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/*
* 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 <fnmatch.h>
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) == 0;
} 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;
}
}
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