lib/libpuffs/creds.c

   1 /*      $NetBSD: creds.c,v 1.13 2007/10/18 13:48:04 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 #include <sys/cdefs.h>
  31 #if !defined(lint)
  32 __RCSID("$NetBSD: creds.c,v 1.13 2007/10/18 13:48:04 pooka Exp $");
  33 #endif /* !lint */
  34
  35 /*
  36  * Interface for dealing with credits.
  37  */
  38
  39 #include <sys/types.h>
  40 #include <sys/param.h>
  41
  42 #include <errno.h>
  43 #include <puffs.h>
  44 #include <stdbool.h>
  45 #include <string.h>
  46
  47 #include "puffs_priv.h"
  48
  49 #define UUCCRED(a) (a->pkcr_type == PUFFCRED_TYPE_UUC)
  50 #define INTCRED(a) (a->pkcr_type == PUFFCRED_TYPE_INTERNAL)
  51
  52 int
  53 puffs_cred_getuid(const struct puffs_cred *pcr, uid_t *ruid)
  54 {
  55         PUFFS_MAKEKCRED(pkcr, pcr);
  56
  57         if (!UUCCRED(pkcr)) {
  58                 errno = EOPNOTSUPP;
  59                 return -1;
  60         }
  61         *ruid = pkcr->pkcr_uuc.cr_uid;
  62
  63         return 0;
  64 }
  65
  66 int
  67 puffs_cred_getgid(const struct puffs_cred *pcr, gid_t *rgid)
  68 {
  69         PUFFS_MAKEKCRED(pkcr, pcr);
  70
  71         if (!UUCCRED(pkcr)) {
  72                 errno = EOPNOTSUPP;
  73                 return -1;
  74         }
  75         *rgid = pkcr->pkcr_uuc.cr_gid;
  76
  77         return 0;
  78 }
  79
  80 int
  81 puffs_cred_getgroups(const struct puffs_cred *pcr, gid_t *rgids, short *ngids)
  82 {
  83         PUFFS_MAKEKCRED(pkcr, pcr);
  84         size_t ncopy;
  85
  86         if (!UUCCRED(pkcr)) {
  87                 errno = EOPNOTSUPP;
  88                 return -1;
  89         }
  90
  91         ncopy = MIN(*ngids, NGROUPS);
  92         (void)memcpy(rgids, pkcr->pkcr_uuc.cr_groups, sizeof(gid_t) * ncopy);
  93         *ngids = (short)ncopy;
  94
  95         return 0;
  96 }
  97
  98 bool
  99 puffs_cred_isuid(const struct puffs_cred *pcr, uid_t uid)
 100 {
 101         PUFFS_MAKEKCRED(pkcr, pcr);
 102
 103         return UUCCRED(pkcr) && pkcr->pkcr_uuc.cr_uid == uid;
 104 }
 105
 106 bool
 107 puffs_cred_hasgroup(const struct puffs_cred *pcr, gid_t gid)
 108 {
 109         PUFFS_MAKEKCRED(pkcr, pcr);
 110         short i;
 111
 112         if (!UUCCRED(pkcr))
 113                 return false;
 114
 115         if (pkcr->pkcr_uuc.cr_gid == gid)
 116                 return true;
 117         for (i = 0; i < pkcr->pkcr_uuc.cr_ngroups; i++)
 118                 if (pkcr->pkcr_uuc.cr_groups[i] == gid)
 119                         return true;
 120
 121         return false;
 122 }
 123
 124 bool
 125 puffs_cred_isregular(const struct puffs_cred *pcr)
 126 {
 127         PUFFS_MAKEKCRED(pkcr, pcr);
 128
 129         return UUCCRED(pkcr);
 130 }
 131
 132 bool
 133 puffs_cred_iskernel(const struct puffs_cred *pcr)
 134 {
 135         PUFFS_MAKEKCRED(pkcr, pcr);
 136
 137         return INTCRED(pkcr) && pkcr->pkcr_internal == PUFFCRED_CRED_NOCRED;
 138 }
 139
 140 bool
 141 puffs_cred_isfs(const struct puffs_cred *pcr)
 142 {
 143         PUFFS_MAKEKCRED(pkcr, pcr);
 144
 145         return INTCRED(pkcr) && pkcr->pkcr_internal == PUFFCRED_CRED_FSCRED;
 146 }
 147
 148 bool
 149 puffs_cred_isjuggernaut(const struct puffs_cred *pcr)
 150 {
 151
 152         return puffs_cred_isuid(pcr, 0) || puffs_cred_iskernel(pcr)
 153             || puffs_cred_isfs(pcr);
 154 }
 155
 156 /*
 157  * Generic routine for checking file access rights.  Modeled after
 158  * vaccess() in the kernel.
 159  */
 160 int
 161 puffs_access(enum vtype type, mode_t file_mode, uid_t uid, gid_t gid,
 162         mode_t acc_mode, const struct puffs_cred *pcr)
 163 {
 164         mode_t mask;
 165
 166         /* megapower */
 167         if (puffs_cred_iskernel(pcr) || puffs_cred_isfs(pcr))
 168                 return 0;
 169
 170         /* superuser, allow all except exec if *ALL* exec bits are unset */
 171         if (puffs_cred_isuid(pcr, 0)) {
 172                 if ((acc_mode & PUFFS_VEXEC) && type != VDIR &&
 173                     (file_mode & (S_IXUSR|S_IXGRP|S_IXOTH)) == 0)
 174                         return EACCES;
 175                 return 0;
 176         }
 177
 178         mask = 0;
 179         /* owner */
 180         if (puffs_cred_isuid(pcr, uid)) {
 181                 if (acc_mode & PUFFS_VEXEC)
 182                         mask |= S_IXUSR;
 183                 if (acc_mode & PUFFS_VREAD)
 184                         mask |= S_IRUSR;
 185                 if (acc_mode & PUFFS_VWRITE)
 186                         mask |= S_IWUSR;
 187         /* group */
 188         } else if (puffs_cred_hasgroup(pcr, gid)) {
 189                 if (acc_mode & PUFFS_VEXEC)
 190                         mask |= S_IXGRP;
 191                 if (acc_mode & PUFFS_VREAD)
 192                         mask |= S_IRGRP;
 193                 if (acc_mode & PUFFS_VWRITE)
 194                         mask |= S_IWGRP;
 195         /* other */
 196         } else {
 197                 if (acc_mode & PUFFS_VEXEC)
 198                         mask |= S_IXOTH;
 199                 if (acc_mode & PUFFS_VREAD)
 200                         mask |= S_IROTH;
 201                 if (acc_mode & PUFFS_VWRITE)
 202                         mask |= S_IWOTH;
 203         }
 204
 205         if ((file_mode & mask) == mask)
 206                 return 0;
 207         else
 208                 return EACCES;
 209 }
 210
 211 int
 212 puffs_access_chown(uid_t owner, gid_t group, uid_t newowner, gid_t newgroup,
 213         const struct puffs_cred *pcr)
 214 {
 215
 216         if (newowner == (uid_t)PUFFS_VNOVAL)
 217                 newowner = owner;
 218         if (newgroup == (gid_t)PUFFS_VNOVAL)
 219                 newgroup = group;
 220
 221         if ((!puffs_cred_isuid(pcr, owner) || newowner != owner ||
 222             ((newgroup != group && !puffs_cred_hasgroup(pcr, newgroup))))
 223             && !puffs_cred_isjuggernaut(pcr))
 224                 return EPERM;
 225
 226         return 0;
 227 }
 228
 229 int
 230 puffs_access_chmod(uid_t owner, gid_t group, enum vtype type, mode_t mode,
 231         const struct puffs_cred *pcr)
 232 {
 233
 234         if (!puffs_cred_isuid(pcr, owner) && !puffs_cred_isjuggernaut(pcr))
 235                 return EPERM;
 236
 237         if (!puffs_cred_isjuggernaut(pcr)) {
 238                 if (type != VDIR && (mode & S_ISTXT))
 239                         return EFTYPE;
 240                 if (!puffs_cred_hasgroup(pcr, group) && (mode & S_ISGID))
 241                         return EPERM;
 242         }
 243
 244         return 0;
 245 }
 246
 247 int
 248 puffs_access_times(uid_t uid, gid_t gid, mode_t mode, int va_utimes_null,
 249         const struct puffs_cred *pcr)
 250 {
 251
 252         if (!puffs_cred_isuid(pcr, uid) && !puffs_cred_isjuggernaut(pcr)
 253             && (va_utimes_null == 0
 254               || puffs_access(VNON, mode, uid, gid, PUFFS_VWRITE, pcr) != 0))
 255                 return EPERM;
 256
 257         return 0;
 258 }