xref: /freebsd/lib/libutil/login_cap.c (revision 069ac184)
1 /*-
2  * Copyright (c) 1996 by
3  * Sean Eric Fagan <sef@kithrup.com>
4  * David Nugent <davidn@blaze.net.au>
5  * All rights reserved.
6  *
7  * Portions copyright (c) 1995,1997
8  * Berkeley Software Design, Inc.
9  * All rights reserved.
10  *
11  * Redistribution and use in source and binary forms, with or without
12  * modification, is permitted provided that the following conditions
13  * are met:
14  * 1. Redistributions of source code must retain the above copyright
15  *    notice immediately at the beginning of the file, without modification,
16  *    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. This work was done expressly for inclusion into FreeBSD.  Other use
21  *    is permitted provided this notation is included.
22  * 4. Absolutely no warranty of function or purpose is made by the authors.
23  * 5. Modifications may be freely made to this file providing the above
24  *    conditions are met.
25  *
26  * Low-level routines relating to the user capabilities database
27  */
28 
29 #include <sys/types.h>
30 #include <sys/time.h>
31 #include <sys/resource.h>
32 #include <sys/param.h>
33 #include <errno.h>
34 #include <fcntl.h>
35 #include <libutil.h>
36 #include <login_cap.h>
37 #include <pwd.h>
38 #include <stdio.h>
39 #include <stdlib.h>
40 #include <string.h>
41 #include <syslog.h>
42 #include <unistd.h>
43 
44 /*
45  * allocstr()
46  * Manage a single static pointer for handling a local char* buffer,
47  * resizing as necessary to contain the string.
48  *
49  * allocarray()
50  * Manage a static array for handling a group of strings, resizing
51  * when necessary.
52  */
53 
54 static int lc_object_count = 0;
55 
56 static size_t internal_stringsz = 0;
57 static char * internal_string = NULL;
58 static size_t internal_arraysz = 0;
59 static const char ** internal_array = NULL;
60 
61 static char path_login_conf[] = _PATH_LOGIN_CONF;
62 
63 static char *
64 allocstr(const char *str)
65 {
66     char    *p;
67 
68     size_t sz = strlen(str) + 1;	/* realloc() only if necessary */
69     if (sz <= internal_stringsz)
70 	p = strcpy(internal_string, str);
71     else if ((p = realloc(internal_string, sz)) != NULL) {
72 	internal_stringsz = sz;
73 	internal_string = strcpy(p, str);
74     }
75     return p;
76 }
77 
78 
79 static const char **
80 allocarray(size_t sz)
81 {
82     static const char    **p;
83 
84     if (sz <= internal_arraysz)
85 	p = internal_array;
86     else if ((p = reallocarray(internal_array, sz, sizeof(char*))) != NULL) {
87 	internal_arraysz = sz;
88 	internal_array = p;
89     }
90     return p;
91 }
92 
93 
94 /*
95  * This is a variant of strcspn, which checks for quoted
96  * strings.  That is,:
97  *   strcspn_quote("how 'now, brown' cow", ",", NULL);
98  * will return the index for the nul, rather than the comma, because
99  * the string is quoted.  It does not handle escaped characters
100  * at this time.
101  */
102 static size_t
103 strcspn_quote(const char *str, const char *exclude, int *is_quoted)
104 {
105 	size_t indx = 0;
106 	char quote = 0;
107 
108 	if (str == NULL)
109 		return 0;
110 
111 	if (is_quoted)
112 		*is_quoted = 0;
113 
114 	for (indx = 0; str[indx] != 0; indx++) {
115 		if (quote && str[indx] == quote) {
116 			if (is_quoted)
117 				*is_quoted = 1;
118 			quote = 0;
119 			continue;
120 		}
121 		if (quote == 0 &&
122 		    (str[indx] == '\'' || str[indx] == '"')) {
123 			quote = str[indx];
124 			continue;
125 		}
126 		if (quote == 0 &&
127 		    strchr(exclude, str[indx]) != NULL)
128 			return indx;
129 	}
130 	return indx;
131 }
132 
133 /*
134  * Remove quotes from the given string.
135  * It's a very simplistic approach:  the first
136  * single or double quote it finds, it looks for
137  * the next one, and if it finds it, moves the
138  * entire string backwards in two chunks
139  * (first quote + 1 to first quote, length
140  * rest of string, and then second quote + 1
141  * to second quote, length rest of the string).
142  */
143 static void
144 remove_quotes(char *str)
145 {
146 	static const char *quote_chars = "'\"";
147 	char qc = 0;
148 	int found = 0;
149 
150 	do {
151 		char *loc = NULL;
152 
153 		found = 0;
154 		/*
155 		 * If qc is 0, then we haven't found
156 		 * a quote yet, so do a strcspn search.
157 		 */
158 		if (qc == 0) {
159 			size_t indx;
160 			indx = strcspn(str, quote_chars);
161 			if (str[indx] == '\0')
162 				return;	/* We're done */
163 			loc = str + indx;
164 			qc = str[indx];
165 		} else {
166 			/*
167 			 * We've found a quote character,
168 			 * so use strchr to find the next one.
169 			 */
170 			loc = strchr(str, qc);
171 			if (loc == NULL)
172 				return;
173 			qc = 0;
174 		}
175 		if (loc) {
176 			/*
177 			 * This gives us the location of the
178 			 * quoted character.  We need to move
179 			 * the entire string down, from loc+1
180 			 * to loc.
181 			 */
182 			size_t len = strlen(loc + 1) + 1;
183 			memmove(loc, loc + 1, len);
184 			found = 1;
185 		}
186 	} while (found != 0);
187 }
188 
189 /*
190  * arrayize()
191  * Turn a simple string <str> separated by any of
192  * the set of <chars> into an array.  The last element
193  * of the array will be NULL, as is proper.
194  * Free using freearraystr()
195  */
196 
197 static const char **
198 arrayize(const char *str, const char *chars, int *size)
199 {
200     int	    i;
201     char *ptr;
202     const char *cptr;
203     const char **res = NULL;
204 
205     /* count the sub-strings */
206     for (i = 0, cptr = str; *cptr; i++) {
207         int count = strcspn_quote(cptr, chars, NULL);
208 	cptr += count;
209 	if (*cptr)
210 	    ++cptr;
211     }
212 
213     /* alloc the array */
214     if ((ptr = allocstr(str)) != NULL) {
215 	if ((res = allocarray(++i)) == NULL)
216 	    free((void *)(uintptr_t)(const void *)str);
217 	else {
218 	    /* now split the string */
219 	    i = 0;
220 	    while (*ptr) {
221 		int quoted = 0;
222 		int count = strcspn_quote(ptr, chars, &quoted);
223 		char *base = ptr;
224 		res[i++] = ptr;
225 		ptr += count;
226 		if (*ptr)
227 		    *ptr++ = '\0';
228 		/*
229 		 * If the string contains a quoted element, we
230 		 * need to remove the quotes.
231 		 */
232 		if (quoted) {
233 			remove_quotes(base);
234 		}
235 
236 	    }
237 	    res[i] = NULL;
238 	}
239     }
240 
241     if (size)
242 	*size = i;
243 
244     return res;
245 }
246 
247 
248 /*
249  * login_close()
250  * Frees up all resources relating to a login class
251  *
252  */
253 
254 void
255 login_close(login_cap_t * lc)
256 {
257     if (lc) {
258 	free(lc->lc_style);
259 	free(lc->lc_class);
260 	free(lc->lc_cap);
261 	free(lc);
262 	if (--lc_object_count == 0) {
263 	    free(internal_string);
264 	    free(internal_array);
265 	    internal_array = NULL;
266 	    internal_arraysz = 0;
267 	    internal_string = NULL;
268 	    internal_stringsz = 0;
269 	    cgetclose();
270 	}
271     }
272 }
273 
274 
275 /*
276  * login_getclassbyname()
277  * Get the login class by its name.
278  * If the name given is NULL or empty, the default class
279  * LOGIN_DEFCLASS (i.e., "default") is fetched.
280  * If the name given is LOGIN_MECLASS and
281  * 'pwd' argument is non-NULL and contains an non-NULL
282  * dir entry, then the file _FILE_LOGIN_CONF is picked
283  * up from that directory and used before the system
284  * login database. In that case the system login database
285  * is looked up using LOGIN_MECLASS, too, which is a bug.
286  * Return a filled-out login_cap_t structure, including
287  * class name, and the capability record buffer.
288  */
289 
290 login_cap_t *
291 login_getclassbyname(char const *name, const struct passwd *pwd)
292 {
293     login_cap_t	*lc;
294 
295     if ((lc = calloc(1, sizeof(login_cap_t))) != NULL) {
296 	int         r, me, i = 0;
297 	uid_t euid = 0;
298 	gid_t egid = 0;
299 	const char  *msg = NULL;
300 	const char  *dir;
301 	char	    userpath[MAXPATHLEN];
302 
303 	static char *login_dbarray[] = { NULL, NULL, NULL };
304 
305 	me = (name != NULL && strcmp(name, LOGIN_MECLASS) == 0);
306 	dir = (!me || pwd == NULL) ? NULL : pwd->pw_dir;
307 	/*
308 	 * Switch to user mode before checking/reading its ~/.login_conf
309 	 * - some NFSes have root read access disabled.
310 	 *
311 	 * XXX: This fails to configure additional groups.
312 	 */
313 	if (dir) {
314 	    euid = geteuid();
315 	    egid = getegid();
316 	    (void)setegid(pwd->pw_gid);
317 	    (void)seteuid(pwd->pw_uid);
318 	}
319 
320 	if (dir && snprintf(userpath, MAXPATHLEN, "%s/%s", dir,
321 			    _FILE_LOGIN_CONF) < MAXPATHLEN) {
322 	    if (_secure_path(userpath, pwd->pw_uid, pwd->pw_gid) != -1)
323 		login_dbarray[i++] = userpath;
324 	}
325 	/*
326 	 * XXX: Why to add the system database if the class is `me'?
327 	 */
328 	if (_secure_path(path_login_conf, 0, 0) != -1)
329 	    login_dbarray[i++] = path_login_conf;
330 	login_dbarray[i] = NULL;
331 
332 	if (name == NULL || *name == '\0')
333 	    name = LOGIN_DEFCLASS;
334 
335 	switch (cgetent(&lc->lc_cap, login_dbarray, name)) {
336 	case -1:		/* Failed, entry does not exist */
337 	    if (me)
338 		break;	/* Don't retry default on 'me' */
339 	    if (i == 0)
340 	        r = -1;
341 	    else if ((r = open(login_dbarray[0], O_RDONLY | O_CLOEXEC)) >= 0)
342 	        close(r);
343 	    /*
344 	     * If there's at least one login class database,
345 	     * and we aren't searching for a default class
346 	     * then complain about a non-existent class.
347 	     */
348 	    if (r >= 0 || strcmp(name, LOGIN_DEFCLASS) != 0)
349 		syslog(LOG_ERR, "login_getclass: unknown class '%s'", name);
350 	    /* fall-back to default class */
351 	    name = LOGIN_DEFCLASS;
352 	    msg = "%s: no default/fallback class '%s'";
353 	    if (cgetent(&lc->lc_cap, login_dbarray, name) != 0 && r >= 0)
354 		break;
355 	    /* FALLTHROUGH - just return system defaults */
356 	case 0:		/* success! */
357 	    if ((lc->lc_class = strdup(name)) != NULL) {
358 		if (dir) {
359 		    (void)seteuid(euid);
360 		    (void)setegid(egid);
361 		}
362 		++lc_object_count;
363 		return lc;
364 	    }
365 	    msg = "%s: strdup: %m";
366 	    break;
367 	case -2:
368 	    msg = "%s: retrieving class information: %m";
369 	    break;
370 	case -3:
371 	    msg = "%s: 'tc=' reference loop '%s'";
372 	    break;
373 	case 1:
374 	    msg = "couldn't resolve 'tc=' reference in '%s'";
375 	    break;
376 	default:
377 	    msg = "%s: unexpected cgetent() error '%s': %m";
378 	    break;
379 	}
380 	if (dir) {
381 	    (void)seteuid(euid);
382 	    (void)setegid(egid);
383 	}
384 	if (msg != NULL)
385 	    syslog(LOG_ERR, msg, "login_getclass", name);
386 	free(lc);
387     }
388 
389     return NULL;
390 }
391 
392 
393 
394 /*
395  * login_getclass()
396  * Get the login class for the system (only) login class database.
397  * Return a filled-out login_cap_t structure, including
398  * class name, and the capability record buffer.
399  */
400 
401 login_cap_t *
402 login_getclass(const char *cls)
403 {
404     return login_getclassbyname(cls, NULL);
405 }
406 
407 
408 /*
409  * login_getpwclass()
410  * Get the login class for a given password entry from
411  * the system (only) login class database.
412  * If the password entry's class field is not set, or
413  * the class specified does not exist, then use the
414  * default of LOGIN_DEFCLASS (i.e., "default") for an unprivileged
415  * user or that of LOGIN_DEFROOTCLASS (i.e., "root") for a super-user.
416  * Return a filled-out login_cap_t structure, including
417  * class name, and the capability record buffer.
418  */
419 
420 login_cap_t *
421 login_getpwclass(const struct passwd *pwd)
422 {
423     const char	*cls = NULL;
424 
425     if (pwd != NULL) {
426 	cls = pwd->pw_class;
427 	if (cls == NULL || *cls == '\0')
428 	    cls = (pwd->pw_uid == 0) ? LOGIN_DEFROOTCLASS : LOGIN_DEFCLASS;
429     }
430     /*
431      * XXX: pwd should be unused by login_getclassbyname() unless cls is `me',
432      *      so NULL can be passed instead of pwd for more safety.
433      */
434     return login_getclassbyname(cls, pwd);
435 }
436 
437 
438 /*
439  * login_getuserclass()
440  * Get the `me' login class, allowing user overrides via ~/.login_conf.
441  * Note that user overrides are allowed only in the `me' class.
442  */
443 
444 login_cap_t *
445 login_getuserclass(const struct passwd *pwd)
446 {
447     return login_getclassbyname(LOGIN_MECLASS, pwd);
448 }
449 
450 
451 /*
452  * login_getcapstr()
453  * Given a login_cap entry, and a capability name, return the
454  * value defined for that capability, a default if not found, or
455  * an error string on error.
456  */
457 
458 const char *
459 login_getcapstr(login_cap_t *lc, const char *cap, const char *def, const char *error)
460 {
461     char    *res;
462     int	    ret;
463 
464     if (lc == NULL || cap == NULL || lc->lc_cap == NULL || *cap == '\0')
465 	return def;
466 
467     if ((ret = cgetstr(lc->lc_cap, cap, &res)) == -1)
468 	return def;
469     return (ret >= 0) ? res : error;
470 }
471 
472 
473 /*
474  * login_getcaplist()
475  * Given a login_cap entry, and a capability name, return the
476  * value defined for that capability split into an array of
477  * strings.
478  */
479 
480 const char **
481 login_getcaplist(login_cap_t *lc, const char *cap, const char *chars)
482 {
483     const char *lstring;
484 
485     if (chars == NULL)
486 	chars = ", \t";
487     if ((lstring = login_getcapstr(lc, cap, NULL, NULL)) != NULL)
488 	return arrayize(lstring, chars, NULL);
489     return NULL;
490 }
491 
492 
493 /*
494  * login_getpath()
495  * From the login_cap_t <lc>, get the capability <cap> which is
496  * formatted as either a space or comma delimited list of paths
497  * and append them all into a string and separate by semicolons.
498  * If there is an error of any kind, return <error>.
499  */
500 
501 const char *
502 login_getpath(login_cap_t *lc, const char *cap, const char *error)
503 {
504     const char *str;
505     char *ptr;
506     int count;
507 
508     str = login_getcapstr(lc, cap, NULL, NULL);
509     if (str == NULL)
510 	return error;
511     ptr = __DECONST(char *, str); /* XXXX Yes, very dodgy */
512     while (*ptr) {
513 	count = strcspn(ptr, ", \t");
514 	ptr += count;
515 	if (*ptr)
516 	    *ptr++ = ':';
517     }
518     return str;
519 }
520 
521 
522 static int
523 isinfinite(const char *s)
524 {
525     static const char *infs[] = {
526 	"infinity",
527 	"inf",
528 	"unlimited",
529 	"unlimit",
530 	"-1",
531 	NULL
532     };
533     const char **i = &infs[0];
534 
535     while (*i != NULL) {
536 	if (strcasecmp(s, *i) == 0)
537 	    return 1;
538 	++i;
539     }
540     return 0;
541 }
542 
543 
544 static u_quad_t
545 rmultiply(u_quad_t n1, u_quad_t n2)
546 {
547     u_quad_t	m, r;
548     int		b1, b2;
549 
550     static int bpw = 0;
551 
552     /* Handle simple cases */
553     if (n1 == 0 || n2 == 0)
554 	return 0;
555     if (n1 == 1)
556 	return n2;
557     if (n2 == 1)
558 	return n1;
559 
560     /*
561      * sizeof() returns number of bytes needed for storage.
562      * This may be different from the actual number of useful bits.
563      */
564     if (!bpw) {
565 	bpw = sizeof(u_quad_t) * 8;
566 	while (((u_quad_t)1 << (bpw-1)) == 0)
567 	    --bpw;
568     }
569 
570     /*
571      * First check the magnitude of each number. If the sum of the
572      * magnatude is way to high, reject the number. (If this test
573      * is not done then the first multiply below may overflow.)
574      */
575     for (b1 = bpw; (((u_quad_t)1 << (b1-1)) & n1) == 0; --b1)
576 	;
577     for (b2 = bpw; (((u_quad_t)1 << (b2-1)) & n2) == 0; --b2)
578 	;
579     if (b1 + b2 - 2 > bpw) {
580 	errno = ERANGE;
581 	return (UQUAD_MAX);
582     }
583 
584     /*
585      * Decompose the multiplication to be:
586      * h1 = n1 & ~1
587      * h2 = n2 & ~1
588      * l1 = n1 & 1
589      * l2 = n2 & 1
590      * (h1 + l1) * (h2 + l2)
591      * (h1 * h2) + (h1 * l2) + (l1 * h2) + (l1 * l2)
592      *
593      * Since h1 && h2 do not have the low bit set, we can then say:
594      *
595      * (h1>>1 * h2>>1 * 4) + ...
596      *
597      * So if (h1>>1 * h2>>1) > (1<<(bpw - 2)) then the result will
598      * overflow.
599      *
600      * Finally, if MAX - ((h1 * l2) + (l1 * h2) + (l1 * l2)) < (h1*h2)
601      * then adding in residual amout will cause an overflow.
602      */
603 
604     m = (n1 >> 1) * (n2 >> 1);
605     if (m >= ((u_quad_t)1 << (bpw-2))) {
606 	errno = ERANGE;
607 	return (UQUAD_MAX);
608     }
609     m *= 4;
610 
611     r = (n1 & n2 & 1)
612 	+ (n2 & 1) * (n1 & ~(u_quad_t)1)
613 	+ (n1 & 1) * (n2 & ~(u_quad_t)1);
614 
615     if ((u_quad_t)(m + r) < m) {
616 	errno = ERANGE;
617 	return (UQUAD_MAX);
618     }
619     m += r;
620 
621     return (m);
622 }
623 
624 
625 /*
626  * login_getcaptime()
627  * From the login_cap_t <lc>, get the capability <cap>, which is
628  * formatted as a time (e.g., "<cap>=10h3m2s").  If <cap> is not
629  * present in <lc>, return <def>; if there is an error of some kind,
630  * return <error>.
631  */
632 
633 rlim_t
634 login_getcaptime(login_cap_t *lc, const char *cap, rlim_t def, rlim_t error)
635 {
636     char    *res, *ep, *oval;
637     int	    r;
638     rlim_t  tot;
639 
640     errno = 0;
641     if (lc == NULL || lc->lc_cap == NULL)
642 	return def;
643 
644     /*
645      * Look for <cap> in lc_cap.
646      * If it's not there (-1), return <def>.
647      * If there's an error, return <error>.
648      */
649 
650     if ((r = cgetstr(lc->lc_cap, cap, &res)) == -1)
651 	return def;
652     else if (r < 0)
653 	return error;
654 
655     /* "inf" and "infinity" are special cases */
656     if (isinfinite(res))
657 	return RLIM_INFINITY;
658 
659     /*
660      * Now go through the string, turning something like 1h2m3s into
661      * an integral value.  Whee.
662      */
663 
664     errno = 0;
665     tot = 0;
666     oval = res;
667     while (*res) {
668 	rlim_t tim = strtoq(res, &ep, 0);
669 	rlim_t mult = 1;
670 
671 	if (ep == NULL || ep == res || errno != 0) {
672 	invalid:
673 	    syslog(LOG_WARNING, "login_getcaptime: class '%s' bad value %s=%s",
674 		   lc->lc_class, cap, oval);
675 	    errno = ERANGE;
676 	    return error;
677 	}
678 	/* Look for suffixes */
679 	switch (*ep++) {
680 	case 0:
681 	    ep--;
682 	    break;	/* end of string */
683 	case 's': case 'S':	/* seconds */
684 	    break;
685 	case 'm': case 'M':	/* minutes */
686 	    mult = 60;
687 	    break;
688 	case 'h': case 'H':	/* hours */
689 	    mult = 60L * 60L;
690 	    break;
691 	case 'd': case 'D':	/* days */
692 	    mult = 60L * 60L * 24L;
693 	    break;
694 	case 'w': case 'W':	/* weeks */
695 	    mult = 60L * 60L * 24L * 7L;
696 	    break;
697 	case 'y': case 'Y':	/* 365-day years */
698 	    mult = 60L * 60L * 24L * 365L;
699 	    break;
700 	default:
701 	    goto invalid;
702 	}
703 	res = ep;
704 	tot += rmultiply(tim, mult);
705 	if (errno)
706 	    goto invalid;
707     }
708 
709     return tot;
710 }
711 
712 
713 /*
714  * login_getcapnum()
715  * From the login_cap_t <lc>, extract the numerical value <cap>.
716  * If it is not present, return <def> for a default, and return
717  * <error> if there is an error.
718  * Like login_getcaptime(), only it only converts to a number, not
719  * to a time; "infinity" and "inf" are 'special.'
720  */
721 
722 rlim_t
723 login_getcapnum(login_cap_t *lc, const char *cap, rlim_t def, rlim_t error)
724 {
725     char    *ep, *res;
726     int	    r;
727     rlim_t  val;
728 
729     if (lc == NULL || lc->lc_cap == NULL)
730 	return def;
731 
732     /*
733      * For BSDI compatibility, try for the tag=<val> first
734      */
735     r = cgetstr(lc->lc_cap, cap, &res);
736     if (r == -1) {
737 	long	lval;
738 	/* string capability not present, so try for tag#<val> as numeric */
739 	if ((r = cgetnum(lc->lc_cap, cap, &lval)) == -1)
740 	    return def; /* Not there, so return default */
741 	else if (r < 0)
742 	    return error;
743 	else
744 	    return (rlim_t)lval;
745     } else if (r < 0)
746 	return error;
747 
748     if (isinfinite(res))
749 	return RLIM_INFINITY;
750 
751     errno = 0;
752     val = strtoq(res, &ep, 0);
753     if (ep == NULL || ep == res || errno != 0) {
754 	syslog(LOG_WARNING, "login_getcapnum: class '%s' bad value %s=%s",
755 	       lc->lc_class, cap, res);
756 	errno = ERANGE;
757 	return error;
758     }
759 
760     return val;
761 }
762 
763 
764 
765 /*
766  * login_getcapsize()
767  * From the login_cap_t <lc>, extract the capability <cap>, which is
768  * formatted as a size (e.g., "<cap>=10M"); it can also be "infinity".
769  * If not present, return <def>, or <error> if there is an error of
770  * some sort.
771  */
772 
773 rlim_t
774 login_getcapsize(login_cap_t *lc, const char *cap, rlim_t def, rlim_t error)
775 {
776     char    *ep, *res, *oval;
777     int	    r;
778     rlim_t  tot;
779 
780     if (lc == NULL || lc->lc_cap == NULL)
781 	return def;
782 
783     if ((r = cgetstr(lc->lc_cap, cap, &res)) == -1)
784 	return def;
785     else if (r < 0)
786 	return error;
787 
788     if (isinfinite(res))
789 	return RLIM_INFINITY;
790 
791     errno = 0;
792     tot = 0;
793     oval = res;
794     while (*res) {
795 	rlim_t siz = strtoq(res, &ep, 0);
796 	rlim_t mult = 1;
797 
798 	if (ep == NULL || ep == res || errno != 0) {
799 	invalid:
800 	    syslog(LOG_WARNING, "login_getcapsize: class '%s' bad value %s=%s",
801 		   lc->lc_class, cap, oval);
802 	    errno = ERANGE;
803 	    return error;
804 	}
805 	switch (*ep++) {
806 	case 0:	/* end of string */
807 	    ep--;
808 	    break;
809 	case 'b': case 'B':	/* 512-byte blocks */
810 	    mult = 512;
811 	    break;
812 	case 'k': case 'K':	/* 1024-byte Kilobytes */
813 	    mult = 1024;
814 	    break;
815 	case 'm': case 'M':	/* 1024-k kbytes */
816 	    mult = 1024 * 1024;
817 	    break;
818 	case 'g': case 'G':	/* 1Gbyte */
819 	    mult = 1024 * 1024 * 1024;
820 	    break;
821 	case 't': case 'T':	/* 1TBte */
822 	    mult = 1024LL * 1024LL * 1024LL * 1024LL;
823 	    break;
824 	default:
825 	    goto invalid;
826 	}
827 	res = ep;
828 	tot += rmultiply(siz, mult);
829 	if (errno)
830 	    goto invalid;
831     }
832 
833     return tot;
834 }
835 
836 
837 /*
838  * login_getcapbool()
839  * From the login_cap_t <lc>, check for the existence of the capability
840  * of <cap>.  Return <def> if <lc>->lc_cap is NULL, otherwise return
841  * the whether or not <cap> exists there.
842  */
843 
844 int
845 login_getcapbool(login_cap_t *lc, const char *cap, int def)
846 {
847     if (lc == NULL || lc->lc_cap == NULL)
848 	return def;
849     return (cgetcap(lc->lc_cap, cap, ':') != NULL);
850 }
851 
852 
853 /*
854  * login_getstyle()
855  * Given a login_cap entry <lc>, and optionally a type of auth <auth>,
856  * and optionally a style <style>, find the style that best suits these
857  * rules:
858  *	1.  If <auth> is non-null, look for an "auth-<auth>=" string
859  *	in the capability; if not present, default to "auth=".
860  *	2.  If there is no auth list found from (1), default to
861  *	"passwd" as an authorization list.
862  *	3.  If <style> is non-null, look for <style> in the list of
863  *	authorization methods found from (2); if <style> is NULL, default
864  *	to LOGIN_DEFSTYLE ("passwd").
865  *	4.  If the chosen style is found in the chosen list of authorization
866  *	methods, return that; otherwise, return NULL.
867  * E.g.:
868  *     login_getstyle(lc, NULL, "ftp");
869  *     login_getstyle(lc, "login", NULL);
870  *     login_getstyle(lc, "skey", "network");
871  */
872 
873 const char *
874 login_getstyle(login_cap_t *lc, const char *style, const char *auth)
875 {
876     int	    i;
877     const char **authtypes = NULL;
878     char    *auths= NULL;
879     char    realauth[64];
880 
881     static const char *defauthtypes[] = { LOGIN_DEFSTYLE, NULL };
882 
883     if (auth != NULL && *auth != '\0') {
884 	if (snprintf(realauth, sizeof realauth, "auth-%s", auth) < (int)sizeof(realauth))
885 	    authtypes = login_getcaplist(lc, realauth, NULL);
886     }
887 
888     if (authtypes == NULL)
889 	authtypes = login_getcaplist(lc, "auth", NULL);
890 
891     if (authtypes == NULL)
892 	authtypes = defauthtypes;
893 
894     /*
895      * We have at least one authtype now; auths is a comma-separated
896      * (or space-separated) list of authentication types.  We have to
897      * convert from this to an array of char*'s; authtypes then gets this.
898      */
899     i = 0;
900     if (style != NULL && *style != '\0') {
901 	while (authtypes[i] != NULL && strcmp(style, authtypes[i]) != 0)
902 	    i++;
903     }
904 
905     lc->lc_style = NULL;
906     if (authtypes[i] != NULL && (auths = strdup(authtypes[i])) != NULL)
907 	lc->lc_style = auths;
908 
909     if (lc->lc_style != NULL)
910 	lc->lc_style = strdup(lc->lc_style);
911 
912     return lc->lc_style;
913 }
914