1 // SPDX-License-Identifier: GPL-2.0 2 #include "vmlinux.h" 3 #include <bpf/bpf_helpers.h> 4 #include <bpf/bpf_tracing.h> 5 #include <bpf/bpf_core_read.h> 6 #include "bpf_misc.h" 7 8 static struct sockaddr_in old; 9 10 static int handle_sys_connect_common(struct sockaddr_in *uservaddr) 11 { 12 struct sockaddr_in new; 13 14 bpf_probe_read_user(&old, sizeof(old), uservaddr); 15 __builtin_memset(&new, 0xab, sizeof(new)); 16 bpf_probe_write_user(uservaddr, &new, sizeof(new)); 17 18 return 0; 19 } 20 21 SEC("ksyscall/connect") 22 int BPF_KSYSCALL(handle_sys_connect, int fd, struct sockaddr_in *uservaddr, 23 int addrlen) 24 { 25 return handle_sys_connect_common(uservaddr); 26 } 27 28 #if defined(bpf_target_s390) 29 #ifndef SYS_CONNECT 30 #define SYS_CONNECT 3 31 #endif 32 33 SEC("ksyscall/socketcall") 34 int BPF_KSYSCALL(handle_sys_socketcall, int call, unsigned long *args) 35 { 36 if (call == SYS_CONNECT) { 37 struct sockaddr_in *uservaddr; 38 39 bpf_probe_read_user(&uservaddr, sizeof(uservaddr), &args[1]); 40 return handle_sys_connect_common(uservaddr); 41 } 42 43 return 0; 44 } 45 #endif 46 47 char _license[] SEC("license") = "GPL"; 48