xref: /netbsd-src/sys/kern/kern_prot.c (revision 23c8222edbfb0f0932d88a8351d3a0cf817dfb9e)
1 /*	$NetBSD: kern_prot.c,v 1.84 2004/05/04 21:27:28 pk Exp $	*/
2 
3 /*
4  * Copyright (c) 1982, 1986, 1989, 1990, 1991, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  * (c) UNIX System Laboratories, Inc.
7  * All or some portions of this file are derived from material licensed
8  * to the University of California by American Telephone and Telegraph
9  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
10  * the permission of UNIX System Laboratories, Inc.
11  *
12  * Redistribution and use in source and binary forms, with or without
13  * modification, are permitted provided that the following conditions
14  * are met:
15  * 1. Redistributions of source code must retain the above copyright
16  *    notice, this list of conditions and the following disclaimer.
17  * 2. Redistributions in binary form must reproduce the above copyright
18  *    notice, this list of conditions and the following disclaimer in the
19  *    documentation and/or other materials provided with the distribution.
20  * 3. Neither the name of the University nor the names of its contributors
21  *    may be used to endorse or promote products derived from this software
22  *    without specific prior written permission.
23  *
24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34  * SUCH DAMAGE.
35  *
36  *	@(#)kern_prot.c	8.9 (Berkeley) 2/14/95
37  */
38 
39 /*
40  * System calls related to processes and protection
41  */
42 
43 #include <sys/cdefs.h>
44 __KERNEL_RCSID(0, "$NetBSD: kern_prot.c,v 1.84 2004/05/04 21:27:28 pk Exp $");
45 
46 #include "opt_compat_43.h"
47 
48 #include <sys/param.h>
49 #include <sys/acct.h>
50 #include <sys/systm.h>
51 #include <sys/ucred.h>
52 #include <sys/proc.h>
53 #include <sys/timeb.h>
54 #include <sys/times.h>
55 #include <sys/pool.h>
56 #include <sys/syslog.h>
57 #include <sys/resourcevar.h>
58 
59 #include <sys/mount.h>
60 #include <sys/sa.h>
61 #include <sys/syscallargs.h>
62 
63 POOL_INIT(cred_pool, sizeof(struct ucred), 0, 0, 0, "credpl",
64     &pool_allocator_nointr);
65 
66 int	sys_getpid(struct lwp *, void *, register_t *);
67 int	sys_getpid_with_ppid(struct lwp *, void *, register_t *);
68 int	sys_getuid(struct lwp *, void *, register_t *);
69 int	sys_getuid_with_euid(struct lwp *, void *, register_t *);
70 int	sys_getgid(struct lwp *, void *, register_t *);
71 int	sys_getgid_with_egid(struct lwp *, void *, register_t *);
72 
73 /* ARGSUSED */
74 int
75 sys_getpid(struct lwp *l, void *v, register_t *retval)
76 {
77 	struct proc *p = l->l_proc;
78 
79 	*retval = p->p_pid;
80 	return (0);
81 }
82 
83 /* ARGSUSED */
84 int
85 sys_getpid_with_ppid(struct lwp *l, void *v, register_t *retval)
86 {
87 	struct proc *p = l->l_proc;
88 
89 	retval[0] = p->p_pid;
90 	retval[1] = p->p_pptr->p_pid;
91 	return (0);
92 }
93 
94 /* ARGSUSED */
95 int
96 sys_getppid(struct lwp *l, void *v, register_t *retval)
97 {
98 	struct proc *p = l->l_proc;
99 
100 	*retval = p->p_pptr->p_pid;
101 	return (0);
102 }
103 
104 /* Get process group ID; note that POSIX getpgrp takes no parameter */
105 int
106 sys_getpgrp(struct lwp *l, void *v, register_t *retval)
107 {
108 	struct proc *p = l->l_proc;
109 
110 	*retval = p->p_pgrp->pg_id;
111 	return (0);
112 }
113 
114 /*
115  * Return the process group ID of the session leader (session ID)
116  * for the specified process.
117  */
118 int
119 sys_getsid(struct lwp *l, void *v, register_t *retval)
120 {
121 	struct sys_getsid_args /* {
122 		syscalldarg(pid_t) pid;
123 	} */ *uap = v;
124 	struct proc *p = l->l_proc;
125 
126 	if (SCARG(uap, pid) == 0)
127 		goto found;
128 	if ((p = pfind(SCARG(uap, pid))) == 0)
129 		return (ESRCH);
130 found:
131 	*retval = p->p_session->s_sid;
132 	return (0);
133 }
134 
135 int
136 sys_getpgid(struct lwp *l, void *v, register_t *retval)
137 {
138 	struct sys_getpgid_args /* {
139 		syscallarg(pid_t) pid;
140 	} */ *uap = v;
141 	struct proc *p = l->l_proc;
142 
143 	if (SCARG(uap, pid) == 0)
144 		goto found;
145 	if ((p = pfind(SCARG(uap, pid))) == 0)
146 		return (ESRCH);
147 found:
148 	*retval = p->p_pgid;
149 	return (0);
150 }
151 
152 /* ARGSUSED */
153 int
154 sys_getuid(struct lwp *l, void *v, register_t *retval)
155 {
156 	struct proc *p = l->l_proc;
157 
158 	*retval = p->p_cred->p_ruid;
159 	return (0);
160 }
161 
162 /* ARGSUSED */
163 int
164 sys_getuid_with_euid(struct lwp *l, void *v, register_t *retval)
165 {
166 	struct proc *p = l->l_proc;
167 
168 	retval[0] = p->p_cred->p_ruid;
169 	retval[1] = p->p_ucred->cr_uid;
170 	return (0);
171 }
172 
173 /* ARGSUSED */
174 int
175 sys_geteuid(struct lwp *l, void *v, register_t *retval)
176 {
177 	struct proc *p = l->l_proc;
178 
179 	*retval = p->p_ucred->cr_uid;
180 	return (0);
181 }
182 
183 /* ARGSUSED */
184 int
185 sys_getgid(struct lwp *l, void *v, register_t *retval)
186 {
187 	struct proc *p = l->l_proc;
188 
189 	*retval = p->p_cred->p_rgid;
190 	return (0);
191 }
192 
193 /* ARGSUSED */
194 int
195 sys_getgid_with_egid(struct lwp *l, void *v, register_t *retval)
196 {
197 	struct proc *p = l->l_proc;
198 
199 	retval[0] = p->p_cred->p_rgid;
200 	retval[1] = p->p_ucred->cr_gid;
201 	return (0);
202 }
203 
204 /*
205  * Get effective group ID.  The "egid" is groups[0], and could be obtained
206  * via getgroups.  This syscall exists because it is somewhat painful to do
207  * correctly in a library function.
208  */
209 /* ARGSUSED */
210 int
211 sys_getegid(struct lwp *l, void *v, register_t *retval)
212 {
213 	struct proc *p = l->l_proc;
214 
215 	*retval = p->p_ucred->cr_gid;
216 	return (0);
217 }
218 
219 int
220 sys_getgroups(struct lwp *l, void *v, register_t *retval)
221 {
222 	struct sys_getgroups_args /* {
223 		syscallarg(int) gidsetsize;
224 		syscallarg(gid_t *) gidset;
225 	} */ *uap = v;
226 	struct proc *p = l->l_proc;
227 	struct pcred *pc = p->p_cred;
228 	u_int ngrp;
229 	int error;
230 
231 	if (SCARG(uap, gidsetsize) == 0) {
232 		*retval = pc->pc_ucred->cr_ngroups;
233 		return (0);
234 	} else if (SCARG(uap, gidsetsize) < 0)
235 		return (EINVAL);
236 	ngrp = SCARG(uap, gidsetsize);
237 	if (ngrp < pc->pc_ucred->cr_ngroups)
238 		return (EINVAL);
239 	ngrp = pc->pc_ucred->cr_ngroups;
240 	error = copyout((caddr_t)pc->pc_ucred->cr_groups,
241 	    (caddr_t)SCARG(uap, gidset), ngrp * sizeof(gid_t));
242 	if (error)
243 		return (error);
244 	*retval = ngrp;
245 	return (0);
246 }
247 
248 /* ARGSUSED */
249 int
250 sys_setsid(struct lwp *l, void *v, register_t *retval)
251 {
252 	struct proc *p = l->l_proc;
253 
254 	if (p->p_pgid == p->p_pid || pgfind(p->p_pid)) {
255 		return (EPERM);
256 	} else {
257 		(void)enterpgrp(p, p->p_pid, 1);
258 		*retval = p->p_pid;
259 		return (0);
260 	}
261 }
262 
263 /*
264  * set process group (setpgid/old setpgrp)
265  *
266  * caller does setpgid(targpid, targpgid)
267  *
268  * pgid must be in valid range (EINVAL)
269  * pid must be caller or child of caller (ESRCH)
270  * if a child
271  *	pid must be in same session (EPERM)
272  *	pid can't have done an exec (EACCES)
273  * if pgid != pid
274  * 	there must exist some pid in same session having pgid (EPERM)
275  * pid must not be session leader (EPERM)
276  *
277  * Permission checks now in enterpgrp()
278  */
279 /* ARGSUSED */
280 int
281 sys_setpgid(struct lwp *l, void *v, register_t *retval)
282 {
283 	struct sys_setpgid_args /* {
284 		syscallarg(int) pid;
285 		syscallarg(int) pgid;
286 	} */ *uap = v;
287 	struct proc *curp = l->l_proc;
288 	struct proc *targp;			/* target process */
289 
290 	if (SCARG(uap, pgid) < 0)
291 		return EINVAL;
292 
293 	/* XXX MP - there is a horrid race here with targp exiting! */
294 	if (SCARG(uap, pid) != 0 && SCARG(uap, pid) != curp->p_pid) {
295 		targp = pfind(SCARG(uap, pid));
296 		if (targp == NULL)
297 			return ESRCH;
298 	} else
299 		targp = curp;
300 
301 	if (SCARG(uap, pgid) == 0)
302 		SCARG(uap, pgid) = targp->p_pid;
303 	return enterpgrp(targp, SCARG(uap, pgid), 0);
304 }
305 
306 /*
307  * Set real, effective and saved uids to the requested values.
308  * non-root callers can only ever change uids to values that match
309  * one of the processes current uid values.
310  * This is further restricted by the flags argument.
311  */
312 
313 int
314 do_setresuid(struct lwp *l, uid_t r, uid_t e, uid_t sv, u_int flags)
315 {
316 	int error;
317 	struct proc *p = l->l_proc;
318 	struct pcred *pcred = p->p_cred;
319 	struct ucred *cred = pcred->pc_ucred;
320 
321 	/* Superuser can do anything it wants to.... */
322 	error = suser(cred, &p->p_acflag);
323 	if (error) {
324 		/* Otherwise check new value is one of the allowed
325 		   existing values. */
326 		if (r != -1 && !((flags & ID_R_EQ_R) && r == pcred->p_ruid)
327 			    && !((flags & ID_R_EQ_E) && r == cred->cr_uid)
328 			    && !((flags & ID_R_EQ_S) && r == pcred->p_svuid))
329 			return error;
330 		if (e != -1 && !((flags & ID_E_EQ_R) && e == pcred->p_ruid)
331 			    && !((flags & ID_E_EQ_E) && e == cred->cr_uid)
332 			    && !((flags & ID_E_EQ_S) && e == pcred->p_svuid))
333 			return error;
334 		if (sv != -1 && !((flags & ID_S_EQ_R) && sv == pcred->p_ruid)
335 			    && !((flags & ID_S_EQ_E) && sv == cred->cr_uid)
336 			    && !((flags & ID_S_EQ_S) && sv == pcred->p_svuid))
337 			return error;
338 	}
339 
340 	/* If nothing has changed, short circuit the request */
341 	if ((r == -1 || r == pcred->p_ruid)
342 	    && (e == -1 || e == cred->cr_uid)
343 	    && (sv == -1 || sv == pcred->p_svuid))
344 		/* nothing to do */
345 		return 0;
346 
347 	/* The pcred structure is not actually shared... */
348 	if (r != -1 && r != pcred->p_ruid) {
349 		/* Update count of processes for this user */
350 		(void)chgproccnt(pcred->p_ruid, -1);
351 		(void)chgproccnt(r, 1);
352 		pcred->p_ruid = r;
353 	}
354 	if (sv != -1)
355 		pcred->p_svuid = sv;
356 	if (e != -1 && e != cred->cr_uid) {
357 		/* Update a clone of the current credentials */
358 		pcred->pc_ucred = cred = crcopy(cred);
359 		cred->cr_uid = e;
360 	}
361 
362 	/* Mark process as having changed credentials, stops tracing etc */
363 	p_sugid(p);
364 	return 0;
365 }
366 
367 /*
368  * Set real, effective and saved gids to the requested values.
369  * non-root callers can only ever change gids to values that match
370  * one of the processes current gid values.
371  * This is further restricted by the flags argument.
372  */
373 
374 int
375 do_setresgid(struct lwp *l, gid_t r, gid_t e, gid_t sv, u_int flags)
376 {
377 	int error;
378 	struct proc *p = l->l_proc;
379 	struct pcred *pcred = p->p_cred;
380 	struct ucred *cred = pcred->pc_ucred;
381 
382 	/* Superuser can do anything it wants to.... */
383 	error = suser(cred, &p->p_acflag);
384 	if (error) {
385 		/* Otherwise check new value is one of the allowed
386 		   existing values. */
387 		if (r != -1 && !((flags & ID_R_EQ_R) && r == pcred->p_rgid)
388 			    && !((flags & ID_R_EQ_E) && r == cred->cr_gid)
389 			    && !((flags & ID_R_EQ_S) && r == pcred->p_svgid))
390 			return error;
391 		if (e != -1 && !((flags & ID_E_EQ_R) && e == pcred->p_rgid)
392 			    && !((flags & ID_E_EQ_E) && e == cred->cr_gid)
393 			    && !((flags & ID_E_EQ_S) && e == pcred->p_svgid))
394 			return error;
395 		if (sv != -1 && !((flags & ID_S_EQ_R) && sv == pcred->p_rgid)
396 			    && !((flags & ID_S_EQ_E) && sv == cred->cr_gid)
397 			    && !((flags & ID_S_EQ_S) && sv == pcred->p_svgid))
398 			return error;
399 	}
400 
401 	/* If nothing has changed, short circuit the request */
402 	if ((r == -1 || r == pcred->p_rgid)
403 	    && (e == -1 || e == cred->cr_gid)
404 	    && (sv == -1 || sv == pcred->p_svgid))
405 		/* nothing to do */
406 		return 0;
407 
408 	/* The pcred structure is not actually shared... */
409 	if (r != -1)
410 		pcred->p_rgid = r;
411 	if (sv != -1)
412 		pcred->p_svgid = sv;
413 	if (e != -1 && e != cred->cr_gid) {
414 		/* Update a clone of the current credentials */
415 		pcred->pc_ucred = cred = crcopy(cred);
416 		cred->cr_gid = e;
417 	}
418 
419 	/* Mark process as having changed credentials, stops tracing etc */
420 	p_sugid(p);
421 	return 0;
422 }
423 
424 /* ARGSUSED */
425 int
426 sys_setuid(struct lwp *l, void *v, register_t *retval)
427 {
428 	struct sys_setuid_args /* {
429 		syscallarg(uid_t) uid;
430 	} */ *uap = v;
431 	uid_t uid = SCARG(uap, uid);
432 
433 	return do_setresuid(l, uid, uid, uid,
434 			    ID_R_EQ_R | ID_E_EQ_R | ID_S_EQ_R);
435 }
436 
437 /* ARGSUSED */
438 int
439 sys_seteuid(struct lwp *l, void *v, register_t *retval)
440 {
441 	struct sys_seteuid_args /* {
442 		syscallarg(uid_t) euid;
443 	} */ *uap = v;
444 
445 	return do_setresuid(l, -1, SCARG(uap, euid), -1, ID_E_EQ_R | ID_E_EQ_S);
446 }
447 
448 int
449 sys_setreuid(struct lwp *l, void *v, register_t *retval)
450 {
451 	struct sys_setreuid_args /* {
452 		syscallarg(uid_t) ruid;
453 		syscallarg(uid_t) euid;
454 	} */ *uap = v;
455 	struct proc *p = l->l_proc;
456 	uid_t ruid, euid, svuid;
457 
458 	ruid = SCARG(uap, ruid);
459 	euid = SCARG(uap, euid);
460 	if (ruid == -1)
461 		ruid = p->p_cred->p_ruid;
462 	if (euid == -1)
463 		euid = p->p_ucred->cr_uid;
464 	/* Saved uid is set to the new euid if the ruid changed */
465 	svuid = (ruid == p->p_cred->p_ruid) ? -1 : euid;
466 
467 	return do_setresuid(l, ruid, euid, svuid,
468 			    ID_R_EQ_R | ID_R_EQ_E |
469 			    ID_E_EQ_R | ID_E_EQ_E | ID_E_EQ_S |
470 			    ID_S_EQ_R | ID_S_EQ_E | ID_S_EQ_S);
471 }
472 
473 /* ARGSUSED */
474 int
475 sys_setgid(struct lwp *l, void *v, register_t *retval)
476 {
477 	struct sys_setgid_args /* {
478 		syscallarg(gid_t) gid;
479 	} */ *uap = v;
480 	gid_t gid = SCARG(uap, gid);
481 
482 	return do_setresgid(l, gid, gid, gid,
483 			    ID_R_EQ_R | ID_E_EQ_R | ID_S_EQ_R);
484 }
485 
486 /* ARGSUSED */
487 int
488 sys_setegid(struct lwp *l, void *v, register_t *retval)
489 {
490 	struct sys_setegid_args /* {
491 		syscallarg(gid_t) egid;
492 	} */ *uap = v;
493 
494 	return do_setresgid(l, -1, SCARG(uap, egid), -1, ID_E_EQ_R | ID_E_EQ_S);
495 }
496 
497 int
498 sys_setregid(struct lwp *l, void *v, register_t *retval)
499 {
500 	struct sys_setregid_args /* {
501 		syscallarg(gid_t) rgid;
502 		syscallarg(gid_t) egid;
503 	} */ *uap = v;
504 	struct proc *p = l->l_proc;
505 	gid_t rgid, egid, svgid;
506 
507 	rgid = SCARG(uap, rgid);
508 	egid = SCARG(uap, egid);
509 	if (rgid == -1)
510 		rgid = p->p_cred->p_rgid;
511 	if (egid == -1)
512 		egid = p->p_ucred->cr_gid;
513 	/* Saved gid is set to the new egid if the rgid changed */
514 	svgid = rgid == p->p_cred->p_rgid ? -1 : egid;
515 
516 	return do_setresgid(l, rgid, egid, svgid,
517 			ID_R_EQ_R | ID_R_EQ_E |
518 			ID_E_EQ_R | ID_E_EQ_E | ID_E_EQ_S |
519 			ID_S_EQ_R | ID_S_EQ_E | ID_S_EQ_S);
520 }
521 
522 int
523 sys_issetugid(struct lwp *l, void *v, register_t *retval)
524 {
525 	struct proc *p = l->l_proc;
526 
527 	/*
528 	 * Note: OpenBSD sets a P_SUGIDEXEC flag set at execve() time,
529 	 * we use P_SUGID because we consider changing the owners as
530 	 * "tainting" as well.
531 	 * This is significant for procs that start as root and "become"
532 	 * a user without an exec - programs cannot know *everything*
533 	 * that libc *might* have put in their data segment.
534 	 */
535 	*retval = (p->p_flag & P_SUGID) != 0;
536 	return (0);
537 }
538 
539 /* ARGSUSED */
540 int
541 sys_setgroups(struct lwp *l, void *v, register_t *retval)
542 {
543 	struct sys_setgroups_args /* {
544 		syscallarg(int) gidsetsize;
545 		syscallarg(const gid_t *) gidset;
546 	} */ *uap = v;
547 	struct proc *p = l->l_proc;
548 	struct pcred *pc = p->p_cred;
549 	int ngrp;
550 	int error;
551 	gid_t grp[NGROUPS];
552 	size_t grsize;
553 
554 	if ((error = suser(pc->pc_ucred, &p->p_acflag)) != 0)
555 		return (error);
556 
557 	ngrp = SCARG(uap, gidsetsize);
558 	if ((u_int)ngrp > NGROUPS)
559 		return (EINVAL);
560 
561 	grsize = ngrp * sizeof(gid_t);
562 	error = copyin(SCARG(uap, gidset), grp, grsize);
563 	if (error)
564 		return (error);
565 	/*
566 	 * Check if this is a no-op.
567 	 */
568 	if (pc->pc_ucred->cr_ngroups == (u_int) ngrp &&
569 	    memcmp(grp, pc->pc_ucred->cr_groups, grsize) == 0)
570 		return (0);
571 
572 	pc->pc_ucred = crcopy(pc->pc_ucred);
573 	(void)memcpy(pc->pc_ucred->cr_groups, grp, grsize);
574 	pc->pc_ucred->cr_ngroups = ngrp;
575 	p_sugid(p);
576 	return (0);
577 }
578 
579 /*
580  * Check if gid is a member of the group set.
581  */
582 int
583 groupmember(gid_t gid, const struct ucred *cred)
584 {
585 	const gid_t *gp;
586 	const gid_t *egp;
587 
588 	egp = &(cred->cr_groups[cred->cr_ngroups]);
589 	for (gp = cred->cr_groups; gp < egp; gp++)
590 		if (*gp == gid)
591 			return (1);
592 	return (0);
593 }
594 
595 /*
596  * Test whether the specified credentials imply "super-user"
597  * privilege; if so, and we have accounting info, set the flag
598  * indicating use of super-powers.
599  * Returns 0 or error.
600  */
601 int
602 suser(const struct ucred *cred, u_short *acflag)
603 {
604 
605 	if (cred->cr_uid == 0) {
606 		if (acflag)
607 			*acflag |= ASU;
608 		return (0);
609 	}
610 	return (EPERM);
611 }
612 
613 /*
614  * Allocate a zeroed cred structure.
615  */
616 struct ucred *
617 crget(void)
618 {
619 	struct ucred *cr;
620 
621 	cr = pool_get(&cred_pool, PR_WAITOK);
622 	memset(cr, 0, sizeof(*cr));
623 	simple_lock_init(&cr->cr_lock);
624 	cr->cr_ref = 1;
625 	return (cr);
626 }
627 
628 /*
629  * Free a cred structure.
630  * Throws away space when ref count gets to 0.
631  */
632 void
633 crfree(struct ucred *cr)
634 {
635 	int n;
636 
637 	simple_lock(&cr->cr_lock);
638 	n = --cr->cr_ref;
639 	simple_unlock(&cr->cr_lock);
640 	if (n == 0)
641 		pool_put(&cred_pool, cr);
642 }
643 
644 /*
645  * Compare cred structures and return 0 if they match
646  */
647 int
648 crcmp(const struct ucred *cr1, const struct uucred *cr2)
649 {
650 	return cr1->cr_uid != cr2->cr_uid ||
651 	    cr1->cr_gid != cr2->cr_gid ||
652 	    cr1->cr_ngroups != (uint32_t)cr2->cr_ngroups ||
653 	    memcmp(cr1->cr_groups, cr2->cr_groups, cr1->cr_ngroups);
654 }
655 
656 /*
657  * Copy cred structure to a new one and free the old one.
658  */
659 struct ucred *
660 crcopy(struct ucred *cr)
661 {
662 	struct ucred *newcr;
663 
664 	if (cr->cr_ref == 1)
665 		return (cr);
666 
667 	newcr = crget();
668 	memcpy(&newcr->cr_startcopy, &cr->cr_startcopy,
669 		sizeof(struct ucred) - offsetof(struct ucred, cr_startcopy));
670 	crfree(cr);
671 	return (newcr);
672 }
673 
674 /*
675  * Dup cred struct to a new held one.
676  */
677 struct ucred *
678 crdup(const struct ucred *cr)
679 {
680 	struct ucred *newcr;
681 
682 	newcr = crget();
683 	memcpy(&newcr->cr_startcopy, &cr->cr_startcopy,
684 		sizeof(struct ucred) - offsetof(struct ucred, cr_startcopy));
685 	return (newcr);
686 }
687 
688 /*
689  * convert from userland credentials to kernel one
690  */
691 void
692 crcvt(struct ucred *uc, const struct uucred *uuc)
693 {
694 
695 	uc->cr_ref = 0;
696 	uc->cr_uid = uuc->cr_uid;
697 	uc->cr_gid = uuc->cr_gid;
698 	uc->cr_ngroups = uuc->cr_ngroups;
699 	(void)memcpy(uc->cr_groups, uuc->cr_groups, sizeof(uuc->cr_groups));
700 }
701 
702 /*
703  * Get login name, if available.
704  */
705 /* ARGSUSED */
706 int
707 sys___getlogin(struct lwp *l, void *v, register_t *retval)
708 {
709 	struct sys___getlogin_args /* {
710 		syscallarg(char *) namebuf;
711 		syscallarg(size_t) namelen;
712 	} */ *uap = v;
713 	struct proc *p = l->l_proc;
714 
715 	if (SCARG(uap, namelen) > sizeof(p->p_pgrp->pg_session->s_login))
716 		SCARG(uap, namelen) = sizeof(p->p_pgrp->pg_session->s_login);
717 	return (copyout((caddr_t) p->p_pgrp->pg_session->s_login,
718 	    (caddr_t) SCARG(uap, namebuf), SCARG(uap, namelen)));
719 }
720 
721 /*
722  * Set login name.
723  */
724 /* ARGSUSED */
725 int
726 sys___setlogin(struct lwp *l, void *v, register_t *retval)
727 {
728 	struct sys___setlogin_args /* {
729 		syscallarg(const char *) namebuf;
730 	} */ *uap = v;
731 	struct proc *p = l->l_proc;
732 	struct session *s = p->p_pgrp->pg_session;
733 	char newname[sizeof s->s_login + 1];
734 	int error;
735 
736 	if ((error = suser(p->p_ucred, &p->p_acflag)) != 0)
737 		return (error);
738 	error = copyinstr(SCARG(uap, namebuf), &newname, sizeof newname, NULL);
739 	if (error != 0)
740 		return (error == ENAMETOOLONG ? EINVAL : error);
741 
742 	if (s->s_flags & S_LOGIN_SET && p->p_pid != s->s_sid &&
743 	    strncmp(newname, s->s_login, sizeof s->s_login) != 0)
744 		log(LOG_WARNING, "%s (pid %d) changing logname from "
745 		    "%.*s to %s\n", p->p_comm, p->p_pid,
746 		    (int)sizeof s->s_login, s->s_login, newname);
747 	s->s_flags |= S_LOGIN_SET;
748 	strncpy(s->s_login, newname, sizeof s->s_login);
749 	return (0);
750 }
751