1 /* $NetBSD: creds.c,v 1.14.12.1 2009/11/28 16:01:03 bouyer 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 1.14.12.1 2009/11/28 16:01:03 bouyer 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 <stdbool.h> 44 #include <string.h> 45 46 #include "puffs.h" 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 } 260