Add unit tests for configuration

tests/Makefile.am

@@ -16,4 +16,7 @@ get_devices_LDADD = $(top_builddir)/libmodule.la
 check_PROGRAMS += expand
 expand_LDADD = $(top_builddir)/libmodule.la
 
+check_PROGRAMS += cfg
+cfg_LDADD = $(top_builddir)/libmodule.la
+
 TESTS = $(check_PROGRAMS)

tests/cfg.c

@@ -0,0 +1,266 @@
+#undef NDEBUG
+
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <assert.h>
+
+#include <security/pam_appl.h>
+
+#include "cfg.h"
+
+static void write_conf(int fd, const char *text) {
+  size_t len;
+  int e;
+
+  len = strlen(text);
+  while (len) {
+    ssize_t w;
+
+    w = write(fd, text, len);
+    assert(w >= 0);
+
+    len -= w;
+    text += w;
+  }
+
+  e = fsync(fd);
+  assert(e == 0);
+}
+
+static char *generate_conf_file_arg(void) {
+  // Generate a conf_file= argument
+  //
+  // The function returns a string which is:
+  // - suitable as argv item for pam_u2f
+  // - suitable as template argument for mkstemp
+  // - referring to the absolute path of the temporary file.
+
+  char cwd[1024];
+  char *template;
+  int err;
+
+  err = !getcwd(cwd, sizeof(cwd));
+  assert(!err);
+
+  err = asprintf(&template, "conf_file=%.*s/test_config_XXXXXX",
+                 (int) sizeof(cwd), cwd) == -1;
+  assert(!err);
+
+  return template;
+}
+
+static void test_regular(void) {
+  // Testing regular behaviour:
+  // - config file inheritance: the config file provides defaults,
+  //   overrides from regular argv
+  // - comments
+  // - indentation
+
+  char *config_arg;
+  int fd, e;
+  cfg_t cfg;
+
+  config_arg = generate_conf_file_arg();
+
+  fd = mkstemp(config_arg + strlen("conf_file="));
+  assert(fd != -1);
+
+  write_conf(fd,
+             "max_devices=10\n"
+             "manual\n"
+             "debug\n"
+             "nouserok\n"
+             "openasuser\n"
+             "alwaysok\n"
+             "interactive\n"
+             "cue\n"
+             "nodetect\n"
+             "expand\n"
+             "userpresence=0\n"
+             "userverification=0\n"
+             "pinverification=0\n"
+             "authfile=/foo/bar\n"
+             "# sshformat\n"                 // Commented -> no effect
+             "  # sshformat\n"               // also commented
+             " authpending_file=/baz/quux\n" // Indented -> accepted
+             "origin=pam://lolcalhost\n"
+             "appid=pam://lolcalhost\n"
+             "prompt=hello\n"
+             "cue_prompt=howdy\n"
+             "debug_file=stdout\n");
+
+  const char *argv[] = {
+    config_arg, "prompt=hi",
+    "debug", // So we have a log file for the test
+  };
+
+  e = cfg_init(&cfg, 0, sizeof(argv) / sizeof(*argv), argv);
+  assert(e == PAM_SUCCESS);
+
+  unlink(config_arg + strlen("conf_file="));
+  free(config_arg);
+  close(fd);
+
+  assert(cfg.alwaysok);
+  assert(strcmp(cfg.auth_file, "/foo/bar") == 0);
+  assert(!cfg.sshformat); // setting is commented out
+  assert(strcmp(cfg.authpending_file, "/baz/quux") == 0);
+  assert(strcmp(cfg.origin, "pam://lolcalhost") == 0);
+  assert(strcmp(cfg.appid, "pam://lolcalhost") == 0);
+  assert(strcmp(cfg.prompt, "hi") == 0);
+  assert(strcmp(cfg.cue_prompt, "howdy") == 0);
+  assert(cfg.debug_file == stdout);
+
+  cfg_free(&cfg);
+}
+
+static void test_config_abspath(void) {
+  /* Ensuring that the library rejects the conf_file= argument
+   * unless it points to an absolute path.
+   */
+
+  const char *argv[] = {
+    NULL,    // replaced with config_arg_{...}
+    "debug", // So we have a log file for the test
+  };
+
+  char config_arg_relative[] = "conf_file=test_config_XXXXXX";
+  char *config_arg_absolute;
+  int fd, e;
+  cfg_t cfg;
+
+  // 1. Generate a valid configuration and pass it around
+  // as relative path.  Assert failure.
+  fd = mkstemp(config_arg_relative + strlen("conf_file="));
+  assert(fd != -1);
+  write_conf(fd, "alwaysok\n"
+                 "prompt=hello");
+
+  argv[0] = config_arg_relative;
+  e = cfg_init(&cfg, 0, sizeof(argv) / sizeof(*argv), argv);
+  assert(e != PAM_SUCCESS);
+
+  unlink(config_arg_relative + strlen("conf_file="));
+  close(fd);
+
+  // 2. Generate a same configuration and pass it around
+  // as absolute path.  Assert success.
+
+  config_arg_absolute = generate_conf_file_arg();
+
+  fd = mkstemp(config_arg_absolute + strlen("conf_file="));
+  assert(fd != -1);
+  write_conf(fd, "alwaysok\n"
+                 "prompt=hello");
+
+  argv[0] = config_arg_absolute;
+  e = cfg_init(&cfg, 0, sizeof(argv) / sizeof(*argv), argv);
+  assert(e == PAM_SUCCESS);
+
+  assert(strcmp(cfg.prompt, "hello") == 0);
+  cfg_free(&cfg);
+
+  unlink(config_arg_absolute + strlen("conf_file="));
+  close(fd);
+  free(config_arg_absolute);
+}
+
+static void test_last_config_wins(void) {
+  // If conf_file= is used multiple times, only
+  // the last one is honored.
+
+  const char *argv[3] = {NULL, NULL, "debug"};
+  char *config_arg1, *config_arg2;
+  int fd1, fd2, e;
+  cfg_t cfg;
+
+  config_arg1 = generate_conf_file_arg();
+  fd1 = mkstemp(config_arg1 + strlen("conf_file="));
+  assert(fd1 != -1);
+
+  config_arg2 = generate_conf_file_arg();
+  fd2 = mkstemp(config_arg2 + strlen("conf_file="));
+  assert(fd2 != -1);
+
+  write_conf(fd1, "max_devices=10\n");
+  write_conf(fd2, "max_devices=12\n");
+
+  argv[0] = config_arg1;
+  argv[1] = config_arg2;
+
+  e = cfg_init(&cfg, 0, sizeof(argv) / sizeof(*argv), argv);
+  assert(e == PAM_SUCCESS);
+  assert(cfg.max_devs == 12);
+  cfg_free(&cfg);
+
+  argv[0] = config_arg2;
+  argv[1] = config_arg1;
+  e = cfg_init(&cfg, 0, sizeof(argv) / sizeof(*argv), argv);
+  assert(e == PAM_SUCCESS);
+  assert(cfg.max_devs == 10);
+  cfg_free(&cfg);
+
+  unlink(config_arg1 + strlen("conf_file="));
+  free(config_arg1);
+  close(fd1);
+
+  unlink(config_arg2 + strlen("conf_file="));
+  free(config_arg2);
+  close(fd2);
+}
+
+static void test_corner_cases(void) {
+  // Testng config file corner cases.
+
+  const char *argv[] = {NULL, "debug"};
+  char *config_arg;
+  int fd, e;
+  size_t size = 0;
+  cfg_t cfg;
+  ssize_t w;
+
+  config_arg = generate_conf_file_arg();
+  argv[0] = config_arg;
+
+  fd = mkstemp(config_arg + strlen("conf_file="));
+  assert(fd != -1);
+
+  // 1. Empty file -> Success
+  e = cfg_init(&cfg, 0, sizeof(argv) / sizeof(*argv), argv);
+  assert(e == PAM_SUCCESS);
+  cfg_free(&cfg);
+
+  // 2. File size within limit (1KiB) -> Success
+  while (size + strlen("manual\n") < CFG_MAX_FILE_SIZE) {
+    w = write(fd, "manual\n", sizeof("manual\n"));
+    assert(w >= 0);
+    size += w;
+  }
+  e = cfg_init(&cfg, 0, sizeof(argv) / sizeof(*argv), argv);
+  assert(e == PAM_SUCCESS);
+  cfg_free(&cfg);
+
+  // 3. File size beyond limit -> Failure
+  w = write(fd, "manual\n", strlen("manual\n"));
+  assert(w == strlen("manual\n"));
+  e = cfg_init(&cfg, 0, sizeof(argv) / sizeof(*argv), argv);
+  assert(e != PAM_SUCCESS);
+
+  // 4. Missing file -> Failure
+  unlink(config_arg + strlen("conf_file="));
+  e = cfg_init(&cfg, 0, sizeof(argv) / sizeof(*argv), argv);
+  assert(e != PAM_SUCCESS);
+
+  free(config_arg);
+  close(fd);
+}
+
+int main(int argc, char **argv) {
+  (void) argc, (void) argv;
+
+  test_regular();
+  test_config_abspath();
+  test_last_config_wins();
+  test_corner_cases();
+}