#include "com_example_jni02_CallSo.h"
#include <jni.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <elf.h>
#include <sys/mman.h>
#include <Android/log.h>
//这里对 Java_com_example_jni02_CallSo_plus这个方法进行加密保护
jint JNICALL Java_com_example_jni02_CallSo_plus(JNIEnv* env, jobject obj, jint a, jint b) __attribute__((section (".mytext")));
JNIEXPORT jstring JNICALL Java_com_example_jni02_CallSo_getString
(JNIEnv* env, jobject obj){
return (*env)->NewStringUTF(env,"Hello");
}
JNIEXPORT jint JNICALL Java_com_example_jni02_CallSo_plus
(JNIEnv* env, jobject obj, jint a, jint b){
return a+b;
}
//在调用so文件进行解密
void init_Java_com_example_jni02_CallSo_plus() __attribute__((constructor));
unsigned long getLibAddr();
void init_Java_com_example_jni02_CallSo_plus(){
char name[15];
unsigned int nblock;
unsigned int nsize;
unsigned long base;
unsigned long text_addr;
unsigned int i;
Elf32_Ehdr *ehdr;
Elf32_Shdr *shdr;
base=getLibAddr();
ehdr=(Elf32_Ehdr *)base;
text_addr=ehdr->e_shoff+base;
nblock=ehdr->e_entry >>16;
nsize=ehdr->e_entry&0xffff;
__android_log_print(ANDROID_LOG_INFO, "JNITag", "nblock = 0x%d,nsize:%d", nblock,nsize);
__android_log_print(ANDROID_LOG_INFO, "JNITag", "base = 0x%x", text_addr);
printf("nblock = %d\n", nblock);
//修改内存权限
if(mprotect((void *) (text_addr / PAGE_SIZE * PAGE_SIZE), 4096 * nsize, PROT_READ | PROT_EXEC | PROT_WRITE) != 0){
puts("mem privilege change failed");
__android_log_print(ANDROID_LOG_INFO, "JNITag", "mem privilege change failed");
}
//进行解密,是针对加密算法的
for(i=0;i<nblock;i++){
char *addr=(char*)(text_addr+i);
*addr=~(*addr);
}
if(mprotect((void *) (text_addr / PAGE_SIZE * PAGE_SIZE), 4096 * nsize, PROT_READ | PROT_EXEC) != 0){
puts("mem privilege change failed");
}
puts("Decrypt success");
}
//获取到SO文件加载到内存中的起始地址,只有找到起始地址才能够进行解密;
unsigned long getLibAddr(){
unsigned long ret=0;
char name[]="libaddcomputer.so";
char buf[4096];
char *temp;
int pid;
FILE *fp;
pid=getpid();
sprintf(buf,"/proc/%d/maps",pid);
fp=fopen(buf,"r");
if(fp==NULL){
puts("open failed");
goto _error;
}
while (fgets(buf,sizeof(buf),fp)){
if(strstr(buf,name)){
temp = strtok(buf, "-");
ret = strtoul(temp, NULL, 16);
break;
}
}
_error:
fclose(fp);
return ret;
}
private static void encodeSection(byte[] fileByteArys){
//读取String Section段
System.out.println();
int string_section_index = Utils.byte2Short(type_32.hdr.e_shstrndx);
elf32_shdr shdr = type_32.shdrList.get(string_section_index);
int size = Utils.byte2Int(shdr.sh_size);
int offset = Utils.byte2Int(shdr.sh_offset);
int mySectionOffset=0,mySectionSize=0;
for(elf32_shdr temp : type_32.shdrList){
int sectionNameOffset = offset+Utils.byte2Int(temp.sh_name);
if(Utils.isEqualByteAry(fileByteArys, sectionNameOffset, encodeSectionName)){
//这里需要读取section段然后进行数据加密
mySectionOffset = Utils.byte2Int(temp.sh_offset);
mySectionSize = Utils.byte2Int(temp.sh_size);
byte[] sectionAry = Utils.copyBytes(fileByteArys, mySectionOffset, mySectionSize);
for(int i=0;i<sectionAry.length;i++){
//sectionAry[i] = (byte)(sectionAry[i] ^ 0xFF);
sectionAry[i]=(byte) ~sectionAry[i];
}
Utils.replaceByteAry(fileByteArys, mySectionOffset, sectionAry);
}
}
//修改Elf Header中的entry和offset值
int nSize = mySectionSize/4096 + (mySectionSize%4096 == 0 ? 0 : 1);
byte[] entry = new byte[4];
entry = Utils.int2Byte((mySectionSize<<16) + nSize);
Utils.replaceByteAry(fileByteArys, 24, entry);
byte[] offsetAry = new byte[4];
offsetAry = Utils.int2Byte(mySectionOffset);
Utils.replaceByteAry(fileByteArys, 32, offsetAry);
}