diff options
author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /security/selinux/ss/conditional.c |
Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'security/selinux/ss/conditional.c')
-rw-r--r-- | security/selinux/ss/conditional.c | 489 |
1 files changed, 489 insertions, 0 deletions
diff --git a/security/selinux/ss/conditional.c b/security/selinux/ss/conditional.c new file mode 100644 index 000000000000..b53441184aca --- /dev/null +++ b/security/selinux/ss/conditional.c @@ -0,0 +1,489 @@ +/* Authors: Karl MacMillan <kmacmillan@tresys.com> + * Frank Mayer <mayerf@tresys.com> + * + * Copyright (C) 2003 - 2004 Tresys Technology, LLC + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, version 2. + */ + +#include <linux/kernel.h> +#include <linux/errno.h> +#include <linux/string.h> +#include <linux/spinlock.h> +#include <asm/semaphore.h> +#include <linux/slab.h> + +#include "security.h" +#include "conditional.h" + +/* + * cond_evaluate_expr evaluates a conditional expr + * in reverse polish notation. It returns true (1), false (0), + * or undefined (-1). Undefined occurs when the expression + * exceeds the stack depth of COND_EXPR_MAXDEPTH. + */ +static int cond_evaluate_expr(struct policydb *p, struct cond_expr *expr) +{ + + struct cond_expr *cur; + int s[COND_EXPR_MAXDEPTH]; + int sp = -1; + + for (cur = expr; cur != NULL; cur = cur->next) { + switch (cur->expr_type) { + case COND_BOOL: + if (sp == (COND_EXPR_MAXDEPTH - 1)) + return -1; + sp++; + s[sp] = p->bool_val_to_struct[cur->bool - 1]->state; + break; + case COND_NOT: + if (sp < 0) + return -1; + s[sp] = !s[sp]; + break; + case COND_OR: + if (sp < 1) + return -1; + sp--; + s[sp] |= s[sp + 1]; + break; + case COND_AND: + if (sp < 1) + return -1; + sp--; + s[sp] &= s[sp + 1]; + break; + case COND_XOR: + if (sp < 1) + return -1; + sp--; + s[sp] ^= s[sp + 1]; + break; + case COND_EQ: + if (sp < 1) + return -1; + sp--; + s[sp] = (s[sp] == s[sp + 1]); + break; + case COND_NEQ: + if (sp < 1) + return -1; + sp--; + s[sp] = (s[sp] != s[sp + 1]); + break; + default: + return -1; + } + } + return s[0]; +} + +/* + * evaluate_cond_node evaluates the conditional stored in + * a struct cond_node and if the result is different than the + * current state of the node it sets the rules in the true/false + * list appropriately. If the result of the expression is undefined + * all of the rules are disabled for safety. + */ +int evaluate_cond_node(struct policydb *p, struct cond_node *node) +{ + int new_state; + struct cond_av_list* cur; + + new_state = cond_evaluate_expr(p, node->expr); + if (new_state != node->cur_state) { + node->cur_state = new_state; + if (new_state == -1) + printk(KERN_ERR "security: expression result was undefined - disabling all rules.\n"); + /* turn the rules on or off */ + for (cur = node->true_list; cur != NULL; cur = cur->next) { + if (new_state <= 0) { + cur->node->datum.specified &= ~AVTAB_ENABLED; + } else { + cur->node->datum.specified |= AVTAB_ENABLED; + } + } + + for (cur = node->false_list; cur != NULL; cur = cur->next) { + /* -1 or 1 */ + if (new_state) { + cur->node->datum.specified &= ~AVTAB_ENABLED; + } else { + cur->node->datum.specified |= AVTAB_ENABLED; + } + } + } + return 0; +} + +int cond_policydb_init(struct policydb *p) +{ + p->bool_val_to_struct = NULL; + p->cond_list = NULL; + if (avtab_init(&p->te_cond_avtab)) + return -1; + + return 0; +} + +static void cond_av_list_destroy(struct cond_av_list *list) +{ + struct cond_av_list *cur, *next; + for (cur = list; cur != NULL; cur = next) { + next = cur->next; + /* the avtab_ptr_t node is destroy by the avtab */ + kfree(cur); + } +} + +static void cond_node_destroy(struct cond_node *node) +{ + struct cond_expr *cur_expr, *next_expr; + + for (cur_expr = node->expr; cur_expr != NULL; cur_expr = next_expr) { + next_expr = cur_expr->next; + kfree(cur_expr); + } + cond_av_list_destroy(node->true_list); + cond_av_list_destroy(node->false_list); + kfree(node); +} + +static void cond_list_destroy(struct cond_node *list) +{ + struct cond_node *next, *cur; + + if (list == NULL) + return; + + for (cur = list; cur != NULL; cur = next) { + next = cur->next; + cond_node_destroy(cur); + } +} + +void cond_policydb_destroy(struct policydb *p) +{ + if (p->bool_val_to_struct != NULL) + kfree(p->bool_val_to_struct); + avtab_destroy(&p->te_cond_avtab); + cond_list_destroy(p->cond_list); +} + +int cond_init_bool_indexes(struct policydb *p) +{ + if (p->bool_val_to_struct) + kfree(p->bool_val_to_struct); + p->bool_val_to_struct = (struct cond_bool_datum**) + kmalloc(p->p_bools.nprim * sizeof(struct cond_bool_datum*), GFP_KERNEL); + if (!p->bool_val_to_struct) + return -1; + return 0; +} + +int cond_destroy_bool(void *key, void *datum, void *p) +{ + if (key) + kfree(key); + kfree(datum); + return 0; +} + +int cond_index_bool(void *key, void *datum, void *datap) +{ + struct policydb *p; + struct cond_bool_datum *booldatum; + + booldatum = datum; + p = datap; + + if (!booldatum->value || booldatum->value > p->p_bools.nprim) + return -EINVAL; + + p->p_bool_val_to_name[booldatum->value - 1] = key; + p->bool_val_to_struct[booldatum->value -1] = booldatum; + + return 0; +} + +static int bool_isvalid(struct cond_bool_datum *b) +{ + if (!(b->state == 0 || b->state == 1)) + return 0; + return 1; +} + +int cond_read_bool(struct policydb *p, struct hashtab *h, void *fp) +{ + char *key = NULL; + struct cond_bool_datum *booldatum; + u32 buf[3], len; + int rc; + + booldatum = kmalloc(sizeof(struct cond_bool_datum), GFP_KERNEL); + if (!booldatum) + return -1; + memset(booldatum, 0, sizeof(struct cond_bool_datum)); + + rc = next_entry(buf, fp, sizeof buf); + if (rc < 0) + goto err; + + booldatum->value = le32_to_cpu(buf[0]); + booldatum->state = le32_to_cpu(buf[1]); + + if (!bool_isvalid(booldatum)) + goto err; + + len = le32_to_cpu(buf[2]); + + key = kmalloc(len + 1, GFP_KERNEL); + if (!key) + goto err; + rc = next_entry(key, fp, len); + if (rc < 0) + goto err; + key[len] = 0; + if (hashtab_insert(h, key, booldatum)) + goto err; + + return 0; +err: + cond_destroy_bool(key, booldatum, NULL); + return -1; +} + +static int cond_read_av_list(struct policydb *p, void *fp, struct cond_av_list **ret_list, + struct cond_av_list *other) +{ + struct cond_av_list *list, *last = NULL, *cur; + struct avtab_key key; + struct avtab_datum datum; + struct avtab_node *node_ptr; + int rc; + u32 buf[1], i, len; + u8 found; + + *ret_list = NULL; + + len = 0; + rc = next_entry(buf, fp, sizeof buf); + if (rc < 0) + return -1; + + len = le32_to_cpu(buf[0]); + if (len == 0) { + return 0; + } + + for (i = 0; i < len; i++) { + if (avtab_read_item(fp, &datum, &key)) + goto err; + + /* + * For type rules we have to make certain there aren't any + * conflicting rules by searching the te_avtab and the + * cond_te_avtab. + */ + if (datum.specified & AVTAB_TYPE) { + if (avtab_search(&p->te_avtab, &key, AVTAB_TYPE)) { + printk("security: type rule already exists outside of a conditional."); + goto err; + } + /* + * If we are reading the false list other will be a pointer to + * the true list. We can have duplicate entries if there is only + * 1 other entry and it is in our true list. + * + * If we are reading the true list (other == NULL) there shouldn't + * be any other entries. + */ + if (other) { + node_ptr = avtab_search_node(&p->te_cond_avtab, &key, AVTAB_TYPE); + if (node_ptr) { + if (avtab_search_node_next(node_ptr, AVTAB_TYPE)) { + printk("security: too many conflicting type rules."); + goto err; + } + found = 0; + for (cur = other; cur != NULL; cur = cur->next) { + if (cur->node == node_ptr) { + found = 1; + break; + } + } + if (!found) { + printk("security: conflicting type rules."); + goto err; + } + } + } else { + if (avtab_search(&p->te_cond_avtab, &key, AVTAB_TYPE)) { + printk("security: conflicting type rules when adding type rule for true."); + goto err; + } + } + } + node_ptr = avtab_insert_nonunique(&p->te_cond_avtab, &key, &datum); + if (!node_ptr) { + printk("security: could not insert rule."); + goto err; + } + + list = kmalloc(sizeof(struct cond_av_list), GFP_KERNEL); + if (!list) + goto err; + memset(list, 0, sizeof(struct cond_av_list)); + + list->node = node_ptr; + if (i == 0) + *ret_list = list; + else + last->next = list; + last = list; + + } + + return 0; +err: + cond_av_list_destroy(*ret_list); + *ret_list = NULL; + return -1; +} + +static int expr_isvalid(struct policydb *p, struct cond_expr *expr) +{ + if (expr->expr_type <= 0 || expr->expr_type > COND_LAST) { + printk("security: conditional expressions uses unknown operator.\n"); + return 0; + } + + if (expr->bool > p->p_bools.nprim) { + printk("security: conditional expressions uses unknown bool.\n"); + return 0; + } + return 1; +} + +static int cond_read_node(struct policydb *p, struct cond_node *node, void *fp) +{ + u32 buf[2], len, i; + int rc; + struct cond_expr *expr = NULL, *last = NULL; + + rc = next_entry(buf, fp, sizeof(u32)); + if (rc < 0) + return -1; + + node->cur_state = le32_to_cpu(buf[0]); + + len = 0; + rc = next_entry(buf, fp, sizeof(u32)); + if (rc < 0) + return -1; + + /* expr */ + len = le32_to_cpu(buf[0]); + + for (i = 0; i < len; i++ ) { + rc = next_entry(buf, fp, sizeof(u32) * 2); + if (rc < 0) + goto err; + + expr = kmalloc(sizeof(struct cond_expr), GFP_KERNEL); + if (!expr) { + goto err; + } + memset(expr, 0, sizeof(struct cond_expr)); + + expr->expr_type = le32_to_cpu(buf[0]); + expr->bool = le32_to_cpu(buf[1]); + + if (!expr_isvalid(p, expr)) { + kfree(expr); + goto err; + } + + if (i == 0) { + node->expr = expr; + } else { + last->next = expr; + } + last = expr; + } + + if (cond_read_av_list(p, fp, &node->true_list, NULL) != 0) + goto err; + if (cond_read_av_list(p, fp, &node->false_list, node->true_list) != 0) + goto err; + return 0; +err: + cond_node_destroy(node); + return -1; +} + +int cond_read_list(struct policydb *p, void *fp) +{ + struct cond_node *node, *last = NULL; + u32 buf[1], i, len; + int rc; + + rc = next_entry(buf, fp, sizeof buf); + if (rc < 0) + return -1; + + len = le32_to_cpu(buf[0]); + + for (i = 0; i < len; i++) { + node = kmalloc(sizeof(struct cond_node), GFP_KERNEL); + if (!node) + goto err; + memset(node, 0, sizeof(struct cond_node)); + + if (cond_read_node(p, node, fp) != 0) + goto err; + + if (i == 0) { + p->cond_list = node; + } else { + last->next = node; + } + last = node; + } + return 0; +err: + cond_list_destroy(p->cond_list); + return -1; +} + +/* Determine whether additional permissions are granted by the conditional + * av table, and if so, add them to the result + */ +void cond_compute_av(struct avtab *ctab, struct avtab_key *key, struct av_decision *avd) +{ + struct avtab_node *node; + + if(!ctab || !key || !avd) + return; + + for(node = avtab_search_node(ctab, key, AVTAB_AV); node != NULL; + node = avtab_search_node_next(node, AVTAB_AV)) { + if ( (__u32) (AVTAB_ALLOWED|AVTAB_ENABLED) == + (node->datum.specified & (AVTAB_ALLOWED|AVTAB_ENABLED))) + avd->allowed |= avtab_allowed(&node->datum); + if ( (__u32) (AVTAB_AUDITDENY|AVTAB_ENABLED) == + (node->datum.specified & (AVTAB_AUDITDENY|AVTAB_ENABLED))) + /* Since a '0' in an auditdeny mask represents a + * permission we do NOT want to audit (dontaudit), we use + * the '&' operand to ensure that all '0's in the mask + * are retained (much unlike the allow and auditallow cases). + */ + avd->auditdeny &= avtab_auditdeny(&node->datum); + if ( (__u32) (AVTAB_AUDITALLOW|AVTAB_ENABLED) == + (node->datum.specified & (AVTAB_AUDITALLOW|AVTAB_ENABLED))) + avd->auditallow |= avtab_auditallow(&node->datum); + } + return; +} |