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creds.c revision 1.12.4.1 
      1 /*	$NetBSD: creds.c,v 1.12.4.1 2007/11/06 23:11:50 matt 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 1.12.4.1 2007/11/06 23:11:50 matt 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 int
    157 puffs_cid_getpid(const struct puffs_cid *pcid, pid_t *pid)
    158 {
    159 	PUFFS_MAKEKCID(pkcid, pcid);
    160 
    161 	if (pkcid->pkcid_type == PUFFCID_TYPE_REAL) {
    162 		*pid = pkcid->pkcid_pid;
    163 		return 0;
    164 	} else {
    165 		errno = ESRCH;
    166 		return -1;
    167 	}
    168 }
    169 
    170 int
    171 puffs_cid_getlwpid(const struct puffs_cid *pcid, lwpid_t *lid)
    172 {
    173 	PUFFS_MAKEKCID(pkcid, pcid);
    174 
    175 	if (pkcid->pkcid_type == PUFFCID_TYPE_REAL) {
    176 		*lid = pkcid->pkcid_lwpid;
    177 		return 0;
    178 	} else {
    179 		errno = ESRCH;
    180 		return -1;
    181 	}
    182 }
    183 
    184 bool
    185 puffs_cid_isequal(const struct puffs_cid *pc1, const struct puffs_cid *pc2)
    186 {
    187 	PUFFS_MAKEKCID(pkc1, pc1);
    188 	PUFFS_MAKEKCID(pkc2, pc2);
    189 
    190 	if (pkc1->pkcid_type != PUFFCID_TYPE_REAL
    191 	    || pkc2->pkcid_type != PUFFCID_TYPE_REAL)
    192 		return false;
    193 
    194 	if (pkc1->pkcid_lwpid == pkc1->pkcid_lwpid
    195 	    && pkc2->pkcid_pid == pkc2->pkcid_pid)
    196 		return true;
    197 
    198 	return false;
    199 }
    200 
    201 /*
    202  * Generic routine for checking file access rights.  Modeled after
    203  * vaccess() in the kernel.
    204  */
    205 int
    206 puffs_access(enum vtype type, mode_t file_mode, uid_t uid, gid_t gid,
    207 	mode_t acc_mode, const struct puffs_cred *pcr)
    208 {
    209 	mode_t mask;
    210 
    211 	/* megapower */
    212 	if (puffs_cred_iskernel(pcr) || puffs_cred_isfs(pcr))
    213 		return 0;
    214 
    215 	/* superuser, allow all except exec if *ALL* exec bits are unset */
    216 	if (puffs_cred_isuid(pcr, 0)) {
    217 		if ((acc_mode & PUFFS_VEXEC) && type != VDIR &&
    218 		    (file_mode & (S_IXUSR|S_IXGRP|S_IXOTH)) == 0)
    219 			return EACCES;
    220 		return 0;
    221 	}
    222 
    223 	mask = 0;
    224 	/* owner */
    225 	if (puffs_cred_isuid(pcr, uid)) {
    226 		if (acc_mode & PUFFS_VEXEC)
    227 			mask |= S_IXUSR;
    228 		if (acc_mode & PUFFS_VREAD)
    229 			mask |= S_IRUSR;
    230 		if (acc_mode & PUFFS_VWRITE)
    231 			mask |= S_IWUSR;
    232 	/* group */
    233 	} else if (puffs_cred_hasgroup(pcr, gid)) {
    234 		if (acc_mode & PUFFS_VEXEC)
    235 			mask |= S_IXGRP;
    236 		if (acc_mode & PUFFS_VREAD)
    237 			mask |= S_IRGRP;
    238 		if (acc_mode & PUFFS_VWRITE)
    239 			mask |= S_IWGRP;
    240 	/* other */
    241 	} else {
    242 		if (acc_mode & PUFFS_VEXEC)
    243 			mask |= S_IXOTH;
    244 		if (acc_mode & PUFFS_VREAD)
    245 			mask |= S_IROTH;
    246 		if (acc_mode & PUFFS_VWRITE)
    247 			mask |= S_IWOTH;
    248 	}
    249 
    250 	if ((file_mode & mask) == mask)
    251 		return 0;
    252 	else
    253 		return EACCES;
    254 }
    255 
    256 int
    257 puffs_access_chown(uid_t owner, gid_t group, uid_t newowner, gid_t newgroup,
    258 	const struct puffs_cred *pcr)
    259 {
    260 
    261 	if (newowner == (uid_t)PUFFS_VNOVAL)
    262 		newowner = owner;
    263 	if (newgroup == (gid_t)PUFFS_VNOVAL)
    264 		newgroup = group;
    265 
    266 	if ((!puffs_cred_isuid(pcr, owner) || newowner != owner ||
    267 	    ((newgroup != group && !puffs_cred_hasgroup(pcr, newgroup))))
    268 	    && !puffs_cred_isjuggernaut(pcr))
    269 		return EPERM;
    270 
    271 	return 0;
    272 }
    273 
    274 int
    275 puffs_access_chmod(uid_t owner, gid_t group, enum vtype type, mode_t mode,
    276 	const struct puffs_cred *pcr)
    277 {
    278 
    279 	if (!puffs_cred_isuid(pcr, owner) && !puffs_cred_isjuggernaut(pcr))
    280 		return EPERM;
    281 
    282 	if (!puffs_cred_isjuggernaut(pcr)) {
    283 		if (type != VDIR && (mode & S_ISTXT))
    284 			return EFTYPE;
    285 		if (!puffs_cred_hasgroup(pcr, group) && (mode & S_ISGID))
    286 			return EPERM;
    287 	}
    288 
    289 	return 0;
    290 }
    291 
    292 int
    293 puffs_access_times(uid_t uid, gid_t gid, mode_t mode, int va_utimes_null,
    294 	const struct puffs_cred *pcr)
    295 {
    296 
    297 	if (!puffs_cred_isuid(pcr, uid) && !puffs_cred_isjuggernaut(pcr)
    298 	    && (va_utimes_null == 0
    299 	      || puffs_access(VNON, mode, uid, gid, PUFFS_VWRITE, pcr) != 0))
    300 		return EPERM;
    301 
    302 	return 0;
    303 }
    304