/* Copyright (C) 1996-2018 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Thorsten Kukuk <kukuk@suse.de>, 1996.
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
<http://www.gnu.org/licenses/>. */
#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <grp.h>
#include <nss.h>
#include <nsswitch.h>
#include <stdio_ext.h>
#include <string.h>
#include <libc-lock.h>
#include <kernel-features.h>
static service_user *ni;
static enum nss_status (*nss_setgrent) (int stayopen);
static enum nss_status (*nss_getgrnam_r) (const char *name,
struct group * grp, char *buffer,
size_t buflen, int *errnop);
static enum nss_status (*nss_getgrgid_r) (gid_t gid, struct group * grp,
char *buffer, size_t buflen,
int *errnop);
static enum nss_status (*nss_getgrent_r) (struct group * grp, char *buffer,
size_t buflen, int *errnop);
static enum nss_status (*nss_endgrent) (void);
/* Get the declaration of the parser function. */
#define ENTNAME grent
#define STRUCTURE group
#define EXTERN_PARSER
#include <nss/nss_files/files-parse.c>
/* Structure for remembering -group members ... */
#define BLACKLIST_INITIAL_SIZE 512
#define BLACKLIST_INCREMENT 256
struct blacklist_t
{
char *data;
int current;
int size;
};
struct ent_t
{
bool files;
enum nss_status setent_status;
FILE *stream;
struct blacklist_t blacklist;
};
typedef struct ent_t ent_t;
static ent_t ext_ent = { true, NSS_STATUS_SUCCESS, NULL, { NULL, 0, 0 }};
/* Protect global state against multiple changers. */
__libc_lock_define_initialized (static, lock)
/* Prototypes for local functions. */
static void blacklist_store_name (const char *, ent_t *);
static bool in_blacklist (const char *, int, ent_t *);
/* Initialize the NSS interface/functions. The calling function must
hold the lock. */
static void
init_nss_interface (void)
{
if (__nss_database_lookup2 ("group_compat", NULL, "nis", &ni) >= 0)
{
nss_setgrent = __nss_lookup_function (ni, "setgrent");
nss_getgrnam_r = __nss_lookup_function (ni, "getgrnam_r");
nss_getgrgid_r = __nss_lookup_function (ni, "getgrgid_r");
nss_getgrent_r = __nss_lookup_function (ni, "getgrent_r");
nss_endgrent = __nss_lookup_function (ni, "endgrent");
}
}
static enum nss_status
internal_setgrent (ent_t *ent, int stayopen, int needent)
{
enum nss_status status = NSS_STATUS_SUCCESS;
ent->files = true;
if (ent->blacklist.data != NULL)
{
ent->blacklist.current = 1;
ent->blacklist.data[0] = '|';
ent->blacklist.data[1] = '\0';
}
else
ent->blacklist.current = 0;
if (ent->stream == NULL)
{
ent->stream = fopen ("/etc/group", "rme");
if (ent->stream == NULL)
status = errno == EAGAIN ? NSS_STATUS_TRYAGAIN : NSS_STATUS_UNAVAIL;
else
/* We take care of locking ourself. */
__fsetlocking (ent->stream, FSETLOCKING_BYCALLER);
}
else
rewind (ent->stream);
if (needent && status == NSS_STATUS_SUCCESS && nss_setgrent)
ent->setent_status = nss_setgrent (stayopen);
return status;
}
enum nss_status
_nss_compat_setgrent (int stayopen)
{
enum nss_status result;
__libc_lock_lock (lock);
if (ni == NULL)
init_nss_interface ();
result = internal_setgrent (&ext_ent, stayopen, 1);
__libc_lock_unlock (lock);
return result;
}
static enum nss_status __attribute_warn_unused_result__
internal_endgrent (ent_t *ent)
{
if (ent->stream != NULL)
{
fclose (ent->stream);
ent->stream = NULL;
}
if (ent->blacklist.data != NULL)
{
ent->blacklist.current = 1;
ent->blacklist.data[0] = '|';
ent->blacklist.data[1] = '\0';
}
else
ent->blacklist.current = 0;
return NSS_STATUS_SUCCESS;
}
/* Like internal_endgrent, but preserve errno in all cases. */
static void
internal_endgrent_noerror (ent_t *ent)
{
int saved_errno = errno;
enum nss_status unused __attribute__ ((unused)) = internal_endgrent (ent);
__set_errno (saved_errno);
}
enum nss_status
_nss_compat_endgrent (void)
{
enum nss_status result;
__libc_lock_lock (lock);
if (nss_endgrent)
nss_endgrent ();
result = internal_endgrent (&ext_ent);
__libc_lock_unlock (lock);
return result;
}
/* get the next group from NSS (+ entry) */
static enum nss_status
getgrent_next_nss (struct group *result, ent_t *ent, char *buffer,
size_t buflen, int *errnop)
{
if (!nss_getgrent_r)
return NSS_STATUS_UNAVAIL;
/* If the setgrent call failed, say so. */
if (ent->setent_status != NSS_STATUS_SUCCESS)
return ent->setent_status;
do
{
enum nss_status status;
if ((status = nss_getgrent_r (result, buffer, buflen, errnop)) !=
NSS_STATUS_SUCCESS)
return status;
}
while (in_blacklist (result->gr_name, strlen (result->gr_name), ent));
return NSS_STATUS_SUCCESS;
}
/* This function handle the +group entrys in /etc/group */
static enum nss_status
getgrnam_plusgroup (const char *name, struct group *result, ent_t *ent,
char *buffer, size_t buflen, int *errnop)
{
if (!nss_getgrnam_r)
return NSS_STATUS_UNAVAIL;
enum nss_status status = nss_getgrnam_r (name, result, buffer, buflen,
errnop);
if (status != NSS_STATUS_SUCCESS)
return status;
if (in_blacklist (result->gr_name, strlen (result->gr_name), ent))
return NSS_STATUS_NOTFOUND;
/* We found the entry. */
return NSS_STATUS_SUCCESS;
}
static enum nss_status
getgrent_next_file (struct group *result, ent_t *ent,
char *buffer, size_t buflen, int *errnop)
{
struct parser_data *data = (void *) buffer;
while (1)
{
fpos_t pos;
int parse_res = 0;
char *p;
do
{
/* We need at least 3 characters for one line. */
if (__glibc_unlikely (buflen < 3))
{
erange:
*errnop = ERANGE;
return NSS_STATUS_TRYAGAIN;
}
fgetpos (ent->stream, &pos);
buffer[buflen - 1] = '\xff';
p = fgets_unlocked (buffer, buflen, ent->stream);
if (p == NULL && feof_unlocked (ent->stream))
return NSS_STATUS_NOTFOUND;
if (p == NULL || __builtin_expect (buffer[buflen - 1] != '\xff', 0))
{
erange_reset:
fsetpos (ent->stream, &pos);
goto erange;
}
/* Terminate the line for any case. */
buffer[buflen - 1] = '\0';
/* Skip leading blanks. */
while (isspace (*p))
++p;
}
while (*p == '\0' || *p == '#' || /* Ignore empty and comment lines. */
/* Parse the line. If it is invalid, loop to
get the next line of the file to parse. */
!(parse_res = _nss_files_parse_grent (p, result, data, buflen,
errnop)));
if (__glibc_unlikely (parse_res == -1))
/* The parser ran out of space. */
goto erange_reset;
if (result->gr_name[0] != '+' && result->gr_name[0] != '-')
/* This is a real entry. */
break;
/* -group */
if (result->gr_name[0] == '-' && result->gr_name[1] != '\0'
&& result->gr_name[1] != '@')
{
blacklist_store_name (&result->gr_name[1], ent);
continue;
}
/* +group */
if (result->gr_name[0] == '+' && result->gr_name[1] != '\0'
&& result->gr_name[1] != '@')
{
size_t len = strlen (result->gr_name);
char buf[len];
enum nss_status status;
/* Store the group in the blacklist for the "+" at the end of
/etc/group */
memcpy (buf, &result->gr_name[1], len);
status = getgrnam_plusgroup (&result->gr_name[1], result, ent,
buffer, buflen, errnop);
blacklist_store_name (buf, ent);
if (status == NSS_STATUS_SUCCESS) /* We found the entry. */
break;
else if (status == NSS_STATUS_RETURN /* We couldn't parse the entry*/
|| status == NSS_STATUS_NOTFOUND) /* No group in NIS */
continue;
else
{
if (status == NSS_STATUS_TRYAGAIN)
/* The parser ran out of space. */
goto erange_reset;
return status;
}
}
/* +:... */
if (result->gr_name[0] == '+' && result->gr_name[1] == '\0')
{
ent->files = false;
return getgrent_next_nss (result, ent, buffer, buflen, errnop);
}
}
return NSS_STATUS_SUCCESS;
}
enum nss_status
_nss_compat_getgrent_r (struct group *grp, char *buffer, size_t buflen,
int *errnop)
{
enum nss_status result = NSS_STATUS_SUCCESS;
__libc_lock_lock (lock);
/* Be prepared that the setgrent function was not called before. */
if (ni == NULL)
init_nss_interface ();
if (ext_ent.stream == NULL)
result = internal_setgrent (&ext_ent, 1, 1);
if (result == NSS_STATUS_SUCCESS)
{
if (ext_ent.files)
result = getgrent_next_file (grp, &ext_ent, buffer, buflen, errnop);
else
result = getgrent_next_nss (grp, &ext_ent, buffer, buflen, errnop);
}
__libc_lock_unlock (lock);
return result;
}
/* Searches in /etc/group and the NIS/NIS+ map for a special group */
static enum nss_status
internal_getgrnam_r (const char *name, struct group *result, ent_t *ent,
char *buffer, size_t buflen, int *errnop)
{
struct parser_data *data = (void *) buffer;
while (1)
{
fpos_t pos;
int parse_res = 0;
char *p;
do
{
/* We need at least 3 characters for one line. */
if (__glibc_unlikely (buflen < 3))
{
erange:
*errnop = ERANGE;
return NSS_STATUS_TRYAGAIN;
}
fgetpos (ent->stream, &pos);
buffer[buflen - 1] = '\xff';
p = fgets_unlocked (buffer, buflen, ent->stream);
if (p == NULL && feof_unlocked (ent->stream))
return NSS_STATUS_NOTFOUND;
if (p == NULL || __builtin_expect (buffer[buflen - 1] != '\xff', 0))
{
erange_reset:
fsetpos (ent->stream, &pos);
goto erange;
}
/* Terminate the line for any case. */
buffer[buflen - 1] = '\0';
/* Skip leading blanks. */
while (isspace (*p))
++p;
}
while (*p == '\0' || *p == '#' || /* Ignore empty and comment lines. */
/* Parse the line. If it is invalid, loop to
get the next line of the file to parse. */
!(parse_res = _nss_files_parse_grent (p, result, data, buflen,
errnop)));
if (__glibc_unlikely (parse_res == -1))
/* The parser ran out of space. */
goto erange_reset;
/* This is a real entry. */
if (result->gr_name[0] != '+' && result->gr_name[0] != '-')
{
if (strcmp (result->gr_name, name) == 0)
return NSS_STATUS_SUCCESS;
else
continue;
}
/* -group */
if (result->gr_name[0] == '-' && result->gr_name[1] != '\0')
{
if (strcmp (&result->gr_name[1], name) == 0)
return NSS_STATUS_NOTFOUND;
else
continue;
}
/* +group */
if (result->gr_name[0] == '+' && result->gr_name[1] != '\0')
{
if (strcmp (name, &result->gr_name[1]) == 0)
{
enum nss_status status;
status = getgrnam_plusgroup (name, result, ent,
buffer, buflen, errnop);
if (status == NSS_STATUS_RETURN)
/* We couldn't parse the entry */
continue;
else
return status;
}
}
/* +:... */
if (result->gr_name[0] == '+' && result->gr_name[1] == '\0')
{
enum nss_status status;
status = getgrnam_plusgroup (name, result, ent,
buffer, buflen, errnop);
if (status == NSS_STATUS_RETURN)
/* We couldn't parse the entry */
continue;
else
return status;
}
}
return NSS_STATUS_SUCCESS;
}
enum nss_status
_nss_compat_getgrnam_r (const char *name, struct group *grp,
char *buffer, size_t buflen, int *errnop)
{
ent_t ent = { true, NSS_STATUS_SUCCESS, NULL, { NULL, 0, 0 }};
enum nss_status result;
if (name[0] == '-' || name[0] == '+')
return NSS_STATUS_NOTFOUND;
__libc_lock_lock (lock);
if (ni == NULL)
init_nss_interface ();
__libc_lock_unlock (lock);
result = internal_setgrent (&ent, 0, 0);
if (result == NSS_STATUS_SUCCESS)
result = internal_getgrnam_r (name, grp, &ent, buffer, buflen, errnop);
internal_endgrent_noerror (&ent);
return result;
}
/* Searches in /etc/group and the NIS/NIS+ map for a special group id */
static enum nss_status
internal_getgrgid_r (gid_t gid, struct group *result, ent_t *ent,
char *buffer, size_t buflen, int *errnop)
{
struct parser_data *data = (void *) buffer;
while (1)
{
fpos_t pos;
int parse_res = 0;
char *p;
do
{
/* We need at least 3 characters for one line. */
if (__glibc_unlikely (buflen < 3))
{
erange:
*errnop = ERANGE;
return NSS_STATUS_TRYAGAIN;
}
fgetpos (ent->stream, &pos);
buffer[buflen - 1] = '\xff';
p = fgets_unlocked (buffer, buflen, ent->stream);
if (p == NULL && feof_unlocked (ent->stream))
return NSS_STATUS_NOTFOUND;
if (p == NULL || __builtin_expect (buffer[buflen - 1] != '\xff', 0))
{
erange_reset:
fsetpos (ent->stream, &pos);
goto erange;
}
/* Terminate the line for any case. */
buffer[buflen - 1] = '\0';
/* Skip leading blanks. */
while (isspace (*p))
++p;
}
while (*p == '\0' || *p == '#' || /* Ignore empty and comment lines. */
/* Parse the line. If it is invalid, loop to
get the next line of the file to parse. */
!(parse_res = _nss_files_parse_grent (p, result, data, buflen,
errnop)));
if (__glibc_unlikely (parse_res == -1))
/* The parser ran out of space. */
goto erange_reset;
/* This is a real entry. */
if (result->gr_name[0] != '+' && result->gr_name[0] != '-')
{
if (result->gr_gid == gid)
return NSS_STATUS_SUCCESS;
else
continue;
}
/* -group */
if (result->gr_name[0] == '-' && result->gr_name[1] != '\0')
{
blacklist_store_name (&result->gr_name[1], ent);
continue;
}
/* +group */
if (result->gr_name[0] == '+' && result->gr_name[1] != '\0')
{
/* Yes, no +1, see the memcpy call below. */
size_t len = strlen (result->gr_name);
char buf[len];
enum nss_status status;
/* Store the group in the blacklist for the "+" at the end of
/etc/group */
memcpy (buf, &result->gr_name[1], len);
status = getgrnam_plusgroup (&result->gr_name[1], result, ent,
buffer, buflen, errnop);
blacklist_store_name (buf, ent);
if (status == NSS_STATUS_SUCCESS && result->gr_gid == gid)
break;
else
continue;
}
/* +:... */
if (result->gr_name[0] == '+' && result->gr_name[1] == '\0')
{
if (!nss_getgrgid_r)
return NSS_STATUS_UNAVAIL;
enum nss_status status = nss_getgrgid_r (gid, result, buffer, buflen,
errnop);
if (status == NSS_STATUS_RETURN) /* We couldn't parse the entry */
return NSS_STATUS_NOTFOUND;
else
return status;
}
}
return NSS_STATUS_SUCCESS;
}
enum nss_status
_nss_compat_getgrgid_r (gid_t gid, struct group *grp,
char *buffer, size_t buflen, int *errnop)
{
ent_t ent = { true, NSS_STATUS_SUCCESS, NULL, { NULL, 0, 0 }};
enum nss_status result;
__libc_lock_lock (lock);
if (ni == NULL)
init_nss_interface ();
__libc_lock_unlock (lock);
result = internal_setgrent (&ent, 0, 0);
if (result == NSS_STATUS_SUCCESS)
result = internal_getgrgid_r (gid, grp, &ent, buffer, buflen, errnop);
internal_endgrent_noerror (&ent);
return result;
}
/* Support routines for remembering -@netgroup and -user entries.
The names are stored in a single string with `|' as separator. */
static void
blacklist_store_name (const char *name, ent_t *ent)
{
int namelen = strlen (name);
char *tmp;
/* first call, setup cache */
if (ent->blacklist.size == 0)
{
ent->blacklist.size = MAX (BLACKLIST_INITIAL_SIZE, 2 * namelen);
ent->blacklist.data = malloc (ent->blacklist.size);
if (ent->blacklist.data == NULL)
return;
ent->blacklist.data[0] = '|';
ent->blacklist.data[1] = '\0';
ent->blacklist.current = 1;
}
else
{
if (in_blacklist (name, namelen, ent))
return; /* no duplicates */
if (ent->blacklist.current + namelen + 1 >= ent->blacklist.size)
{
ent->blacklist.size += MAX (BLACKLIST_INCREMENT, 2 * namelen);
tmp = realloc (ent->blacklist.data, ent->blacklist.size);
if (tmp == NULL)
{
free (ent->blacklist.data);
ent->blacklist.size = 0;
return;
}
ent->blacklist.data = tmp;
}
}
tmp = stpcpy (ent->blacklist.data + ent->blacklist.current, name);
*tmp++ = '|';
*tmp = '\0';
ent->blacklist.current += namelen + 1;
return;
}
/* Return whether ent->blacklist contains name. */
static bool
in_blacklist (const char *name, int namelen, ent_t *ent)
{
char buf[namelen + 3];
char *cp;
if (ent->blacklist.data == NULL)
return false;
buf[0] = '|';
cp = stpcpy (&buf[1], name);
*cp++ = '|';
*cp = '\0';
return strstr (ent->blacklist.data, buf) != NULL;
}