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 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 } 259