OwlCyberSecurity - MANAGER

Edit File: tcpaccept-bpfcc

#! /usr/bin/python3 # @lint-avoid-python-3-compatibility-imports # # tcpaccept Trace TCP accept()s. # For Linux, uses BCC, eBPF. Embedded C. # # USAGE: tcpaccept [-h] [-T] [-t] [-p PID] [-P PORTS] [-4 | -6] # # This uses dynamic tracing of the kernel inet_csk_accept() socket function # (from tcp_prot.accept), and will need to be modified to match kernel changes. # # Copyright (c) 2015 Brendan Gregg. # Licensed under the Apache License, Version 2.0 (the "License") # # 13-Oct-2015 Brendan Gregg Created this. # 14-Feb-2016 " " Switch to bpf_perf_output. from __future__ import print_function from bcc.containers import filter_by_containers from bcc import BPF from socket import inet_ntop, AF_INET, AF_INET6 from struct import pack import argparse from bcc.utils import printb from time import strftime # arguments examples = """examples: ./tcpaccept # trace all TCP accept()s ./tcpaccept -t # include timestamps ./tcpaccept -P 80,81 # only trace port 80 and 81 ./tcpaccept -p 181 # only trace PID 181 ./tcpaccept --cgroupmap mappath # only trace cgroups in this BPF map ./tcpaccept --mntnsmap mappath # only trace mount namespaces in the map ./tcpaccept -4 # trace IPv4 family ./tcpaccept -6 # trace IPv6 family """ parser = argparse.ArgumentParser( description="Trace TCP accepts", formatter_class=argparse.RawDescriptionHelpFormatter, epilog=examples) parser.add_argument("-T", "--time", action="store_true", help="include time column on output (HH:MM:SS)") parser.add_argument("-t", "--timestamp", action="store_true", help="include timestamp on output") parser.add_argument("-p", "--pid", help="trace this PID only") parser.add_argument("-P", "--port", help="comma-separated list of local ports to trace") group = parser.add_mutually_exclusive_group() group.add_argument("-4", "--ipv4", action="store_true", help="trace IPv4 family only") group.add_argument("-6", "--ipv6", action="store_true", help="trace IPv6 family only") parser.add_argument("--cgroupmap", help="trace cgroups in this BPF map only") parser.add_argument("--mntnsmap", help="trace mount namespaces in this BPF map only") parser.add_argument("--ebpf", action="store_true", help=argparse.SUPPRESS) args = parser.parse_args() debug = 0 # define BPF program bpf_text = """ #include <uapi/linux/ptrace.h> #include <net/sock.h> #include <bcc/proto.h> // separate data structs for ipv4 and ipv6 struct ipv4_data_t { u64 ts_us; u32 pid; u32 saddr; u32 daddr; u64 ip; u16 lport; u16 dport; char task[TASK_COMM_LEN]; }; BPF_PERF_OUTPUT(ipv4_events); struct ipv6_data_t { u64 ts_us; u32 pid; unsigned __int128 saddr; unsigned __int128 daddr; u64 ip; u16 lport; u16 dport; char task[TASK_COMM_LEN]; }; BPF_PERF_OUTPUT(ipv6_events); """ # # The following code uses kprobes to instrument inet_csk_accept(). # On Linux 4.16 and later, we could use sock:inet_sock_set_state # tracepoint for efficiency, but it may output wrong PIDs. This is # because sock:inet_sock_set_state may run outside of process context. # Hence, we stick to kprobes until we find a proper solution. # bpf_text_kprobe = """ int kretprobe__inet_csk_accept(struct pt_regs *ctx) { if (container_should_be_filtered()) { return 0; } struct sock *newsk = (struct sock *)PT_REGS_RC(ctx); u32 pid = bpf_get_current_pid_tgid() >> 32; ##FILTER_PID## if (newsk == NULL) return 0; // check this is TCP u16 protocol = 0; // workaround for reading the sk_protocol bitfield: // Following comments add by Joe Yin: // Unfortunately,it can not work since Linux 4.10, // because the sk_wmem_queued is not following the bitfield of sk_protocol. // And the following member is sk_gso_max_segs. // So, we can use this: // bpf_probe_read_kernel(&protocol, 1, (void *)((u64)&newsk->sk_gso_max_segs) - 3); // In order to diff the pre-4.10 and 4.10+ ,introduce the variables gso_max_segs_offset,sk_lingertime, // sk_lingertime is closed to the gso_max_segs_offset,and // the offset between the two members is 4 int gso_max_segs_offset = offsetof(struct sock, sk_gso_max_segs); int sk_lingertime_offset = offsetof(struct sock, sk_lingertime); // Since kernel v5.6 sk_protocol is its own u16 field and gso_max_segs // precedes sk_lingertime. if (sk_lingertime_offset - gso_max_segs_offset == 2) protocol = newsk->sk_protocol; else if (sk_lingertime_offset - gso_max_segs_offset == 4) // 4.10+ with little endian #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ protocol = *(u8 *)((u64)&newsk->sk_gso_max_segs - 3); else // pre-4.10 with little endian protocol = *(u8 *)((u64)&newsk->sk_wmem_queued - 3); #elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__ // 4.10+ with big endian protocol = *(u8 *)((u64)&newsk->sk_gso_max_segs - 1); else // pre-4.10 with big endian protocol = *(u8 *)((u64)&newsk->sk_wmem_queued - 1); #else # error "Fix your compiler's __BYTE_ORDER__?!" #endif if (protocol != IPPROTO_TCP) return 0; // pull in details u16 family = 0, lport = 0, dport; family = newsk->__sk_common.skc_family; lport = newsk->__sk_common.skc_num; dport = newsk->__sk_common.skc_dport; dport = ntohs(dport); ##FILTER_FAMILY## ##FILTER_PORT## if (family == AF_INET) { struct ipv4_data_t data4 = {.pid = pid, .ip = 4}; data4.ts_us = bpf_ktime_get_ns() / 1000; data4.saddr = newsk->__sk_common.skc_rcv_saddr; data4.daddr = newsk->__sk_common.skc_daddr; data4.lport = lport; data4.dport = dport; bpf_get_current_comm(&data4.task, sizeof(data4.task)); ipv4_events.perf_submit(ctx, &data4, sizeof(data4)); } else if (family == AF_INET6) { struct ipv6_data_t data6 = {.pid = pid, .ip = 6}; data6.ts_us = bpf_ktime_get_ns() / 1000; bpf_probe_read_kernel(&data6.saddr, sizeof(data6.saddr), &newsk->__sk_common.skc_v6_rcv_saddr.in6_u.u6_addr32); bpf_probe_read_kernel(&data6.daddr, sizeof(data6.daddr), &newsk->__sk_common.skc_v6_daddr.in6_u.u6_addr32); data6.lport = lport; data6.dport = dport; bpf_get_current_comm(&data6.task, sizeof(data6.task)); ipv6_events.perf_submit(ctx, &data6, sizeof(data6)); } // else drop return 0; } """ bpf_text += bpf_text_kprobe # code substitutions if args.pid: bpf_text = bpf_text.replace('##FILTER_PID##', 'if (pid != %s) { return 0; }' % args.pid) else: bpf_text = bpf_text.replace('##FILTER_PID##', '') if args.port: lports = [int(lport) for lport in args.port.split(',')] lports_if = ' && '.join(['lport != %d' % lport for lport in lports]) bpf_text = bpf_text.replace('##FILTER_PORT##', 'if (%s) { return 0; }' % lports_if) if args.ipv4: bpf_text = bpf_text.replace('##FILTER_FAMILY##', 'if (family != AF_INET) { return 0; }') elif args.ipv6: bpf_text = bpf_text.replace('##FILTER_FAMILY##', 'if (family != AF_INET6) { return 0; }') bpf_text = filter_by_containers(args) + bpf_text if debug or args.ebpf: print(bpf_text) if args.ebpf: exit() bpf_text = bpf_text.replace('##FILTER_PORT##', '') bpf_text = bpf_text.replace('##FILTER_FAMILY##', '') # process event def print_ipv4_event(cpu, data, size): event = b["ipv4_events"].event(data) global start_ts if args.time: printb(b"%-9s" % strftime("%H:%M:%S").encode('ascii'), nl="") if args.timestamp: if start_ts == 0: start_ts = event.ts_us printb(b"%-9.3f" % ((float(event.ts_us) - start_ts) / 1000000), nl="") printb(b"%-7d %-12.12s %-2d %-16s %-5d %-16s %-5d" % (event.pid, event.task, event.ip, inet_ntop(AF_INET, pack("I", event.daddr)).encode(), event.dport, inet_ntop(AF_INET, pack("I", event.saddr)).encode(), event.lport)) def print_ipv6_event(cpu, data, size): event = b["ipv6_events"].event(data) global start_ts if args.time: printb(b"%-9s" % strftime("%H:%M:%S").encode('ascii'), nl="") if args.timestamp: if start_ts == 0: start_ts = event.ts_us printb(b"%-9.3f" % ((float(event.ts_us) - start_ts) / 1000000), nl="") printb(b"%-7d %-12.12s %-2d %-16s %-5d %-16s %-5d" % (event.pid, event.task, event.ip, inet_ntop(AF_INET6, event.daddr).encode(), event.dport, inet_ntop(AF_INET6, event.saddr).encode(), event.lport)) # initialize BPF b = BPF(text=bpf_text) # header if args.time: print("%-9s" % ("TIME"), end="") if args.timestamp: print("%-9s" % ("TIME(s)"), end="") print("%-7s %-12s %-2s %-16s %-5s %-16s %-5s" % ("PID", "COMM", "IP", "RADDR", "RPORT", "LADDR", "LPORT")) start_ts = 0 # read events b["ipv4_events"].open_perf_buffer(print_ipv4_event) b["ipv6_events"].open_perf_buffer(print_ipv6_event) while 1: try: b.perf_buffer_poll() except KeyboardInterrupt: exit()