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glibc-2.34
grp/initgroups.c
218 строк
6 KB
Paul Eggert
Update copyright dates with scripts/update-copyrights
02 янв 2021, 23:17
02 янв 2021, 23:17
2b778ce
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/* Copyright (C) 1989, 1991-2021 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 <assert.h> #include <errno.h> #include <grp.h> #include <limits.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #include <sys/param.h> #include <sys/types.h> #include <nsswitch.h> #include <scratch_buffer.h> #include <config.h> #include "../nscd/nscd-client.h" #include "../nscd/nscd_proto.h" /* Type of the lookup function. */ typedef enum nss_status (*initgroups_dyn_function) (const char *, gid_t, long int *, long int *, gid_t **, long int, int *); static bool use_initgroups_entry; #include "compat-initgroups.c" static int internal_getgrouplist (const char *user, gid_t group, long int *size, gid_t **groupsp, long int limit) { #ifdef USE_NSCD if (__nss_not_use_nscd_group > 0 && ++__nss_not_use_nscd_group > NSS_NSCD_RETRY) __nss_not_use_nscd_group = 0; if (!__nss_not_use_nscd_group && !__nss_database_custom[NSS_DBSIDX_group]) { int n = __nscd_getgrouplist (user, group, size, groupsp, limit); if (n >= 0) return n; /* nscd is not usable. */ __nss_not_use_nscd_group = 1; } #endif enum nss_status status = NSS_STATUS_UNAVAIL; /* Never store more than the starting *SIZE number of elements. */ assert (*size > 0); (*groupsp)[0] = group; /* Start is one, because we have the first group as parameter. */ long int start = 1; nss_action_list nip; if (__nss_database_get (nss_database_initgroups, &nip) && nip != NULL) { use_initgroups_entry = true; } else if (__nss_database_get (nss_database_group, &nip) && nip != NULL) { use_initgroups_entry = false; } else { nip = __nss_action_parse ("files"); use_initgroups_entry = false; } while (nip && nip->module) { long int prev_start = start; initgroups_dyn_function fct = __nss_lookup_function (nip, "initgroups_dyn"); if (fct == NULL) status = compat_call (nip, user, group, &start, size, groupsp, limit, &errno); else status = DL_CALL_FCT (fct, (user, group, &start, size, groupsp, limit, &errno)); /* Remove duplicates. */ long int cnt = prev_start; while (cnt < start) { long int inner; for (inner = 0; inner < prev_start; ++inner) if ((*groupsp)[inner] == (*groupsp)[cnt]) break; if (inner < prev_start) (*groupsp)[cnt] = (*groupsp)[--start]; else ++cnt; } /* This is really only for debugging. */ if (NSS_STATUS_TRYAGAIN > status || status > NSS_STATUS_RETURN) __libc_fatal ("Illegal status in internal_getgrouplist.\n"); /* For compatibility reason we will continue to look for more entries using the next service even though data has already been found if the nsswitch.conf file contained only a 'groups' line and no 'initgroups' line. If the latter is available we always respect the status. This means that the default for successful lookups is to return. */ if ((use_initgroups_entry || status != NSS_STATUS_SUCCESS) && nss_next_action (nip, status) == NSS_ACTION_RETURN) break; nip++; } return start; } /* Store at most *NGROUPS members of the group set for USER into *GROUPS. Also include GROUP. The actual number of groups found is returned in *NGROUPS. Return -1 if the if *NGROUPS is too small. */ int getgrouplist (const char *user, gid_t group, gid_t *groups, int *ngroups) { long int size = MAX (1, *ngroups); gid_t *newgroups = (gid_t *) malloc (size * sizeof (gid_t)); if (__glibc_unlikely (newgroups == NULL)) /* No more memory. */ // XXX This is wrong. The user provided memory, we have to use // XXX it. The internal functions must be called with the user // XXX provided buffer and not try to increase the size if it is // XXX too small. For initgroups a flag could say: increase size. return -1; int total = internal_getgrouplist (user, group, &size, &newgroups, -1); memcpy (groups, newgroups, MIN (*ngroups, total) * sizeof (gid_t)); free (newgroups); int retval = total > *ngroups ? -1 : total; *ngroups = total; return retval; } nss_interface_function (getgrouplist) /* Initialize the group set for the current user by reading the group database and using all groups of which USER is a member. Also include GROUP. */ int initgroups (const char *user, gid_t group) { #if defined NGROUPS_MAX && NGROUPS_MAX == 0 /* No extra groups allowed. */ return 0; #else long int size; gid_t *groups; int ngroups; int result; /* We always use sysconf even if NGROUPS_MAX is defined. That way, the limit can be raised in the kernel configuration without having to recompile libc. */ long int limit = __sysconf (_SC_NGROUPS_MAX); if (limit > 0) /* We limit the size of the intially allocated array. */ size = MIN (limit, 64); else /* No fixed limit on groups. Pick a starting buffer size. */ size = 16; groups = (gid_t *) malloc (size * sizeof (gid_t)); if (__glibc_unlikely (groups == NULL)) /* No more memory. */ return -1; ngroups = internal_getgrouplist (user, group, &size, &groups, limit); /* Try to set the maximum number of groups the kernel can handle. */ do result = setgroups (ngroups, groups); while (result == -1 && errno == EINVAL && --ngroups > 0); free (groups); return result; #endif } nss_interface_function (initgroups)