kern_prot.c revision 11332 
1/*
2 * Copyright (c) 1982, 1986, 1989, 1990, 1991, 1993
3 *	The Regents of the University of California.  All rights reserved.
4 * (c) UNIX System Laboratories, Inc.
5 * All or some portions of this file are derived from material licensed
6 * to the University of California by American Telephone and Telegraph
7 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
8 * the permission of UNIX System Laboratories, Inc.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 * 3. All advertising materials mentioning features or use of this software
19 *    must display the following acknowledgement:
20 *	This product includes software developed by the University of
21 *	California, Berkeley and its contributors.
22 * 4. Neither the name of the University nor the names of its contributors
23 *    may be used to endorse or promote products derived from this software
24 *    without specific prior written permission.
25 *
26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36 * SUCH DAMAGE.
37 *
38 *	@(#)kern_prot.c	8.6 (Berkeley) 1/21/94
39 * $Id: kern_prot.c,v 1.12 1995/06/15 22:32:03 ache Exp $
40 */
41
42/*
43 * System calls related to processes and protection
44 */
45
46#include <sys/param.h>
47#include <sys/acct.h>
48#include <sys/systm.h>
49#include <sys/ucred.h>
50#include <sys/proc.h>
51#include <sys/timeb.h>
52#include <sys/times.h>
53#include <sys/malloc.h>
54
55struct getpid_args {
56	int	dummy;
57};
58
59/* ARGSUSED */
60int
61getpid(p, uap, retval)
62	struct proc *p;
63	struct getpid_args *uap;
64	int *retval;
65{
66
67	*retval = p->p_pid;
68#if defined(COMPAT_43) || defined(COMPAT_SUNOS)
69	retval[1] = p->p_pptr->p_pid;
70#endif
71	return (0);
72}
73
74struct getppid_args {
75        int     dummy;
76};
77/* ARGSUSED */
78int
79getppid(p, uap, retval)
80	struct proc *p;
81	struct getppid_args *uap;
82	int *retval;
83{
84
85	*retval = p->p_pptr->p_pid;
86	return (0);
87}
88
89/* Get process group ID; note that POSIX getpgrp takes no parameter */
90struct getpgrp_args {
91        int     dummy;
92};
93
94int
95getpgrp(p, uap, retval)
96	struct proc *p;
97	struct getpgrp_args *uap;
98	int *retval;
99{
100
101	*retval = p->p_pgrp->pg_id;
102	return (0);
103}
104
105struct getuid_args {
106        int     dummy;
107};
108
109/* ARGSUSED */
110int
111getuid(p, uap, retval)
112	struct proc *p;
113	struct getuid_args *uap;
114	int *retval;
115{
116
117	*retval = p->p_cred->p_ruid;
118#if defined(COMPAT_43) || defined(COMPAT_SUNOS)
119	retval[1] = p->p_ucred->cr_uid;
120#endif
121	return (0);
122}
123
124struct geteuid_args {
125        int     dummy;
126};
127
128/* ARGSUSED */
129int
130geteuid(p, uap, retval)
131	struct proc *p;
132	struct geteuid_args *uap;
133	int *retval;
134{
135
136	*retval = p->p_ucred->cr_uid;
137	return (0);
138}
139
140struct getgid_args {
141        int     dummy;
142};
143
144/* ARGSUSED */
145int
146getgid(p, uap, retval)
147	struct proc *p;
148	struct getgid_args *uap;
149	int *retval;
150{
151
152	*retval = p->p_cred->p_rgid;
153#if defined(COMPAT_43) || defined(COMPAT_SUNOS)
154	retval[1] = p->p_ucred->cr_groups[0];
155#endif
156	return (0);
157}
158
159/*
160 * Get effective group ID.  The "egid" is groups[0], and could be obtained
161 * via getgroups.  This syscall exists because it is somewhat painful to do
162 * correctly in a library function.
163 */
164struct getegid_args {
165        int     dummy;
166};
167
168/* ARGSUSED */
169int
170getegid(p, uap, retval)
171	struct proc *p;
172	struct getegid_args *uap;
173	int *retval;
174{
175
176	*retval = p->p_ucred->cr_groups[0];
177	return (0);
178}
179
180struct getgroups_args {
181	u_int	gidsetsize;
182	gid_t	*gidset;
183};
184int
185getgroups(p, uap, retval)
186	struct proc *p;
187	register struct	getgroups_args *uap;
188	int *retval;
189{
190	register struct pcred *pc = p->p_cred;
191	register u_int ngrp;
192	int error;
193
194	if ((ngrp = uap->gidsetsize) == 0) {
195		*retval = pc->pc_ucred->cr_ngroups;
196		return (0);
197	}
198	if (ngrp < pc->pc_ucred->cr_ngroups)
199		return (EINVAL);
200	ngrp = pc->pc_ucred->cr_ngroups;
201	if ((error = copyout((caddr_t)pc->pc_ucred->cr_groups,
202	    (caddr_t)uap->gidset, ngrp * sizeof(gid_t))))
203		return (error);
204	*retval = ngrp;
205	return (0);
206}
207
208struct getsid_args {
209        int     dummy;
210};
211
212/* ARGSUSED */
213int
214setsid(p, uap, retval)
215	register struct proc *p;
216	struct getsid_args *uap;
217	int *retval;
218{
219
220	if (p->p_pgid == p->p_pid || pgfind(p->p_pid)) {
221		return (EPERM);
222	} else {
223		(void)enterpgrp(p, p->p_pid, 1);
224		*retval = p->p_pid;
225		return (0);
226	}
227}
228
229/*
230 * set process group (setpgid/old setpgrp)
231 *
232 * caller does setpgid(targpid, targpgid)
233 *
234 * pid must be caller or child of caller (ESRCH)
235 * if a child
236 *	pid must be in same session (EPERM)
237 *	pid can't have done an exec (EACCES)
238 * if pgid != pid
239 * 	there must exist some pid in same session having pgid (EPERM)
240 * pid must not be session leader (EPERM)
241 */
242struct setpgid_args {
243	int	pid;	/* target process id */
244	int	pgid;	/* target pgrp id */
245};
246/* ARGSUSED */
247int
248setpgid(curp, uap, retval)
249	struct proc *curp;
250	register struct setpgid_args *uap;
251	int *retval;
252{
253	register struct proc *targp;		/* target process */
254	register struct pgrp *pgrp;		/* target pgrp */
255
256	if (uap->pid != 0 && uap->pid != curp->p_pid) {
257		if ((targp = pfind(uap->pid)) == 0 || !inferior(targp))
258			return (ESRCH);
259		if (targp->p_session != curp->p_session)
260			return (EPERM);
261		if (targp->p_flag & P_EXEC)
262			return (EACCES);
263	} else
264		targp = curp;
265	if (SESS_LEADER(targp))
266		return (EPERM);
267	if (uap->pgid == 0)
268		uap->pgid = targp->p_pid;
269	else if (uap->pgid != targp->p_pid)
270		if ((pgrp = pgfind(uap->pgid)) == 0 ||
271	            pgrp->pg_session != curp->p_session)
272			return (EPERM);
273	return (enterpgrp(targp, uap->pgid, 0));
274}
275
276struct setuid_args {
277	uid_t	uid;
278};
279/* ARGSUSED */
280int
281setuid(p, uap, retval)
282	struct proc *p;
283	struct setuid_args *uap;
284	int *retval;
285{
286	register struct pcred *pc = p->p_cred;
287	register uid_t uid;
288	int error;
289
290	uid = uap->uid;
291	if (uid != pc->p_ruid && uid != pc->p_svuid &&
292	    (error = suser(pc->pc_ucred, &p->p_acflag)))
293		return (error);
294	/*
295	 * Everything's okay, do it.
296	 * Transfer proc count to new user.
297	 * Copy credentials so other references do not see our changes.
298	 */
299	if (pc->pc_ucred->cr_uid == 0 && uid != pc->p_ruid) {
300		(void)chgproccnt(pc->p_ruid, -1);
301		(void)chgproccnt(uid, 1);
302	}
303	pc->pc_ucred = crcopy(pc->pc_ucred);
304	if (pc->pc_ucred->cr_uid == 0) {
305		pc->p_ruid = uid;
306		pc->p_svuid = uid;
307	}
308	pc->pc_ucred->cr_uid = uid;
309	p->p_flag |= P_SUGID;
310	return (0);
311}
312
313struct seteuid_args {
314	uid_t	euid;
315};
316/* ARGSUSED */
317int
318seteuid(p, uap, retval)
319	struct proc *p;
320	struct seteuid_args *uap;
321	int *retval;
322{
323	register struct pcred *pc = p->p_cred;
324	register uid_t euid;
325	int error;
326
327	euid = uap->euid;
328	if (euid != pc->p_ruid && euid != pc->p_svuid &&
329	    (error = suser(pc->pc_ucred, &p->p_acflag)))
330		return (error);
331	/*
332	 * Everything's okay, do it.  Copy credentials so other references do
333	 * not see our changes.
334	 */
335	pc->pc_ucred = crcopy(pc->pc_ucred);
336	pc->pc_ucred->cr_uid = euid;
337	p->p_flag |= P_SUGID;
338	return (0);
339}
340
341struct setgid_args {
342	gid_t	gid;
343};
344/* ARGSUSED */
345int
346setgid(p, uap, retval)
347	struct proc *p;
348	struct setgid_args *uap;
349	int *retval;
350{
351	register struct pcred *pc = p->p_cred;
352	register gid_t gid;
353	int error;
354
355	gid = uap->gid;
356	if (gid != pc->p_rgid && gid != pc->p_svgid &&
357	    (error = suser(pc->pc_ucred, &p->p_acflag)))
358		return (error);
359	pc->pc_ucred = crcopy(pc->pc_ucred);
360	pc->pc_ucred->cr_groups[0] = gid;
361	if (pc->pc_ucred->cr_uid == 0) {
362		pc->p_rgid = gid;
363		pc->p_svgid = gid;
364	}
365	p->p_flag |= P_SUGID;
366	return (0);
367}
368
369struct setegid_args {
370	gid_t	egid;
371};
372/* ARGSUSED */
373int
374setegid(p, uap, retval)
375	struct proc *p;
376	struct setegid_args *uap;
377	int *retval;
378{
379	register struct pcred *pc = p->p_cred;
380	register gid_t egid;
381	int error;
382
383	egid = uap->egid;
384	if (egid != pc->p_rgid && egid != pc->p_svgid &&
385	    (error = suser(pc->pc_ucred, &p->p_acflag)))
386		return (error);
387	pc->pc_ucred = crcopy(pc->pc_ucred);
388	pc->pc_ucred->cr_groups[0] = egid;
389	p->p_flag |= P_SUGID;
390	return (0);
391}
392
393struct setgroups_args {
394	u_int	gidsetsize;
395	gid_t	*gidset;
396};
397/* ARGSUSED */
398int
399setgroups(p, uap, retval)
400	struct proc *p;
401	struct setgroups_args *uap;
402	int *retval;
403{
404	register struct pcred *pc = p->p_cred;
405	register u_int ngrp;
406	int error;
407
408	if ((error = suser(pc->pc_ucred, &p->p_acflag)))
409		return (error);
410	if ((ngrp = uap->gidsetsize) > NGROUPS)
411		return (EINVAL);
412	pc->pc_ucred = crcopy(pc->pc_ucred);
413	if ((error = copyin((caddr_t)uap->gidset,
414	    (caddr_t)pc->pc_ucred->cr_groups, ngrp * sizeof(gid_t))))
415		return (error);
416	pc->pc_ucred->cr_ngroups = ngrp;
417	p->p_flag |= P_SUGID;
418	return (0);
419}
420
421struct setreuid_args {
422	uid_t	ruid;
423	uid_t	euid;
424};
425/* ARGSUSED */
426int
427setreuid(p, uap, retval)
428	register struct proc *p;
429	struct setreuid_args *uap;
430	int *retval;
431{
432	register struct pcred *pc = p->p_cred;
433	register uid_t ruid, euid;
434	int error;
435
436	ruid = uap->ruid;
437	euid = uap->euid;
438	if ((ruid != (uid_t)-1 && ruid != pc->p_ruid && ruid != pc->p_svuid ||
439	     euid != (uid_t)-1 && euid != pc->p_ruid && euid != pc->p_svuid) &&
440	    (error = suser(pc->pc_ucred, &p->p_acflag)))
441		return (error);
442
443	pc->pc_ucred = crcopy(pc->pc_ucred);
444	if (euid != (uid_t)-1)
445		pc->pc_ucred->cr_uid = euid;
446	if (ruid != (uid_t)-1 && ruid != pc->p_ruid) {
447		(void)chgproccnt(pc->p_ruid, -1);
448		(void)chgproccnt(ruid, 1);
449		pc->p_ruid = ruid;
450	}
451	if (ruid != (uid_t)-1 || pc->pc_ucred->cr_uid != pc->p_ruid)
452		pc->p_svuid = pc->pc_ucred->cr_uid;
453	p->p_flag |= P_SUGID;
454	return (0);
455}
456
457struct setregid_args {
458	gid_t	rgid;
459	gid_t	egid;
460};
461/* ARGSUSED */
462int
463setregid(p, uap, retval)
464	register struct proc *p;
465	struct setregid_args *uap;
466	int *retval;
467{
468	register struct pcred *pc = p->p_cred;
469	register gid_t rgid, egid;
470	int error;
471
472	rgid = uap->rgid;
473	egid = uap->egid;
474	if ((rgid != (gid_t)-1 && rgid != pc->p_rgid && rgid != pc->p_svgid ||
475	     egid != (gid_t)-1 && egid != pc->p_rgid && egid != pc->p_svgid) &&
476	    (error = suser(pc->pc_ucred, &p->p_acflag)))
477		return (error);
478
479	pc->pc_ucred = crcopy(pc->pc_ucred);
480	if (egid != (gid_t)-1)
481		pc->pc_ucred->cr_groups[0] = egid;
482	if (rgid != (gid_t)-1)
483		pc->p_rgid = rgid;
484	if (rgid != (gid_t)-1 || pc->pc_ucred->cr_groups[0] != pc->p_rgid)
485		pc->p_svgid = pc->pc_ucred->cr_groups[0];
486	p->p_flag |= P_SUGID;
487	return (0);
488}
489
490/*
491 * Check if gid is a member of the group set.
492 */
493int
494groupmember(gid, cred)
495	gid_t gid;
496	register struct ucred *cred;
497{
498	register gid_t *gp;
499	gid_t *egp;
500
501	egp = &(cred->cr_groups[cred->cr_ngroups]);
502	for (gp = cred->cr_groups; gp < egp; gp++)
503		if (*gp == gid)
504			return (1);
505	return (0);
506}
507
508/*
509 * Test whether the specified credentials imply "super-user"
510 * privilege; if so, and we have accounting info, set the flag
511 * indicating use of super-powers.
512 * Returns 0 or error.
513 */
514int
515suser(cred, acflag)
516	struct ucred *cred;
517	u_short *acflag;
518{
519	if (cred->cr_uid == 0) {
520		if (acflag)
521			*acflag |= ASU;
522		return (0);
523	}
524	return (EPERM);
525}
526
527/*
528 * Allocate a zeroed cred structure.
529 */
530struct ucred *
531crget()
532{
533	register struct ucred *cr;
534
535	MALLOC(cr, struct ucred *, sizeof(*cr), M_CRED, M_WAITOK);
536	bzero((caddr_t)cr, sizeof(*cr));
537	cr->cr_ref = 1;
538	return (cr);
539}
540
541/*
542 * Free a cred structure.
543 * Throws away space when ref count gets to 0.
544 */
545void
546crfree(cr)
547	struct ucred *cr;
548{
549	int s;
550
551	s = splimp();				/* ??? */
552	if (--cr->cr_ref == 0)
553		FREE((caddr_t)cr, M_CRED);
554	(void) splx(s);
555}
556
557/*
558 * Copy cred structure to a new one and free the old one.
559 */
560struct ucred *
561crcopy(cr)
562	struct ucred *cr;
563{
564	struct ucred *newcr;
565
566	if (cr->cr_ref == 1)
567		return (cr);
568	newcr = crget();
569	*newcr = *cr;
570	crfree(cr);
571	newcr->cr_ref = 1;
572	return (newcr);
573}
574
575/*
576 * Dup cred struct to a new held one.
577 */
578struct ucred *
579crdup(cr)
580	struct ucred *cr;
581{
582	struct ucred *newcr;
583
584	newcr = crget();
585	*newcr = *cr;
586	newcr->cr_ref = 1;
587	return (newcr);
588}
589
590/*
591 * Get login name, if available.
592 */
593struct getlogin_args {
594	char	*namebuf;
595	u_int	namelen;
596};
597/* ARGSUSED */
598int
599getlogin(p, uap, retval)
600	struct proc *p;
601	struct getlogin_args *uap;
602	int *retval;
603{
604
605	if (uap->namelen > sizeof (p->p_pgrp->pg_session->s_login))
606		uap->namelen = sizeof (p->p_pgrp->pg_session->s_login);
607	return (copyout((caddr_t) p->p_pgrp->pg_session->s_login,
608	    (caddr_t) uap->namebuf, uap->namelen));
609}
610
611/*
612 * Set login name.
613 */
614struct setlogin_args {
615	char	*namebuf;
616};
617/* ARGSUSED */
618int
619setlogin(p, uap, retval)
620	struct proc *p;
621	struct setlogin_args *uap;
622	int *retval;
623{
624	int error;
625
626	if ((error = suser(p->p_ucred, &p->p_acflag)))
627		return (error);
628	error = copyinstr((caddr_t) uap->namebuf,
629	    (caddr_t) p->p_pgrp->pg_session->s_login,
630	    sizeof (p->p_pgrp->pg_session->s_login) - 1, (u_int *)0);
631	if (error == ENAMETOOLONG)
632		error = EINVAL;
633	return (error);
634}
635