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143 lines
3.6 KiB
C
143 lines
3.6 KiB
C
/* Initgroups handling in nss_files module.
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Copyright (C) 2011-2012 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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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 <alloca.h>
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#include <errno.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 <sys/param.h>
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#include <stdbool.h>
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#include <stdlib.h>
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enum nss_status
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_nss_files_initgroups_dyn (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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int *errnop)
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{
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FILE *stream = fopen ("/etc/group", "rce");
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if (stream == NULL)
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{
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*errnop = errno;
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return *errnop == ENOMEM ? NSS_STATUS_TRYAGAIN : NSS_STATUS_UNAVAIL;
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}
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/* No other thread using this stream. */
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__fsetlocking (stream, FSETLOCKING_BYCALLER);
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char *line = NULL;
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size_t linelen = 0;
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enum nss_status status = NSS_STATUS_SUCCESS;
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bool any = false;
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size_t buflen = 1024;
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void *buffer = alloca (buflen);
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bool buffer_use_malloc = false;
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gid_t *groups = *groupsp;
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/* We have to iterate over the entire file. */
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while (1)
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{
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fpos_t pos;
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fgetpos (stream, &pos);
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ssize_t n = getline (&line, &linelen, stream);
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if (n < 0)
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{
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if (! feof_unlocked (stream))
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status = ((*errnop = errno) == ENOMEM
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? NSS_STATUS_TRYAGAIN : NSS_STATUS_UNAVAIL);
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break;
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}
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struct group grp;
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int res = _nss_files_parse_grent (line, &grp, buffer, buflen, errnop);
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if (res == -1)
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{
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size_t newbuflen = 2 * buflen;
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if (buffer_use_malloc || ! __libc_use_alloca (buflen + newbuflen))
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{
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void *newbuf = realloc (buffer_use_malloc ? buffer : NULL,
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newbuflen);
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if (newbuf == NULL)
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{
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*errnop = ENOMEM;
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status = NSS_STATUS_TRYAGAIN;
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goto out;
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}
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buffer = newbuf;
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buflen = newbuflen;
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buffer_use_malloc = true;
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}
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else
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buffer = extend_alloca (buffer, buflen, newbuflen);
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/* Reread current line, the parser has clobbered it. */
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fsetpos (stream, &pos);
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continue;
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}
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if (res > 0 && grp.gr_gid != group)
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for (char **m = grp.gr_mem; *m != NULL; ++m)
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if (strcmp (*m, user) == 0)
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{
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/* Matches user. Insert this group. */
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if (*start == *size)
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{
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/* Need a bigger buffer. */
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if (limit > 0 && *size == limit)
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/* We reached the maximum. */
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goto out;
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long int newsize;
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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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gid_t *newgroups = realloc (groups,
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newsize * sizeof (*groups));
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if (newgroups == NULL)
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{
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*errnop = ENOMEM;
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status = NSS_STATUS_TRYAGAIN;
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goto out;
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}
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*groupsp = groups = newgroups;
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*size = newsize;
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}
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groups[*start] = grp.gr_gid;
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*start += 1;
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any = true;
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break;
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}
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}
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out:
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/* Free memory. */
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if (buffer_use_malloc)
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free (buffer);
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free (line);
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fclose (stream);
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return status == NSS_STATUS_SUCCESS && !any ? NSS_STATUS_NOTFOUND : status;
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}
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