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Move nss_compat from nis to nss subdir and install it unconditionally
This has been tested that local lookup still works with and without an installed libnss_nis, and that NIS lookup works when libnss_nis is available.
This commit is contained in:
Andreas Schwab
575
nss/nss_compat/compat-initgroups.c
Normal file
575
nss/nss_compat/compat-initgroups.c
Normal file
@@ -0,0 +1,575 @@
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/* Copyright (C) 1998-2017 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Thorsten Kukuk <kukuk@suse.de>, 1998.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#include <ctype.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <grp.h>
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#include <nss.h>
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#include <stdio_ext.h>
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#include <string.h>
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#include <unistd.h>
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#include <sys/param.h>
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#include <nsswitch.h>
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#include <libc-lock.h>
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#include <kernel-features.h>
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#include <scratch_buffer.h>
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static service_user *ni;
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/* Type of the lookup function. */
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static enum nss_status (*nss_initgroups_dyn) (const char *, gid_t,
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long int *, long int *,
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gid_t **, long int, int *);
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static enum nss_status (*nss_getgrnam_r) (const char *name,
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struct group * grp, char *buffer,
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size_t buflen, int *errnop);
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static enum nss_status (*nss_getgrgid_r) (gid_t gid, struct group * grp,
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char *buffer, size_t buflen,
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int *errnop);
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static enum nss_status (*nss_setgrent) (int stayopen);
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static enum nss_status (*nss_getgrent_r) (struct group * grp, char *buffer,
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size_t buflen, int *errnop);
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static enum nss_status (*nss_endgrent) (void);
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/* Protect global state against multiple changers. */
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__libc_lock_define_initialized (static, lock)
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/* Get the declaration of the parser function. */
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#define ENTNAME grent
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#define STRUCTURE group
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#define EXTERN_PARSER
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#include <nss/nss_files/files-parse.c>
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/* Structure for remembering -group members ... */
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#define BLACKLIST_INITIAL_SIZE 512
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#define BLACKLIST_INCREMENT 256
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struct blacklist_t
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{
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char *data;
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int current;
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int size;
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};
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struct ent_t
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{
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bool files;
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bool need_endgrent;
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bool skip_initgroups_dyn;
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FILE *stream;
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struct blacklist_t blacklist;
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};
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typedef struct ent_t ent_t;
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/* Prototypes for local functions. */
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static void blacklist_store_name (const char *, ent_t *);
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static bool in_blacklist (const char *, int, ent_t *);
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/* Initialize the NSS interface/functions. The calling function must
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hold the lock. */
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static void
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init_nss_interface (void)
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{
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__libc_lock_lock (lock);
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/* Retest. */
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if (ni == NULL
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&& __nss_database_lookup ("group_compat", NULL, "nis", &ni) >= 0)
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{
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nss_initgroups_dyn = __nss_lookup_function (ni, "initgroups_dyn");
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nss_getgrnam_r = __nss_lookup_function (ni, "getgrnam_r");
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nss_getgrgid_r = __nss_lookup_function (ni, "getgrgid_r");
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nss_setgrent = __nss_lookup_function (ni, "setgrent");
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nss_getgrent_r = __nss_lookup_function (ni, "getgrent_r");
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nss_endgrent = __nss_lookup_function (ni, "endgrent");
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}
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__libc_lock_unlock (lock);
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}
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static enum nss_status
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internal_setgrent (ent_t *ent)
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{
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enum nss_status status = NSS_STATUS_SUCCESS;
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ent->files = true;
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if (ni == NULL)
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init_nss_interface ();
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if (ent->blacklist.data != NULL)
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{
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ent->blacklist.current = 1;
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ent->blacklist.data[0] = '|';
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ent->blacklist.data[1] = '\0';
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}
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else
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ent->blacklist.current = 0;
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ent->stream = fopen ("/etc/group", "rme");
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if (ent->stream == NULL)
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status = errno == EAGAIN ? NSS_STATUS_TRYAGAIN : NSS_STATUS_UNAVAIL;
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else
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/* We take care of locking ourself. */
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__fsetlocking (ent->stream, FSETLOCKING_BYCALLER);
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return status;
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}
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static enum nss_status
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internal_endgrent (ent_t *ent)
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{
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if (ent->stream != NULL)
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{
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fclose (ent->stream);
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ent->stream = NULL;
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}
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if (ent->blacklist.data != NULL)
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{
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ent->blacklist.current = 1;
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ent->blacklist.data[0] = '|';
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ent->blacklist.data[1] = '\0';
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}
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else
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ent->blacklist.current = 0;
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if (ent->need_endgrent && nss_endgrent != NULL)
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nss_endgrent ();
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return NSS_STATUS_SUCCESS;
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}
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/* Add new group record. */
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static void
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add_group (long int *start, long int *size, gid_t **groupsp, long int limit,
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gid_t gid)
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{
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gid_t *groups = *groupsp;
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/* Matches user. Insert this group. */
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if (__glibc_unlikely (*start == *size))
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{
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/* Need a bigger buffer. */
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gid_t *newgroups;
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long int newsize;
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if (limit > 0 && *size == limit)
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/* We reached the maximum. */
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return;
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if (limit <= 0)
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newsize = 2 * *size;
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else
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newsize = MIN (limit, 2 * *size);
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newgroups = realloc (groups, newsize * sizeof (*groups));
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if (newgroups == NULL)
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return;
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*groupsp = groups = newgroups;
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*size = newsize;
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}
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groups[*start] = gid;
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*start += 1;
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}
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/* This function checks, if the user is a member of this group and if
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yes, add the group id to the list. Return nonzero is we couldn't
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handle the group because the user is not in the member list. */
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static int
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check_and_add_group (const char *user, gid_t group, long int *start,
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long int *size, gid_t **groupsp, long int limit,
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struct group *grp)
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{
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char **member;
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/* Don't add main group to list of groups. */
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if (grp->gr_gid == group)
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return 0;
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for (member = grp->gr_mem; *member != NULL; ++member)
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if (strcmp (*member, user) == 0)
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{
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add_group (start, size, groupsp, limit, grp->gr_gid);
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return 0;
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}
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return 1;
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}
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/* Get the next group from NSS (+ entry). If the NSS module supports
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initgroups_dyn, get all entries at once. */
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static enum nss_status
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getgrent_next_nss (ent_t *ent, char *buffer, size_t buflen, const char *user,
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gid_t group, long int *start, long int *size,
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gid_t **groupsp, long int limit, int *errnop)
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{
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enum nss_status status;
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struct group grpbuf;
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/* Try nss_initgroups_dyn if supported. We also need getgrgid_r.
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If this function is not supported, step through the whole group
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database with getgrent_r. */
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if (! ent->skip_initgroups_dyn)
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{
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long int mystart = 0;
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long int mysize = limit <= 0 ? *size : limit;
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gid_t *mygroups = malloc (mysize * sizeof (gid_t));
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if (mygroups == NULL)
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return NSS_STATUS_TRYAGAIN;
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/* For every gid in the list we get from the NSS module,
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get the whole group entry. We need to do this, since we
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need the group name to check if it is in the blacklist.
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In worst case, this is as twice as slow as stepping with
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getgrent_r through the whole group database. But for large
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group databases this is faster, since the user can only be
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in a limited number of groups. */
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if (nss_initgroups_dyn (user, group, &mystart, &mysize, &mygroups,
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limit, errnop) == NSS_STATUS_SUCCESS)
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{
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status = NSS_STATUS_NOTFOUND;
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/* If there is no blacklist we can trust the underlying
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initgroups implementation. */
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if (ent->blacklist.current <= 1)
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for (int i = 0; i < mystart; i++)
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add_group (start, size, groupsp, limit, mygroups[i]);
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else
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{
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/* A temporary buffer. We use the normal buffer, until we find
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an entry, for which this buffer is to small. In this case, we
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overwrite the pointer with one to a bigger buffer. */
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char *tmpbuf = buffer;
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size_t tmplen = buflen;
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bool use_malloc = false;
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for (int i = 0; i < mystart; i++)
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{
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while ((status = nss_getgrgid_r (mygroups[i], &grpbuf,
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tmpbuf, tmplen, errnop))
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== NSS_STATUS_TRYAGAIN
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&& *errnop == ERANGE)
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{
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if (__libc_use_alloca (tmplen * 2))
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{
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if (tmpbuf == buffer)
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{
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tmplen *= 2;
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tmpbuf = __alloca (tmplen);
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}
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else
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tmpbuf = extend_alloca (tmpbuf, tmplen, tmplen * 2);
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}
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else
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{
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tmplen *= 2;
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char *newbuf = realloc (use_malloc ? tmpbuf : NULL, tmplen);
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if (newbuf == NULL)
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{
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status = NSS_STATUS_TRYAGAIN;
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goto done;
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}
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use_malloc = true;
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tmpbuf = newbuf;
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}
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}
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if (__builtin_expect (status != NSS_STATUS_NOTFOUND, 1))
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{
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if (__builtin_expect (status != NSS_STATUS_SUCCESS, 0))
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goto done;
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if (!in_blacklist (grpbuf.gr_name,
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strlen (grpbuf.gr_name), ent)
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&& check_and_add_group (user, group, start, size,
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groupsp, limit, &grpbuf))
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{
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if (nss_setgrent != NULL)
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{
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nss_setgrent (1);
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ent->need_endgrent = true;
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}
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ent->skip_initgroups_dyn = true;
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goto iter;
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}
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}
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}
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status = NSS_STATUS_NOTFOUND;
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done:
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if (use_malloc)
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free (tmpbuf);
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}
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free (mygroups);
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return status;
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}
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free (mygroups);
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}
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/* If we come here, the NSS module does not support initgroups_dyn
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or we were confronted with a split group. In these cases we have
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to step through the whole list ourself. */
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iter:
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do
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{
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if ((status = nss_getgrent_r (&grpbuf, buffer, buflen, errnop)) !=
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NSS_STATUS_SUCCESS)
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break;
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}
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while (in_blacklist (grpbuf.gr_name, strlen (grpbuf.gr_name), ent));
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if (status == NSS_STATUS_SUCCESS)
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check_and_add_group (user, group, start, size, groupsp, limit, &grpbuf);
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return status;
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}
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static enum nss_status
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internal_getgrent_r (ent_t *ent, char *buffer, size_t buflen, const char *user,
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gid_t group, long int *start, long int *size,
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gid_t **groupsp, long int limit, int *errnop)
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{
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struct parser_data *data = (void *) buffer;
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struct group grpbuf;
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if (!ent->files)
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return getgrent_next_nss (ent, buffer, buflen, user, group,
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start, size, groupsp, limit, errnop);
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while (1)
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{
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fpos_t pos;
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int parse_res = 0;
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char *p;
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do
|
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{
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/* We need at least 3 characters for one line. */
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if (__glibc_unlikely (buflen < 3))
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{
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erange:
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*errnop = ERANGE;
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return NSS_STATUS_TRYAGAIN;
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}
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fgetpos (ent->stream, &pos);
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buffer[buflen - 1] = '\xff';
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p = fgets_unlocked (buffer, buflen, ent->stream);
|
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if (p == NULL && feof_unlocked (ent->stream))
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return NSS_STATUS_NOTFOUND;
|
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|
||||
if (p == NULL || __builtin_expect (buffer[buflen - 1] != '\xff', 0))
|
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{
|
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erange_reset:
|
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fsetpos (ent->stream, &pos);
|
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goto erange;
|
||||
}
|
||||
|
||||
/* Terminate the line for any case. */
|
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buffer[buflen - 1] = '\0';
|
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|
||||
/* Skip leading blanks. */
|
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while (isspace (*p))
|
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++p;
|
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}
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while (*p == '\0' || *p == '#' || /* Ignore empty and comment lines. */
|
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/* 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, &grpbuf, data, buflen,
|
||||
errnop)));
|
||||
|
||||
if (__glibc_unlikely (parse_res == -1))
|
||||
/* The parser ran out of space. */
|
||||
goto erange_reset;
|
||||
|
||||
if (grpbuf.gr_name[0] != '+' && grpbuf.gr_name[0] != '-')
|
||||
/* This is a real entry. */
|
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break;
|
||||
|
||||
/* -group */
|
||||
if (grpbuf.gr_name[0] == '-' && grpbuf.gr_name[1] != '\0'
|
||||
&& grpbuf.gr_name[1] != '@')
|
||||
{
|
||||
blacklist_store_name (&grpbuf.gr_name[1], ent);
|
||||
continue;
|
||||
}
|
||||
|
||||
/* +group */
|
||||
if (grpbuf.gr_name[0] == '+' && grpbuf.gr_name[1] != '\0'
|
||||
&& grpbuf.gr_name[1] != '@')
|
||||
{
|
||||
if (in_blacklist (&grpbuf.gr_name[1],
|
||||
strlen (&grpbuf.gr_name[1]), ent))
|
||||
continue;
|
||||
/* Store the group in the blacklist for the "+" at the end of
|
||||
/etc/group */
|
||||
blacklist_store_name (&grpbuf.gr_name[1], ent);
|
||||
if (nss_getgrnam_r == NULL)
|
||||
return NSS_STATUS_UNAVAIL;
|
||||
else if (nss_getgrnam_r (&grpbuf.gr_name[1], &grpbuf, buffer,
|
||||
buflen, errnop) != NSS_STATUS_SUCCESS)
|
||||
continue;
|
||||
|
||||
check_and_add_group (user, group, start, size, groupsp,
|
||||
limit, &grpbuf);
|
||||
|
||||
return NSS_STATUS_SUCCESS;
|
||||
}
|
||||
|
||||
/* +:... */
|
||||
if (grpbuf.gr_name[0] == '+' && grpbuf.gr_name[1] == '\0')
|
||||
{
|
||||
/* If the selected module does not support getgrent_r or
|
||||
initgroups_dyn, abort. We cannot find the needed group
|
||||
entries. */
|
||||
if (nss_initgroups_dyn == NULL || nss_getgrgid_r == NULL)
|
||||
{
|
||||
if (nss_setgrent != NULL)
|
||||
{
|
||||
nss_setgrent (1);
|
||||
ent->need_endgrent = true;
|
||||
}
|
||||
ent->skip_initgroups_dyn = true;
|
||||
|
||||
if (nss_getgrent_r == NULL)
|
||||
return NSS_STATUS_UNAVAIL;
|
||||
}
|
||||
|
||||
ent->files = false;
|
||||
|
||||
return getgrent_next_nss (ent, buffer, buflen, user, group,
|
||||
start, size, groupsp, limit, errnop);
|
||||
}
|
||||
}
|
||||
|
||||
check_and_add_group (user, group, start, size, groupsp, limit, &grpbuf);
|
||||
|
||||
return NSS_STATUS_SUCCESS;
|
||||
}
|
||||
|
||||
|
||||
enum nss_status
|
||||
_nss_compat_initgroups_dyn (const char *user, gid_t group, long int *start,
|
||||
long int *size, gid_t **groupsp, long int limit,
|
||||
int *errnop)
|
||||
{
|
||||
enum nss_status status;
|
||||
ent_t intern = { true, false, false, NULL, {NULL, 0, 0} };
|
||||
|
||||
status = internal_setgrent (&intern);
|
||||
if (status != NSS_STATUS_SUCCESS)
|
||||
return status;
|
||||
|
||||
struct scratch_buffer tmpbuf;
|
||||
scratch_buffer_init (&tmpbuf);
|
||||
|
||||
do
|
||||
{
|
||||
while ((status = internal_getgrent_r (&intern, tmpbuf.data, tmpbuf.length,
|
||||
user, group, start, size,
|
||||
groupsp, limit, errnop))
|
||||
== NSS_STATUS_TRYAGAIN && *errnop == ERANGE)
|
||||
if (!scratch_buffer_grow (&tmpbuf))
|
||||
goto done;
|
||||
}
|
||||
while (status == NSS_STATUS_SUCCESS);
|
||||
|
||||
status = NSS_STATUS_SUCCESS;
|
||||
|
||||
done:
|
||||
scratch_buffer_free (&tmpbuf);
|
||||
|
||||
internal_endgrent (&intern);
|
||||
|
||||
return status;
|
||||
}
|
||||
|
||||
|
||||
/* 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;
|
||||
}
|
||||
Reference in New Issue
Block a user