/* Test parsing of /etc/resolv.conf. Genric version. Copyright (C) 2017 Free Software Foundation, Inc. This file is part of the GNU C Library. The GNU C Library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. The GNU C Library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with the GNU C Library; if not, see . */ /* Before including this file, TEST_THREAD has to be defined to 0 or 1, depending on whether the threading tests should be compiled in. */ #include #include #include #include /* For DEPRECATED_RES_USE_INET6. */ #include #include #include #include #include #include #include #include #include #include #include #if TEST_THREAD # include #endif /* This is the host name used to ensure predictable behavior of res_init. */ static const char *const test_hostname = "www.example.com"; /* Path to the test root directory. */ static char *path_chroot; /* Path to resolv.conf under path_chroot (outside the chroot). */ static char *path_resolv_conf; static void prepare (int argc, char **argv) { path_chroot = xasprintf ("%s/tst-resolv-res_init-XXXXXX", test_dir); if (mkdtemp (path_chroot) == NULL) FAIL_EXIT1 ("mkdtemp (\"%s\"): %m", path_chroot); add_temp_file (path_chroot); /* Create the /etc directory in the chroot environment. */ char *path_etc = xasprintf ("%s/etc", path_chroot); xmkdir (path_etc, 0777); add_temp_file (path_etc); /* Create an empty resolv.conf file. */ path_resolv_conf = xasprintf ("%s/resolv.conf", path_etc); add_temp_file (path_resolv_conf); support_write_file_string (path_resolv_conf, ""); free (path_etc); /* valgrind needs a temporary directory in the chroot. */ { char *path_tmp = xasprintf ("%s/tmp", path_chroot); xmkdir (path_tmp, 0777); add_temp_file (path_tmp); free (path_tmp); } } /* Verify that the chroot environment has been set up. */ static void check_chroot_working (void *closure) { xchroot (path_chroot); FILE *fp = xfopen (_PATH_RESCONF, "r"); xfclose (fp); TEST_VERIFY_EXIT (res_init () == 0); TEST_VERIFY (_res.options & RES_INIT); char buf[100]; if (gethostname (buf, sizeof (buf)) < 0) FAIL_EXIT1 ("gethostname: %m"); if (strcmp (buf, test_hostname) != 0) FAIL_EXIT1 ("unexpected host name: %s", buf); } /* If FLAG is set in *OPTIONS, write NAME to FP, and clear it in *OPTIONS. */ static void print_option_flag (FILE *fp, int *options, int flag, const char *name) { if (*options & flag) { fprintf (fp, " %s", name); *options &= ~flag; } } /* Write a decoded version of the resolver configuration *RESP to the stream FP. */ static void print_resp (FILE *fp, res_state resp) { /* The options directive. */ { /* RES_INIT is used internally for tracking initialization. */ TEST_VERIFY (resp->options & RES_INIT); /* Also mask out other default flags which cannot be set through the options directive. */ int options = resp->options & ~(RES_INIT | RES_RECURSE | RES_DEFNAMES | RES_DNSRCH); if (options != 0 || resp->ndots != 1 || resp->retrans != RES_TIMEOUT || resp->retry != RES_DFLRETRY) { fputs ("options", fp); if (resp->ndots != 1) fprintf (fp, " ndots:%d", resp->ndots); if (resp->retrans != RES_TIMEOUT) fprintf (fp, " timeout:%d", resp->retrans); if (resp->retry != RES_DFLRETRY) fprintf (fp, " attempts:%d", resp->retry); print_option_flag (fp, &options, RES_USEVC, "use-vc"); print_option_flag (fp, &options, DEPRECATED_RES_USE_INET6, "inet6"); print_option_flag (fp, &options, RES_ROTATE, "rotate"); print_option_flag (fp, &options, RES_USE_EDNS0, "edns0"); print_option_flag (fp, &options, RES_SNGLKUP, "single-request"); print_option_flag (fp, &options, RES_SNGLKUPREOP, "single-request-reopen"); print_option_flag (fp, &options, RES_NOTLDQUERY, "no-tld-query"); fputc ('\n', fp); if (options != 0) fprintf (fp, "; error: unresolved option bits: 0x%x\n", options); } } /* The search and domain directives. */ if (resp->dnsrch[0] != NULL) { fputs ("search", fp); for (int i = 0; i < MAXDNSRCH && resp->dnsrch[i] != NULL; ++i) { fputc (' ', fp); fputs (resp->dnsrch[i], fp); } fputc ('\n', fp); } else if (resp->defdname[0] != '\0') fprintf (fp, "domain %s\n", resp->defdname); /* The sortlist directive. */ if (resp->nsort > 0) { fputs ("sortlist", fp); for (int i = 0; i < resp->nsort && i < MAXRESOLVSORT; ++i) { char net[20]; if (inet_ntop (AF_INET, &resp->sort_list[i].addr, net, sizeof (net)) == NULL) FAIL_EXIT1 ("inet_ntop: %m\n"); char mask[20]; if (inet_ntop (AF_INET, &resp->sort_list[i].mask, mask, sizeof (mask)) == NULL) FAIL_EXIT1 ("inet_ntop: %m\n"); fprintf (fp, " %s/%s", net, mask); } fputc ('\n', fp); } /* The nameserver directives. */ for (size_t i = 0; i < resp->nscount; ++i) { char host[NI_MAXHOST]; char service[NI_MAXSERV]; /* See get_nsaddr in res_send.c. */ void *addr; size_t addrlen; if (resp->nsaddr_list[i].sin_family == 0 && resp->_u._ext.nsaddrs[i] != NULL) { addr = resp->_u._ext.nsaddrs[i]; addrlen = sizeof (*resp->_u._ext.nsaddrs[i]); } else { addr = &resp->nsaddr_list[i]; addrlen = sizeof (resp->nsaddr_list[i]); } int ret = getnameinfo (addr, addrlen, host, sizeof (host), service, sizeof (service), NI_NUMERICHOST | NI_NUMERICSERV); if (ret != 0) { if (ret == EAI_SYSTEM) fprintf (fp, "; error: getnameinfo: %m\n"); else fprintf (fp, "; error: getnameinfo: %s\n", gai_strerror (ret)); } else { fprintf (fp, "nameserver %s\n", host); if (strcmp (service, "53") != 0) fprintf (fp, "; unrepresentable port number %s\n\n", service); } } TEST_VERIFY (!ferror (fp)); } /* Parameters of one test case. */ struct test_case { /* A short, descriptive name of the test. */ const char *name; /* The contents of the /etc/resolv.conf file. */ const char *conf; /* The expected output from print_resp. */ const char *expected; /* Setting for the LOCALDOMAIN environment variable. NULL if the variable is not to be set. */ const char *localdomain; /* Setting for the RES_OPTIONS environment variable. NULL if the variable is not to be set. */ const char *res_options; }; enum test_init { test_init, test_ninit, test_mkquery, test_gethostbyname, test_getaddrinfo, test_init_method_last = test_getaddrinfo }; /* Closure argument for run_res_init. */ struct test_context { enum test_init init; const struct test_case *t; }; static void setup_nss_dns_and_chroot (void) { /* Load nss_dns outside of the chroot. */ if (dlopen (LIBNSS_DNS_SO, RTLD_LAZY) == NULL) FAIL_EXIT1 ("could not load " LIBNSS_DNS_SO ": %s", dlerror ()); xchroot (path_chroot); /* Force the use of nss_dns. */ __nss_configure_lookup ("hosts", "dns"); } /* Run res_ninit or res_init in a subprocess and dump the parsed resolver state to standard output. */ static void run_res_init (void *closure) { struct test_context *ctx = closure; TEST_VERIFY (getenv ("LOCALDOMAIN") == NULL); TEST_VERIFY (getenv ("RES_OPTIONS") == NULL); if (ctx->t->localdomain != NULL) setenv ("LOCALDOMAIN", ctx->t->localdomain, 1); if (ctx->t->res_options != NULL) setenv ("RES_OPTIONS", ctx->t->res_options, 1); switch (ctx->init) { case test_init: xchroot (path_chroot); TEST_VERIFY (res_init () == 0); print_resp (stdout, &_res); return; case test_ninit: xchroot (path_chroot); res_state resp = xmalloc (sizeof (*resp)); memset (resp, 0, sizeof (*resp)); TEST_VERIFY (res_ninit (resp) == 0); print_resp (stdout, resp); res_nclose (resp); free (resp); return; case test_mkquery: xchroot (path_chroot); unsigned char buf[512]; TEST_VERIFY (res_mkquery (QUERY, "www.example", C_IN, ns_t_a, NULL, 0, NULL, buf, sizeof (buf)) > 0); print_resp (stdout, &_res); return; case test_gethostbyname: setup_nss_dns_and_chroot (); /* Trigger implicit initialization of the _res structure. The actual lookup result is immaterial. */ (void )gethostbyname ("www.example"); print_resp (stdout, &_res); return; case test_getaddrinfo: setup_nss_dns_and_chroot (); /* Trigger implicit initialization of the _res structure. The actual lookup result is immaterial. */ struct addrinfo *ai; (void) getaddrinfo ("www.example", NULL, NULL, &ai); print_resp (stdout, &_res); return; } FAIL_EXIT1 ("invalid init method %d", ctx->init); } #if TEST_THREAD /* Helper function which calls run_res_init from a thread. */ static void * run_res_init_thread_func (void *closure) { run_res_init (closure); return NULL; } /* Variant of res_run_init which runs the function on a non-main thread. */ static void run_res_init_on_thread (void *closure) { xpthread_join (xpthread_create (NULL, run_res_init_thread_func, closure)); } #endif /* TEST_THREAD */ struct test_case test_cases[] = { {.name = "empty file", .conf = "", .expected = "search example.com\n" "nameserver 127.0.0.1\n" }, {.name = "empty file with LOCALDOMAIN", .conf = "", .expected = "search example.net\n" "nameserver 127.0.0.1\n", .localdomain = "example.net", }, {.name = "empty file with RES_OPTIONS", .conf = "", .expected = "options attempts:5 edns0\n" "search example.com\n" "nameserver 127.0.0.1\n", .res_options = "edns0 attempts:5", }, {.name = "empty file with RES_OPTIONS and LOCALDOMAIN", .conf = "", .expected = "options attempts:5 edns0\n" "search example.org\n" "nameserver 127.0.0.1\n", .localdomain = "example.org", .res_options = "edns0 attempts:5", }, {.name = "basic", .conf = "domain example.net\n" "search corp.example.com example.com\n" "nameserver 192.0.2.1\n", .expected = "search corp.example.com example.com\n" "nameserver 192.0.2.1\n" }, {.name = "whitespace", .conf = "# This test covers comment and whitespace processing " " (trailing whitespace,\n" "# missing newline at end of file).\n" "\n" "domain example.net\n" ";search commented out\n" "search corp.example.com\texample.com\n" "#nameserver 192.0.2.3\n" "nameserver 192.0.2.1 \n" "nameserver 192.0.2.2", /* No \n at end of file. */ .expected = "search corp.example.com example.com\n" "nameserver 192.0.2.1\n" "nameserver 192.0.2.2\n" }, {.name = "option values, multiple servers", .conf = "options\tinet6\tndots:3 edns0\tattempts:5\ttimeout:19\n" "domain example.net\n" ";domain comment\n" "search corp.example.com\texample.com\n" "nameserver 192.0.2.1\n" "nameserver ::1\n" "nameserver 192.0.2.2\n", .expected = "options ndots:3 timeout:19 attempts:5 inet6 edns0\n" "search corp.example.com example.com\n" "nameserver 192.0.2.1\n" "nameserver ::1\n" "nameserver 192.0.2.2\n" }, {.name = "out-of-range option vales", .conf = "options use-vc timeout:999 attempts:999 ndots:99\n" "search example.com\n", .expected = "options ndots:15 timeout:30 attempts:5 use-vc\n" "search example.com\n" "nameserver 127.0.0.1\n" }, {.name = "repeated directives", .conf = "options ndots:3 use-vc\n" "options edns0 ndots:2\n" "domain corp.example\n" "search example.net corp.example.com example.com\n" "search example.org\n" "search\n", .expected = "options ndots:2 use-vc edns0\n" "search example.org\n" "nameserver 127.0.0.1\n" }, {.name = "many name servers, sortlist", .conf = "options single-request\n" "search example.org example.com example.net corp.example.com\n" "sortlist 192.0.2.0/255.255.255.0\n" "nameserver 192.0.2.1\n" "nameserver 192.0.2.2\n" "nameserver 192.0.2.3\n" "nameserver 192.0.2.4\n" "nameserver 192.0.2.5\n" "nameserver 192.0.2.6\n" "nameserver 192.0.2.7\n" "nameserver 192.0.2.8\n", .expected = "options single-request\n" "search example.org example.com example.net corp.example.com\n" "sortlist 192.0.2.0/255.255.255.0\n" "nameserver 192.0.2.1\n" "nameserver 192.0.2.2\n" "nameserver 192.0.2.3\n" }, {.name = "IPv4 and IPv6 nameservers", .conf = "options single-request\n" "search example.org example.com example.net corp.example.com" " legacy.example.com\n" "sortlist 192.0.2.0\n" "nameserver 192.0.2.1\n" "nameserver 2001:db8::2\n" "nameserver 192.0.2.3\n" "nameserver 2001:db8::4\n" "nameserver 192.0.2.5\n" "nameserver 2001:db8::6\n" "nameserver 192.0.2.7\n" "nameserver 2001:db8::8\n", .expected = "options single-request\n" "search example.org example.com example.net corp.example.com" " legacy.example.com\n" "sortlist 192.0.2.0/255.255.255.0\n" "nameserver 192.0.2.1\n" "nameserver 2001:db8::2\n" "nameserver 192.0.2.3\n" }, {.name = "garbage after nameserver", .conf = "nameserver 192.0.2.1 garbage\n" "nameserver 192.0.2.2:5353\n" "nameserver 192.0.2.3 5353\n", .expected = "search example.com\n" "nameserver 192.0.2.1\n" "nameserver 192.0.2.3\n" }, {.name = "RES_OPTIONS is cummulative", .conf = "options timeout:7 ndots:2 use-vc\n" "nameserver 192.0.2.1\n", .expected = "options ndots:3 timeout:7 attempts:5 use-vc edns0\n" "search example.com\n" "nameserver 192.0.2.1\n", .res_options = "attempts:5 ndots:3 edns0 ", }, { NULL } }; /* Run the indicated test case. This function assumes that the chroot contents has already been set up. */ static void test_file_contents (const struct test_case *t) { #if TEST_THREAD for (int do_thread = 0; do_thread < 2; ++do_thread) #endif for (int init_method = 0; init_method <= test_init_method_last; ++init_method) { if (test_verbose > 0) printf ("info: testing init method %d\n", init_method); struct test_context ctx = { .init = init_method, .t = t }; void (*func) (void *) = run_res_init; #if TEST_THREAD if (do_thread) func = run_res_init_on_thread; #endif struct support_capture_subprocess proc = support_capture_subprocess (func, &ctx); if (strcmp (proc.out.buffer, t->expected) != 0) { support_record_failure (); printf ("error: output mismatch for %s\n", t->name); support_run_diff ("expected", t->expected, "actual", proc.out.buffer); } support_capture_subprocess_check (&proc, t->name, 0, sc_allow_stdout); support_capture_subprocess_free (&proc); } } static int do_test (void) { support_become_root (); support_enter_network_namespace (); if (!support_in_uts_namespace () || !support_can_chroot ()) return EXIT_UNSUPPORTED; /* We are in an UTS namespace, so we can set the host name without altering the state of the entire system. */ if (sethostname (test_hostname, strlen (test_hostname)) != 0) FAIL_EXIT1 ("sethostname: %m"); /* These environment variables affect resolv.conf parsing. */ unsetenv ("LOCALDOMAIN"); unsetenv ("RES_OPTIONS"); /* Ensure that the chroot setup worked. */ { struct support_capture_subprocess proc = support_capture_subprocess (check_chroot_working, NULL); support_capture_subprocess_check (&proc, "chroot", 0, sc_allow_none); support_capture_subprocess_free (&proc); } for (size_t i = 0; test_cases[i].name != NULL; ++i) { if (test_verbose > 0) printf ("info: running test: %s\n", test_cases[i].name); TEST_VERIFY (test_cases[i].conf != NULL); TEST_VERIFY (test_cases[i].expected != NULL); support_write_file_string (path_resolv_conf, test_cases[i].conf); test_file_contents (&test_cases[i]); /* The expected output from the empty file test is used for further tests. */ if (test_cases[i].conf[0] == '\0') { if (test_verbose > 0) printf ("info: special test: missing file\n"); TEST_VERIFY (unlink (path_resolv_conf) == 0); test_file_contents (&test_cases[i]); if (test_verbose > 0) printf ("info: special test: dangling symbolic link\n"); TEST_VERIFY (symlink ("does-not-exist", path_resolv_conf) == 0); test_file_contents (&test_cases[i]); TEST_VERIFY (unlink (path_resolv_conf) == 0); if (test_verbose > 0) printf ("info: special test: unreadable file\n"); support_write_file_string (path_resolv_conf, ""); TEST_VERIFY (chmod (path_resolv_conf, 0) == 0); test_file_contents (&test_cases[i]); /* Restore the empty file. */ TEST_VERIFY (unlink (path_resolv_conf) == 0); support_write_file_string (path_resolv_conf, ""); } } free (path_chroot); path_chroot = NULL; free (path_resolv_conf); path_resolv_conf = NULL; return 0; } #define PREPARE prepare #include