cregit-Linux how code gets into the kernel

Release 4.16 samples/bpf/tracex5_kern.c

Directory: samples/bpf
/* Copyright (c) 2015 PLUMgrid, http://plumgrid.com
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of version 2 of the GNU General Public
 * License as published by the Free Software Foundation.
 */
#include <linux/ptrace.h>
#include <linux/version.h>
#include <uapi/linux/bpf.h>
#include <uapi/linux/seccomp.h>
#include <uapi/linux/unistd.h>
#include "syscall_nrs.h"
#include "bpf_helpers.h"


#define PROG(F) SEC("kprobe/"__stringify(F)) int bpf_func_##F

struct bpf_map_def SEC("maps") progs = {
	.type = BPF_MAP_TYPE_PROG_ARRAY,
	.key_size = sizeof(u32),
	.value_size = sizeof(u32),
#ifdef __mips__
	.max_entries = 6000, /* MIPS n64 syscalls start at 5000 */
#else
	.max_entries = 1024,
#endif
};

SEC("kprobe/__seccomp_filter")

int bpf_prog1(struct pt_regs *ctx) { int sc_nr = (int)PT_REGS_PARM1(ctx); /* dispatch into next BPF program depending on syscall number */ bpf_tail_call(ctx, &progs, sc_nr); /* fall through -> unknown syscall */ if (sc_nr >= __NR_getuid && sc_nr <= __NR_getsid) { char fmt[] = "syscall=%d (one of get/set uid/pid/gid)\n"; bpf_trace_printk(fmt, sizeof(fmt), sc_nr); } return 0; }

Contributors

PersonTokensPropCommitsCommitProp
Alexei Starovoitov5481.82%133.33%
Naveen N. Rao913.64%133.33%
Michael Holzheu34.55%133.33%
Total66100.00%3100.00%

/* we jump here when syscall number == __NR_write */
PROG(SYS__NR_write)(struct pt_regs *ctx) { struct seccomp_data sd; bpf_probe_read(&sd, sizeof(sd), (void *)PT_REGS_PARM2(ctx)); if (sd.args[2] == 512) { char fmt[] = "write(fd=%d, buf=%p, size=%d)\n"; bpf_trace_printk(fmt, sizeof(fmt), sd.args[0], sd.args[1], sd.args[2]); } return 0; }

Contributors

PersonTokensPropCommitsCommitProp
Alexei Starovoitov8595.51%125.00%
Michael Holzheu22.25%125.00%
David Daney11.12%125.00%
Naveen N. Rao11.12%125.00%
Total89100.00%4100.00%


PROG(SYS__NR_read)(struct pt_regs *ctx) { struct seccomp_data sd; bpf_probe_read(&sd, sizeof(sd), (void *)PT_REGS_PARM2(ctx)); if (sd.args[2] > 128 && sd.args[2] <= 1024) { char fmt[] = "read(fd=%d, buf=%p, size=%d)\n"; bpf_trace_printk(fmt, sizeof(fmt), sd.args[0], sd.args[1], sd.args[2]); } return 0; }

Contributors

PersonTokensPropCommitsCommitProp
Alexei Starovoitov9495.92%125.00%
Michael Holzheu22.04%125.00%
Naveen N. Rao11.02%125.00%
David Daney11.02%125.00%
Total98100.00%4100.00%


PROG(SYS__NR_mmap)(struct pt_regs *ctx) { char fmt[] = "mmap\n"; bpf_trace_printk(fmt, sizeof(fmt)); return 0; }

Contributors

PersonTokensPropCommitsCommitProp
Alexei Starovoitov3096.77%150.00%
David Daney13.23%150.00%
Total31100.00%2100.00%

char _license[] SEC("license") = "GPL"; u32 _version SEC("version") = LINUX_VERSION_CODE;

Overall Contributors

PersonTokensPropCommitsCommitProp
Alexei Starovoitov34488.89%120.00%
David Daney215.43%120.00%
Naveen N. Rao123.10%120.00%
Michael Holzheu71.81%120.00%
Mickaël Salaün30.78%120.00%
Total387100.00%5100.00%
Directory: samples/bpf
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