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/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License, Version 1.0 only
* (the "License"). You may not use this file except in compliance
* with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 1989-1999,2001-2003 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
#pragma ident "%Z%%M% %I% %E% SMI"
#include <sys/types.h>
#include <sys/errno.h>
#include <sys/param.h>
#include <sys/t_lock.h>
#include <sys/systm.h>
#include <sys/sysmacros.h>
#include <sys/debug.h>
#include <sys/time.h>
#include <sys/cmn_err.h>
#include <sys/vnode.h>
#include <sys/stat.h>
#include <sys/vfs.h>
#include <sys/cred.h>
#include <sys/kmem.h>
#include <sys/atomic.h>
#include <sys/policy.h>
#include <sys/fs/tmp.h>
#include <sys/fs/tmpnode.h>
#define MODESHIFT 3
int
tmp_taccess(void *vtp, int mode, struct cred *cred)
{
struct tmpnode *tp = vtp;
int shift = 0;
/*
* Check access based on owner, group and
* public permissions in tmpnode.
*/
if (crgetuid(cred) != tp->tn_uid) {
shift += MODESHIFT;
if (groupmember(tp->tn_gid, cred) == 0)
shift += MODESHIFT;
}
/* compute missing mode bits */
mode &= ~(tp->tn_mode << shift);
if (mode == 0)
return (0);
return (secpolicy_vnode_access(cred, TNTOV(tp), tp->tn_uid, mode));
}
/*
* Decide whether it is okay to remove within a sticky directory.
* Two conditions need to be met: write access to the directory
* is needed. In sticky directories, write access is not sufficient;
* you can remove entries from a directory only if you own the directory,
* if you are privileged, if you own the entry or if they entry is
* a plain file and you have write access to that file.
* Function returns 0 if remove access is granted.
*/
int
tmp_sticky_remove_access(struct tmpnode *dir, struct tmpnode *entry,
struct cred *cr)
{
uid_t uid = crgetuid(cr);
if ((dir->tn_mode & S_ISVTX) &&
uid != dir->tn_uid &&
uid != entry->tn_uid &&
(entry->tn_type != VREG ||
tmp_taccess(entry, VWRITE, cr) != 0))
return (secpolicy_vnode_remove(cr));
return (0);
}
/*
* Allocate zeroed memory if tmpfs_maxkmem has not been exceeded
* or the 'musthave' flag is set. 'musthave' allocations should
* always be subordinate to normal allocations so that tmpfs_maxkmem
* can't be exceeded by more than a few KB. Example: when creating
* a new directory, the tmpnode is a normal allocation; if that
* succeeds, the dirents for "." and ".." are 'musthave' allocations.
*/
void *
tmp_memalloc(size_t size, int musthave)
{
static time_t last_warning;
time_t now;
if (atomic_add_long_nv(&tmp_kmemspace, size) < tmpfs_maxkmem ||
musthave)
return (kmem_zalloc(size, KM_SLEEP));
atomic_add_long(&tmp_kmemspace, -size);
now = gethrestime_sec();
if (last_warning != now) {
last_warning = now;
cmn_err(CE_WARN, "tmp_memalloc: tmpfs over memory limit");
}
return (NULL);
}
void
tmp_memfree(void *cp, size_t size)
{
kmem_free(cp, size);
atomic_add_long(&tmp_kmemspace, -size);
}
/*
* Convert a string containing a number (number of bytes) to a pgcnt_t,
* containing the corresponding number of pages. On 32-bit kernels, the
* maximum value encoded in 'str' is PAGESIZE * ULONG_MAX, while the value
* returned in 'maxpg' is at most ULONG_MAX.
*
* If the number is followed by a "k" or "K", the value is converted from
* kilobytes to bytes. If it is followed by an "m" or "M" it is converted
* from megabytes to bytes. If it is not followed by a character it is
* assumed to be in bytes. Multiple letter options are allowed, so for instance
* '2mk' is interpreted as 2gb.
*
* Parse and overflow errors are detected and a non-zero number returned on
* error.
*/
int
tmp_convnum(char *str, pgcnt_t *maxpg)
{
uint64_t num = 0, oldnum;
#ifdef _LP64
uint64_t max_bytes = ULONG_MAX;
#else
uint64_t max_bytes = PAGESIZE * (uint64_t)ULONG_MAX;
#endif
char *c;
if (str == NULL)
return (EINVAL);
c = str;
/*
* Convert str to number
*/
while ((*c >= '0') && (*c <= '9')) {
oldnum = num;
num = num * 10 + (*c++ - '0');
if (oldnum > num) /* overflow */
return (EINVAL);
}
/*
* Terminate on null
*/
while (*c != '\0') {
switch (*c++) {
/*
* convert from kilobytes
*/
case 'k':
case 'K':
if (num > max_bytes / 1024) /* will overflow */
return (EINVAL);
num *= 1024;
break;
/*
* convert from megabytes
*/
case 'm':
case 'M':
if (num > max_bytes / (1024 * 1024)) /* will overflow */
return (EINVAL);
num *= 1024 * 1024;
break;
default:
return (EINVAL);
}
}
/*
* Since btopr() rounds up to page granularity, this round-up can
* cause an overflow only if 'num' is between (max_bytes - PAGESIZE)
* and (max_bytes). In this case the resulting number is zero, which
* is what we check for below.
*/
if ((*maxpg = (pgcnt_t)btopr(num)) == 0 && num != 0)
return (EINVAL);
return (0);
}
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