lib/libpuffs/creds.c

   1 /*      $NetBSD: creds.c,v 1.14 2007/12/08 19:57:02 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 1.14 2007/12/08 19:57:02 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                 *ngids = 0;
  89                 return -1;
  90         }
  91
  92         ncopy = MIN(*ngids, pkcr->pkcr_uuc.cr_ngroups);
  93         (void)memcpy(rgids, pkcr->pkcr_uuc.cr_groups, sizeof(gid_t) * ncopy);
  94         *ngids = (short)ncopy;
  95
  96         return 0;
  97 }
  98
  99 bool
 100 puffs_cred_isuid(const struct puffs_cred *pcr, uid_t uid)
 101 {
 102         PUFFS_MAKEKCRED(pkcr, pcr);
 103
 104         return UUCCRED(pkcr) && pkcr->pkcr_uuc.cr_uid == uid;
 105 }
 106
 107 bool
 108 puffs_cred_hasgroup(const struct puffs_cred *pcr, gid_t gid)
 109 {
 110         PUFFS_MAKEKCRED(pkcr, pcr);
 111         short i;
 112
 113         if (!UUCCRED(pkcr))
 114                 return false;
 115
 116         if (pkcr->pkcr_uuc.cr_gid == gid)
 117                 return true;
 118         for (i = 0; i < pkcr->pkcr_uuc.cr_ngroups; i++)
 119                 if (pkcr->pkcr_uuc.cr_groups[i] == gid)
 120                         return true;
 121
 122         return false;
 123 }
 124
 125 bool
 126 puffs_cred_isregular(const struct puffs_cred *pcr)
 127 {
 128         PUFFS_MAKEKCRED(pkcr, pcr);
 129
 130         return UUCCRED(pkcr);
 131 }
 132
 133 bool
 134 puffs_cred_iskernel(const struct puffs_cred *pcr)
 135 {
 136         PUFFS_MAKEKCRED(pkcr, pcr);
 137
 138         return INTCRED(pkcr) && pkcr->pkcr_internal == PUFFCRED_CRED_NOCRED;
 139 }
 140
 141 bool
 142 puffs_cred_isfs(const struct puffs_cred *pcr)
 143 {
 144         PUFFS_MAKEKCRED(pkcr, pcr);
 145
 146         return INTCRED(pkcr) && pkcr->pkcr_internal == PUFFCRED_CRED_FSCRED;
 147 }
 148
 149 bool
 150 puffs_cred_isjuggernaut(const struct puffs_cred *pcr)
 151 {
 152
 153         return puffs_cred_isuid(pcr, 0) || puffs_cred_iskernel(pcr)
 154             || puffs_cred_isfs(pcr);
 155 }
 156
 157 /*
 158  * Generic routine for checking file access rights.  Modeled after
 159  * vaccess() in the kernel.
 160  */
 161 int
 162 puffs_access(enum vtype type, mode_t file_mode, uid_t uid, gid_t gid,
 163         mode_t acc_mode, const struct puffs_cred *pcr)
 164 {
 165         mode_t mask;
 166
 167         /* megapower */
 168         if (puffs_cred_iskernel(pcr) || puffs_cred_isfs(pcr))
 169                 return 0;
 170
 171         /* superuser, allow all except exec if *ALL* exec bits are unset */
 172         if (puffs_cred_isuid(pcr, 0)) {
 173                 if ((acc_mode & PUFFS_VEXEC) && type != VDIR &&
 174                     (file_mode & (S_IXUSR|S_IXGRP|S_IXOTH)) == 0)
 175                         return EACCES;
 176                 return 0;
 177         }
 178
 179         mask = 0;
 180         /* owner */
 181         if (puffs_cred_isuid(pcr, uid)) {
 182                 if (acc_mode & PUFFS_VEXEC)
 183                         mask |= S_IXUSR;
 184                 if (acc_mode & PUFFS_VREAD)
 185                         mask |= S_IRUSR;
 186                 if (acc_mode & PUFFS_VWRITE)
 187                         mask |= S_IWUSR;
 188         /* group */
 189         } else if (puffs_cred_hasgroup(pcr, gid)) {
 190                 if (acc_mode & PUFFS_VEXEC)
 191                         mask |= S_IXGRP;
 192                 if (acc_mode & PUFFS_VREAD)
 193                         mask |= S_IRGRP;
 194                 if (acc_mode & PUFFS_VWRITE)
 195                         mask |= S_IWGRP;
 196         /* other */
 197         } else {
 198                 if (acc_mode & PUFFS_VEXEC)
 199                         mask |= S_IXOTH;
 200                 if (acc_mode & PUFFS_VREAD)
 201                         mask |= S_IROTH;
 202                 if (acc_mode & PUFFS_VWRITE)
 203                         mask |= S_IWOTH;
 204         }
 205
 206         if ((file_mode & mask) == mask)
 207                 return 0;
 208         else
 209                 return EACCES;
 210 }
 211
 212 int
 213 puffs_access_chown(uid_t owner, gid_t group, uid_t newowner, gid_t newgroup,
 214         const struct puffs_cred *pcr)
 215 {
 216
 217         if (newowner == (uid_t)PUFFS_VNOVAL)
 218                 newowner = owner;
 219         if (newgroup == (gid_t)PUFFS_VNOVAL)
 220                 newgroup = group;
 221
 222         if ((!puffs_cred_isuid(pcr, owner) || newowner != owner ||
 223             ((newgroup != group && !puffs_cred_hasgroup(pcr, newgroup))))
 224             && !puffs_cred_isjuggernaut(pcr))
 225                 return EPERM;
 226
 227         return 0;
 228 }
 229
 230 int
 231 puffs_access_chmod(uid_t owner, gid_t group, enum vtype type, mode_t mode,
 232         const struct puffs_cred *pcr)
 233 {
 234
 235         if (!puffs_cred_isuid(pcr, owner) && !puffs_cred_isjuggernaut(pcr))
 236                 return EPERM;
 237
 238         if (!puffs_cred_isjuggernaut(pcr)) {
 239                 if (type != VDIR && (mode & S_ISTXT))
 240                         return EFTYPE;
 241                 if (!puffs_cred_hasgroup(pcr, group) && (mode & S_ISGID))
 242                         return EPERM;
 243         }
 244
 245         return 0;
 246 }
 247
 248 int
 249 puffs_access_times(uid_t uid, gid_t gid, mode_t mode, int va_utimes_null,
 250         const struct puffs_cred *pcr)
 251 {
 252
 253         if (!puffs_cred_isuid(pcr, uid) && !puffs_cred_isjuggernaut(pcr)
 254             && (va_utimes_null == 0
 255               || puffs_access(VNON, mode, uid, gid, PUFFS_VWRITE, pcr) != 0))
 256                 return EPERM;
 257
 258         return 0;
 259 }