Add sample approval plugin that simply tests for "business hours"

plugins/sample_approval/sample_approval.c

@@ -0,0 +1,194 @@
+/*
+ * SPDX-License-Identifier: ISC
+ *
+ * Copyright (c) 2020 Todd C. Miller <Todd.Miller@sudo.ws>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+/*
+ * This is an open source non-commercial project. Dear PVS-Studio, please check it.
+ * PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com
+ */
+
+#include <config.h>
+
+#include <sys/types.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#ifdef HAVE_STDBOOL_H
+# include <stdbool.h>
+#else
+# include "compat/stdbool.h"
+#endif /* HAVE_STDBOOL_H */
+#ifdef HAVE_STRING_H
+# include <string.h>
+#endif /* HAVE_STRING_H */
+#ifdef HAVE_STRINGS_H
+# include <strings.h>
+#endif /* HAVE_STRINGS_H */
+#include <unistd.h>
+#include <ctype.h>
+#include <time.h>
+
+#include "sudo_gettext.h"	/* must be included before sudo_compat.h */
+
+#include "sudo_compat.h"
+#include "sudo_conf.h"
+#include "sudo_debug.h"
+#include "sudo_fatal.h"
+#include "sudo_plugin.h"
+#include "sudo_util.h"
+
+static int approval_debug_instance = SUDO_DEBUG_INSTANCE_INITIALIZER;
+
+/*
+ * Parse the "filename flags,..." debug_flags entry and insert a new
+ * sudo_debug_file struct into debug_files.
+ * XXX - move to libsudoutil
+ */
+static bool
+sudo_debug_parse_flags(struct sudo_conf_debug_file_list *debug_files,
+    const char *entry)
+{
+    struct sudo_debug_file *debug_file;
+    const char *filename, *flags;
+    size_t namelen;
+
+    /* Only process new-style debug flags: filename flags,... */
+    filename = entry;
+    if (*filename != '/' || (flags = strpbrk(filename, " \t")) == NULL)
+	return true;
+    namelen = (size_t)(flags - filename);
+    while (isblank((unsigned char)*flags))
+	flags++;
+    if (*flags != '\0') {
+	if ((debug_file = calloc(1, sizeof(*debug_file))) == NULL)
+	    goto oom;
+	if ((debug_file->debug_file = strndup(filename, namelen)) == NULL)
+	    goto oom;
+	if ((debug_file->debug_flags = strdup(flags)) == NULL)
+	    goto oom;
+	TAILQ_INSERT_TAIL(debug_files, debug_file, entries);
+    }
+    return true;
+oom:
+    if (debug_file != NULL) {
+	free(debug_file->debug_file);
+	free(debug_file->debug_flags);
+	free(debug_file);
+    }
+    return false;
+}
+
+static int
+approval_check(unsigned int version, sudo_conv_t conversation,
+    sudo_printf_t plugin_printf, char * const settings[],
+    char * const user_info[], int submit_optind, char * const submit_argv[],
+    char * const submit_envp[], char * const command_info[],
+    char * const run_argv[], char * const run_envp[],
+    char * const plugin_options[], const char **errstr)
+{
+    struct sudo_conf_debug_file_list debug_files =
+	TAILQ_HEAD_INITIALIZER(debug_files);
+    struct sudo_debug_file *debug_file;
+    const char *cp, *plugin_path = NULL;
+    char * const *cur;
+    struct tm *tm;
+    time_t now;
+    int ret = -1;
+    debug_decl(approval_check, SUDO_DEBUG_PLUGIN);
+
+    /* Initialize the debug subsystem.  */
+    for (cur = settings; (cp = *cur) != NULL; cur++) {
+        if (strncmp(cp, "debug_flags=", sizeof("debug_flags=") - 1) == 0) {
+            cp += sizeof("debug_flags=") - 1;
+            if (!sudo_debug_parse_flags(&debug_files, cp)) {
+                goto oom;
+	    }
+            continue;
+        }
+        if (strncmp(cp, "plugin_path=", sizeof("plugin_path=") - 1) == 0) {
+            plugin_path = cp + sizeof("plugin_path=") - 1;
+            continue;
+        }
+    }
+    if (plugin_path != NULL && !TAILQ_EMPTY(&debug_files)) {
+	approval_debug_instance =
+	    sudo_debug_register(plugin_path, NULL, NULL, &debug_files);
+	if (approval_debug_instance == SUDO_DEBUG_INSTANCE_ERROR) {
+	    *errstr = U_("unable to initialize debugging");
+	    goto bad;
+	}
+    }
+
+    /*
+     * Only approve requests that are within business hours,
+     * which are 9am - 5pm local time.  Does not check holidays.
+     */
+    ret = 0;
+    time(&now);
+    tm = localtime(&now);
+    if (tm->tm_wday < 1 || tm->tm_wday > 5) {
+	/* bad weekday */
+	goto bad;
+    }
+    if (tm->tm_hour < 9 || tm->tm_hour > 17 ||
+	    (tm->tm_hour == 17 && tm->tm_min > 0)) {
+	/* bad hour */
+	goto bad;
+    }
+
+    ret = 1;
+    goto done;
+
+oom:
+    sudo_warnx(U_("%s: %s"), __func__, U_("unable to allocate memory"));
+    *errstr = U_("unable to allocate memory");
+
+bad:
+    if (ret == 0) {
+	*errstr = U_("You are not allowed to use sudo outside business hours");
+	plugin_printf(SUDO_CONV_ERROR_MSG, "%s\n", *errstr);
+    }
+
+done:
+    while ((debug_file = TAILQ_FIRST(&debug_files))) {
+	TAILQ_REMOVE(&debug_files, debug_file, entries);
+	free(debug_file->debug_file);
+	free(debug_file->debug_flags);
+	free(debug_file);
+    }
+
+    debug_return_int(ret);
+}
+
+static int
+approval_show_version(unsigned int version, sudo_conv_t conversation,
+    sudo_printf_t plugin_printf, int verbose)
+{
+    debug_decl(approval_show_version, SUDO_DEBUG_PLUGIN);
+
+    plugin_printf(SUDO_CONV_INFO_MSG, "sample approval plugin version %s\n",
+        PACKAGE_VERSION);
+
+    debug_return_int(true);
+}
+
+__dso_public struct approval_plugin sample_approval = {
+    SUDO_APPROVAL_PLUGIN,
+    SUDO_API_VERSION,
+    approval_check,
+    approval_show_version
+};