shadow/lib/chkname.c
Alejandro Colomar 1c127bd173 lib/chkname.c: is_valid_{user,group}_name(): Set errno to distinguish the reasons
Signed-off-by: Alejandro Colomar <alx@kernel.org>
2024-09-01 08:17:11 -05:00

141 lines
2.7 KiB
C

// SPDX-FileCopyrightText: 1990-1994, Julianne Frances Haugh
// SPDX-FileCopyrightText: 1996-2000, Marek Michałkiewicz
// SPDX-FileCopyrightText: 2001-2005, Tomasz Kłoczko
// SPDX-FileCopyrightText: 2005-2008, Nicolas François
// SPDX-FileCopyrightText: 2023-2024, Alejandro Colomar <alx@kernel.org>
// SPDX-License-Identifier: BSD-3-Clause
/*
* is_valid_user_name(), is_valid_group_name() - check the new user/group
* name for validity;
* return values:
* true - OK
* false - bad name
* errors:
* EINVAL Invalid name characters or sequences
* EOVERFLOW Name longer than maximum size
*/
#include <config.h>
#ident "$Id$"
#include <ctype.h>
#include <errno.h>
#include <limits.h>
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
#include <sys/param.h>
#include <unistd.h>
#include "defines.h"
#include "chkname.h"
int allow_bad_names = false;
size_t
login_name_max_size(void)
{
long conf;
errno = 0;
conf = sysconf(_SC_LOGIN_NAME_MAX);
if (conf == -1 && errno != 0)
return LOGIN_NAME_MAX;
return MIN(conf, PTRDIFF_MAX);
}
static bool
is_valid_name(const char *name)
{
if (allow_bad_names) {
return true;
}
/*
* User/group names must match BRE regex:
* [a-zA-Z0-9_.][a-zA-Z0-9_.-]*$\?
*
* as a non-POSIX, extension, allow "$" as the last char for
* sake of Samba 3.x "add machine script"
*
* Also do not allow fully numeric names or just "." or "..".
*/
int numeric;
if ('\0' == *name ||
('.' == *name && (('.' == name[1] && '\0' == name[2]) ||
'\0' == name[1])) ||
!((*name >= 'a' && *name <= 'z') ||
(*name >= 'A' && *name <= 'Z') ||
(*name >= '0' && *name <= '9') ||
*name == '_' ||
*name == '.'))
{
errno = EINVAL;
return false;
}
numeric = isdigit(*name);
while ('\0' != *++name) {
if (!((*name >= 'a' && *name <= 'z') ||
(*name >= 'A' && *name <= 'Z') ||
(*name >= '0' && *name <= '9') ||
*name == '_' ||
*name == '.' ||
*name == '-' ||
(*name == '$' && name[1] == '\0')
))
{
errno = EINVAL;
return false;
}
numeric &= isdigit(*name);
}
if (numeric) {
errno = EINVAL;
return false;
}
return true;
}
bool
is_valid_user_name(const char *name)
{
if (strlen(name) >= login_name_max_size()) {
errno = EOVERFLOW;
return false;
}
return is_valid_name(name);
}
bool
is_valid_group_name(const char *name)
{
/*
* Arbitrary limit for group names.
* HP-UX 10 limits to 16 characters
*/
if ( (GROUP_NAME_MAX_LENGTH > 0)
&& (strlen (name) > GROUP_NAME_MAX_LENGTH))
{
errno = EOVERFLOW;
return false;
}
return is_valid_name (name);
}