3 * $Id: class.c,v 1.9 2003/10/12 00:14:55 mdw Exp $
5 * Handling classes of things nicely
10 /*----- Licensing notice --------------------------------------------------*
12 * This file is part of `become'
14 * `Become' is free software; you can redistribute it and/or modify
15 * it under the terms of the GNU General Public License as published by
16 * the Free Software Foundation; either version 2 of the License, or
17 * (at your option) any later version.
19 * `Become' is distributed in the hope that it will be useful,
20 * but WITHOUT ANY WARRANTY; without even the implied warranty of
21 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
22 * GNU General Public License for more details.
24 * You should have received a copy of the GNU General Public License
25 * along with `become'; if not, write to the Free Software Foundation,
26 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
29 /*----- Revision history --------------------------------------------------*
32 * Revision 1.9 2003/10/12 00:14:55 mdw
33 * Major overhaul. Now uses DSA signatures rather than the bogus symmetric
34 * encrypt-and-hope thing. Integrated with mLib and Catacomb.
36 * Revision 1.8 1998/06/08 11:20:36 mdw
37 * (class__wildMatch) Fixed bug which overran pattern string, spotted by
40 * Revision 1.7 1998/01/12 16:45:50 mdw
43 * Revision 1.6 1997/09/17 10:14:56 mdw
44 * Complete rewrite to support class trees. Makes the behaviour of the set
45 * operators much more logical.
47 * Revision 1.5 1997/08/20 16:16:13 mdw
48 * Patch memory leak. Don't try to trace when tracing's turned off.
50 * Revision 1.4 1997/08/07 09:56:37 mdw
51 * (Log entry for previous version is bogus.) Minor changes to host
54 * Revision 1.2 1997/08/04 10:24:21 mdw
55 * Sources placed under CVS control.
57 * Revision 1.1 1997/07/21 13:47:52 mdw
62 /*----- Header files ------------------------------------------------------*/
64 /* --- ANSI headers --- */
70 /* --- Unix headers --- */
72 #include <sys/types.h>
73 #include <sys/socket.h>
75 #include <netinet/in.h>
77 #include <arpa/inet.h>
81 /* --- mLib headers --- */
83 #include <mLib/alloc.h>
84 #include <mLib/report.h>
87 /* --- Local headers --- */
92 /*----- Global variables --------------------------------------------------*/
94 static class_node class__all = { clType_all | clNode_any, -1, { 0 }};
95 class_node *class_all = &class__all;
97 static class_node class__none = { clType_all | clNode_any, -1, { 0 }};
98 class_node *class_none = &class__none;
100 /*----- Wildcard matching -------------------------------------------------*/
102 /* --- @class__wildMatch@ --- *
104 * Arguments: @const char *pat@ = pointer to pattern string
105 * @const char *p@ = pointer to target string
107 * Returns: Zero if no match, nonzero if match.
109 * Use: Wildcard-matches the pattern against the target string.
112 static int class__wildMatch(const char *pat, const char *p)
115 if (*pat == 0 && *p == 0)
116 return (42); /* For sadism's sake */
117 else if (*pat == '*') {
123 if (class__wildMatch(pat, p))
124 return (27); /* Nyahaha */
128 } else if (*pat == '?' || *pat == *p)
135 /*----- Creating new class nodes ------------------------------------------*/
137 /* --- @class_fromString@ --- *
139 * Arguments: @unsigned type@ = a type field
140 * @const char *s@ = pointer to string to copy
142 * Returns: A pointer to a class node containing that string, typed to
143 * be the right thing.
145 * Use: Given a string, wrap a class node around it. The node has
146 * one reference (the one you get returned). The string is
147 * copied, so you can get rid of your original one if you like.
150 class_node *class_fromString(unsigned type, const char *s)
152 class_node *c = xmalloc(sizeof(*c));
153 c->type = type | clNode_immed;
154 if (s[strcspn(s, "*?")] == 0)
155 c->type |= clFlag_friendly;
161 /* --- @class_fromUser@ --- *
163 * Arguments: @unsigned type@ = a type field
164 * @uid_t u@ = a user-id number
166 * Returns: A pointer to a class node containing the uid, typed to be
167 * the thing you asked for. Hopefully this will be
170 * Use: Given a uid, wrap a class node around it.
173 class_node *class_fromUser(unsigned type, uid_t u)
175 class_node *c = xmalloc(sizeof(*c));
176 c->type = type | clNode_immed | clFlag_friendly;
182 /*----- Reference counter tricks ------------------------------------------*/
184 /* --- @class_inc@ --- *
186 * Arguments: @class_node *c@ = pointer to a class block
190 * Use: Adds a reference to the class definition.
193 void class_inc(class_node *c)
195 if (c != class_all && c != class_none)
199 /* --- @class_dec@ --- *
201 * Arguments: @class_node *c@ = pointer to a class block
205 * Use: Removes a reference to a class block.
208 void class_dec(class_node *c)
212 for (cc = 0; c; c = cc, cc = 0) {
213 if (c == class_all || c == class_none || --c->ref)
215 switch (c->type & clNode_mask) {
220 if (c->type & (clType_host | clType_command))
224 sym_destroy(&c->v.t);
237 /* --- @class_mod@ --- *
239 * Arguments: @class_node *c@ = pointer to a class node
241 * Returns: A pointer to a class node, maybe the same one, maybe not,
242 * with a reference count of 1, containing the same data.
244 * Use: Gives you a node which you can modify. Don't call this
245 * for @class_all@ or @class_none@.
248 class_node *class_mod(class_node *c)
255 cc = xmalloc(sizeof(*cc));
258 switch (c->type & clNode_mask) {
260 die(1, "internal: class_mod called on non-modifiable class node");
264 if (c->type & clType_user)
267 cc->v.s = xstrdup(c->v.s);
274 sym_create(&cc->v.t);
275 for (sym_mkiter(&i, &c->v.t); (b = sym_next(&i)) != 0; )
276 sym_find(&cc->v.t, b->name, b->len, sizeof(sym_base), 0);
282 cc->v.c.l = c->v.c.l;
283 cc->v.c.r = c->v.c.r;
284 class_inc(cc->v.c.l);
285 class_inc(cc->v.c.r);
293 /*----- Some weirder operations on classes --------------------------------*/
295 /* --- @class__hashify@ --- *
297 * Arguments: @class_node *c@ = pointer to a node
299 * Returns: A pointer to a hash node containing the node's value.
301 * Use: The original node must have type `immediate', and it must
302 * be friendly. The old reference is discarded -- you get this
306 static class_node *class__hashify(class_node *c)
308 /* --- Some sanity checking --- */
310 if (~c->type & clFlag_friendly)
311 die(1, "internal: class__hashify can't hashify unfriendly nodes");
312 if ((c->type & clNode_mask) != clNode_immed)
313 die(1, "internal: class__hashify can't hashify non-immediate nodes");
315 /* --- Split off a private copy of the node --- */
319 c->type = (c->type & clType_mask) | clNode_hash | clFlag_friendly;
321 if (c->type & clType_user) {
324 sym_find(&c->v.t, (char *)&u, sizeof(u), sizeof(sym_base), 0);
328 sym_find(&c->v.t, s, -1, sizeof(sym_base), 0);
335 /*----- Arithmetic on classes ---------------------------------------------*/
337 /* --- @class__binop@ --- *
339 * Arguments: @class_node *l@ = left argument
340 * @class_node *r@ = right argument
341 * @unsigned op@ = the binop code
343 * Returns: A class node representing the result of a binary operation
346 * Use: Performs a binary operation on classes. If the types don't
347 * match, then a null pointer is returned. Both @l@ and @r@
348 * may be modified, and will be decremented before they get
349 * returned to you. If you don't want that to happen, ensure
350 * that you've claimed a reference to the original versions.
352 * If both nodes are `friendly' (see below), then an attempt is
353 * made to combine them sensibly using a hashtable.
355 * If one or both nodes is/are unfriendly, a binop node is
356 * created with type @op@ to allow the matcher to decide on
357 * membership appropriately at match time.
359 * A friendly node is one which can be placed in a hash table to
360 * speed up searching. It's friendly, because it doesn't mind
361 * living with other nodes. Uid numbers are friendly.
362 * Wildcarded strings aren't. Hashtables are trivially
366 class_node *class__binop(class_node *l, class_node *r, int op)
368 unsigned type = l->type & r->type & clType_mask;
369 unsigned lnode = l->type & clNode_mask, rnode = r->type & clNode_mask;
371 /* --- Check for compatible types --- */
379 /* --- Handle `friendly' nodes --- */
381 if ((l->type & r->type & clFlag_friendly)) {
383 /* --- Consider promoting an item to a hash --- *
385 * If both are immediate nodes, and they're both `friendly', we can
386 * profitably hash them together.
388 * Life gets complicated when we do subtraction, because it's not
389 * commutative. In this case, I have to promote the left operand anyway.
392 if (lnode == clNode_immed &&
393 (rnode == clNode_immed || op == clNode_diff)) {
395 /* --- Quick check for triviality --- *
397 * There are some more short-cuts I can employ if the values are
401 if (rnode == clNode_immed) {
403 /* --- See whether the two items are equal --- */
405 int eq = (type & clType_user ?
406 l->v.u == r->v.u : strcmp(l->v.s, r->v.s) == 0);
408 /* --- Now do something appropriate --- */
437 /* --- Turn @l@ into a hash containing itself --- */
439 l = class__hashify(l);
443 /* --- Otherwise, make @l@ the hash --- *
445 * Both @l@ and @r@ are friendly. Since they're not both immediates,
446 * one must be a hash.
449 else if ((l->type & clNode_mask) == clNode_immed) {
453 tn = l, l = r, r = tn;
454 tt = lnode, lnode = rnode, rnode = tt;
457 /* --- Now merge @r@ with @l@ --- */
463 /* --- The union operation isn't hard --- */
466 if (rnode == clNode_immed) {
467 if (type & clType_user) {
468 sym_find(&l->v.t, (char *)&r->v.u,
469 sizeof(r->v.u), sizeof(sym_base), 0);
471 sym_find(&l->v.t, r->v.s, -1, sizeof(sym_base), 0);
476 for (sym_mkiter(&i, &r->v.t); (b = sym_next(&i)) != 0; )
477 sym_find(&l->v.t, b->name, b->len, sizeof(sym_base), 0);
481 /* --- Set difference is similar in spirit --- */
484 if (rnode == clNode_immed) {
487 if (type & clType_user)
488 f = sym_find(&l->v.t, (char *)&r->v.u, sizeof(r->v.u), 0, 0);
490 f = sym_find(&l->v.t, r->v.s, -1, 0, 0);
492 sym_remove(&l->v.t, f);
497 for (sym_mkiter(&i, &r->v.t); (b = sym_next(&i)) != 0; ) {
498 if ((f = sym_find(&l->v.t, b->name, b->len, 0, 0)) != 0)
499 sym_remove(&l->v.t, f);
504 /* --- Intersection is wild and wacky --- */
507 if (rnode == clNode_immed) {
510 if (type & clType_user)
511 f = sym_find(&l->v.t, (char *)&r->v.u, sizeof(r->v.u), 0, 0);
513 f = sym_find(&l->v.t, r->v.s, -1, 0, 0);
526 for (sym_mkiter(&i, &l->v.t); (b = sym_next(&i)) != 0; ) {
527 if (!sym_find(&r->v.t, b->name, b->len, 0, 0))
528 sym_remove(&l->v.t, b);
534 /* --- Now trim the @l@ table to size --- *
536 * It may have lost a load of elements. Maybe it can be represented
537 * better as an immediate or even as @class_none@.
546 sym_mkiter(&i, &l->v.t);
547 if ((b = sym_next(&i)) == 0) {
552 if (type & clType_user) {
553 uid_t u = *(uid_t *)b->name;
554 sym_destroy(&l->v.t);
555 l->type = (l->type & ~clNode_mask) | clNode_immed;
558 char *s = xstrdup(b->name);
559 sym_destroy(&l->v.t);
560 l->type = (l->type & ~clNode_mask) | clNode_immed;
571 /* --- Unfriendly nodes --- *
573 * Create a binop node and return that. If @l@ is a binop node, and @r@
574 * isn't, and the operation isn't set difference (i.e., it's commutative)
575 * then swap the two over to lessen the depth of recursion later.
579 class_node *c = xmalloc(sizeof(*c));
583 if (lnode >= clNode_binop && rnode < clNode_binop && op != clNode_diff) {
594 /* --- @class_union@ --- *
596 * Arguments: @class_node *l@ = left argument
597 * @class_node *r@ = right argument
599 * Returns: A class node representing the union of the two classes.
601 * Use: Performs the union operation on classes. If the types don't
602 * match, then a null pointer is returned. Both @l@ and @r@
603 * may be modified, and will be decremented before they get
604 * returned to you. If you don't want that to happen, ensure
605 * that you've claimed a reference to the original versions.
608 class_node *class_union(class_node *l, class_node *r)
610 /* --- Check for the really simple cases --- */
612 if (l == class_all || r == class_all) {
623 /* --- Do the job --- */
625 return (class__binop(l, r, clNode_union));
628 /* --- @class_diff@ --- *
630 * Arguments: @class_node *l@ = left argument
631 * @class_node *r@ = right argument
633 * Returns: A class node representing the difference of the two classes.
635 * Use: Performs the set difference operation on classes. If the
636 * types don't match, then a null pointer is returned. Both
637 * @l@ and @r@ may be modified, and will be decremented before
638 * they get returned to you. If you don't want that to happen,
639 * ensure that you've claimed a reference to the original
643 class_node *class_diff(class_node *l, class_node *r)
645 /* --- Check for the really simple cases --- */
647 if (l == class_none || r == class_all) {
656 /* --- Do the job --- */
658 return (class__binop(l, r, clNode_diff));
661 /* --- @class_isect@ --- *
663 * Arguments: @class_node *l@ = left argument
664 * @class_node *r@ = right argument
666 * Returns: A class node representing the intersection of the two
669 * Use: Performs the intersecion operation on classes. If the types
670 * don't match, then a null pointer is returned. Both @l@ and
671 * @r@ may be modified, and will be decremented before they get
672 * returned to you. If you don't want that to happen, ensure
673 * that you've claimed a reference to the original versions.
676 class_node *class_isect(class_node *l, class_node *r)
678 /* --- Check for the really simple cases --- */
680 if (l == class_none || r == class_none) {
691 /* --- Do the job --- */
693 return (class__binop(l, r, clNode_isect));
696 /*----- Building the predefined classes -----------------------------------*/
698 /* --- @class_addUser@ --- *
700 * Arguments: @class_node *c@ = pointer to a class node (may be null)
701 * @uid_t u@ = user id number
703 * Returns: Pointer to the combined node.
705 * Use: Adds a user to a node, maybe hashifying it.
708 class_node *class_addUser(class_node *c, uid_t u)
711 return (class_fromUser(clType_user, u));
712 if ((c->type & clNode_mask) == clNode_immed)
713 c = class__hashify(c);
714 sym_find(&c->v.t, (char *)&u, sizeof(u), sizeof(sym_base), 0);
718 /* --- @class_addString@ --- *
720 * Arguments: @class_node *c@ = pointer to a class node (may be null)
721 * @const char *s@ = pointer to a string
723 * Returns: Pointer to the combined node.
725 * Use: Adds a user to a node, maybe hashifying it.
728 class_node *class_addString(class_node *c, const char *s)
730 class_node *n = class_fromString(clType_host, s); /* hack */
732 return (class_union(c, n));
737 /*----- Matching functions ------------------------------------------------*/
739 /* --- @class_matchUser@ --- *
741 * Arguments: @class_node *c@ = pointer to root class node
742 * @uid_t u@ = user id number
744 * Returns: Nonzero if it matches, zero if it doesn't.
746 * Use: Determines whether a user is matched by a class. Assumes
747 * that the types are correct.
750 int class_matchUser(class_node *c, uid_t u)
754 for (cc = 0; c; c = cc, cc = 0) {
759 switch (c->type & clNode_mask) {
761 return (u == c->v.u);
764 return (sym_find(&c->v.t, (char *)&u, sizeof(u), 0, 0) != 0);
767 if (class_matchUser(c->v.c.l, u))
772 if (!class_matchUser(c->v.c.l, u))
777 return (class_matchUser(c->v.c.l, u) &&
778 !class_matchUser(c->v.c.r, u));
783 die(1, "internal: can't get here in class_matchUser");
787 /* --- @class_matchCommand@ --- *
789 * Arguments: @class_node *c@ = pointer to root class node
790 * @const char *s@ = pointer to a string
792 * Returns: Nonzero if it matches, zero if it doesn't.
794 * Use: Determines whether a string is matched by a class. Assumes
795 * that the types are correct.
798 int class_matchCommand(class_node *c, const char *s)
802 for (cc = 0; c; c = cc, cc = 0) {
807 switch (c->type & clNode_mask) {
809 return (class__wildMatch(c->v.s, s));
812 return (sym_find(&c->v.t, s, -1, 0, 0) != 0);
815 if (class_matchCommand(c->v.c.l, s))
820 if (!class_matchCommand(c->v.c.l, s))
825 return (class_matchCommand(c->v.c.l, s) &&
826 !class_matchCommand(c->v.c.r, s));
831 die(1, "internal: can't get here in class_matchCommand");
835 /* --- @class_matchHost@ --- *
837 * Arguments: @class_node *c@ = pointer to root class node
838 * @struct in_addr a@ = IP address to match
840 * Returns: Nonzero if it matches, zero if it doesn't.
842 * Use: Determines whether a host matches a host class. Assumes
843 * that the types are correct. The actual mechanism is a bit
844 * odd here, but I think this is the Right Thing. At each stage
845 * I try to match %%@/all/%% of the possible names for the host.
846 * Thus host `splat' with address 1.2.3.4 would fail to match
847 * the class "1.2.*" - "splat". This seems to be what the
848 * author intuitively expects. It's just a bit weird.
851 static int class__doMatchHost(class_node *c, const char *ip,
852 const char *name, char **aliases)
856 for (cc = 0; c; c = cc, cc = 0) {
861 switch (c->type & clNode_mask) {
863 if ((ip && class__wildMatch(c->v.s, ip)) ||
864 (name && class__wildMatch(c->v.s, name)))
866 if (aliases) for (; *aliases; aliases++) {
867 if (class__wildMatch(c->v.s, *aliases))
873 if ((ip && sym_find(&c->v.t, ip, -1, 0, 0)) ||
874 (name && sym_find(&c->v.t, name, -1, 0, 0)))
876 if (aliases) for (; *aliases; aliases++) {
877 if (sym_find(&c->v.t, *aliases, -1, 0, 0))
883 if (class__doMatchHost(c->v.c.l, ip, name, aliases))
888 if (!class__doMatchHost(c->v.c.l, ip, name, aliases))
893 return (class__doMatchHost(c->v.c.l, ip, name, aliases) &&
894 !class__doMatchHost(c->v.c.r, ip, name, aliases));
899 die(1, "internal: can't get here in class_matchUser");
903 int class_matchHost(class_node *c, struct in_addr a)
905 char *ip, *name, **aliases;
909 if ((h = gethostbyaddr((char *)&a, sizeof(a), AF_INET)) != 0) {
911 aliases = h->h_aliases;
917 return (class__doMatchHost(c, ip, name, aliases));
920 /*----- Debugging code ----------------------------------------------------*/
922 /* --- @class_dump@ --- *
924 * Argumemnts: @class_node *c@ = pointer to root node
925 * @int indent@ = indent depth
929 * Use: Dumps a class to the trace output.
932 void class_dump(class_node *c, int indent)
936 static char *types[] = {
944 static char *nodes[] = {
951 "binop: intersection"
954 /* --- Handle some magical cases --- */
956 if (c == class_all) {
957 trace(TRACE_RULE, "rule:%*s class ALL", indent * 2, "");
960 if (c == class_none) {
961 trace(TRACE_RULE, "rule:%*s class NONE", indent * 2, "");
965 /* --- Dump basic type information --- */
967 trace(TRACE_RULE, "rule:%*s type == [%s], node type == [%s]%s",
969 types[c->type & clType_mask],
970 nodes[(c->type & clNode_mask) >> 4],
971 (c->type & clFlag_friendly) ? " Friendly" : "");
973 /* --- Now trace the contents --- */
975 switch (c->type & clNode_mask) {
977 if (c->type & clType_user) {
978 trace(TRACE_RULE, "rule:%*s user %lu",
979 indent * 2, "", (unsigned long)c->v.u);
981 trace(TRACE_RULE, "rule:%*s `%s'", indent * 2, "", c->v.s);
987 for (sym_mkiter(&i, &c->v.t); (b = sym_next(&i)) != 0; ) {
988 if (c->type & clType_user) {
989 trace(TRACE_RULE, "rule:%*s user %lu",
990 indent * 2, "", (unsigned long)*(uid_t *)b->name);
992 trace(TRACE_RULE, "rule:%*s `%s'", indent * 2, "", b->name);
998 class_dump(c->v.c.l, indent + 1);
999 class_dump(c->v.c.r, indent + 1);
1006 /*----- That's all, folks -------------------------------------------------*/