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111 lines
2.8 KiB
111 lines
2.8 KiB
4 months ago
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/* Copyright 2016 The Chromium OS Authors. All rights reserved.
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* Use of this source code is governed by a BSD-style license that can be
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* found in the LICENSE file.
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*/
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#include <getopt.h>
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#include <stdio.h>
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#include <string.h>
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#include <string>
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#include "bpf.h"
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#include "syscall_filter.h"
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#include "util.h"
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namespace {
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void DumpBpfProg(struct sock_fprog* fprog) {
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struct sock_filter* filter = fprog->filter;
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unsigned short len = fprog->len;
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printf("len == %d\n", len);
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printf("filter:\n");
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for (size_t i = 0; i < len; i++) {
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printf("%zu: \t{ code=%#x, jt=%u, jf=%u, k=%#x \t}\n", i, filter[i].code,
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filter[i].jt, filter[i].jf, filter[i].k);
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}
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}
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void Usage(const char* progn, int status) {
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// clang-format off
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fprintf(status ? stderr : stdout,
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"Usage: %s [--dump[=<output.bpf>]] [<policy file>]\n"
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"\n"
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"With no <policy file>, or when <policy file> is -, reads from standard input.\n"
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"\n"
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" --dump[=<output>]: Dump the BPF program into stdout (or <output>,\n"
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" -d[<output>]: if provided). Useful if you want to inspect it\n"
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" with libseccomp's scmp_bpf_disasm.\n",
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progn);
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// clang-format on
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exit(status);
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}
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} // namespace
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int main(int argc, char** argv) {
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init_logging(LOG_TO_FD, STDERR_FILENO, LOG_INFO);
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const char* optstring = "d:h";
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const struct option long_options[] = {
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{"help", no_argument, 0, 'h'},
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{"dump", optional_argument, 0, 'd'},
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{0, 0, 0, 0},
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};
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bool dump = false;
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std::string dump_path;
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int opt;
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while ((opt = getopt_long(argc, argv, optstring, long_options, NULL)) != -1) {
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switch (opt) {
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case 'h':
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Usage(argv[0], 0);
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return 0;
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case 'd':
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dump = true;
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if (optarg)
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dump_path = optarg;
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break;
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}
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}
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FILE* f = stdin;
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// If there is at least one additional unparsed argument, treat it as the
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// policy script.
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if (argc > optind && strcmp(argv[optind], "-") != 0)
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f = fopen(argv[optind], "re");
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if (!f)
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pdie("fopen(%s) failed", argv[1]);
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struct filter_options fopts {
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.action = ACTION_RET_KILL,
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.allow_logging = 0,
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.allow_syscalls_for_logging = 0,
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.allow_duplicate_syscalls = allow_duplicate_syscalls(),
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};
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struct sock_fprog fp;
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int res = compile_filter(argv[1], f, &fp, &fopts);
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fclose(f);
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if (res != 0)
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die("compile_filter failed");
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if (dump) {
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FILE* out = stdout;
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if (!dump_path.empty()) {
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out = fopen(dump_path.c_str(), "we");
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if (!out)
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pdie("fopen(%s) failed", dump_path.c_str());
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}
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if (fwrite(fp.filter, sizeof(struct sock_filter), fp.len, out) != fp.len)
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pdie("fwrite(%s) failed", dump_path.c_str());
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fclose(out);
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} else {
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DumpBpfProg(&fp);
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}
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free(fp.filter);
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return 0;
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}
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