glibc/nis/nis_local_names.c
Stefan Liebler 1e0c8356f5 nis: Fix stringop-truncation warning with -O3 in nis_local_host.
When building with -O3 on s390x/x86_64, I get this stringop-truncation warning
which leads to a build fail:

In function ‘nis_local_host’,
    inlined from ‘nis_local_host’ at nis_local_names.c:147:1:
nis_local_names.c:171:11: error: ‘strncpy’ output may be truncated copying between 0 and 1023 bytes from a string of length 1024 [-Werror=stringop-truncation]
171 |           strncpy (cp, nis_local_directory (), NIS_MAXNAMELEN - len -1);
       |           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We can just ignore this warning as the hostname + '.' + directory-name + '\0' always fits
in __nishostname with length of (NIS_MAXNAMELEN + 1) as there is the runtime check above.
Furthermore as we already know the length of the directory-name, we can also just use
memcpy to copy the directory-name inclusive the NUL-termination.

Note: This werror was introduced with commit
32c7acd464
"Replace rawmemchr (s, '\0') with strchr"

Reviewed-by: Wilco Dijkstra  <Wilco.Dijkstra@arm.com>
2023-03-02 14:22:54 +01:00

183 lines
4.4 KiB
C

/* Copyright (c) 1997-2023 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#include <errno.h>
#include <string.h>
#include <unistd.h>
#include <libintl.h>
#include <rpcsvc/nis.h>
#include <shlib-compat.h>
nis_name
nis_local_group (void)
{
static char __nisgroup[NIS_MAXNAMELEN + 1];
char *cptr;
if (__nisgroup[0] == '\0'
&& (cptr = getenv ("NIS_GROUP")) != NULL
&& cptr[0] != '\0'
&& strlen (cptr) < NIS_MAXNAMELEN)
{
char *cp = stpcpy (__nisgroup, cptr);
if (cp[-1] != '.')
{
cptr = nis_local_directory ();
if ((cp - __nisgroup) + strlen (cptr) + 1 < NIS_MAXNAMELEN)
{
*cp++ = '.';
strcpy (cp, cptr);
}
else
__nisgroup[0] = '\0';
}
}
return __nisgroup;
}
libnsl_hidden_nolink_def (nis_local_group, GLIBC_2_1)
nis_name
nis_local_directory (void)
{
static char __nisdomainname[NIS_MAXNAMELEN + 1];
if (__nisdomainname[0] == '\0')
{
if (getdomainname (__nisdomainname, NIS_MAXNAMELEN) < 0)
__nisdomainname[0] = '\0';
else
{
char *cp = strchr (__nisdomainname, '\0');
/* Missing trailing dot? */
if (cp[-1] != '.')
{
*cp++ = '.';
*cp = '\0';
}
}
}
return __nisdomainname;
}
libnsl_hidden_nolink_def (nis_local_directory, GLIBC_2_1)
nis_name
nis_local_principal (void)
{
static char __principal[NIS_MAXNAMELEN + 1];
if (__principal[0] == '\0')
{
char buf[NIS_MAXNAMELEN + 1];
nis_result *res;
uid_t uid = geteuid ();
if (uid != 0)
{
int len = snprintf (buf, NIS_MAXNAMELEN - 1,
"[auth_name=%d,auth_type=LOCAL],cred.org_dir.%s",
uid, nis_local_directory ());
if (len >= NIS_MAXNAMELEN - 1)
nobody:
/* XXX The buffer is too small. Can this happen??? */
return strcpy (__principal, "nobody");
if (buf[len - 1] != '.')
{
buf[len++] = '.';
buf[len] = '\0';
}
res = nis_list (buf, USE_DGRAM + NO_AUTHINFO + FOLLOW_LINKS
+ FOLLOW_PATH, NULL, NULL);
if (res == NULL)
goto nobody;
if (NIS_RES_STATUS (res) == NIS_SUCCESS)
{
if (res->objects.objects_len > 1)
{
/* More than one principal with same uid? something
wrong with cred table. Should be unique. Warn user
and continue. */
printf (_("\
LOCAL entry for UID %d in directory %s not unique\n"),
uid, nis_local_directory ());
}
strcpy (__principal, ENTRY_VAL (res->objects.objects_val, 0));
nis_freeresult (res);
return __principal;
}
else
{
nis_freeresult (res);
goto nobody;
}
}
else
return strcpy (__principal, nis_local_host ());
/* Should be never reached */
goto nobody;
}
return __principal;
}
libnsl_hidden_nolink_def (nis_local_principal, GLIBC_2_1)
nis_name
nis_local_host (void)
{
static char __nishostname[NIS_MAXNAMELEN + 1];
if (__nishostname[0] == '\0')
{
if (gethostname (__nishostname, NIS_MAXNAMELEN) < 0)
__nishostname[0] = '\0';
else
{
char *cp = strchr (__nishostname, '\0');
int len = cp - __nishostname;
/* Hostname already fully qualified? */
if (cp[-1] == '.')
return __nishostname;
nis_name local_directory = nis_local_directory ();
size_t local_directory_len = strlen (local_directory);
if (len + 1 + local_directory_len > NIS_MAXNAMELEN)
{
__nishostname[0] = '\0';
return __nishostname;
}
/* We have enough space in __nishostname with length of
(NIS_MAXNAMELEN + 1) for
hostname + '.' + directory-name + '\0'. */
*cp++ = '.';
memcpy (cp, local_directory, local_directory_len + 1);
}
}
return __nishostname;
}
libnsl_hidden_nolink_def (nis_local_host, GLIBC_2_1)