module/os/linux/spl/spl-cred.c

   1 /*
   2  *  Copyright (C) 2007-2010 Lawrence Livermore National Security, LLC.
   3  *  Copyright (C) 2007 The Regents of the University of California.
   4  *  Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER).
   5  *  Written by Brian Behlendorf <behlendorf1@llnl.gov>.
   6  *  UCRL-CODE-235197
   7  *
   8  *  This file is part of the SPL, Solaris Porting Layer.
   9  *
  10  *  The SPL is free software; you can redistribute it and/or modify it
  11  *  under the terms of the GNU General Public License as published by the
  12  *  Free Software Foundation; either version 2 of the License, or (at your
  13  *  option) any later version.
  14  *
  15  *  The SPL is distributed in the hope that it will be useful, but WITHOUT
  16  *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  17  *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  18  *  for more details.
  19  *
  20  *  You should have received a copy of the GNU General Public License along
  21  *  with the SPL.  If not, see <http://www.gnu.org/licenses/>.
  22  *
  23  *  Solaris Porting Layer (SPL) Credential Implementation.
  24  */
  25
  26 #include <sys/cred.h>
  27
  28 static int
  29 cr_groups_search(const struct group_info *group_info, kgid_t grp)
  30 {
  31         unsigned int left, right, mid;
  32         int cmp;
  33
  34         if (!group_info)
  35                 return (0);
  36
  37         left = 0;
  38         right = group_info->ngroups;
  39         while (left < right) {
  40                 mid = (left + right) / 2;
  41                 cmp = KGID_TO_SGID(grp) -
  42                     KGID_TO_SGID(GROUP_AT(group_info, mid));
  43
  44                 if (cmp > 0)
  45                         left = mid + 1;
  46                 else if (cmp < 0)
  47                         right = mid;
  48                 else
  49                         return (1);
  50         }
  51         return (0);
  52 }
  53
  54 /* Hold a reference on the credential */
  55 void
  56 crhold(cred_t *cr)
  57 {
  58         (void) get_cred((const cred_t *)cr);
  59 }
  60
  61 /* Free a reference on the credential */
  62 void
  63 crfree(cred_t *cr)
  64 {
  65         put_cred((const cred_t *)cr);
  66 }
  67
  68 /* Return the number of supplemental groups */
  69 int
  70 crgetngroups(const cred_t *cr)
  71 {
  72         struct group_info *gi;
  73         int rc;
  74
  75         gi = cr->group_info;
  76         rc = gi->ngroups;
  77 #ifndef HAVE_GROUP_INFO_GID
  78         /*
  79          * For Linux <= 4.8,
  80          * crgetgroups will only returns gi->blocks[0], which contains only
  81          * the first NGROUPS_PER_BLOCK groups.
  82          */
  83         if (rc > NGROUPS_PER_BLOCK) {
  84                 WARN_ON_ONCE(1);
  85                 rc = NGROUPS_PER_BLOCK;
  86         }
  87 #endif
  88         return (rc);
  89 }
  90
  91 /*
  92  * Return an array of supplemental gids.  The returned address is safe
  93  * to use as long as the caller has taken a reference with crhold().
  94  *
  95  * Linux 4.9 API change, group_info changed from 2d array via ->blocks to 1d
  96  * array via ->gid.
  97  */
  98 gid_t *
  99 crgetgroups(const cred_t *cr)
 100 {
 101         struct group_info *gi;
 102         gid_t *gids = NULL;
 103
 104         gi = cr->group_info;
 105 #ifdef HAVE_GROUP_INFO_GID
 106         gids = KGIDP_TO_SGIDP(gi->gid);
 107 #else
 108         if (gi->nblocks > 0)
 109                 gids = KGIDP_TO_SGIDP(gi->blocks[0]);
 110 #endif
 111         return (gids);
 112 }
 113
 114 /* Check if the passed gid is available in supplied credential. */
 115 int
 116 groupmember(gid_t gid, const cred_t *cr)
 117 {
 118         struct group_info *gi;
 119         int rc;
 120
 121         gi = cr->group_info;
 122         rc = cr_groups_search(gi, SGID_TO_KGID(gid));
 123
 124         return (rc);
 125 }
 126
 127 /* Return the effective user id */
 128 uid_t
 129 crgetuid(const cred_t *cr)
 130 {
 131         return (KUID_TO_SUID(cr->fsuid));
 132 }
 133
 134 /* Return the real user id */
 135 uid_t
 136 crgetruid(const cred_t *cr)
 137 {
 138         return (KUID_TO_SUID(cr->uid));
 139 }
 140
 141 /* Return the effective group id */
 142 gid_t
 143 crgetgid(const cred_t *cr)
 144 {
 145         return (KGID_TO_SGID(cr->fsgid));
 146 }
 147
 148 /* Return the initial user ns or nop_mnt_idmap */
 149 zidmap_t *
 150 zfs_get_init_idmap(void)
 151 {
 152 #ifdef HAVE_IOPS_CREATE_IDMAP
 153         return ((zidmap_t *)&nop_mnt_idmap);
 154 #else
 155         return ((zidmap_t *)&init_user_ns);
 156 #endif
 157 }
 158
 159 EXPORT_SYMBOL(zfs_get_init_idmap);
 160 EXPORT_SYMBOL(crhold);
 161 EXPORT_SYMBOL(crfree);
 162 EXPORT_SYMBOL(crgetuid);
 163 EXPORT_SYMBOL(crgetruid);
 164 EXPORT_SYMBOL(crgetgid);
 165 EXPORT_SYMBOL(crgetngroups);
 166 EXPORT_SYMBOL(crgetgroups);
 167 EXPORT_SYMBOL(groupmember);