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fix(ebpf): handle x86 32-bit socketcall syscall
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The Linux kernel version determines x86 32-bit compatibility: older
versions use 'socketcall' syscall for socket functions (like socket,
bind, connect), while newer versions use individual syscalls directly.

These changes were also tested on an arm64 running an armhf binary.

Context: #3676
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@geyslan
geyslan committed Nov 23, 2023
1 parent 7d3d385 commit ebdd285
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Showing 2 changed files with 71 additions and 10 deletions.
2 changes: 2 additions & 0 deletions pkg/ebpf/c/common/arch.h
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Expand Up @@ -181,6 +181,8 @@ statfunc struct pt_regs *get_task_pt_regs(struct task_struct *task)
#define SYSCALL_LANDLOCK_RESTRICT_SELF 446
#define SYSCALL_PROCESS_MRELEASE 448

#define SYSCALL_SOCKETCALL 473 // x86 only

#elif defined(bpf_target_arm64)
#define SYSCALL_READ 63
#define SYSCALL_WRITE 64
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79 changes: 69 additions & 10 deletions pkg/ebpf/c/tracee.bpf.c
View file
Expand Up @@ -2455,10 +2455,22 @@ int BPF_KPROBE(trace_security_socket_listen)

// Load the arguments given to the listen syscall (which eventually invokes this function)
syscall_data_t *sys = &p.task_info->syscall_data;
if (!p.task_info->syscall_traced || sys->id != SYSCALL_LISTEN)
if (!p.task_info->syscall_traced)
return 0;

save_to_submit_buf(&p.event->args_buf, (void *) &sys->args.args[0], sizeof(u32), 0);
switch (sys->id) {
case SYSCALL_LISTEN:
save_to_submit_buf(&p.event->args_buf, (void *) &sys->args.args[0], sizeof(u32), 0);
break;
#if defined(bpf_target_x86) // armhf makes use of SYSCALL_LISTEN
case SYSCALL_SOCKETCALL:
save_to_submit_buf(&p.event->args_buf, (void *) sys->args.args[1], sizeof(u32), 0);
break;
#endif
default:
return 0;
}

save_sockaddr_to_buf(&p.event->args_buf, sock, 1);
save_to_submit_buf(&p.event->args_buf, (void *) &backlog, sizeof(int), 2);

Expand Down Expand Up @@ -2490,10 +2502,21 @@ int BPF_KPROBE(trace_security_socket_connect)

// Load the arguments given to the connect syscall (which eventually invokes this function)
syscall_data_t *sys = &p.task_info->syscall_data;
if (!p.task_info->syscall_traced || sys->id != SYSCALL_CONNECT)
if (!p.task_info->syscall_traced)
return 0;

save_to_submit_buf(&p.event->args_buf, (void *) &sys->args.args[0], sizeof(u32), 0);
switch (sys->id) {
case SYSCALL_CONNECT:
save_to_submit_buf(&p.event->args_buf, (void *) &sys->args.args[0], sizeof(u32), 0);
break;
#if defined(bpf_target_x86) // armhf makes use of SYSCALL_CONNECT
case SYSCALL_SOCKETCALL:
save_to_submit_buf(&p.event->args_buf, (void *) sys->args.args[1], sizeof(u32), 0);
break;
#endif
default:
return 0;
}

if (sa_fam == AF_INET) {
save_to_submit_buf(&p.event->args_buf, (void *) address, sizeof(struct sockaddr_in), 1);
Expand Down Expand Up @@ -2541,10 +2564,23 @@ int BPF_KPROBE(trace_security_socket_accept)
return 0;

// Load the arguments given to the accept syscall (which eventually invokes this function)
if (!p.task_info->syscall_traced || (sys->id != SYSCALL_ACCEPT && sys->id != SYSCALL_ACCEPT4))
if (!p.task_info->syscall_traced)
return 0;

save_to_submit_buf(&p.event->args_buf, (void *) &sys->args.args[0], sizeof(u32), 0);
switch (sys->id) {
case SYSCALL_ACCEPT:
case SYSCALL_ACCEPT4:
save_to_submit_buf(&p.event->args_buf, (void *) &sys->args.args[0], sizeof(u32), 0);
break;
#if defined(bpf_target_x86) // armhf makes use of SYSCALL_ACCEPT/4
case SYSCALL_SOCKETCALL:
save_to_submit_buf(&p.event->args_buf, (void *) sys->args.args[1], sizeof(u32), 0);
break;
#endif
default:
return 0;
}

save_sockaddr_to_buf(&p.event->args_buf, sock, 1);

return events_perf_submit(&p, SECURITY_SOCKET_ACCEPT, 0);
Expand Down Expand Up @@ -2578,10 +2614,21 @@ int BPF_KPROBE(trace_security_socket_bind)

// Load the arguments given to the bind syscall (which eventually invokes this function)
syscall_data_t *sys = &p.task_info->syscall_data;
if (!p.task_info->syscall_traced || sys->id != SYSCALL_BIND)
if (!p.task_info->syscall_traced)
return 0;

save_to_submit_buf(&p.event->args_buf, (void *) &sys->args.args[0], sizeof(u32), 0);
switch (sys->id) {
case SYSCALL_BIND:
save_to_submit_buf(&p.event->args_buf, (void *) &sys->args.args[0], sizeof(u32), 0);
break;
#if defined(bpf_target_x86) // armhf makes use of SYSCALL_BIND
case SYSCALL_SOCKETCALL:
save_to_submit_buf(&p.event->args_buf, (void *) sys->args.args[1], sizeof(u32), 0);
break;
#endif
default:
return 0;
}

u16 protocol = get_sock_protocol(sk);
net_id_t connect_id = {0};
Expand Down Expand Up @@ -2644,10 +2691,22 @@ int BPF_KPROBE(trace_security_socket_setsockopt)
return -1;
}

if (!p.task_info->syscall_traced || sys->id != SYSCALL_SETSOCKOPT)
if (!p.task_info->syscall_traced)
return 0;

save_to_submit_buf(&p.event->args_buf, (void *) &sys->args.args[0], sizeof(u32), 0);
switch (sys->id) {
case SYSCALL_SETSOCKOPT:
save_to_submit_buf(&p.event->args_buf, (void *) &sys->args.args[0], sizeof(u32), 0);
break;
#if defined(bpf_target_x86) // armhf makes use of SYSCALL_SETSOCKOPT
case SYSCALL_SOCKETCALL:
save_to_submit_buf(&p.event->args_buf, (void *) sys->args.args[1], sizeof(u32), 0);
break;
#endif
default:
return 0;
}

save_to_submit_buf(&p.event->args_buf, (void *) &level, sizeof(int), 1);
save_to_submit_buf(&p.event->args_buf, (void *) &optname, sizeof(int), 2);
save_sockaddr_to_buf(&p.event->args_buf, sock, 3);
Expand Down

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