogin(p, uap)
	struct proc *p;
	struct setlogin_args *uap;
{
	int error;
	char logintmp[MAXLOGNAME];

	if ((error = suser(p->p_ucred, &p->p_acflag)))
		return (error);
	error = copyinstr((caddr_t) uap->namebuf, (caddr_t) logintmp,
	    sizeof(logintmp), (size_t *)0);
	if (error == ENAMETOOLONG)
		error = EINVAL;
	else if (!error)
		(void) memcpy(p->p_pgrp->pg_session->s_login, logintmp,
		    sizeof(logintmp));
	return (error);
}

void
setsugid(p)
     struct proc *p;
{
	p->p_flag |= P_SUGID;
	if (!(p->p_pfsflags & PF_ISUGID))
		p->p_stops = 0;
}
OpenPOWER on IntegriCloud