xref: /netbsd-src/sys/kern/kern_prot.c (revision b7ae68fde0d8ef1c03714e8bbb1ee7c6118ea93b)
1 /*	$NetBSD: kern_prot.c,v 1.94 2006/09/08 20:58:57 elad 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 1.94 2006/09/08 20:58:57 elad 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 #include <sys/kauth.h>
59 
60 #include <sys/mount.h>
61 #include <sys/sa.h>
62 #include <sys/syscallargs.h>
63 
64 #include <sys/malloc.h>
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 static int grsortu(gid_t *, int);
74 
75 /* ARGSUSED */
76 int
77 sys_getpid(struct lwp *l, void *v, register_t *retval)
78 {
79 	struct proc *p = l->l_proc;
80 
81 	*retval = p->p_pid;
82 	return (0);
83 }
84 
85 /* ARGSUSED */
86 int
87 sys_getpid_with_ppid(struct lwp *l, void *v, register_t *retval)
88 {
89 	struct proc *p = l->l_proc;
90 
91 	retval[0] = p->p_pid;
92 	retval[1] = p->p_pptr->p_pid;
93 	return (0);
94 }
95 
96 /* ARGSUSED */
97 int
98 sys_getppid(struct lwp *l, void *v, register_t *retval)
99 {
100 	struct proc *p = l->l_proc;
101 
102 	*retval = p->p_pptr->p_pid;
103 	return (0);
104 }
105 
106 /* Get process group ID; note that POSIX getpgrp takes no parameter */
107 int
108 sys_getpgrp(struct lwp *l, void *v, register_t *retval)
109 {
110 	struct proc *p = l->l_proc;
111 
112 	*retval = p->p_pgrp->pg_id;
113 	return (0);
114 }
115 
116 /*
117  * Return the process group ID of the session leader (session ID)
118  * for the specified process.
119  */
120 int
121 sys_getsid(struct lwp *l, void *v, register_t *retval)
122 {
123 	struct sys_getsid_args /* {
124 		syscalldarg(pid_t) pid;
125 	} */ *uap = v;
126 	struct proc *p = l->l_proc;
127 
128 	if (SCARG(uap, pid) == 0)
129 		goto found;
130 	if ((p = pfind(SCARG(uap, pid))) == 0)
131 		return (ESRCH);
132 found:
133 	*retval = p->p_session->s_sid;
134 	return (0);
135 }
136 
137 int
138 sys_getpgid(struct lwp *l, void *v, register_t *retval)
139 {
140 	struct sys_getpgid_args /* {
141 		syscallarg(pid_t) pid;
142 	} */ *uap = v;
143 	struct proc *p = l->l_proc;
144 
145 	if (SCARG(uap, pid) == 0)
146 		goto found;
147 	if ((p = pfind(SCARG(uap, pid))) == 0)
148 		return (ESRCH);
149 found:
150 	*retval = p->p_pgid;
151 	return (0);
152 }
153 
154 /* ARGSUSED */
155 int
156 sys_getuid(struct lwp *l, void *v, register_t *retval)
157 {
158 
159 	*retval = kauth_cred_getuid(l->l_cred);
160 	return (0);
161 }
162 
163 /* ARGSUSED */
164 int
165 sys_getuid_with_euid(struct lwp *l, void *v, register_t *retval)
166 {
167 
168 	retval[0] = kauth_cred_getuid(l->l_cred);
169 	retval[1] = kauth_cred_geteuid(l->l_cred);
170 	return (0);
171 }
172 
173 /* ARGSUSED */
174 int
175 sys_geteuid(struct lwp *l, void *v, register_t *retval)
176 {
177 
178 	*retval = kauth_cred_geteuid(l->l_cred);
179 	return (0);
180 }
181 
182 /* ARGSUSED */
183 int
184 sys_getgid(struct lwp *l, void *v, register_t *retval)
185 {
186 
187 	*retval = kauth_cred_getgid(l->l_cred);
188 	return (0);
189 }
190 
191 /* ARGSUSED */
192 int
193 sys_getgid_with_egid(struct lwp *l, void *v, register_t *retval)
194 {
195 
196 	retval[0] = kauth_cred_getgid(l->l_cred);
197 	retval[1] = kauth_cred_getegid(l->l_cred);
198 	return (0);
199 }
200 
201 /*
202  * Get effective group ID.  The "egid" is groups[0], and could be obtained
203  * via getgroups.  This syscall exists because it is somewhat painful to do
204  * correctly in a library function.
205  */
206 /* ARGSUSED */
207 int
208 sys_getegid(struct lwp *l, void *v, register_t *retval)
209 {
210 
211 	*retval = kauth_cred_getegid(l->l_cred);
212 	return (0);
213 }
214 
215 int
216 sys_getgroups(struct lwp *l, void *v, register_t *retval)
217 {
218 	struct sys_getgroups_args /* {
219 		syscallarg(int) gidsetsize;
220 		syscallarg(gid_t *) gidset;
221 	} */ *uap = v;
222 	kauth_cred_t cred = l->l_cred;
223 	u_int ngrp;
224 	int error;
225 	gid_t *grbuf;
226 
227 	if (SCARG(uap, gidsetsize) == 0) {
228 		*retval = kauth_cred_ngroups(cred);
229 		return (0);
230 	} else if (SCARG(uap, gidsetsize) < 0)
231 		return (EINVAL);
232 	ngrp = SCARG(uap, gidsetsize);
233 	if (ngrp < kauth_cred_ngroups(cred))
234 		return (EINVAL);
235 	ngrp = kauth_cred_ngroups(cred);
236 
237 	grbuf = malloc(ngrp * sizeof(*grbuf), M_TEMP, M_WAITOK);
238 	kauth_cred_getgroups(cred, grbuf, ngrp);
239 	error = copyout(grbuf, (caddr_t)SCARG(uap, gidset),
240 			ngrp * sizeof(gid_t));
241 	free(grbuf, M_TEMP);
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 	struct proc *p = l->l_proc;
317 	kauth_cred_t cred;
318 
319 	/* Get a write lock on the process credential. */
320 	proc_crmod_enter(p);
321 	cred = p->p_cred;
322 
323 	/*
324 	 * Check that the new value is one of the allowed existing values,
325 	 * or that we have root privilege.
326 	 */
327 	if ((r != -1
328 	    && !((flags & ID_R_EQ_R) && r == kauth_cred_getuid(cred))
329 	    && !((flags & ID_R_EQ_E) && r == kauth_cred_geteuid(cred))
330 	    && !((flags & ID_R_EQ_S) && r == kauth_cred_getsvuid(cred))) ||
331 	    (e != -1
332 	    && !((flags & ID_E_EQ_R) && e == kauth_cred_getuid(cred))
333 	    && !((flags & ID_E_EQ_E) && e == kauth_cred_geteuid(cred))
334 	    && !((flags & ID_E_EQ_S) && e == kauth_cred_getsvuid(cred))) ||
335 	    (sv != -1
336 	    && !((flags & ID_S_EQ_R) && sv == kauth_cred_getuid(cred))
337 	    && !((flags & ID_S_EQ_E) && sv == kauth_cred_geteuid(cred))
338 	    && !((flags & ID_S_EQ_S) && sv == kauth_cred_getsvuid(cred)))) {
339 		int error;
340 
341 		error = kauth_authorize_process(cred, KAUTH_PROCESS_SETID,
342 		    p, NULL, NULL, NULL);
343 		if (error != 0) {
344 		 	proc_crmod_leave(p, cred, NULL);
345 			return error;
346 		}
347 	}
348 
349 	/* If nothing has changed, short circuit the request */
350 	if ((r == -1 || r == kauth_cred_getuid(cred))
351 	    && (e == -1 || e == kauth_cred_geteuid(cred))
352 	    && (sv == -1 || sv == kauth_cred_getsvuid(cred))) {
353 		proc_crmod_leave(p, cred, NULL);
354 		return 0;
355 	}
356 
357 	cred = kauth_cred_dup(cred);
358 
359 	if (r != -1 && r != kauth_cred_getuid(cred)) {
360 		/* Update count of processes for this user */
361 		(void)chgproccnt(kauth_cred_getuid(cred), -1);
362 		(void)chgproccnt(r, 1);
363 		kauth_cred_setuid(cred, r);
364 	}
365 	if (sv != -1)
366 		kauth_cred_setsvuid(cred, sv);
367 	if (e != -1)
368 		kauth_cred_seteuid(cred, e);
369 
370 	/* Mark process as having changed credentials, stops tracing etc. */
371 	p_sugid(p);
372 
373 	/* Broadcast our credentials to the process and other LWPs. */
374  	proc_crmod_leave(p, cred, p->p_cred);
375 
376 	/* Update our copy of the credentials. */
377  	lwp_update_creds(l);
378 
379 	return 0;
380 }
381 
382 /*
383  * Set real, effective and saved gids to the requested values.
384  * non-root callers can only ever change gids to values that match
385  * one of the processes current gid values.
386  * This is further restricted by the flags argument.
387  */
388 
389 int
390 do_setresgid(struct lwp *l, gid_t r, gid_t e, gid_t sv, u_int flags)
391 {
392 	struct proc *p = l->l_proc;
393 	kauth_cred_t cred;
394 
395 	/* Get a write lock on the process credential. */
396 	proc_crmod_enter(p);
397 	cred = p->p_cred;
398 
399 	/*
400 	 * check new value is one of the allowed existing values.
401 	 * otherwise, check if we have root privilege.
402 	 */
403 	if ((r != -1
404 	    && !((flags & ID_R_EQ_R) && r == kauth_cred_getgid(cred))
405 	    && !((flags & ID_R_EQ_E) && r == kauth_cred_getegid(cred))
406 	    && !((flags & ID_R_EQ_S) && r == kauth_cred_getsvgid(cred))) ||
407 	    (e != -1
408 	    && !((flags & ID_E_EQ_R) && e == kauth_cred_getgid(cred))
409 	    && !((flags & ID_E_EQ_E) && e == kauth_cred_getegid(cred))
410 	    && !((flags & ID_E_EQ_S) && e == kauth_cred_getsvgid(cred))) ||
411 	    (sv != -1
412 	    && !((flags & ID_S_EQ_R) && sv == kauth_cred_getgid(cred))
413 	    && !((flags & ID_S_EQ_E) && sv == kauth_cred_getegid(cred))
414 	    && !((flags & ID_S_EQ_S) && sv == kauth_cred_getsvgid(cred)))) {
415 		int error;
416 
417 		error = kauth_authorize_process(cred, KAUTH_PROCESS_SETID,
418 		    p, NULL, NULL, NULL);
419 		if (error != 0) {
420 		 	proc_crmod_leave(p, cred, NULL);
421 			return error;
422 		}
423 	}
424 
425 	/* If nothing has changed, short circuit the request */
426 	if ((r == -1 || r == kauth_cred_getgid(cred))
427 	    && (e == -1 || e == kauth_cred_getegid(cred))
428 	    && (sv == -1 || sv == kauth_cred_getsvgid(cred))) {
429 	 	proc_crmod_leave(p, cred, NULL);
430 		return 0;
431 	}
432 
433 	cred = kauth_cred_dup(cred);
434 
435 	if (r != -1)
436 		kauth_cred_setgid(cred, r);
437 	if (sv != -1)
438 		kauth_cred_setsvgid(cred, sv);
439 	if (e != -1)
440 		kauth_cred_setegid(cred, e);
441 
442 	/* Mark process as having changed credentials, stops tracing etc. */
443 	p_sugid(p);
444 
445 	/* Broadcast our credentials to the process and other LWPs. */
446  	proc_crmod_leave(p, cred, p->p_cred);
447 
448 	/* Update our copy of the credentials. */
449  	lwp_update_creds(l);
450 
451 	return 0;
452 }
453 
454 /* ARGSUSED */
455 int
456 sys_setuid(struct lwp *l, void *v, register_t *retval)
457 {
458 	struct sys_setuid_args /* {
459 		syscallarg(uid_t) uid;
460 	} */ *uap = v;
461 	uid_t uid = SCARG(uap, uid);
462 
463 	return do_setresuid(l, uid, uid, uid,
464 			    ID_R_EQ_R | ID_E_EQ_R | ID_S_EQ_R);
465 }
466 
467 /* ARGSUSED */
468 int
469 sys_seteuid(struct lwp *l, void *v, register_t *retval)
470 {
471 	struct sys_seteuid_args /* {
472 		syscallarg(uid_t) euid;
473 	} */ *uap = v;
474 
475 	return do_setresuid(l, -1, SCARG(uap, euid), -1, ID_E_EQ_R | ID_E_EQ_S);
476 }
477 
478 int
479 sys_setreuid(struct lwp *l, void *v, register_t *retval)
480 {
481 	struct sys_setreuid_args /* {
482 		syscallarg(uid_t) ruid;
483 		syscallarg(uid_t) euid;
484 	} */ *uap = v;
485 	kauth_cred_t cred = l->l_cred;
486 	uid_t ruid, euid, svuid;
487 
488 	ruid = SCARG(uap, ruid);
489 	euid = SCARG(uap, euid);
490 
491 	if (ruid == -1)
492 		ruid = kauth_cred_getuid(cred);
493 	if (euid == -1)
494 		euid = kauth_cred_geteuid(cred);
495 
496 	/* Saved uid is set to the new euid if the ruid changed */
497 	svuid = (ruid == kauth_cred_getuid(cred)) ? -1 : euid;
498 
499 	return do_setresuid(l, ruid, euid, svuid,
500 			    ID_R_EQ_R | ID_R_EQ_E |
501 			    ID_E_EQ_R | ID_E_EQ_E | ID_E_EQ_S |
502 			    ID_S_EQ_R | ID_S_EQ_E | ID_S_EQ_S);
503 }
504 
505 /* ARGSUSED */
506 int
507 sys_setgid(struct lwp *l, void *v, register_t *retval)
508 {
509 	struct sys_setgid_args /* {
510 		syscallarg(gid_t) gid;
511 	} */ *uap = v;
512 	gid_t gid = SCARG(uap, gid);
513 
514 	return do_setresgid(l, gid, gid, gid,
515 			    ID_R_EQ_R | ID_E_EQ_R | ID_S_EQ_R);
516 }
517 
518 /* ARGSUSED */
519 int
520 sys_setegid(struct lwp *l, void *v, register_t *retval)
521 {
522 	struct sys_setegid_args /* {
523 		syscallarg(gid_t) egid;
524 	} */ *uap = v;
525 
526 	return do_setresgid(l, -1, SCARG(uap, egid), -1, ID_E_EQ_R | ID_E_EQ_S);
527 }
528 
529 int
530 sys_setregid(struct lwp *l, void *v, register_t *retval)
531 {
532 	struct sys_setregid_args /* {
533 		syscallarg(gid_t) rgid;
534 		syscallarg(gid_t) egid;
535 	} */ *uap = v;
536 	kauth_cred_t cred = l->l_cred;
537 	gid_t rgid, egid, svgid;
538 
539 	rgid = SCARG(uap, rgid);
540 	egid = SCARG(uap, egid);
541 
542 	if (rgid == -1)
543 		rgid = kauth_cred_getgid(cred);
544 	if (egid == -1)
545 		egid = kauth_cred_getegid(cred);
546 
547 	/* Saved gid is set to the new egid if the rgid changed */
548 	svgid = rgid == kauth_cred_getgid(cred) ? -1 : egid;
549 
550 	return do_setresgid(l, rgid, egid, svgid,
551 			ID_R_EQ_R | ID_R_EQ_E |
552 			ID_E_EQ_R | ID_E_EQ_E | ID_E_EQ_S |
553 			ID_S_EQ_R | ID_S_EQ_E | ID_S_EQ_S);
554 }
555 
556 int
557 sys_issetugid(struct lwp *l, void *v, register_t *retval)
558 {
559 	struct proc *p = l->l_proc;
560 
561 	/*
562 	 * Note: OpenBSD sets a P_SUGIDEXEC flag set at execve() time,
563 	 * we use P_SUGID because we consider changing the owners as
564 	 * "tainting" as well.
565 	 * This is significant for procs that start as root and "become"
566 	 * a user without an exec - programs cannot know *everything*
567 	 * that libc *might* have put in their data segment.
568 	 */
569 	*retval = (p->p_flag & P_SUGID) != 0;
570 	return (0);
571 }
572 
573 /*
574  * sort -u for groups.
575  */
576 static int
577 grsortu(gid_t *grp, int ngrp)
578 {
579 	const gid_t *src, *end;
580 	gid_t *dst;
581 	gid_t group;
582 	int i, j;
583 
584 	/* bubble sort */
585 	for (i = 0; i < ngrp; i++)
586 		for (j = i + 1; j < ngrp; j++)
587 			if (grp[i] > grp[j]) {
588 				gid_t tmp = grp[i];
589 				grp[i] = grp[j];
590 				grp[j] = tmp;
591 			}
592 
593 	/* uniq */
594 	end = grp + ngrp;
595 	src = grp;
596 	dst = grp;
597 	while (src < end) {
598 		group = *src++;
599 		while (src < end && *src == group)
600 			src++;
601 		*dst++ = group;
602 	}
603 
604 #ifdef DIAGNOSTIC
605 	/* zero out the rest of the array */
606 	(void)memset(dst, 0, sizeof(*grp) * (end - dst));
607 #endif
608 
609 	return dst - grp;
610 }
611 
612 /* ARGSUSED */
613 int
614 sys_setgroups(struct lwp *l, void *v, register_t *retval)
615 {
616 	struct sys_setgroups_args /* {
617 		syscallarg(int) gidsetsize;
618 		syscallarg(const gid_t *) gidset;
619 	} */ *uap = v;
620 	kauth_cred_t cred;
621 	struct proc *p = l->l_proc;
622 	int ngrp;
623 	int error;
624 	gid_t grp[NGROUPS];
625 	size_t grsize;
626 
627 	proc_crmod_enter(p);
628 	cred = p->p_cred;
629 
630 	if ((error = kauth_authorize_process(cred, KAUTH_PROCESS_SETID,
631 	    p, NULL, NULL, NULL)) != 0)
632 		goto bad;
633 
634 	ngrp = SCARG(uap, gidsetsize);
635 	if ((u_int)ngrp > NGROUPS) {
636 		error = EINVAL;
637 		goto bad;
638 	}
639 
640 	grsize = ngrp * sizeof(gid_t);
641 	error = copyin(SCARG(uap, gidset), grp, grsize);
642 	if (error)
643 		goto bad;
644 
645 	ngrp = grsortu(grp, ngrp);
646 	cred = kauth_cred_dup(cred);
647 	kauth_cred_setgroups(cred, grp, ngrp, -1);
648 
649 	/* Mark process as having changed credentials, stops tracing etc. */
650 	p_sugid(p);
651 
652 	/* Broadcast our credentials to the process and other LWPs. */
653  	proc_crmod_leave(p, cred, p->p_cred);
654 
655 	/* Update our copy of the credentials. */
656  	lwp_update_creds(l);
657 
658 	return (0);
659   bad:
660   	proc_crmod_leave(p, cred, NULL);
661 	return (error);
662 }
663 
664 /*
665  * Get login name, if available.
666  */
667 /* ARGSUSED */
668 int
669 sys___getlogin(struct lwp *l, void *v, register_t *retval)
670 {
671 	struct sys___getlogin_args /* {
672 		syscallarg(char *) namebuf;
673 		syscallarg(size_t) namelen;
674 	} */ *uap = v;
675 	struct proc *p = l->l_proc;
676 
677 	if (SCARG(uap, namelen) > sizeof(p->p_pgrp->pg_session->s_login))
678 		SCARG(uap, namelen) = sizeof(p->p_pgrp->pg_session->s_login);
679 	return (copyout((caddr_t) p->p_pgrp->pg_session->s_login,
680 	    (caddr_t) SCARG(uap, namebuf), SCARG(uap, namelen)));
681 }
682 
683 /*
684  * Set login name.
685  */
686 /* ARGSUSED */
687 int
688 sys___setlogin(struct lwp *l, void *v, register_t *retval)
689 {
690 	struct sys___setlogin_args /* {
691 		syscallarg(const char *) namebuf;
692 	} */ *uap = v;
693 	struct proc *p = l->l_proc;
694 	struct session *s = p->p_pgrp->pg_session;
695 	char newname[sizeof s->s_login + 1];
696 	int error;
697 
698 	if ((error = kauth_authorize_process(l->l_cred, KAUTH_PROCESS_SETID,
699 	    p, NULL, NULL, NULL)) != 0)
700 		return (error);
701 	error = copyinstr(SCARG(uap, namebuf), &newname, sizeof newname, NULL);
702 	if (error != 0)
703 		return (error == ENAMETOOLONG ? EINVAL : error);
704 
705 	if (s->s_flags & S_LOGIN_SET && p->p_pid != s->s_sid &&
706 	    strncmp(newname, s->s_login, sizeof s->s_login) != 0)
707 		log(LOG_WARNING, "%s (pid %d) changing logname from "
708 		    "%.*s to %s\n", p->p_comm, p->p_pid,
709 		    (int)sizeof s->s_login, s->s_login, newname);
710 	s->s_flags |= S_LOGIN_SET;
711 	strncpy(s->s_login, newname, sizeof s->s_login);
712 	return (0);
713 }
714