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#include<linux/fs.h>
#include<linux/slab.h>
#include<linux/sched.h>
#include<linux/sort.h>
#include<asm/msr.h>
#include<asm/unistd.h>
#include<asm/uaccess.h>
#include"judge_def.h"
#include"judgk.h"
#include"judgk_com.h"
#include"judgk_syscall.h"
int judgk_syscall_hook(){
int i;
int j;
unsigned int size;
unsigned int restore;
syscall_init_hook();
syscall_addr_write((unsigned long)syscall_table,&size,&restore);
for(i = 0,j = 0;i < syscall_max;i++){
if(size == 0){
syscall_addr_restore((unsigned long)(syscall_table + i - 1),restore);
syscall_addr_write((unsigned long)(syscall_table + i),&size,&restore);
}
size -= sizeof(unsigned long);
if(i == syscall_whitelist[j]){
j++;
continue;
}
syscall_table[i] = (unsigned long)hook_sys_block;
}
syscall_addr_restore((unsigned long)(&syscall_table[i - 1]),restore);
return 0;
}
int judgk_syscall_unhook(){
int i;
unsigned int size;
unsigned int restore;
syscall_addr_write((unsigned long)syscall_table,&size,&restore);
for(i = 0;i < syscall_max;i++){
if(size == 0){
syscall_addr_restore((unsigned long)(&syscall_table[i - 1]),restore);
syscall_addr_write((unsigned long)(&syscall_table[i]),&size,&restore);
}
size -= sizeof(unsigned long);
syscall_table[i] = (unsigned long)judgk_syscall_ori_table[i];
}
syscall_addr_restore((unsigned long)(&syscall_table[i - 1]),restore);
kfree(judgk_syscall_ori_table);
return 0;
}
static int syscall_init_hook(){
ssize_t ret;
int i;
int j;
struct file *f;
char line[128];
unsigned char code[3] = {0xff,0x14,0xc5};
unsigned long addr;
f = filp_open("/proc/kallsyms",O_RDONLY,0);
set_fs(KERNEL_DS);
i = 0;
addr = 0;
while(true){
ret = f->f_op->read(f,&line[i],1,&f->f_pos);
if(line[i] == '\n' || ret <= 0){
line[i] = '\0';
addr = 0;
for(j = 0;j < i;j++){
if(line[j] == ' '){
j++;
break;
}
addr *= 16UL;
if(line[j] >= '0' && line[j] <= '9'){
addr += (unsigned long)(line[j] - '0');
}else{
addr += (unsigned long)(line[j] - 'a' + 10);
}
}
for(;j < i;j++){
if(line[j] == ' '){
j++;
break;
}
}
if(j < i){
if(strcmp("system_call",line + j) == 0){
break;
}
}
i = 0;
}else{
i++;
}
if(ret <= 0){
break;
}
}
set_fs(USER_DS);
filp_close(f,NULL);
while(true){
for(i = 0;i < 3;i++){
if(*(unsigned char*)addr != code[i]){
addr++;
break;
}
addr++;
}
if(i == 3){
break;
}
}
syscall_table = (unsigned long*)(0xffffffff00000000 + *((unsigned int*)addr));
addr -= 4L;
while(true){
if(*(unsigned char*)addr == 0x3d){
addr++;
break;
}
addr--;
}
syscall_max = *(unsigned int*)addr;
judgk_syscall_ori_table = kmalloc(sizeof(unsigned long) * (syscall_max + 1),GFP_KERNEL);
memcpy(judgk_syscall_ori_table,syscall_table,sizeof(unsigned long) * syscall_max);
sort(syscall_whitelist,SYSCALL_WHITELIST_SIZE,sizeof(unsigned int),syscall_whitelist_cmp,NULL);
return 0;
}
static int syscall_whitelist_cmp(const void *a,const void *b){
if(*(unsigned int*)a < *(unsigned int*)b){
return -1;
}else if(*(unsigned int*)a == *(unsigned int*)b){
return 0;
}else{
return 1;
}
}
static int syscall_addr_write(unsigned long addr,unsigned int *size,int *restore){
unsigned int level;
pte_t *pte;
pte = lookup_address(addr,&level);
if(pte->pte & _PAGE_RW){
*restore = 0;
}else{
pte->pte |= _PAGE_RW;
*restore = 1;
}
switch(level){
case PG_LEVEL_4K:
*size = 4096;
break;
case PG_LEVEL_2M:
*size = 2097152;
break;
case PG_LEVEL_1G:
*size = 1073741824;
break;
}
*size -= (((unsigned int)addr) & (*size - 1));
return 0;
}
static int syscall_addr_restore(unsigned long addr,int restore){
unsigned int level;
pte_t *pte;
if(restore){
pte = lookup_address(addr,&level);
pte->pte ^= _PAGE_RW;
}
return 0;
}
int judgk_syscall_check(){
if(judgk_proc_task_lookup(current)){
return 1;
}
return 0;
}
int judgk_syscall_block(){
struct judgk_proc_info *info;
if((info = judgk_proc_task_lookup(current)) == NULL){
return 0;
}
info->status = JUDGE_RF;
send_sig(SIGKILL,current,0);
return 0;
}
/*asmlinkage long hook_sys_nanosleep(struct timespec __user *rqtp,struct timespec __user *rmtp){
long ret;
struct judgm_proc_info *info;
atomic64_inc(&syscall_pending);
info = judgm_proc_task_lookup(current);
if(info == NULL){
ret = ori_sys_nanosleep(rqtp,rmtp);
atomic64_dec(&syscall_pending);
return ret;
}
pr_alert("judgm:PID %d nanosleep\n",current->tgid);
info->status = JUDGE_RF;
send_sig(SIGKILL,current,0);
atomic64_dec(&syscall_pending);
return -EACCES;
}*/
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