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93 lines
2.2 KiB
93 lines
2.2 KiB
/* Copyright (c) 2015 PLUMgrid, http://plumgrid.com |
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* |
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* This program is free software; you can redistribute it and/or |
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* modify it under the terms of version 2 of the GNU General Public |
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* License as published by the Free Software Foundation. |
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*/ |
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#include <linux/ptrace.h> |
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#include <linux/version.h> |
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#include <uapi/linux/bpf.h> |
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#include <uapi/linux/seccomp.h> |
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#include <uapi/linux/unistd.h> |
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#include "syscall_nrs.h" |
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#include <bpf/bpf_helpers.h> |
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#include <bpf/bpf_tracing.h> |
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#define PROG(F) SEC("kprobe/"__stringify(F)) int bpf_func_##F |
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struct { |
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__uint(type, BPF_MAP_TYPE_PROG_ARRAY); |
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__uint(key_size, sizeof(u32)); |
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__uint(value_size, sizeof(u32)); |
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#ifdef __mips__ |
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__uint(max_entries, 6000); /* MIPS n64 syscalls start at 5000 */ |
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#else |
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__uint(max_entries, 1024); |
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#endif |
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} progs SEC(".maps"); |
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SEC("kprobe/__seccomp_filter") |
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int bpf_prog1(struct pt_regs *ctx) |
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{ |
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int sc_nr = (int)PT_REGS_PARM1(ctx); |
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/* dispatch into next BPF program depending on syscall number */ |
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bpf_tail_call(ctx, &progs, sc_nr); |
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/* fall through -> unknown syscall */ |
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if (sc_nr >= __NR_getuid && sc_nr <= __NR_getsid) { |
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char fmt[] = "syscall=%d (one of get/set uid/pid/gid)\n"; |
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bpf_trace_printk(fmt, sizeof(fmt), sc_nr); |
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} |
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return 0; |
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} |
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/* we jump here when syscall number == __NR_write */ |
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PROG(SYS__NR_write)(struct pt_regs *ctx) |
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{ |
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struct seccomp_data sd; |
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bpf_probe_read_kernel(&sd, sizeof(sd), (void *)PT_REGS_PARM2(ctx)); |
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if (sd.args[2] == 512) { |
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char fmt[] = "write(fd=%d, buf=%p, size=%d)\n"; |
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bpf_trace_printk(fmt, sizeof(fmt), |
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sd.args[0], sd.args[1], sd.args[2]); |
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} |
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return 0; |
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} |
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PROG(SYS__NR_read)(struct pt_regs *ctx) |
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{ |
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struct seccomp_data sd; |
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bpf_probe_read_kernel(&sd, sizeof(sd), (void *)PT_REGS_PARM2(ctx)); |
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if (sd.args[2] > 128 && sd.args[2] <= 1024) { |
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char fmt[] = "read(fd=%d, buf=%p, size=%d)\n"; |
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bpf_trace_printk(fmt, sizeof(fmt), |
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sd.args[0], sd.args[1], sd.args[2]); |
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} |
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return 0; |
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} |
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#ifdef __NR_mmap2 |
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PROG(SYS__NR_mmap2)(struct pt_regs *ctx) |
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{ |
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char fmt[] = "mmap2\n"; |
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bpf_trace_printk(fmt, sizeof(fmt)); |
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return 0; |
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} |
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#endif |
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#ifdef __NR_mmap |
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PROG(SYS__NR_mmap)(struct pt_regs *ctx) |
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{ |
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char fmt[] = "mmap\n"; |
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bpf_trace_printk(fmt, sizeof(fmt)); |
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return 0; |
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} |
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#endif |
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char _license[] SEC("license") = "GPL"; |
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u32 _version SEC("version") = LINUX_VERSION_CODE;
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