/*
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* Class and permission mappings.
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*/
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#include <errno.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <stdarg.h>
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#include <stdbool.h>
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#include <selinux/selinux.h>
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#include <selinux/avc.h>
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#include "callbacks.h"
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#include "mapping.h"
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#include "selinux_internal.h"
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/*
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* Class and permission mappings
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*/
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struct selinux_mapping {
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security_class_t value; /* real, kernel value */
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unsigned num_perms;
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access_vector_t perms[sizeof(access_vector_t) * 8];
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};
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static struct selinux_mapping *current_mapping = NULL;
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static security_class_t current_mapping_size = 0;
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/*
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* Mapping setting function
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*/
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int
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selinux_set_mapping(struct security_class_mapping *map)
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{
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size_t size = sizeof(struct selinux_mapping);
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security_class_t i, j;
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unsigned k;
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bool print_unknown_handle = false;
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bool reject = (security_reject_unknown() == 1);
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bool deny = (security_deny_unknown() == 1);
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free(current_mapping);
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current_mapping = NULL;
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current_mapping_size = 0;
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if (avc_reset() < 0)
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goto err;
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/* Find number of classes in the input mapping */
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if (!map) {
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errno = EINVAL;
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goto err;
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}
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i = 0;
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while (map[i].name)
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i++;
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/* Allocate space for the class records, plus one for class zero */
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current_mapping = (struct selinux_mapping *)calloc(++i, size);
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if (!current_mapping)
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goto err;
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/* Store the raw class and permission values */
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j = 0;
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while (map[j].name) {
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struct security_class_mapping *p_in = map + (j++);
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struct selinux_mapping *p_out = current_mapping + j;
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p_out->value = string_to_security_class(p_in->name);
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if (!p_out->value) {
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selinux_log(SELINUX_INFO,
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"SELinux: Class %s not defined in policy.\n",
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p_in->name);
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if (reject)
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goto err2;
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p_out->num_perms = 0;
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print_unknown_handle = true;
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continue;
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}
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k = 0;
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while (p_in->perms[k]) {
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/* An empty permission string skips ahead */
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if (!*p_in->perms[k]) {
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k++;
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continue;
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}
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p_out->perms[k] = string_to_av_perm(p_out->value,
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p_in->perms[k]);
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if (!p_out->perms[k]) {
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selinux_log(SELINUX_INFO,
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"SELinux: Permission %s in class %s not defined in policy.\n",
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p_in->perms[k], p_in->name);
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if (reject)
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goto err2;
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print_unknown_handle = true;
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}
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k++;
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}
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p_out->num_perms = k;
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}
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if (print_unknown_handle)
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selinux_log(SELINUX_INFO,
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"SELinux: the above unknown classes and permissions will be %s\n",
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deny ? "denied" : "allowed");
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/* Set the mapping size here so the above lookups are "raw" */
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current_mapping_size = i;
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return 0;
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err2:
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free(current_mapping);
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current_mapping = NULL;
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current_mapping_size = 0;
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err:
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return -1;
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}
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/*
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* Get real, kernel values from mapped values
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*/
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security_class_t
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unmap_class(security_class_t tclass)
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{
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if (tclass < current_mapping_size)
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return current_mapping[tclass].value;
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/* If here no mapping set or the class requested is not valid. */
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if (current_mapping_size != 0) {
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errno = EINVAL;
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return 0;
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}
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else
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return tclass;
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}
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access_vector_t
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unmap_perm(security_class_t tclass, access_vector_t tperm)
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{
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if (tclass < current_mapping_size) {
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unsigned i;
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access_vector_t kperm = 0;
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for (i=0; i<current_mapping[tclass].num_perms; i++)
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if (tperm & (1<<i)) {
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kperm |= current_mapping[tclass].perms[i];
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tperm &= ~(1<<i);
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}
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return kperm;
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}
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/* If here no mapping set or the perm requested is not valid. */
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if (current_mapping_size != 0) {
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errno = EINVAL;
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return 0;
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}
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else
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return tperm;
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}
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/*
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* Get mapped values from real, kernel values
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*/
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security_class_t
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map_class(security_class_t kclass)
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{
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security_class_t i;
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for (i=0; i<current_mapping_size; i++)
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if (current_mapping[i].value == kclass)
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return i;
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/* If here no mapping set or the class requested is not valid. */
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if (current_mapping_size != 0) {
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errno = EINVAL;
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return 0;
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}
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else
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return kclass;
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}
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access_vector_t
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map_perm(security_class_t tclass, access_vector_t kperm)
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{
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if (tclass < current_mapping_size) {
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unsigned i;
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access_vector_t tperm = 0;
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for (i=0; i<current_mapping[tclass].num_perms; i++)
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if (kperm & current_mapping[tclass].perms[i]) {
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tperm |= 1<<i;
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kperm &= ~current_mapping[tclass].perms[i];
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}
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if (tperm == 0) {
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errno = EINVAL;
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return 0;
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}
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else
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return tperm;
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}
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return kperm;
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}
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void
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map_decision(security_class_t tclass, struct av_decision *avd)
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{
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if (tclass < current_mapping_size) {
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bool allow_unknown = (security_deny_unknown() == 0);
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struct selinux_mapping *mapping = ¤t_mapping[tclass];
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unsigned int i, n = mapping->num_perms;
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access_vector_t result;
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for (i = 0, result = 0; i < n; i++) {
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if (avd->allowed & mapping->perms[i])
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result |= 1<<i;
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else if (allow_unknown && !mapping->perms[i])
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result |= 1<<i;
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}
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avd->allowed = result;
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for (i = 0, result = 0; i < n; i++) {
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if (avd->decided & mapping->perms[i])
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result |= 1<<i;
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else if (allow_unknown && !mapping->perms[i])
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result |= 1<<i;
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}
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avd->decided = result;
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for (i = 0, result = 0; i < n; i++)
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if (avd->auditallow & mapping->perms[i])
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result |= 1<<i;
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avd->auditallow = result;
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for (i = 0, result = 0; i < n; i++) {
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if (avd->auditdeny & mapping->perms[i])
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result |= 1<<i;
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else if (!allow_unknown && !mapping->perms[i])
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result |= 1<<i;
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}
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/*
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* Make sure we audit denials for any permission check
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* beyond the mapping->num_perms since this indicates
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* a bug in the object manager.
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*/
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for (; i < (sizeof(result)*8); i++)
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result |= 1<<i;
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avd->auditdeny = result;
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}
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}
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