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git.proxmox.com Git - mirror_ubuntu-jammy-kernel.git/blob - security/selinux/ss/conditional.c
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 <asm/semaphore.h>
15 #include <linux/slab.h>
18 #include "conditional.h"
21 * cond_evaluate_expr evaluates a conditional expr
22 * in reverse polish notation. It returns true (1), false (0),
23 * or undefined (-1). Undefined occurs when the expression
24 * exceeds the stack depth of COND_EXPR_MAXDEPTH.
26 static int cond_evaluate_expr(struct policydb
*p
, struct cond_expr
*expr
)
29 struct cond_expr
*cur
;
30 int s
[COND_EXPR_MAXDEPTH
];
33 for (cur
= expr
; cur
!= NULL
; cur
= cur
->next
) {
34 switch (cur
->expr_type
) {
36 if (sp
== (COND_EXPR_MAXDEPTH
- 1))
39 s
[sp
] = p
->bool_val_to_struct
[cur
->bool - 1]->state
;
68 s
[sp
] = (s
[sp
] == s
[sp
+ 1]);
74 s
[sp
] = (s
[sp
] != s
[sp
+ 1]);
84 * evaluate_cond_node evaluates the conditional stored in
85 * a struct cond_node and if the result is different than the
86 * current state of the node it sets the rules in the true/false
87 * list appropriately. If the result of the expression is undefined
88 * all of the rules are disabled for safety.
90 int evaluate_cond_node(struct policydb
*p
, struct cond_node
*node
)
93 struct cond_av_list
*cur
;
95 new_state
= cond_evaluate_expr(p
, node
->expr
);
96 if (new_state
!= node
->cur_state
) {
97 node
->cur_state
= new_state
;
99 printk(KERN_ERR
"SELinux: expression result was undefined - disabling all rules.\n");
100 /* turn the rules on or off */
101 for (cur
= node
->true_list
; cur
!= NULL
; cur
= cur
->next
) {
103 cur
->node
->key
.specified
&= ~AVTAB_ENABLED
;
105 cur
->node
->key
.specified
|= AVTAB_ENABLED
;
108 for (cur
= node
->false_list
; cur
!= NULL
; cur
= cur
->next
) {
111 cur
->node
->key
.specified
&= ~AVTAB_ENABLED
;
113 cur
->node
->key
.specified
|= AVTAB_ENABLED
;
119 int cond_policydb_init(struct policydb
*p
)
121 p
->bool_val_to_struct
= NULL
;
123 if (avtab_init(&p
->te_cond_avtab
))
129 static void cond_av_list_destroy(struct cond_av_list
*list
)
131 struct cond_av_list
*cur
, *next
;
132 for (cur
= list
; cur
!= NULL
; cur
= next
) {
134 /* the avtab_ptr_t node is destroy by the avtab */
139 static void cond_node_destroy(struct cond_node
*node
)
141 struct cond_expr
*cur_expr
, *next_expr
;
143 for (cur_expr
= node
->expr
; cur_expr
!= NULL
; cur_expr
= next_expr
) {
144 next_expr
= cur_expr
->next
;
147 cond_av_list_destroy(node
->true_list
);
148 cond_av_list_destroy(node
->false_list
);
152 static void cond_list_destroy(struct cond_node
*list
)
154 struct cond_node
*next
, *cur
;
159 for (cur
= list
; cur
!= NULL
; cur
= next
) {
161 cond_node_destroy(cur
);
165 void cond_policydb_destroy(struct policydb
*p
)
167 kfree(p
->bool_val_to_struct
);
168 avtab_destroy(&p
->te_cond_avtab
);
169 cond_list_destroy(p
->cond_list
);
172 int cond_init_bool_indexes(struct policydb
*p
)
174 kfree(p
->bool_val_to_struct
);
175 p
->bool_val_to_struct
= (struct cond_bool_datum
**)
176 kmalloc(p
->p_bools
.nprim
* sizeof(struct cond_bool_datum
*), GFP_KERNEL
);
177 if (!p
->bool_val_to_struct
)
182 int cond_destroy_bool(void *key
, void *datum
, void *p
)
189 int cond_index_bool(void *key
, void *datum
, void *datap
)
192 struct cond_bool_datum
*booldatum
;
197 if (!booldatum
->value
|| booldatum
->value
> p
->p_bools
.nprim
)
200 p
->p_bool_val_to_name
[booldatum
->value
- 1] = key
;
201 p
->bool_val_to_struct
[booldatum
->value
- 1] = booldatum
;
206 static int bool_isvalid(struct cond_bool_datum
*b
)
208 if (!(b
->state
== 0 || b
->state
== 1))
213 int cond_read_bool(struct policydb
*p
, struct hashtab
*h
, void *fp
)
216 struct cond_bool_datum
*booldatum
;
221 booldatum
= kzalloc(sizeof(struct cond_bool_datum
), GFP_KERNEL
);
225 rc
= next_entry(buf
, fp
, sizeof buf
);
229 booldatum
->value
= le32_to_cpu(buf
[0]);
230 booldatum
->state
= le32_to_cpu(buf
[1]);
232 if (!bool_isvalid(booldatum
))
235 len
= le32_to_cpu(buf
[2]);
237 key
= kmalloc(len
+ 1, GFP_KERNEL
);
240 rc
= next_entry(key
, fp
, len
);
244 if (hashtab_insert(h
, key
, booldatum
))
249 cond_destroy_bool(key
, booldatum
, NULL
);
253 struct cond_insertf_data
{
255 struct cond_av_list
*other
;
256 struct cond_av_list
*head
;
257 struct cond_av_list
*tail
;
260 static int cond_insertf(struct avtab
*a
, struct avtab_key
*k
, struct avtab_datum
*d
, void *ptr
)
262 struct cond_insertf_data
*data
= ptr
;
263 struct policydb
*p
= data
->p
;
264 struct cond_av_list
*other
= data
->other
, *list
, *cur
;
265 struct avtab_node
*node_ptr
;
270 * For type rules we have to make certain there aren't any
271 * conflicting rules by searching the te_avtab and the
274 if (k
->specified
& AVTAB_TYPE
) {
275 if (avtab_search(&p
->te_avtab
, k
)) {
276 printk("SELinux: type rule already exists outside of a conditional.");
280 * If we are reading the false list other will be a pointer to
281 * the true list. We can have duplicate entries if there is only
282 * 1 other entry and it is in our true list.
284 * If we are reading the true list (other == NULL) there shouldn't
285 * be any other entries.
288 node_ptr
= avtab_search_node(&p
->te_cond_avtab
, k
);
290 if (avtab_search_node_next(node_ptr
, k
->specified
)) {
291 printk("SELinux: too many conflicting type rules.");
295 for (cur
= other
; cur
!= NULL
; cur
= cur
->next
) {
296 if (cur
->node
== node_ptr
) {
302 printk("SELinux: conflicting type rules.\n");
307 if (avtab_search(&p
->te_cond_avtab
, k
)) {
308 printk("SELinux: conflicting type rules when adding type rule for true.\n");
314 node_ptr
= avtab_insert_nonunique(&p
->te_cond_avtab
, k
, d
);
316 printk("SELinux: could not insert rule.");
320 list
= kzalloc(sizeof(struct cond_av_list
), GFP_KERNEL
);
324 list
->node
= node_ptr
;
328 data
->tail
->next
= list
;
333 cond_av_list_destroy(data
->head
);
338 static int cond_read_av_list(struct policydb
*p
, void *fp
, struct cond_av_list
**ret_list
, struct cond_av_list
*other
)
343 struct cond_insertf_data data
;
348 rc
= next_entry(buf
, fp
, sizeof(u32
));
352 len
= le32_to_cpu(buf
[0]);
360 for (i
= 0; i
< len
; i
++) {
361 rc
= avtab_read_item(&p
->te_cond_avtab
, fp
, p
, cond_insertf
,
368 *ret_list
= data
.head
;
372 static int expr_isvalid(struct policydb
*p
, struct cond_expr
*expr
)
374 if (expr
->expr_type
<= 0 || expr
->expr_type
> COND_LAST
) {
375 printk("SELinux: conditional expressions uses unknown operator.\n");
379 if (expr
->bool > p
->p_bools
.nprim
) {
380 printk("SELinux: conditional expressions uses unknown bool.\n");
386 static int cond_read_node(struct policydb
*p
, struct cond_node
*node
, void *fp
)
391 struct cond_expr
*expr
= NULL
, *last
= NULL
;
393 rc
= next_entry(buf
, fp
, sizeof(u32
));
397 node
->cur_state
= le32_to_cpu(buf
[0]);
400 rc
= next_entry(buf
, fp
, sizeof(u32
));
405 len
= le32_to_cpu(buf
[0]);
407 for (i
= 0; i
< len
; i
++) {
408 rc
= next_entry(buf
, fp
, sizeof(u32
) * 2);
412 expr
= kzalloc(sizeof(struct cond_expr
), GFP_KERNEL
);
416 expr
->expr_type
= le32_to_cpu(buf
[0]);
417 expr
->bool = le32_to_cpu(buf
[1]);
419 if (!expr_isvalid(p
, expr
)) {
431 if (cond_read_av_list(p
, fp
, &node
->true_list
, NULL
) != 0)
433 if (cond_read_av_list(p
, fp
, &node
->false_list
, node
->true_list
) != 0)
437 cond_node_destroy(node
);
441 int cond_read_list(struct policydb
*p
, void *fp
)
443 struct cond_node
*node
, *last
= NULL
;
448 rc
= next_entry(buf
, fp
, sizeof buf
);
452 len
= le32_to_cpu(buf
[0]);
454 rc
= avtab_alloc(&(p
->te_cond_avtab
), p
->te_avtab
.nel
);
458 for (i
= 0; i
< len
; i
++) {
459 node
= kzalloc(sizeof(struct cond_node
), GFP_KERNEL
);
463 if (cond_read_node(p
, node
, fp
) != 0)
474 cond_list_destroy(p
->cond_list
);
479 /* Determine whether additional permissions are granted by the conditional
480 * av table, and if so, add them to the result
482 void cond_compute_av(struct avtab
*ctab
, struct avtab_key
*key
, struct av_decision
*avd
)
484 struct avtab_node
*node
;
486 if (!ctab
|| !key
|| !avd
)
489 for (node
= avtab_search_node(ctab
, key
); node
!= NULL
;
490 node
= avtab_search_node_next(node
, key
->specified
)) {
491 if ((u16
)(AVTAB_ALLOWED
|AVTAB_ENABLED
) ==
492 (node
->key
.specified
& (AVTAB_ALLOWED
|AVTAB_ENABLED
)))
493 avd
->allowed
|= node
->datum
.data
;
494 if ((u16
)(AVTAB_AUDITDENY
|AVTAB_ENABLED
) ==
495 (node
->key
.specified
& (AVTAB_AUDITDENY
|AVTAB_ENABLED
)))
496 /* Since a '0' in an auditdeny mask represents a
497 * permission we do NOT want to audit (dontaudit), we use
498 * the '&' operand to ensure that all '0's in the mask
499 * are retained (much unlike the allow and auditallow cases).
501 avd
->auditdeny
&= node
->datum
.data
;
502 if ((u16
)(AVTAB_AUDITALLOW
|AVTAB_ENABLED
) ==
503 (node
->key
.specified
& (AVTAB_AUDITALLOW
|AVTAB_ENABLED
)))
504 avd
->auditallow
|= node
->datum
.data
;