lustre/obdclass/idmap.c

   1 /*
   2  * GPL HEADER START
   3  *
   4  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 only,
   8  * as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * General Public License version 2 for more details (a copy is included
  14  * in the LICENSE file that accompanied this code).
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * version 2 along with this program; If not, see
  18  * http://www.gnu.org/licenses/gpl-2.0.html
  19  *
  20  * GPL HEADER END
  21  */
  22 /*
  23  * Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
  24  * Use is subject to license terms.
  25  *
  26  * Copyright (c) 2012, 2017, Intel Corporation.
  27  */
  28 /*
  29  * This file is part of Lustre, http://www.lustre.org/
  30  *
  31  * lustre/obdclass/idmap.c
  32  *
  33  * Lustre user identity mapping.
  34  *
  35  * Author: Fan Yong <fanyong@clusterfs.com>
  36  */
  37
  38 #define DEBUG_SUBSYSTEM S_SEC
  39
  40 #include <linux/user_namespace.h>
  41 #include <linux/uidgid.h>
  42
  43 #include <lustre_idmap.h>
  44 #include <upcall_cache.h>
  45 #include <md_object.h>
  46 #include <obd_support.h>
  47
  48 /*
  49  * groups_search() is copied from linux kernel!
  50  * A simple bsearch.
  51  */
  52 static int lustre_groups_search(struct group_info *group_info,
  53                                 gid_t grp)
  54 {
  55         int left, right;
  56
  57         if (!group_info)
  58                 return 0;
  59
  60         left = 0;
  61         right = group_info->ngroups;
  62         while (left < right) {
  63                 int mid = (left + right) / 2;
  64                 int cmp = grp -
  65                         from_kgid(&init_user_ns, CFS_GROUP_AT(group_info, mid));
  66
  67                 if (cmp > 0)
  68                         left = mid + 1;
  69                 else if (cmp < 0)
  70                         right = mid;
  71                 else
  72                         return 1;
  73         }
  74         return 0;
  75 }
  76
  77 void lustre_groups_from_list(struct group_info *ginfo, gid_t *glist)
  78 {
  79 #ifdef HAVE_GROUP_INFO_GID
  80         memcpy(ginfo->gid, glist, ginfo->ngroups * sizeof(__u32));
  81 #else
  82         int i;
  83         int count = ginfo->ngroups;
  84
  85         /* fill group_info from gid array */
  86         for (i = 0; i < ginfo->nblocks && count > 0; i++) {
  87                 int cp_count = min(CFS_NGROUPS_PER_BLOCK, count);
  88                 int off = i * CFS_NGROUPS_PER_BLOCK;
  89                 int len = cp_count * sizeof(*glist);
  90
  91                 memcpy(ginfo->blocks[i], glist + off, len);
  92                 count -= cp_count;
  93         }
  94 #endif
  95 }
  96 EXPORT_SYMBOL(lustre_groups_from_list);
  97
  98 /* groups_sort() is copied from linux kernel! */
  99 /* a simple shell-metzner sort */
 100 void lustre_groups_sort(struct group_info *group_info)
 101 {
 102         int base, max, stride;
 103         int gidsetsize = group_info->ngroups;
 104
 105         for (stride = 1; stride < gidsetsize; stride = 3 * stride + 1)
 106                 ; /* nothing */
 107         stride /= 3;
 108
 109         while (stride) {
 110                 max = gidsetsize - stride;
 111                 for (base = 0; base < max; base++) {
 112                         int left = base;
 113                         int right = left + stride;
 114                         gid_t tmp = from_kgid(&init_user_ns,
 115                                               CFS_GROUP_AT(group_info, right));
 116
 117                         while (left >= 0 &&
 118                                tmp < from_kgid(&init_user_ns,
 119                                                CFS_GROUP_AT(group_info, left))) {
 120                                 CFS_GROUP_AT(group_info, right) =
 121                                         CFS_GROUP_AT(group_info, left);
 122                                 right = left;
 123                                 left -= stride;
 124                         }
 125                         CFS_GROUP_AT(group_info, right) =
 126                                                 make_kgid(&init_user_ns, tmp);
 127                 }
 128                 stride /= 3;
 129         }
 130 }
 131 EXPORT_SYMBOL(lustre_groups_sort);
 132
 133 int lustre_in_group_p(struct lu_ucred *mu, gid_t grp)
 134 {
 135         int rc = 1;
 136
 137         if (grp != mu->uc_fsgid) {
 138                 struct group_info *group_info = NULL;
 139
 140                 if (mu->uc_ginfo || !mu->uc_identity ||
 141                     mu->uc_valid == UCRED_OLD)
 142                         if (grp == mu->uc_suppgids[0] ||
 143                             grp == mu->uc_suppgids[1])
 144                                 return 1;
 145
 146                 if (mu->uc_ginfo)
 147                         group_info = mu->uc_ginfo;
 148                 else if (mu->uc_identity)
 149                         group_info = mu->uc_identity->mi_ginfo;
 150
 151                 if (!group_info)
 152                         return 0;
 153
 154                 atomic_inc(&group_info->usage);
 155                 rc = lustre_groups_search(group_info, grp);
 156                 if (atomic_dec_and_test(&group_info->usage))
 157                         groups_free(group_info);
 158         }
 159         return rc;
 160 }
 161 EXPORT_SYMBOL(lustre_in_group_p);