1 /* Authors: Karl MacMillan <kmacmillan@tresys.com>
2 * Frank Mayer <mayerf@tresys.com>
4 * Copyright (C) 2003 - 2004 Tresys Technology, LLC
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation, version 2.
10 #include <linux/kernel.h>
11 #include <linux/errno.h>
12 #include <linux/string.h>
13 #include <linux/spinlock.h>
14 #include <linux/slab.h>
17 #include "conditional.h"
20 * cond_evaluate_expr evaluates a conditional expr
21 * in reverse polish notation. It returns true (1), false (0),
22 * or undefined (-1). Undefined occurs when the expression
23 * exceeds the stack depth of COND_EXPR_MAXDEPTH.
25 static int cond_evaluate_expr(struct policydb
*p
, struct cond_expr
*expr
)
28 struct cond_expr
*cur
;
29 int s
[COND_EXPR_MAXDEPTH
];
32 for (cur
= expr
; cur
; cur
= cur
->next
) {
33 switch (cur
->expr_type
) {
35 if (sp
== (COND_EXPR_MAXDEPTH
- 1))
38 s
[sp
] = p
->bool_val_to_struct
[cur
->bool - 1]->state
;
67 s
[sp
] = (s
[sp
] == s
[sp
+ 1]);
73 s
[sp
] = (s
[sp
] != s
[sp
+ 1]);
83 * evaluate_cond_node evaluates the conditional stored in
84 * a struct cond_node and if the result is different than the
85 * current state of the node it sets the rules in the true/false
86 * list appropriately. If the result of the expression is undefined
87 * all of the rules are disabled for safety.
89 int evaluate_cond_node(struct policydb
*p
, struct cond_node
*node
)
92 struct cond_av_list
*cur
;
94 new_state
= cond_evaluate_expr(p
, node
->expr
);
95 if (new_state
!= node
->cur_state
) {
96 node
->cur_state
= new_state
;
98 printk(KERN_ERR
"SELinux: expression result was undefined - disabling all rules.\n");
99 /* turn the rules on or off */
100 for (cur
= node
->true_list
; cur
; cur
= cur
->next
) {
102 cur
->node
->key
.specified
&= ~AVTAB_ENABLED
;
104 cur
->node
->key
.specified
|= AVTAB_ENABLED
;
107 for (cur
= node
->false_list
; cur
; cur
= cur
->next
) {
110 cur
->node
->key
.specified
&= ~AVTAB_ENABLED
;
112 cur
->node
->key
.specified
|= AVTAB_ENABLED
;
118 int cond_policydb_init(struct policydb
*p
)
122 p
->bool_val_to_struct
= NULL
;
125 rc
= avtab_init(&p
->te_cond_avtab
);
132 static void cond_av_list_destroy(struct cond_av_list
*list
)
134 struct cond_av_list
*cur
, *next
;
135 for (cur
= list
; cur
; cur
= next
) {
137 /* the avtab_ptr_t node is destroy by the avtab */
142 static void cond_node_destroy(struct cond_node
*node
)
144 struct cond_expr
*cur_expr
, *next_expr
;
146 for (cur_expr
= node
->expr
; cur_expr
; cur_expr
= next_expr
) {
147 next_expr
= cur_expr
->next
;
150 cond_av_list_destroy(node
->true_list
);
151 cond_av_list_destroy(node
->false_list
);
155 static void cond_list_destroy(struct cond_node
*list
)
157 struct cond_node
*next
, *cur
;
162 for (cur
= list
; cur
; cur
= next
) {
164 cond_node_destroy(cur
);
168 void cond_policydb_destroy(struct policydb
*p
)
170 kfree(p
->bool_val_to_struct
);
171 avtab_destroy(&p
->te_cond_avtab
);
172 cond_list_destroy(p
->cond_list
);
175 int cond_init_bool_indexes(struct policydb
*p
)
177 kfree(p
->bool_val_to_struct
);
178 p
->bool_val_to_struct
= (struct cond_bool_datum
**)
179 kmalloc(p
->p_bools
.nprim
* sizeof(struct cond_bool_datum
*), GFP_KERNEL
);
180 if (!p
->bool_val_to_struct
)
185 int cond_destroy_bool(void *key
, void *datum
, void *p
)
192 int cond_index_bool(void *key
, void *datum
, void *datap
)
195 struct cond_bool_datum
*booldatum
;
200 if (!booldatum
->value
|| booldatum
->value
> p
->p_bools
.nprim
)
203 p
->p_bool_val_to_name
[booldatum
->value
- 1] = key
;
204 p
->bool_val_to_struct
[booldatum
->value
- 1] = booldatum
;
209 static int bool_isvalid(struct cond_bool_datum
*b
)
211 if (!(b
->state
== 0 || b
->state
== 1))
216 int cond_read_bool(struct policydb
*p
, struct hashtab
*h
, void *fp
)
219 struct cond_bool_datum
*booldatum
;
224 booldatum
= kzalloc(sizeof(struct cond_bool_datum
), GFP_KERNEL
);
228 rc
= next_entry(buf
, fp
, sizeof buf
);
232 booldatum
->value
= le32_to_cpu(buf
[0]);
233 booldatum
->state
= le32_to_cpu(buf
[1]);
236 if (!bool_isvalid(booldatum
))
239 len
= le32_to_cpu(buf
[2]);
242 key
= kmalloc(len
+ 1, GFP_KERNEL
);
245 rc
= next_entry(key
, fp
, len
);
249 rc
= hashtab_insert(h
, key
, booldatum
);
255 cond_destroy_bool(key
, booldatum
, NULL
);
259 struct cond_insertf_data
{
261 struct cond_av_list
*other
;
262 struct cond_av_list
*head
;
263 struct cond_av_list
*tail
;
266 static int cond_insertf(struct avtab
*a
, struct avtab_key
*k
, struct avtab_datum
*d
, void *ptr
)
268 struct cond_insertf_data
*data
= ptr
;
269 struct policydb
*p
= data
->p
;
270 struct cond_av_list
*other
= data
->other
, *list
, *cur
;
271 struct avtab_node
*node_ptr
;
276 * For type rules we have to make certain there aren't any
277 * conflicting rules by searching the te_avtab and the
280 if (k
->specified
& AVTAB_TYPE
) {
281 if (avtab_search(&p
->te_avtab
, k
)) {
282 printk(KERN_ERR
"SELinux: type rule already exists outside of a conditional.\n");
286 * If we are reading the false list other will be a pointer to
287 * the true list. We can have duplicate entries if there is only
288 * 1 other entry and it is in our true list.
290 * If we are reading the true list (other == NULL) there shouldn't
291 * be any other entries.
294 node_ptr
= avtab_search_node(&p
->te_cond_avtab
, k
);
296 if (avtab_search_node_next(node_ptr
, k
->specified
)) {
297 printk(KERN_ERR
"SELinux: too many conflicting type rules.\n");
301 for (cur
= other
; cur
; cur
= cur
->next
) {
302 if (cur
->node
== node_ptr
) {
308 printk(KERN_ERR
"SELinux: conflicting type rules.\n");
313 if (avtab_search(&p
->te_cond_avtab
, k
)) {
314 printk(KERN_ERR
"SELinux: conflicting type rules when adding type rule for true.\n");
320 node_ptr
= avtab_insert_nonunique(&p
->te_cond_avtab
, k
, d
);
322 printk(KERN_ERR
"SELinux: could not insert rule.\n");
327 list
= kzalloc(sizeof(struct cond_av_list
), GFP_KERNEL
);
333 list
->node
= node_ptr
;
337 data
->tail
->next
= list
;
342 cond_av_list_destroy(data
->head
);
347 static int cond_read_av_list(struct policydb
*p
, void *fp
, struct cond_av_list
**ret_list
, struct cond_av_list
*other
)
352 struct cond_insertf_data data
;
357 rc
= next_entry(buf
, fp
, sizeof(u32
));
361 len
= le32_to_cpu(buf
[0]);
369 for (i
= 0; i
< len
; i
++) {
370 rc
= avtab_read_item(&p
->te_cond_avtab
, fp
, p
, cond_insertf
,
376 *ret_list
= data
.head
;
380 static int expr_isvalid(struct policydb
*p
, struct cond_expr
*expr
)
382 if (expr
->expr_type
<= 0 || expr
->expr_type
> COND_LAST
) {
383 printk(KERN_ERR
"SELinux: conditional expressions uses unknown operator.\n");
387 if (expr
->bool > p
->p_bools
.nprim
) {
388 printk(KERN_ERR
"SELinux: conditional expressions uses unknown bool.\n");
394 static int cond_read_node(struct policydb
*p
, struct cond_node
*node
, void *fp
)
399 struct cond_expr
*expr
= NULL
, *last
= NULL
;
401 rc
= next_entry(buf
, fp
, sizeof(u32
));
405 node
->cur_state
= le32_to_cpu(buf
[0]);
408 rc
= next_entry(buf
, fp
, sizeof(u32
));
413 len
= le32_to_cpu(buf
[0]);
415 for (i
= 0; i
< len
; i
++) {
416 rc
= next_entry(buf
, fp
, sizeof(u32
) * 2);
421 expr
= kzalloc(sizeof(struct cond_expr
), GFP_KERNEL
);
425 expr
->expr_type
= le32_to_cpu(buf
[0]);
426 expr
->bool = le32_to_cpu(buf
[1]);
428 if (!expr_isvalid(p
, expr
)) {
441 rc
= cond_read_av_list(p
, fp
, &node
->true_list
, NULL
);
444 rc
= cond_read_av_list(p
, fp
, &node
->false_list
, node
->true_list
);
449 cond_node_destroy(node
);
453 int cond_read_list(struct policydb
*p
, void *fp
)
455 struct cond_node
*node
, *last
= NULL
;
460 rc
= next_entry(buf
, fp
, sizeof buf
);
464 len
= le32_to_cpu(buf
[0]);
466 rc
= avtab_alloc(&(p
->te_cond_avtab
), p
->te_avtab
.nel
);
470 for (i
= 0; i
< len
; i
++) {
472 node
= kzalloc(sizeof(struct cond_node
), GFP_KERNEL
);
476 rc
= cond_read_node(p
, node
, fp
);
488 cond_list_destroy(p
->cond_list
);
493 int cond_write_bool(void *vkey
, void *datum
, void *ptr
)
496 struct cond_bool_datum
*booldatum
= datum
;
497 struct policy_data
*pd
= ptr
;
504 buf
[0] = cpu_to_le32(booldatum
->value
);
505 buf
[1] = cpu_to_le32(booldatum
->state
);
506 buf
[2] = cpu_to_le32(len
);
507 rc
= put_entry(buf
, sizeof(u32
), 3, fp
);
510 rc
= put_entry(key
, 1, len
, fp
);
517 * cond_write_cond_av_list doesn't write out the av_list nodes.
518 * Instead it writes out the key/value pairs from the avtab. This
519 * is necessary because there is no way to uniquely identifying rules
520 * in the avtab so it is not possible to associate individual rules
521 * in the avtab with a conditional without saving them as part of
522 * the conditional. This means that the avtab with the conditional
523 * rules will not be saved but will be rebuilt on policy load.
525 static int cond_write_av_list(struct policydb
*p
,
526 struct cond_av_list
*list
, struct policy_file
*fp
)
529 struct cond_av_list
*cur_list
;
534 for (cur_list
= list
; cur_list
!= NULL
; cur_list
= cur_list
->next
)
537 buf
[0] = cpu_to_le32(len
);
538 rc
= put_entry(buf
, sizeof(u32
), 1, fp
);
545 for (cur_list
= list
; cur_list
!= NULL
; cur_list
= cur_list
->next
) {
546 rc
= avtab_write_item(p
, cur_list
->node
, fp
);
554 int cond_write_node(struct policydb
*p
, struct cond_node
*node
,
555 struct policy_file
*fp
)
557 struct cond_expr
*cur_expr
;
562 buf
[0] = cpu_to_le32(node
->cur_state
);
563 rc
= put_entry(buf
, sizeof(u32
), 1, fp
);
567 for (cur_expr
= node
->expr
; cur_expr
!= NULL
; cur_expr
= cur_expr
->next
)
570 buf
[0] = cpu_to_le32(len
);
571 rc
= put_entry(buf
, sizeof(u32
), 1, fp
);
575 for (cur_expr
= node
->expr
; cur_expr
!= NULL
; cur_expr
= cur_expr
->next
) {
576 buf
[0] = cpu_to_le32(cur_expr
->expr_type
);
577 buf
[1] = cpu_to_le32(cur_expr
->bool);
578 rc
= put_entry(buf
, sizeof(u32
), 2, fp
);
583 rc
= cond_write_av_list(p
, node
->true_list
, fp
);
586 rc
= cond_write_av_list(p
, node
->false_list
, fp
);
593 int cond_write_list(struct policydb
*p
, struct cond_node
*list
, void *fp
)
595 struct cond_node
*cur
;
601 for (cur
= list
; cur
!= NULL
; cur
= cur
->next
)
603 buf
[0] = cpu_to_le32(len
);
604 rc
= put_entry(buf
, sizeof(u32
), 1, fp
);
608 for (cur
= list
; cur
!= NULL
; cur
= cur
->next
) {
609 rc
= cond_write_node(p
, cur
, fp
);
616 /* Determine whether additional permissions are granted by the conditional
617 * av table, and if so, add them to the result
619 void cond_compute_av(struct avtab
*ctab
, struct avtab_key
*key
, struct av_decision
*avd
)
621 struct avtab_node
*node
;
623 if (!ctab
|| !key
|| !avd
)
626 for (node
= avtab_search_node(ctab
, key
); node
;
627 node
= avtab_search_node_next(node
, key
->specified
)) {
628 if ((u16
)(AVTAB_ALLOWED
|AVTAB_ENABLED
) ==
629 (node
->key
.specified
& (AVTAB_ALLOWED
|AVTAB_ENABLED
)))
630 avd
->allowed
|= node
->datum
.data
;
631 if ((u16
)(AVTAB_AUDITDENY
|AVTAB_ENABLED
) ==
632 (node
->key
.specified
& (AVTAB_AUDITDENY
|AVTAB_ENABLED
)))
633 /* Since a '0' in an auditdeny mask represents a
634 * permission we do NOT want to audit (dontaudit), we use
635 * the '&' operand to ensure that all '0's in the mask
636 * are retained (much unlike the allow and auditallow cases).
638 avd
->auditdeny
&= node
->datum
.data
;
639 if ((u16
)(AVTAB_AUDITALLOW
|AVTAB_ENABLED
) ==
640 (node
->key
.specified
& (AVTAB_AUDITALLOW
|AVTAB_ENABLED
)))
641 avd
->auditallow
|= node
->datum
.data
;