/*
* Copyright (C) 2012 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#define LOG_TAG "SELinuxJNI"
#include <utils/Log.h>
#include "JNIHelp.h"
#include "jni.h"
#include "core_jni_helpers.h"
#include "selinux/selinux.h"
#include "selinux/android.h"
#include <errno.h>
#include <ScopedLocalRef.h>
#include <ScopedUtfChars.h>
#include <UniquePtr.h>
namespace android {
struct SecurityContext_Delete {
void operator()(security_context_t p) const {
freecon(p);
}
};
typedef UniquePtr<char[], SecurityContext_Delete> Unique_SecurityContext;
static jboolean isSELinuxDisabled = true;
/*
* Function: isSELinuxEnabled
* Purpose: checks whether SELinux is enabled/disbaled
* Parameters: none
* Return value : true (enabled) or false (disabled)
* Exceptions: none
*/
static jboolean isSELinuxEnabled(JNIEnv *env, jobject) {
return !isSELinuxDisabled;
}
/*
* Function: isSELinuxEnforced
* Purpose: return the current SELinux enforce mode
* Parameters: none
* Return value: true (enforcing) or false (permissive)
* Exceptions: none
*/
static jboolean isSELinuxEnforced(JNIEnv *env, jobject) {
return (security_getenforce() == 1) ? true : false;
}
/*
* Function: getPeerCon
* Purpose: retrieves security context of peer socket
* Parameters:
* fileDescriptor: peer socket file as a FileDescriptor object
* Returns: jstring representing the security_context of socket or NULL if error
* Exceptions: NullPointerException if fileDescriptor object is NULL
*/
static jstring getPeerCon(JNIEnv *env, jobject, jobject fileDescriptor) {
if (isSELinuxDisabled) {
return NULL;
}
if (fileDescriptor == NULL) {
jniThrowNullPointerException(env,
"Trying to check security context of a null peer socket.");
return NULL;
}
int fd = jniGetFDFromFileDescriptor(env, fileDescriptor);
if (env->ExceptionCheck()) {
ALOGE("getPeerCon => getFD for %p failed", fileDescriptor);
return NULL;
}
security_context_t tmp = NULL;
int ret = getpeercon(fd, &tmp);
Unique_SecurityContext context(tmp);
ScopedLocalRef<jstring> contextStr(env, NULL);
if (ret != -1) {
contextStr.reset(env->NewStringUTF(context.get()));
}
ALOGV("getPeerCon(%d) => %s", fd, context.get());
return contextStr.release();
}
/*
* Function: setFSCreateCon
* Purpose: set security context used for creating a new file system object
* Parameters:
* context: security_context_t representing the new context of a file system object,
* set to NULL to return to the default policy behavior
* Returns: true on success, false on error
* Exception: none
*/
static jboolean setFSCreateCon(JNIEnv *env, jobject, jstring contextStr) {
if (isSELinuxDisabled) {
return false;
}
UniquePtr<ScopedUtfChars> context;
const char* context_c_str = NULL;
if (contextStr != NULL) {
context.reset(new ScopedUtfChars(env, contextStr));
context_c_str = context->c_str();
if (context_c_str == NULL) {
return false;
}
}
int ret = setfscreatecon(const_cast<char *>(context_c_str));
ALOGV("setFSCreateCon(%s) => %d", context_c_str, ret);
return (ret == 0) ? true : false;
}
/*
* Function: setFileCon
* Purpose: set the security context of a file object
* Parameters:
* path: the location of the file system object
* context: the new security context of the file system object
* Returns: true on success, false on error
* Exception: NullPointerException is thrown if either path or context strign are NULL
*/
static jboolean setFileCon(JNIEnv *env, jobject, jstring pathStr, jstring contextStr) {
if (isSELinuxDisabled) {
return false;
}
ScopedUtfChars path(env, pathStr);
if (path.c_str() == NULL) {
return false;
}
ScopedUtfChars context(env, contextStr);
if (context.c_str() == NULL) {
return false;
}
// GetStringUTFChars returns const char * yet setfilecon needs char *
char *tmp = const_cast<char *>(context.c_str());
int ret = setfilecon(path.c_str(), tmp);
ALOGV("setFileCon(%s, %s) => %d", path.c_str(), context.c_str(), ret);
return (ret == 0) ? true : false;
}
/*
* Function: getFileCon
* Purpose: retrieves the context associated with the given path in the file system
* Parameters:
* path: given path in the file system
* Returns:
* string representing the security context string of the file object
* the string may be NULL if an error occured
* Exceptions: NullPointerException if the path object is null
*/
static jstring getFileCon(JNIEnv *env, jobject, jstring pathStr) {
if (isSELinuxDisabled) {
return NULL;
}
ScopedUtfChars path(env, pathStr);
if (path.c_str() == NULL) {
return NULL;
}
security_context_t tmp = NULL;
int ret = getfilecon(path.c_str(), &tmp);
Unique_SecurityContext context(tmp);
ScopedLocalRef<jstring> securityString(env, NULL);
if (ret != -1) {
securityString.reset(env->NewStringUTF(context.get()));
}
ALOGV("getFileCon(%s) => %s", path.c_str(), context.get());
return securityString.release();
}
/*
* Function: getCon
* Purpose: Get the context of the current process.
* Parameters: none
* Returns: a jstring representing the security context of the process,
* the jstring may be NULL if there was an error
* Exceptions: none
*/
static jstring getCon(JNIEnv *env, jobject) {
if (isSELinuxDisabled) {
return NULL;
}
security_context_t tmp = NULL;
int ret = getcon(&tmp);
Unique_SecurityContext context(tmp);
ScopedLocalRef<jstring> securityString(env, NULL);
if (ret != -1) {
securityString.reset(env->NewStringUTF(context.get()));
}
ALOGV("getCon() => %s", context.get());
return securityString.release();
}
/*
* Function: getPidCon
* Purpose: Get the context of a process identified by its pid
* Parameters:
* pid: a jint representing the process
* Returns: a jstring representing the security context of the pid,
* the jstring may be NULL if there was an error
* Exceptions: none
*/
static jstring getPidCon(JNIEnv *env, jobject, jint pid) {
if (isSELinuxDisabled) {
return NULL;
}
security_context_t tmp = NULL;
int ret = getpidcon(static_cast<pid_t>(pid), &tmp);
Unique_SecurityContext context(tmp);
ScopedLocalRef<jstring> securityString(env, NULL);
if (ret != -1) {
securityString.reset(env->NewStringUTF(context.get()));
}
ALOGV("getPidCon(%d) => %s", pid, context.get());
return securityString.release();
}
/*
* Function: checkSELinuxAccess
* Purpose: Check permissions between two security contexts.
* Parameters: subjectContextStr: subject security context as a string
* objectContextStr: object security context as a string
* objectClassStr: object's security class name as a string
* permissionStr: permission name as a string
* Returns: boolean: (true) if permission was granted, (false) otherwise
* Exceptions: None
*/
static jboolean checkSELinuxAccess(JNIEnv *env, jobject, jstring subjectContextStr,
jstring objectContextStr, jstring objectClassStr, jstring permissionStr) {
if (isSELinuxDisabled) {
return true;
}
ScopedUtfChars subjectContext(env, subjectContextStr);
if (subjectContext.c_str() == NULL) {
return false;
}
ScopedUtfChars objectContext(env, objectContextStr);
if (objectContext.c_str() == NULL) {
return false;
}
ScopedUtfChars objectClass(env, objectClassStr);
if (objectClass.c_str() == NULL) {
return false;
}
ScopedUtfChars permission(env, permissionStr);
if (permission.c_str() == NULL) {
return false;
}
char *tmp1 = const_cast<char *>(subjectContext.c_str());
char *tmp2 = const_cast<char *>(objectContext.c_str());
int accessGranted = selinux_check_access(tmp1, tmp2, objectClass.c_str(), permission.c_str(),
NULL);
ALOGV("checkSELinuxAccess(%s, %s, %s, %s) => %d", subjectContext.c_str(), objectContext.c_str(),
objectClass.c_str(), permission.c_str(), accessGranted);
return (accessGranted == 0) ? true : false;
}
/*
* Function: native_restorecon
* Purpose: restore default SELinux security context
* Parameters: pathname: the pathname for the file to be relabeled
* Returns: boolean: (true) file label successfully restored, (false) otherwise
* Exceptions: none
*/
static jboolean native_restorecon(JNIEnv *env, jobject, jstring pathnameStr, jint flags) {
if (isSELinuxDisabled) {
return true;
}
ScopedUtfChars pathname(env, pathnameStr);
if (pathname.c_str() == NULL) {
ALOGV("restorecon(%p) => threw exception", pathnameStr);
return false;
}
int ret = selinux_android_restorecon(pathname.c_str(), flags);
ALOGV("restorecon(%s) => %d", pathname.c_str(), ret);
return (ret == 0);
}
/*
* JNI registration.
*/
static const JNINativeMethod method_table[] = {
/* name, signature, funcPtr */
{ "checkSELinuxAccess" , "(Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;)Z" , (void*)checkSELinuxAccess },
{ "getContext" , "()Ljava/lang/String;" , (void*)getCon },
{ "getFileContext" , "(Ljava/lang/String;)Ljava/lang/String;" , (void*)getFileCon },
{ "getPeerContext" , "(Ljava/io/FileDescriptor;)Ljava/lang/String;" , (void*)getPeerCon },
{ "getPidContext" , "(I)Ljava/lang/String;" , (void*)getPidCon },
{ "isSELinuxEnforced" , "()Z" , (void*)isSELinuxEnforced},
{ "isSELinuxEnabled" , "()Z" , (void*)isSELinuxEnabled },
{ "native_restorecon" , "(Ljava/lang/String;I)Z" , (void*)native_restorecon},
{ "setFileContext" , "(Ljava/lang/String;Ljava/lang/String;)Z" , (void*)setFileCon },
{ "setFSCreateContext" , "(Ljava/lang/String;)Z" , (void*)setFSCreateCon },
};
static int log_callback(int type, const char *fmt, ...) {
va_list ap;
int priority;
switch (type) {
case SELINUX_WARNING:
priority = ANDROID_LOG_WARN;
break;
case SELINUX_INFO:
priority = ANDROID_LOG_INFO;
break;
default:
priority = ANDROID_LOG_ERROR;
break;
}
va_start(ap, fmt);
LOG_PRI_VA(priority, "SELinux", fmt, ap);
va_end(ap);
return 0;
}
int register_android_os_SELinux(JNIEnv *env) {
union selinux_callback cb;
cb.func_log = log_callback;
selinux_set_callback(SELINUX_CB_LOG, cb);
isSELinuxDisabled = (is_selinux_enabled() != 1) ? true : false;
return RegisterMethodsOrDie(env, "android/os/SELinux", method_table, NELEM(method_table));
}
}