glibc/nss/nss_compat/compat-spwd.c
DJ Delorie 9b456c5da9 nss: fix nss_database_lookup2's alternate handling [BZ #27416]
__nss_database_lookup2's extra arguments were left unused in the
nsswitch reloading patch set; this broke compat (default config
ignored) and shadow files (secondary name ignored) which relies on
these fallbacks.

This patch adds in the previous behavior by correcting the
initialization of the database list to reflect the fallbacks.  This
means that the nss_database_lookup2 interface no longer needs to be
passed the fallback info, so API and callers were adjusted.

Since all callers needed to be edited anyway, the calls were changed
from __nss_database_lookup2 to the faster __nss_database_get.  This
was an intended optimization which was deferred during the initial
lookup changes to avoid touching so many files.

The test case verifies that compat targets work (passwd) and that the
default configuration works (group).  Tested on x86-64.
2021-03-09 14:34:50 -05:00

865 lines
21 KiB
C

/* Copyright (C) 1996-2021 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Thorsten Kukuk <kukuk@vt.uni-paderborn.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
<https://www.gnu.org/licenses/>. */
#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <netdb.h>
#include <nss.h>
#include <nsswitch.h>
#include <shadow.h>
#include <stdio_ext.h>
#include <string.h>
#include <libc-lock.h>
#include <kernel-features.h>
#include <nss_files.h>
#include "netgroup.h"
#include "nisdomain.h"
NSS_DECLARE_MODULE_FUNCTIONS (compat)
static nss_action_list ni;
static enum nss_status (*setspent_impl) (int stayopen);
static enum nss_status (*getspnam_r_impl) (const char *name, struct spwd * sp,
char *buffer, size_t buflen,
int *errnop);
static enum nss_status (*getspent_r_impl) (struct spwd * sp, char *buffer,
size_t buflen, int *errnop);
static enum nss_status (*endspent_impl) (void);
/* Get the declaration of the parser function. */
#define ENTNAME spent
#define STRUCTURE spwd
#define EXTERN_PARSER
#include <nss/nss_files/files-parse.c>
/* Structure for remembering -@netgroup and -user members ... */
#define BLACKLIST_INITIAL_SIZE 512
#define BLACKLIST_INCREMENT 256
struct blacklist_t
{
char *data;
int current;
int size;
};
struct ent_t
{
bool netgroup;
bool files;
bool first;
enum nss_status setent_status;
FILE *stream;
struct blacklist_t blacklist;
struct spwd pwd;
struct __netgrent netgrdata;
};
typedef struct ent_t ent_t;
static ent_t ext_ent = { false, true, false, NSS_STATUS_SUCCESS, NULL,
{ NULL, 0, 0},
{ NULL, NULL, 0, 0, 0, 0, 0, 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_get (nss_database_shadow_compat, &ni))
{
setspent_impl = __nss_lookup_function (ni, "setspent");
getspnam_r_impl = __nss_lookup_function (ni, "getspnam_r");
getspent_r_impl = __nss_lookup_function (ni, "getspent_r");
endspent_impl = __nss_lookup_function (ni, "endspent");
}
}
static void
give_spwd_free (struct spwd *pwd)
{
free (pwd->sp_namp);
free (pwd->sp_pwdp);
memset (pwd, '\0', sizeof (struct spwd));
pwd->sp_warn = -1;
pwd->sp_inact = -1;
pwd->sp_expire = -1;
pwd->sp_flag = ~0ul;
}
static int
spwd_need_buflen (struct spwd *pwd)
{
int len = 0;
if (pwd->sp_pwdp != NULL)
len += strlen (pwd->sp_pwdp) + 1;
return len;
}
static void
copy_spwd_changes (struct spwd *dest, struct spwd *src,
char *buffer, size_t buflen)
{
if (src->sp_pwdp != NULL && strlen (src->sp_pwdp))
{
if (buffer == NULL)
dest->sp_pwdp = strdup (src->sp_pwdp);
else if (dest->sp_pwdp
&& strlen (dest->sp_pwdp) >= strlen (src->sp_pwdp))
strcpy (dest->sp_pwdp, src->sp_pwdp);
else
{
dest->sp_pwdp = buffer;
strcpy (dest->sp_pwdp, src->sp_pwdp);
buffer += strlen (dest->sp_pwdp) + 1;
buflen = buflen - (strlen (dest->sp_pwdp) + 1);
}
}
if (src->sp_lstchg != 0)
dest->sp_lstchg = src->sp_lstchg;
if (src->sp_min != 0)
dest->sp_min = src->sp_min;
if (src->sp_max != 0)
dest->sp_max = src->sp_max;
if (src->sp_warn != -1)
dest->sp_warn = src->sp_warn;
if (src->sp_inact != -1)
dest->sp_inact = src->sp_inact;
if (src->sp_expire != -1)
dest->sp_expire = src->sp_expire;
if (src->sp_flag != ~0ul)
dest->sp_flag = src->sp_flag;
}
static enum nss_status
internal_setspent (ent_t *ent, int stayopen, int needent)
{
enum nss_status status = NSS_STATUS_SUCCESS;
ent->first = ent->netgroup = 0;
ent->files = true;
/* If something was left over free it. */
if (ent->netgroup)
__internal_endnetgrent (&ent->netgrdata);
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 = __nss_files_fopen ("/etc/shadow");
if (ent->stream == NULL)
status = errno == EAGAIN ? NSS_STATUS_TRYAGAIN : NSS_STATUS_UNAVAIL;
}
else
rewind (ent->stream);
give_spwd_free (&ent->pwd);
if (needent && status == NSS_STATUS_SUCCESS && setspent_impl)
ent->setent_status = setspent_impl (stayopen);
return status;
}
enum nss_status
_nss_compat_setspent (int stayopen)
{
enum nss_status result;
__libc_lock_lock (lock);
if (ni == NULL)
init_nss_interface ();
result = internal_setspent (&ext_ent, stayopen, 1);
__libc_lock_unlock (lock);
return result;
}
static enum nss_status __attribute_warn_unused_result__
internal_endspent (ent_t *ent)
{
if (ent->stream != NULL)
{
fclose (ent->stream);
ent->stream = NULL;
}
if (ent->netgroup)
__internal_endnetgrent (&ent->netgrdata);
ent->first = ent->netgroup = false;
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;
give_spwd_free (&ent->pwd);
return NSS_STATUS_SUCCESS;
}
/* Like internal_endspent, but preserve errno in all cases. */
static void
internal_endspent_noerror (ent_t *ent)
{
int saved_errno = errno;
enum nss_status unused __attribute__ ((unused)) = internal_endspent (ent);
__set_errno (saved_errno);
}
enum nss_status
_nss_compat_endspent (void)
{
enum nss_status result;
__libc_lock_lock (lock);
if (endspent_impl)
endspent_impl ();
result = internal_endspent (&ext_ent);
__libc_lock_unlock (lock);
return result;
}
static enum nss_status
getspent_next_nss_netgr (const char *name, struct spwd *result, ent_t *ent,
char *group, char *buffer, size_t buflen,
int *errnop)
{
char *curdomain = NULL, *host, *user, *domain, *p2;
size_t p2len;
if (!getspnam_r_impl)
return NSS_STATUS_UNAVAIL;
/* If the setpwent call failed, say so. */
if (ent->setent_status != NSS_STATUS_SUCCESS)
return ent->setent_status;
if (ent->first)
{
memset (&ent->netgrdata, 0, sizeof (struct __netgrent));
__internal_setnetgrent (group, &ent->netgrdata);
ent->first = false;
}
while (1)
{
enum nss_status status;
status = __internal_getnetgrent_r (&host, &user, &domain,
&ent->netgrdata, buffer, buflen,
errnop);
if (status != 1)
{
__internal_endnetgrent (&ent->netgrdata);
ent->netgroup = false;
give_spwd_free (&ent->pwd);
return NSS_STATUS_RETURN;
}
if (user == NULL || user[0] == '-')
continue;
if (domain != NULL)
{
if (curdomain == NULL
&& __nss_get_default_domain (&curdomain) != 0)
{
__internal_endnetgrent (&ent->netgrdata);
ent->netgroup = false;
give_spwd_free (&ent->pwd);
return NSS_STATUS_UNAVAIL;
}
if (strcmp (curdomain, domain) != 0)
continue;
}
/* If name != NULL, we are called from getpwnam */
if (name != NULL)
if (strcmp (user, name) != 0)
continue;
p2len = spwd_need_buflen (&ent->pwd);
if (p2len > buflen)
{
*errnop = ERANGE;
return NSS_STATUS_TRYAGAIN;
}
p2 = buffer + (buflen - p2len);
buflen -= p2len;
if (getspnam_r_impl (user, result, buffer, buflen, errnop)
!= NSS_STATUS_SUCCESS)
continue;
if (!in_blacklist (result->sp_namp, strlen (result->sp_namp), ent))
{
/* Store the User in the blacklist for possible the "+" at the
end of /etc/passwd */
blacklist_store_name (result->sp_namp, ent);
copy_spwd_changes (result, &ent->pwd, p2, p2len);
break;
}
}
return NSS_STATUS_SUCCESS;
}
static enum nss_status
getspent_next_nss (struct spwd *result, ent_t *ent,
char *buffer, size_t buflen, int *errnop)
{
enum nss_status status;
char *p2;
size_t p2len;
if (!getspent_r_impl)
return NSS_STATUS_UNAVAIL;
p2len = spwd_need_buflen (&ent->pwd);
if (p2len > buflen)
{
*errnop = ERANGE;
return NSS_STATUS_TRYAGAIN;
}
p2 = buffer + (buflen - p2len);
buflen -= p2len;
do
{
if ((status = getspent_r_impl (result, buffer, buflen, errnop))
!= NSS_STATUS_SUCCESS)
return status;
}
while (in_blacklist (result->sp_namp, strlen (result->sp_namp), ent));
copy_spwd_changes (result, &ent->pwd, p2, p2len);
return NSS_STATUS_SUCCESS;
}
/* This function handle the +user entrys in /etc/shadow */
static enum nss_status
getspnam_plususer (const char *name, struct spwd *result, ent_t *ent,
char *buffer, size_t buflen, int *errnop)
{
if (!getspnam_r_impl)
return NSS_STATUS_UNAVAIL;
struct spwd pwd;
memset (&pwd, '\0', sizeof (struct spwd));
pwd.sp_warn = -1;
pwd.sp_inact = -1;
pwd.sp_expire = -1;
pwd.sp_flag = ~0ul;
copy_spwd_changes (&pwd, result, NULL, 0);
size_t plen = spwd_need_buflen (&pwd);
if (plen > buflen)
{
*errnop = ERANGE;
return NSS_STATUS_TRYAGAIN;
}
char *p = buffer + (buflen - plen);
buflen -= plen;
enum nss_status status = getspnam_r_impl (name, result, buffer, buflen,
errnop);
if (status != NSS_STATUS_SUCCESS)
return status;
if (in_blacklist (result->sp_namp, strlen (result->sp_namp), ent))
return NSS_STATUS_NOTFOUND;
copy_spwd_changes (result, &pwd, p, plen);
give_spwd_free (&pwd);
/* We found the entry. */
return NSS_STATUS_SUCCESS;
}
static enum nss_status
getspent_next_file (struct spwd *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;
}
/* 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_spent (p, result, data,
buflen, errnop)));
if (__glibc_unlikely (parse_res == -1))
/* The parser ran out of space. */
goto erange_reset;
if (result->sp_namp[0] != '+' && result->sp_namp[0] != '-')
/* This is a real entry. */
break;
/* -@netgroup */
if (result->sp_namp[0] == '-' && result->sp_namp[1] == '@'
&& result->sp_namp[2] != '\0')
{
/* XXX Do not use fixed length buffers. */
char buf2[1024];
char *user, *host, *domain;
struct __netgrent netgrdata;
memset (&netgrdata, 0, sizeof (struct __netgrent));
__internal_setnetgrent (&result->sp_namp[2], &netgrdata);
while (__internal_getnetgrent_r (&host, &user, &domain,
&netgrdata, buf2, sizeof (buf2),
errnop))
{
if (user != NULL && user[0] != '-')
blacklist_store_name (user, ent);
}
__internal_endnetgrent (&netgrdata);
continue;
}
/* +@netgroup */
if (result->sp_namp[0] == '+' && result->sp_namp[1] == '@'
&& result->sp_namp[2] != '\0')
{
int status;
ent->netgroup = true;
ent->first = true;
copy_spwd_changes (&ent->pwd, result, NULL, 0);
status = getspent_next_nss_netgr (NULL, result, ent,
&result->sp_namp[2],
buffer, buflen, errnop);
if (status == NSS_STATUS_RETURN)
continue;
else
return status;
}
/* -user */
if (result->sp_namp[0] == '-' && result->sp_namp[1] != '\0'
&& result->sp_namp[1] != '@')
{
blacklist_store_name (&result->sp_namp[1], ent);
continue;
}
/* +user */
if (result->sp_namp[0] == '+' && result->sp_namp[1] != '\0'
&& result->sp_namp[1] != '@')
{
size_t len = strlen (result->sp_namp);
char buf[len];
enum nss_status status;
/* Store the User in the blacklist for the "+" at the end of
/etc/passwd */
memcpy (buf, &result->sp_namp[1], len);
status = getspnam_plususer (&result->sp_namp[1], result, ent,
buffer, buflen, errnop);
blacklist_store_name (buf, ent);
if (status == NSS_STATUS_SUCCESS) /* We found the entry. */
break;
/* We couldn't parse the entry */
else if (status == NSS_STATUS_RETURN
/* entry doesn't exist */
|| status == NSS_STATUS_NOTFOUND)
continue;
else
{
if (status == NSS_STATUS_TRYAGAIN)
{
fsetpos (ent->stream, &pos);
*errnop = ERANGE;
}
return status;
}
}
/* +:... */
if (result->sp_namp[0] == '+' && result->sp_namp[1] == '\0')
{
ent->files = false;
ent->first = true;
copy_spwd_changes (&ent->pwd, result, NULL, 0);
return getspent_next_nss (result, ent, buffer, buflen, errnop);
}
}
return NSS_STATUS_SUCCESS;
}
static enum nss_status
internal_getspent_r (struct spwd *pw, ent_t *ent,
char *buffer, size_t buflen, int *errnop)
{
if (ent->netgroup)
{
enum nss_status status;
/* We are searching members in a netgroup */
/* Since this is not the first call, we don't need the group name */
status = getspent_next_nss_netgr (NULL, pw, ent, NULL, buffer,
buflen, errnop);
if (status == NSS_STATUS_RETURN)
return getspent_next_file (pw, ent, buffer, buflen, errnop);
else
return status;
}
else if (ent->files)
return getspent_next_file (pw, ent, buffer, buflen, errnop);
else
return getspent_next_nss (pw, ent, buffer, buflen, errnop);
}
enum nss_status
_nss_compat_getspent_r (struct spwd *pwd, char *buffer, size_t buflen,
int *errnop)
{
enum nss_status result = NSS_STATUS_SUCCESS;
__libc_lock_lock (lock);
/* Be prepared that the setpwent function was not called before. */
if (ni == NULL)
init_nss_interface ();
if (ext_ent.stream == NULL)
result = internal_setspent (&ext_ent, 1, 1);
if (result == NSS_STATUS_SUCCESS)
result = internal_getspent_r (pwd, &ext_ent, buffer, buflen, errnop);
__libc_lock_unlock (lock);
return result;
}
/* Searches in /etc/passwd and the NIS/NIS+ map for a special user */
static enum nss_status
internal_getspnam_r (const char *name, struct spwd *result, ent_t *ent,
char *buffer, size_t buflen, int *errnop)
{
struct parser_data *data = (void *) buffer;
while (1)
{
fpos_t pos;
char *p;
int parse_res;
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 || buffer[buflen - 1] != '\xff')
{
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_spent (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->sp_namp[0] != '+' && result->sp_namp[0] != '-')
{
if (strcmp (result->sp_namp, name) == 0)
return NSS_STATUS_SUCCESS;
else
continue;
}
/* -@netgroup */
/* If the loaded NSS module does not support this service, add
all users from a +@netgroup entry to the blacklist, too. */
if (result->sp_namp[0] == '-' && result->sp_namp[1] == '@'
&& result->sp_namp[2] != '\0')
{
if (innetgr (&result->sp_namp[2], NULL, name, NULL))
return NSS_STATUS_NOTFOUND;
continue;
}
/* +@netgroup */
if (result->sp_namp[0] == '+' && result->sp_namp[1] == '@'
&& result->sp_namp[2] != '\0')
{
enum nss_status status;
if (innetgr (&result->sp_namp[2], NULL, name, NULL))
{
status = getspnam_plususer (name, result, ent, buffer,
buflen, errnop);
if (status == NSS_STATUS_RETURN)
continue;
return status;
}
continue;
}
/* -user */
if (result->sp_namp[0] == '-' && result->sp_namp[1] != '\0'
&& result->sp_namp[1] != '@')
{
if (strcmp (&result->sp_namp[1], name) == 0)
return NSS_STATUS_NOTFOUND;
else
continue;
}
/* +user */
if (result->sp_namp[0] == '+' && result->sp_namp[1] != '\0'
&& result->sp_namp[1] != '@')
{
if (strcmp (name, &result->sp_namp[1]) == 0)
{
enum nss_status status;
status = getspnam_plususer (name, result, ent,
buffer, buflen, errnop);
if (status == NSS_STATUS_RETURN)
/* We couldn't parse the entry */
return NSS_STATUS_NOTFOUND;
else
return status;
}
}
/* +:... */
if (result->sp_namp[0] == '+' && result->sp_namp[1] == '\0')
{
enum nss_status status;
status = getspnam_plususer (name, result, ent,
buffer, buflen, errnop);
if (status == NSS_STATUS_SUCCESS)
/* We found the entry. */
break;
else 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_getspnam_r (const char *name, struct spwd *pwd,
char *buffer, size_t buflen, int *errnop)
{
enum nss_status result;
ent_t ent = { false, true, false, NSS_STATUS_SUCCESS, NULL, { NULL, 0, 0},
{ NULL, NULL, 0, 0, 0, 0, 0, 0, 0}};
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_setspent (&ent, 0, 0);
if (result == NSS_STATUS_SUCCESS)
result = internal_getspnam_r (name, pwd, &ent, buffer, buflen, errnop);
internal_endspent_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;
}
/* Returns 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;
}