lib/libpuffs/creds.c

   1 /*      $NetBSD: creds.c,v 1.15 2009/11/20 14:23:54 pooka Exp $ */
   2
   3 /*
   4  * Copyright (c) 2006  Antti Kantee.  All Rights Reserved.
   5  *
   6  * Development of this software was supported by the Ulla Tuominen Foundation.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
  18  * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  19  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  20  * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
  23  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  */
  29
  30 /*
  31  * Interface for dealing with credits.
  32  */
  33
  34 #include <sys/types.h>
  35 #include <sys/param.h>
  36
  37 #include <errno.h>
  38 #include <stdbool.h>
  39 #include <string.h>
  40
  41 #include "puffs.h"
  42 #include "puffs_priv.h"
  43
  44 #define UUCCRED(a) (a->pkcr_type == PUFFCRED_TYPE_UUC)
  45 #define INTCRED(a) (a->pkcr_type == PUFFCRED_TYPE_INTERNAL)
  46
  47 int
  48 puffs_cred_getuid(const struct puffs_cred *pcr, uid_t *ruid)
  49 {
  50         PUFFS_MAKEKCRED(pkcr, pcr);
  51
  52         if (!UUCCRED(pkcr)) {
  53                 errno = EOPNOTSUPP;
  54                 return -1;
  55         }
  56         *ruid = pkcr->pkcr_uuc.cr_uid;
  57
  58         return 0;
  59 }
  60
  61 int
  62 puffs_cred_getgid(const struct puffs_cred *pcr, gid_t *rgid)
  63 {
  64         PUFFS_MAKEKCRED(pkcr, pcr);
  65
  66         if (!UUCCRED(pkcr)) {
  67                 errno = EOPNOTSUPP;
  68                 return -1;
  69         }
  70         *rgid = pkcr->pkcr_uuc.cr_gid;
  71
  72         return 0;
  73 }
  74
  75 int
  76 puffs_cred_getgroups(const struct puffs_cred *pcr, gid_t *rgids, short *ngids)
  77 {
  78         PUFFS_MAKEKCRED(pkcr, pcr);
  79         size_t ncopy;
  80
  81         if (!UUCCRED(pkcr)) {
  82                 errno = EOPNOTSUPP;
  83                 *ngids = 0;
  84                 return -1;
  85         }
  86
  87         ncopy = MIN(*ngids, pkcr->pkcr_uuc.cr_ngroups);
  88         (void)memcpy(rgids, pkcr->pkcr_uuc.cr_groups, sizeof(gid_t) * ncopy);
  89         *ngids = (short)ncopy;
  90
  91         return 0;
  92 }
  93
  94 bool
  95 puffs_cred_isuid(const struct puffs_cred *pcr, uid_t uid)
  96 {
  97         PUFFS_MAKEKCRED(pkcr, pcr);
  98
  99         return UUCCRED(pkcr) && pkcr->pkcr_uuc.cr_uid == uid;
 100 }
 101
 102 bool
 103 puffs_cred_hasgroup(const struct puffs_cred *pcr, gid_t gid)
 104 {
 105         PUFFS_MAKEKCRED(pkcr, pcr);
 106         short i;
 107
 108         if (!UUCCRED(pkcr))
 109                 return false;
 110
 111         if (pkcr->pkcr_uuc.cr_gid == gid)
 112                 return true;
 113         for (i = 0; i < pkcr->pkcr_uuc.cr_ngroups; i++)
 114                 if (pkcr->pkcr_uuc.cr_groups[i] == gid)
 115                         return true;
 116
 117         return false;
 118 }
 119
 120 bool
 121 puffs_cred_isregular(const struct puffs_cred *pcr)
 122 {
 123         PUFFS_MAKEKCRED(pkcr, pcr);
 124
 125         return UUCCRED(pkcr);
 126 }
 127
 128 bool
 129 puffs_cred_iskernel(const struct puffs_cred *pcr)
 130 {
 131         PUFFS_MAKEKCRED(pkcr, pcr);
 132
 133         return INTCRED(pkcr) && pkcr->pkcr_internal == PUFFCRED_CRED_NOCRED;
 134 }
 135
 136 bool
 137 puffs_cred_isfs(const struct puffs_cred *pcr)
 138 {
 139         PUFFS_MAKEKCRED(pkcr, pcr);
 140
 141         return INTCRED(pkcr) && pkcr->pkcr_internal == PUFFCRED_CRED_FSCRED;
 142 }
 143
 144 bool
 145 puffs_cred_isjuggernaut(const struct puffs_cred *pcr)
 146 {
 147
 148         return puffs_cred_isuid(pcr, 0) || puffs_cred_iskernel(pcr)
 149             || puffs_cred_isfs(pcr);
 150 }
 151
 152 /*
 153  * Generic routine for checking file access rights.  Modeled after
 154  * vaccess() in the kernel.
 155  */
 156 int
 157 puffs_access(enum vtype type, mode_t file_mode, uid_t uid, gid_t gid,
 158         mode_t acc_mode, const struct puffs_cred *pcr)
 159 {
 160         mode_t mask;
 161
 162         /* megapower */
 163         if (puffs_cred_iskernel(pcr) || puffs_cred_isfs(pcr))
 164                 return 0;
 165
 166         /* superuser, allow all except exec if *ALL* exec bits are unset */
 167         if (puffs_cred_isuid(pcr, 0)) {
 168                 if ((acc_mode & PUFFS_VEXEC) && type != VDIR &&
 169                     (file_mode & (S_IXUSR|S_IXGRP|S_IXOTH)) == 0)
 170                         return EACCES;
 171                 return 0;
 172         }
 173
 174         mask = 0;
 175         /* owner */
 176         if (puffs_cred_isuid(pcr, uid)) {
 177                 if (acc_mode & PUFFS_VEXEC)
 178                         mask |= S_IXUSR;
 179                 if (acc_mode & PUFFS_VREAD)
 180                         mask |= S_IRUSR;
 181                 if (acc_mode & PUFFS_VWRITE)
 182                         mask |= S_IWUSR;
 183         /* group */
 184         } else if (puffs_cred_hasgroup(pcr, gid)) {
 185                 if (acc_mode & PUFFS_VEXEC)
 186                         mask |= S_IXGRP;
 187                 if (acc_mode & PUFFS_VREAD)
 188                         mask |= S_IRGRP;
 189                 if (acc_mode & PUFFS_VWRITE)
 190                         mask |= S_IWGRP;
 191         /* other */
 192         } else {
 193                 if (acc_mode & PUFFS_VEXEC)
 194                         mask |= S_IXOTH;
 195                 if (acc_mode & PUFFS_VREAD)
 196                         mask |= S_IROTH;
 197                 if (acc_mode & PUFFS_VWRITE)
 198                         mask |= S_IWOTH;
 199         }
 200
 201         if ((file_mode & mask) == mask)
 202                 return 0;
 203         else
 204                 return EACCES;
 205 }
 206
 207 int
 208 puffs_access_chown(uid_t owner, gid_t group, uid_t newowner, gid_t newgroup,
 209         const struct puffs_cred *pcr)
 210 {
 211
 212         if (newowner == (uid_t)PUFFS_VNOVAL)
 213                 newowner = owner;
 214         if (newgroup == (gid_t)PUFFS_VNOVAL)
 215                 newgroup = group;
 216
 217         if ((!puffs_cred_isuid(pcr, owner) || newowner != owner ||
 218             ((newgroup != group && !puffs_cred_hasgroup(pcr, newgroup))))
 219             && !puffs_cred_isjuggernaut(pcr))
 220                 return EPERM;
 221
 222         return 0;
 223 }
 224
 225 int
 226 puffs_access_chmod(uid_t owner, gid_t group, enum vtype type, mode_t mode,
 227         const struct puffs_cred *pcr)
 228 {
 229
 230         if (!puffs_cred_isuid(pcr, owner) && !puffs_cred_isjuggernaut(pcr))
 231                 return EPERM;
 232
 233         if (!puffs_cred_isjuggernaut(pcr)) {
 234                 if (type != VDIR && (mode & S_ISTXT))
 235                         return EFTYPE;
 236                 if (!puffs_cred_hasgroup(pcr, group) && (mode & S_ISGID))
 237                         return EPERM;
 238         }
 239
 240         return 0;
 241 }
 242
 243 int
 244 puffs_access_times(uid_t uid, gid_t gid, mode_t mode, int va_utimes_null,
 245         const struct puffs_cred *pcr)
 246 {
 247
 248         if (!puffs_cred_isuid(pcr, uid) && !puffs_cred_isjuggernaut(pcr)
 249             && (va_utimes_null == 0
 250               || puffs_access(VNON, mode, uid, gid, PUFFS_VWRITE, pcr) != 0))
 251                 return EPERM;
 252
 253         return 0;
 254 }