* settings from krb5.conf. This wraps the somewhat awkward
* krb5_appdefaults_* functions.
*
- * Written by Russ Allbery <rra@stanford.edu>
+ * Written by Russ Allbery <eagle@eyrie.org>
+ * Copyright 2016 Russ Allbery <eagle@eyrie.org>
* Copyright 2013
* The Board of Trustees of the Leland Stanford Junior University
*
- * See LICENSE for licensing terms.
+ * SPDX-License-Identifier: MIT
*/
#include <config.h>
#include <portable/krb5.h>
#include <portable/system.h>
+#include <ctype.h>
#include <errno.h>
#include <plugin/internal.h>
typedef krb5_data *realm_type;
#endif
+/* Maximum number of character classes. */
+#define MAX_CLASSES 4
+
/*
* Obtain the default realm and translate it into the format required by
return NULL;
code = krb5_get_default_realm(ctx, &realm);
if (code != 0) {
- free(realm);
+ free(realm_data);
return NULL;
}
realm_data->magic = KV5M_DATA;
krb5_free_default_realm(ctx, realm);
return NULL;
}
- realm_data->length = strlen(realm);
+ realm_data->length = (unsigned int) strlen(realm);
krb5_free_default_realm(ctx, realm);
return realm_data;
}
#endif /* !HAVE_KRB5_REALM */
+/*
+ * Helper function to parse a number. Takes the string to parse, the unsigned
+ * int in which to store the number, and the pointer to set to the first
+ * invalid character after the number. Returns true if a number could be
+ * successfully parsed and false otherwise.
+ */
+static bool
+parse_number(const char *string, unsigned long *result, const char **end)
+{
+ unsigned long value;
+
+ errno = 0;
+ value = strtoul(string, (char **) end, 10);
+ if (errno != 0 || *end == string)
+ return false;
+ *result = value;
+ return true;
+}
+
+
/*
* Load a boolean option from Kerberos appdefaults. Takes the Kerberos
* context, the option, and the result location.
}
+/*
+ * Parse a single class specification. Currently, this assumes that the class
+ * specification is a comma-separated list of required classes, and those
+ * classes are required for any length of password. This will be enhanced
+ * later.
+ */
+static krb5_error_code
+parse_class(krb5_context ctx, const char *spec, struct class_rule **rule)
+{
+ struct vector *classes = NULL;
+ size_t i;
+ krb5_error_code code;
+ const char *class, *end;
+ bool okay;
+
+ /* Create the basic rule structure. */
+ *rule = calloc(1, sizeof(struct class_rule));
+ if (*rule == NULL)
+ return strength_error_system(ctx, "cannot allocate memory");
+
+ /*
+ * If the rule starts with a digit and contains a '-', it starts
+ * with a range of affected password lengths. Parse that range.
+ */
+ if (isdigit((unsigned char) *spec) && strchr(spec, '-') != NULL) {
+ okay = parse_number(spec, &(*rule)->min, &end);
+ if (okay)
+ okay = (*end == '-');
+ if (okay)
+ okay = parse_number(end + 1, &(*rule)->max, &end);
+ if (okay)
+ okay = (*end == ':');
+ if (okay)
+ spec = end + 1;
+ else {
+ code = strength_error_config(ctx,
+ "bad character class requirement in"
+ " configuration: %s",
+ spec);
+ goto fail;
+ }
+ }
+
+ /* Parse the required classes into a vector. */
+ classes = strength_vector_split_multi(spec, ",", NULL);
+ if (classes == NULL) {
+ code = strength_error_system(ctx, "cannot allocate memory");
+ goto fail;
+ }
+
+ /*
+ * Walk the list of required classes and set our flags, diagnosing an
+ * unknown character class.
+ */
+ for (i = 0; i < classes->count; i++) {
+ class = classes->strings[i];
+ if (strcmp(class, "upper") == 0)
+ (*rule)->upper = true;
+ else if (strcmp(class, "lower") == 0)
+ (*rule)->lower = true;
+ else if (strcmp(class, "digit") == 0)
+ (*rule)->digit = true;
+ else if (strcmp(class, "symbol") == 0)
+ (*rule)->symbol = true;
+ else if (isdigit((unsigned char) *class)) {
+ okay = parse_number(class, &(*rule)->num_classes, &end);
+ if (!okay || *end != '\0' || (*rule)->num_classes > MAX_CLASSES) {
+ code = strength_error_config(ctx,
+ "bad character class minimum in"
+ " configuration: %s",
+ class);
+ goto fail;
+ }
+ } else {
+ code = strength_error_config(ctx, "unknown character class %s",
+ class);
+ goto fail;
+ }
+ }
+ strength_vector_free(classes);
+ return 0;
+
+fail:
+ strength_vector_free(classes);
+ free(*rule);
+ *rule = NULL;
+ return code;
+}
+
+
+/*
+ * Parse character class requirements from Kerberos appdefaults. Takes the
+ * Kerberos context, the option, and the place to store the linked list of
+ * class requirements.
+ */
+krb5_error_code
+strength_config_classes(krb5_context ctx, const char *opt,
+ struct class_rule **result)
+{
+ struct vector *config = NULL;
+ struct class_rule *rules, *last, *tmp;
+ krb5_error_code code;
+ size_t i;
+
+ /* Get the basic configuration as a list. */
+ code = strength_config_list(ctx, opt, &config);
+ if (code != 0)
+ return code;
+ if (config == NULL || config->count == 0) {
+ *result = NULL;
+ return 0;
+ }
+
+ /* Each word in the list will be a class rule. */
+ code = parse_class(ctx, config->strings[0], &rules);
+ if (code != 0 || rules == NULL)
+ goto fail;
+ last = rules;
+ for (i = 1; i < config->count; i++) {
+ code = parse_class(ctx, config->strings[i], &last->next);
+ if (code != 0 || last->next == NULL)
+ goto fail;
+ last = last->next;
+ }
+
+ /* Success. Free the vector and return the results. */
+ strength_vector_free(config);
+ *result = rules;
+ return 0;
+
+fail:
+ last = rules;
+ while (last != NULL) {
+ tmp = last;
+ last = last->next;
+ free(tmp);
+ }
+ strength_vector_free(config);
+ return code;
+}
+
+
+/*
+ * Load a list option from Kerberos appdefaults. Takes the Kerberos context,
+ * the option, and the result location. The option is read as a string and
+ * the split on spaces and tabs into a list.
+ *
+ * This requires an annoying workaround because one cannot specify a default
+ * value of NULL with MIT Kerberos, since MIT Kerberos unconditionally calls
+ * strdup on the default value. There's also no way to determine if memory
+ * allocation failed while parsing or while setting the default value.
+ */
+krb5_error_code
+strength_config_list(krb5_context ctx, const char *opt, struct vector **result)
+{
+ realm_type realm;
+ char *value = NULL;
+
+ /* Obtain the string from [appdefaults]. */
+ realm = default_realm(ctx);
+ krb5_appdefault_string(ctx, "krb5-strength", realm, opt, "", &value);
+ free_default_realm(ctx, realm);
+
+ /* If we got something back, store it in result. */
+ if (value != NULL) {
+ if (value[0] != '\0') {
+ *result = strength_vector_split_multi(value, " \t", *result);
+ if (*result == NULL)
+ return strength_error_system(ctx, "cannot allocate memory");
+ }
+ krb5_free_string(ctx, value);
+ }
+ return 0;
+}
+
+
/*
* Load a number option from Kerberos appdefaults. Takes the Kerberos
* context, the option, and the result location. The native interface doesn't
projects / kerberos / krb5-strength.git / blobdiff