/* $NetBSD: acl.c,v 1.2.22.1 2023/08/11 13:40:00 martin Exp $ */ /* * Copyright (c) 2000 - 2002, 2004 Kungliga Tekniska Högskolan * (Royal Institute of Technology, Stockholm, Sweden). * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * 3. Neither the name of the Institute nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #include "krb5_locl.h" #include struct acl_field { enum { acl_string, acl_fnmatch, acl_retval } type; union { const char *cstr; char **retv; } u; struct acl_field *next, **last; }; static void free_retv(struct acl_field *acl) { while(acl != NULL) { if (acl->type == acl_retval) { if (*acl->u.retv) free(*acl->u.retv); *acl->u.retv = NULL; } acl = acl->next; } } static void acl_free_list(struct acl_field *acl, int retv) { struct acl_field *next; if (retv) free_retv(acl); while(acl != NULL) { next = acl->next; free(acl); acl = next; } } static krb5_error_code acl_parse_format(krb5_context context, struct acl_field **acl_ret, const char *format, va_list ap) { const char *p; struct acl_field *acl = NULL, *tmp; for(p = format; *p != '\0'; p++) { tmp = malloc(sizeof(*tmp)); if(tmp == NULL) { acl_free_list(acl, 0); return krb5_enomem(context); } if(*p == 's') { tmp->type = acl_string; tmp->u.cstr = va_arg(ap, const char*); } else if(*p == 'f') { tmp->type = acl_fnmatch; tmp->u.cstr = va_arg(ap, const char*); } else if(*p == 'r') { tmp->type = acl_retval; tmp->u.retv = va_arg(ap, char **); *tmp->u.retv = NULL; } else { krb5_set_error_message(context, EINVAL, N_("Unknown format specifier %c while " "parsing ACL", "specifier"), *p); acl_free_list(acl, 0); free(tmp); return EINVAL; } tmp->next = NULL; if(acl == NULL) acl = tmp; else *acl->last = tmp; acl->last = &tmp->next; } *acl_ret = acl; return 0; } static krb5_boolean acl_match_field(krb5_context context, const char *string, struct acl_field *field) { if(field->type == acl_string) { return !strcmp(field->u.cstr, string); } else if(field->type == acl_fnmatch) { return !fnmatch(field->u.cstr, string, 0); } else if(field->type == acl_retval) { *field->u.retv = strdup(string); return TRUE; } return FALSE; } static krb5_boolean acl_match_acl(krb5_context context, struct acl_field *acl, const char *string) { char buf[256]; while(strsep_copy(&string, " \t", buf, sizeof(buf)) != -1) { if(buf[0] == '\0') continue; /* skip ws */ if (acl == NULL) return FALSE; if(!acl_match_field(context, buf, acl)) { return FALSE; } acl = acl->next; } if (acl) return FALSE; return TRUE; } /** * krb5_acl_match_string matches ACL format against a string. * * The ACL format has three format specifiers: s, f, and r. Each * specifier will retrieve one argument from the variable arguments * for either matching or storing data. The input string is split up * using " " (space) and "\t" (tab) as a delimiter; multiple and "\t" * in a row are considered to be the same. * * List of format specifiers: * - s Matches a string using strcmp(3) (case sensitive). * - f Matches the string with fnmatch(3). Theflags * argument (the last argument) passed to the fnmatch function is 0. * - r Returns a copy of the string in the char ** passed in; the copy * must be freed with free(3). There is no need to free(3) the * string on error: the function will clean up and set the pointer * to NULL. * * @param context Kerberos 5 context * @param string string to match with * @param format format to match * @param ... parameter to format string * * @return Return an error code or 0. * * * @code * char *s; * * ret = krb5_acl_match_string(context, "foo", "s", "foo"); * if (ret) * krb5_errx(context, 1, "acl didn't match"); * ret = krb5_acl_match_string(context, "foo foo baz/kaka", * "ss", "foo", &s, "foo/\\*"); * if (ret) { * // no need to free(s) on error * assert(s == NULL); * krb5_errx(context, 1, "acl didn't match"); * } * free(s); * @endcode * * @sa krb5_acl_match_file * @ingroup krb5_support */ KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL krb5_acl_match_string(krb5_context context, const char *string, const char *format, ...) { krb5_error_code ret; krb5_boolean found; struct acl_field *acl; va_list ap; va_start(ap, format); ret = acl_parse_format(context, &acl, format, ap); va_end(ap); if(ret) return ret; found = acl_match_acl(context, acl, string); acl_free_list(acl, !found); if (found) { return 0; } else { krb5_set_error_message(context, EACCES, N_("ACL did not match", "")); return EACCES; } } /** * krb5_acl_match_file matches ACL format against each line in a file * using krb5_acl_match_string(). Lines starting with # are treated * like comments and ignored. * * @param context Kerberos 5 context. * @param file file with acl listed in the file. * @param format format to match. * @param ... parameter to format string. * * @return Return an error code or 0. * * @sa krb5_acl_match_string * @ingroup krb5_support */ KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL krb5_acl_match_file(krb5_context context, const char *file, const char *format, ...) { krb5_error_code ret; struct acl_field *acl = NULL; char buf[256]; va_list ap; FILE *f; krb5_boolean found; f = fopen(file, "r"); if(f == NULL) { int save_errno = errno; rk_strerror_r(save_errno, buf, sizeof(buf)); krb5_set_error_message(context, save_errno, N_("open(%s): %s", "file, errno"), file, buf); return save_errno; } rk_cloexec_file(f); va_start(ap, format); ret = acl_parse_format(context, &acl, format, ap); va_end(ap); if(ret) { fclose(f); return ret; } found = FALSE; while(fgets(buf, sizeof(buf), f)) { if(buf[0] == '#') continue; if(acl_match_acl(context, acl, buf)) { found = TRUE; break; } free_retv(acl); } fclose(f); acl_free_list(acl, !found); if (found) { return 0; } else { krb5_set_error_message(context, EACCES, N_("ACL did not match", "")); return EACCES; } }