src/systemctl/fuzz-systemctl-parse-argv.c

   1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
   2
   3 #include <stdio.h>
   4 #include <unistd.h>
   5
   6 #include "env-util.h"
   7 #include "fd-util.h"
   8 #include "fuzz.h"
   9 #include "selinux-util.h"
  10 #include "static-destruct.h"
  11 #include "stdio-util.h"
  12 #include "strv.h"
  13 #include "systemctl.h"
  14 #include "systemctl-util.h"
  15
  16 int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
  17         _cleanup_strv_free_ char **argv = NULL;
  18         _cleanup_close_ int orig_stdout_fd = -1;
  19         int r;
  20
  21         /* We don't want to fill the logs with messages about parse errors.
  22          * Disable most logging if not running standalone */
  23         if (!getenv("SYSTEMD_LOG_LEVEL"))
  24                 log_set_max_level(LOG_CRIT);
  25
  26         arg_pager_flags = PAGER_DISABLE; /* We shouldn't execute the pager */
  27
  28         argv = strv_parse_nulstr((const char *)data, size);
  29         if (!argv)
  30                 return log_oom();
  31
  32         if (!argv[0])
  33                 return 0; /* argv[0] should always be present, but may be zero-length. */
  34         if (strv_length(argv) > 1024)
  35                 return 0; /* oss-fuzz reports timeouts which are caused by appending to a very long strv.
  36                            * The code is indeed not very efficient, but it's designed for normal command-line
  37                            * use, where we don't expect more than a dozen of entries. The fact that it is
  38                            * slow with ~100k entries is not particularly interesting. Let's just refuse such
  39                            * long command lines. */
  40
  41         if (getenv_bool("SYSTEMD_FUZZ_OUTPUT") <= 0) {
  42                 orig_stdout_fd = fcntl(fileno(stdout), F_DUPFD_CLOEXEC, 3);
  43                 if (orig_stdout_fd < 0)
  44                         log_warning_errno(orig_stdout_fd, "Failed to duplicate fd 1: %m");
  45                 else
  46                         assert_se(freopen("/dev/null", "w", stdout));
  47
  48                 opterr = 0; /* do not print errors */
  49         }
  50
  51         optind = 0; /* this tells the getopt machinery to reinitialize */
  52
  53         r = systemctl_dispatch_parse_argv(strv_length(argv), argv);
  54         if (r < 0)
  55                 log_error_errno(r, "Failed to parse args: %m");
  56         else
  57                 log_info(r == 0 ? "Done!" : "Action!");
  58
  59         if (orig_stdout_fd >= 0)
  60                 assert_se(freopen(FORMAT_PROC_FD_PATH(orig_stdout_fd), "w", stdout));
  61
  62         release_busses(); /* We open the bus for communication with logind.
  63                            * It needs to be closed to avoid apparent leaks. */
  64
  65         mac_selinux_finish();
  66
  67         /* Call static destructors to do global state cleanup. We do it here, and not in fuzz-main.c so that
  68          * any global state is destroyed between fuzzer runs. */
  69         static_destruct();
  70
  71         return 0;
  72 }