Always define _PATH_SUDO_NOEXEC, _PATH_SUDO_SESH, _PATH_SUDO_PLUGIN_DIR,

even if only defined to NULL.  This means the accessors can always be
present.

Use RTLD_PRELOAD_VAR instead of _PATH_SUDO_NOEXEC to tell when
noexec is available.

Add ENABLE_SUDO_PLUGIN_API and use it instead of _PATH_SUDO_PLUGIN_DIR
to tell when the plugin API is available.

Add sudo_conf_clear_paths() to clear the path values so the
regress tests are not affected by compile-time settings.

config.h.in

@@ -16,6 +16,9 @@
 /* A colon-separated list of pathnames to be used as the editor for visudo. */
 #undef EDITOR
 
+/* Define to 1 to enable sudo's plugin interface. */
+#undef ENABLE_SUDO_PLUGIN_API
+
 /* Define to 1 to enable environment function debugging. */
 #undef ENV_DEBUG
 

configure

@@ -24396,14 +24396,29 @@ EOF
 #define _PATH_SUDO_PLUGIN_DIR "$PLUGINDIR/"
 EOF
 
+
+$as_echo "#define ENABLE_SUDO_PLUGIN_API 1" >>confdefs.h
+
     fi
     exec_prefix="$oexec_prefix"
+fi
+if test X"$with_noexec" = X"no"; then
+    cat >>confdefs.h <<EOF
+#define _PATH_SUDO_NOEXEC NULL
+EOF
+
 fi
 if test X"$with_selinux" = X"no"; then
     cat >>confdefs.h <<EOF
 #define _PATH_SUDO_SESH NULL
 EOF
 
+fi
+if test X"$enable_shared" = X"no"; then
+    cat >>confdefs.h <<EOF
+#define _PATH_SUDO_PLUGIN_DIR NULL
+EOF
+
 fi
 
 if test X"$LDFLAGS_R" != X""; then

configure.ac

@@ -4183,12 +4183,19 @@ if test X"$with_noexec" != X"no" -o X"$with_selinux" != X"no" -o "$enabled_share
 	    eval PLUGINDIR="$_PLUGINDIR"
 	done
 	SUDO_DEFINE_UNQUOTED(_PATH_SUDO_PLUGIN_DIR, "$PLUGINDIR/")
+	AC_DEFINE(ENABLE_SUDO_PLUGIN_API, 1, [Define to 1 to enable sudo's plugin interface.])
     fi
     exec_prefix="$oexec_prefix"
 fi
+if test X"$with_noexec" = X"no"; then
+    SUDO_DEFINE_UNQUOTED(_PATH_SUDO_NOEXEC, NULL)
+fi
 if test X"$with_selinux" = X"no"; then
     SUDO_DEFINE_UNQUOTED(_PATH_SUDO_SESH, NULL)
 fi
+if test X"$enable_shared" = X"no"; then
+    SUDO_DEFINE_UNQUOTED(_PATH_SUDO_PLUGIN_DIR, NULL)
+fi
 
 dnl
 dnl Add -R options to LDFLAGS, etc.

include/sudo_conf.h

@@ -66,6 +66,7 @@ __dso_public bool sudo_conf_disable_coredump_v1(void);
 __dso_public bool sudo_conf_probe_interfaces_v1(void);
 __dso_public int sudo_conf_group_source_v1(void);
 __dso_public int sudo_conf_max_groups_v1(void);
+__dso_public void sudo_conf_clear_paths_v1(void);
 #define sudo_conf_askpass_path() sudo_conf_askpass_path_v1()
 #define sudo_conf_sesh_path() sudo_conf_sesh_path_v1()
 #define sudo_conf_noexec_path() sudo_conf_noexec_path_v1()
@@ -77,5 +78,6 @@ __dso_public int sudo_conf_max_groups_v1(void);
 #define sudo_conf_probe_interfaces() sudo_conf_probe_interfaces_v1()
 #define sudo_conf_group_source() sudo_conf_group_source_v1()
 #define sudo_conf_max_groups() sudo_conf_max_groups_v1()
+#define sudo_conf_clear_paths() sudo_conf_clear_paths_v1()
 
 #endif /* SUDO_CONF_H */

lib/util/regress/sudo_conf/conf_test.c

@@ -53,6 +53,7 @@ main(int argc, char *argv[])
 	fprintf(stderr, "usage: %s conf_file\n", getprogname());
 	exit(EXIT_FAILURE);
     }
+    sudo_conf_clear_paths();
     if (sudo_conf_read(argv[1], SUDO_CONF_ALL) == -1)
 	exit(EXIT_FAILURE);
     sudo_conf_dump();
@@ -77,10 +78,12 @@ sudo_conf_dump(void)
     printf("Set max_groups %d\n", sudo_conf_max_groups());
     if (sudo_conf_askpass_path() != NULL)
 	printf("Path askpass %s\n", sudo_conf_askpass_path());
-#ifdef _PATH_SUDO_NOEXEC
+    if (sudo_conf_sesh_path() != NULL)
+	printf("Path sesh %s\n", sudo_conf_sesh_path());
     if (sudo_conf_noexec_path() != NULL)
 	printf("Path noexec %s\n", sudo_conf_noexec_path());
-#endif
+    if (sudo_conf_plugin_dir_path() != NULL)
+	printf("Path plugin_dir %s\n", sudo_conf_plugin_dir_path());
     TAILQ_FOREACH(info, plugins, entries) {
 	printf("Plugin %s %s", info->symbol_name, info->path);
 	if (info->options) {

lib/util/regress/sudo_conf/test1.out.ok

@@ -2,5 +2,6 @@ Set disable_coredump false
 Set group_source static
 Set max_groups -1
 Path askpass /usr/X11R6/bin/ssh-askpass
+Path noexec /usr/libexec/sudo_noexec.so
 Plugin sudoers_policy sudoers.so
 Plugin sudoers_io sudoers.so

lib/util/sudo_conf.c

@@ -55,14 +55,6 @@
 # define ROOT_UID	0
 #endif
 
-/* Avoid excessive #ifdefs in the code. */
-#ifndef _PATH_SUDO_NOEXEC
-# define _PATH_SUDO_NOEXEC	NULL
-#endif
-#ifndef _PATH_SUDO_PLUGIN_DIR
-# define _PATH_SUDO_PLUGIN_DIR	NULL
-#endif
-
 struct sudo_conf_table {
     const char *name;
     unsigned int namelen;
@@ -631,3 +623,16 @@ done:
     free(prev_locale);
     debug_return_int(ret);
 }
+
+/*
+ * Used by the sudo_conf regress test to clear compile-time path settings.
+ */
+void
+sudo_conf_clear_paths_v1(void)
+{
+    struct sudo_conf_path_table *cur;
+    debug_decl(sudo_conf_clear_paths, SUDO_DEBUG_UTIL)
+
+    for (cur = sudo_conf_data.path_table; cur->pname != NULL; cur++)
+	cur->pval = NULL;
+}

lib/util/util.exp.in

@@ -1,5 +1,6 @@
 @COMPAT_EXP@initprogname
 sudo_conf_askpass_path_v1
+sudo_conf_clear_paths_v1
 sudo_conf_debug_files_v1
 sudo_conf_debugging_v1
 sudo_conf_disable_coredump_v1

plugins/sudoers/policy.c

@@ -256,7 +256,7 @@ sudoers_policy_deserialize_info(void *v, char **runas_user, char **runas_group)
 	    remhost = *cur + sizeof("remote_host=") - 1;
 	    continue;
 	}
-#ifdef _PATH_SUDO_PLUGIN_DIR
+#ifdef ENABLE_SUDO_PLUGIN_API
 	if (MATCHES(*cur, "plugin_dir=")) {
 	    path_plugin_dir = *cur + sizeof("plugin_dir=") - 1;
 	    continue;

src/exec_common.c

@@ -36,7 +36,7 @@
 #include "sudo.h"
 #include "sudo_exec.h"
 
-#ifdef _PATH_SUDO_NOEXEC
+#ifdef RTLD_PRELOAD_VAR
 /*
  * Add a DSO file to LD_PRELOAD or the system equivalent.
  */
@@ -144,7 +144,7 @@ preload_dso(char *envp[], const char *dso_file)
 
     debug_return_ptr(envp);
 }
-#endif /* _PATH_SUDO_NOEXEC */
+#endif /* RTLD_PRELOAD_VAR */
 
 /*
  * Disable execution of child processes in the command we are about
@@ -166,10 +166,10 @@ disable_execute(char *envp[], const char *dso)
     sudo_warn(U_("unable to remove PRIV_PROC_EXEC from PRIV_LIMIT"));
 #endif /* HAVE_PRIV_SET */
 
-#ifdef _PATH_SUDO_NOEXEC
+#ifdef RTLD_PRELOAD_VAR
     if (dso != NULL)
 	envp = preload_dso(envp, dso);
-#endif /* _PATH_SUDO_NOEXEC */
+#endif /* RTLD_PRELOAD_VAR */
 
     debug_return_ptr(envp);
 }

src/load_plugins.c

@@ -37,7 +37,7 @@
 /* We always use the same name for the sudoers plugin, regardless of the OS */
 #define SUDOERS_PLUGIN	"sudoers.so"
 
-#ifdef _PATH_SUDO_PLUGIN_DIR
+#ifdef ENABLE_SUDO_PLUGIN_API
 static int
 sudo_stat_plugin(struct plugin_info *info, char *fullpath,
     size_t pathsize, struct stat *sb)
@@ -144,7 +144,7 @@ sudo_check_plugin(struct plugin_info *info, char *fullpath, size_t pathsize)
     (void)strlcpy(fullpath, info->path, pathsize);
     debug_return_bool(true);
 }
-#endif /* _PATH_SUDO_PLUGIN_DIR */
+#endif /* ENABLE_SUDO_PLUGIN_API */
 
 /*
  * Load the plugin specified by "info".

src/parse_args.c

@@ -441,7 +441,7 @@ parse_args(int argc, char **argv, int *nargc, char ***nargv,
 	SET(flags, (MODE_IMPLIED_SHELL | MODE_SHELL));
 	sudo_settings[ARG_IMPLIED_SHELL].value = "true";
     }
-#ifdef _PATH_SUDO_PLUGIN_DIR
+#ifdef ENABLE_SUDO_PLUGIN_API
     sudo_settings[ARG_PLUGIN_DIR].value = sudo_conf_plugin_dir_path();
 #endif