minix/lib/libpuffs/creds.c

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/* $NetBSD: creds.c,v 1.16 2012/03/15 12:49:36 njoly Exp $ */
/*
* Copyright (c) 2006 Antti Kantee. All Rights Reserved.
*
* Development of this software was supported by the Ulla Tuominen Foundation.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
* OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
#if !defined(lint)
__RCSID("$NetBSD: creds.c,v 1.16 2012/03/15 12:49:36 njoly Exp $");
#endif /* !lint */
/*
* Interface for dealing with credits.
*/
#include <sys/types.h>
#include <sys/param.h>
#include <errno.h>
#include <puffs.h>
#include <stdbool.h>
#include <string.h>
#include "puffs_priv.h"
#define UUCCRED(a) (a->pkcr_type == PUFFCRED_TYPE_UUC)
#define INTCRED(a) (a->pkcr_type == PUFFCRED_TYPE_INTERNAL)
int
puffs_cred_getuid(const struct puffs_cred *pcr, uid_t *ruid)
{
PUFFS_MAKEKCRED(pkcr, pcr);
if (!UUCCRED(pkcr)) {
errno = EOPNOTSUPP;
return -1;
}
*ruid = pkcr->pkcr_uuc.cr_uid;
return 0;
}
int
puffs_cred_getgid(const struct puffs_cred *pcr, gid_t *rgid)
{
PUFFS_MAKEKCRED(pkcr, pcr);
if (!UUCCRED(pkcr)) {
errno = EOPNOTSUPP;
return -1;
}
*rgid = pkcr->pkcr_uuc.cr_gid;
return 0;
}
int
puffs_cred_getgroups(const struct puffs_cred *pcr, gid_t *rgids, short *ngids)
{
PUFFS_MAKEKCRED(pkcr, pcr);
size_t ncopy;
if (!UUCCRED(pkcr)) {
errno = EOPNOTSUPP;
*ngids = 0;
return -1;
}
ncopy = MIN(*ngids, pkcr->pkcr_uuc.cr_ngroups);
(void)memcpy(rgids, pkcr->pkcr_uuc.cr_groups, sizeof(gid_t) * ncopy);
*ngids = (short)ncopy;
return 0;
}
bool
puffs_cred_isuid(const struct puffs_cred *pcr, uid_t uid)
{
PUFFS_MAKEKCRED(pkcr, pcr);
return UUCCRED(pkcr) && pkcr->pkcr_uuc.cr_uid == uid;
}
bool
puffs_cred_hasgroup(const struct puffs_cred *pcr, gid_t gid)
{
PUFFS_MAKEKCRED(pkcr, pcr);
short i;
if (!UUCCRED(pkcr))
return false;
if (pkcr->pkcr_uuc.cr_gid == gid)
return true;
for (i = 0; i < pkcr->pkcr_uuc.cr_ngroups; i++)
if (pkcr->pkcr_uuc.cr_groups[i] == gid)
return true;
return false;
}
bool
puffs_cred_isregular(const struct puffs_cred *pcr)
{
PUFFS_MAKEKCRED(pkcr, pcr);
return UUCCRED(pkcr);
}
bool
puffs_cred_iskernel(const struct puffs_cred *pcr)
{
PUFFS_MAKEKCRED(pkcr, pcr);
return INTCRED(pkcr) && pkcr->pkcr_internal == PUFFCRED_CRED_NOCRED;
}
bool
puffs_cred_isfs(const struct puffs_cred *pcr)
{
PUFFS_MAKEKCRED(pkcr, pcr);
return INTCRED(pkcr) && pkcr->pkcr_internal == PUFFCRED_CRED_FSCRED;
}
bool
puffs_cred_isjuggernaut(const struct puffs_cred *pcr)
{
return puffs_cred_isuid(pcr, 0) || puffs_cred_iskernel(pcr)
|| puffs_cred_isfs(pcr);
}
/*
* Generic routine for checking file access rights. Modeled after
* vaccess() in the kernel.
*/
int
puffs_access(enum vtype type, mode_t file_mode, uid_t uid, gid_t gid,
mode_t acc_mode, const struct puffs_cred *pcr)
{
mode_t mask;
/* megapower */
if (puffs_cred_iskernel(pcr) || puffs_cred_isfs(pcr))
return 0;
/* superuser, allow all except exec if *ALL* exec bits are unset */
if (puffs_cred_isuid(pcr, 0)) {
if ((acc_mode & PUFFS_VEXEC) && type != VDIR &&
(file_mode & (S_IXUSR|S_IXGRP|S_IXOTH)) == 0)
return EACCES;
return 0;
}
mask = 0;
/* owner */
if (puffs_cred_isuid(pcr, uid)) {
if (acc_mode & PUFFS_VEXEC)
mask |= S_IXUSR;
if (acc_mode & PUFFS_VREAD)
mask |= S_IRUSR;
if (acc_mode & PUFFS_VWRITE)
mask |= S_IWUSR;
/* group */
} else if (puffs_cred_hasgroup(pcr, gid)) {
if (acc_mode & PUFFS_VEXEC)
mask |= S_IXGRP;
if (acc_mode & PUFFS_VREAD)
mask |= S_IRGRP;
if (acc_mode & PUFFS_VWRITE)
mask |= S_IWGRP;
/* other */
} else {
if (acc_mode & PUFFS_VEXEC)
mask |= S_IXOTH;
if (acc_mode & PUFFS_VREAD)
mask |= S_IROTH;
if (acc_mode & PUFFS_VWRITE)
mask |= S_IWOTH;
}
if ((file_mode & mask) == mask)
return 0;
else
return EACCES;
}
int
puffs_access_chown(uid_t owner, gid_t group, uid_t newowner, gid_t newgroup,
const struct puffs_cred *pcr)
{
if (newowner == (uid_t)PUFFS_VNOVAL)
newowner = owner;
if (newgroup == (gid_t)PUFFS_VNOVAL)
newgroup = group;
if ((!puffs_cred_isuid(pcr, owner) || newowner != owner ||
((newgroup != group && !puffs_cred_hasgroup(pcr, newgroup))))
&& !puffs_cred_isjuggernaut(pcr))
return EPERM;
return 0;
}
int
puffs_access_chmod(uid_t owner, gid_t group, enum vtype type, mode_t mode,
const struct puffs_cred *pcr)
{
if (!puffs_cred_isuid(pcr, owner) && !puffs_cred_isjuggernaut(pcr))
return EPERM;
if (!puffs_cred_isjuggernaut(pcr)) {
if (type != VDIR && (mode & S_ISTXT))
return EFTYPE;
if (!puffs_cred_hasgroup(pcr, group) && (mode & S_ISGID))
return EPERM;
}
return 0;
}
int
puffs_access_times(uid_t uid, gid_t gid, mode_t mode, int va_utimes_null,
const struct puffs_cred *pcr)
{
if (puffs_cred_isuid(pcr, uid) || puffs_cred_isjuggernaut(pcr))
return 0;
if (va_utimes_null == 0)
return EPERM;
return puffs_access(VNON, mode, uid, gid, PUFFS_VWRITE, pcr);
}