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/*-
* Copyright (c) 2013 The FreeBSD Foundation
* All rights reserved.
*
* This software was developed by Pawel Jakub Dawidek under sponsorship from
* the FreeBSD 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 AUTHORS AND CONTRIBUTORS ``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 AUTHORS 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>
__FBSDID("$FreeBSD$");
#include <sys/types.h>
#include <sys/sysctl.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <libcapsicum.h>
#include <libcapsicum_sysctl.h>
#include <libcasper.h>
#include <nv.h>
#include <pjdlog.h>
static int
sysctl_check_one(const nvlist_t *nvl, bool islimit)
{
const char *name;
void *cookie;
int type;
unsigned int fields;
/* NULL nvl is of course invalid. */
if (nvl == NULL)
return (EINVAL);
if (nvlist_error(nvl) != 0)
return (nvlist_error(nvl));
#define HAS_NAME 0x01
#define HAS_OPERATION 0x02
fields = 0;
cookie = NULL;
while ((name = nvlist_next(nvl, &type, &cookie)) != NULL) {
/* We accept only one 'name' and one 'operation' in nvl. */
if (strcmp(name, "name") == 0) {
if (type != NV_TYPE_STRING)
return (EINVAL);
/* Only one 'name' can be present. */
if ((fields & HAS_NAME) != 0)
return (EINVAL);
fields |= HAS_NAME;
} else if (strcmp(name, "operation") == 0) {
uint64_t operation;
if (type != NV_TYPE_NUMBER)
return (EINVAL);
/*
* We accept only CAP_SYSCTL_READ and
* CAP_SYSCTL_WRITE flags.
*/
operation = nvlist_get_number(nvl, name);
if ((operation & ~(CAP_SYSCTL_RDWR)) != 0)
return (EINVAL);
/* ...but there has to be at least one of them. */
if ((operation & (CAP_SYSCTL_RDWR)) == 0)
return (EINVAL);
/* Only one 'operation' can be present. */
if ((fields & HAS_OPERATION) != 0)
return (EINVAL);
fields |= HAS_OPERATION;
} else if (islimit) {
/* If this is limit, there can be no other fields. */
return (EINVAL);
}
}
/* Both fields has to be there. */
if (fields != (HAS_NAME | HAS_OPERATION))
return (EINVAL);
#undef HAS_OPERATION
#undef HAS_NAME
return (0);
}
static bool
sysctl_allowed(const nvlist_t *limits, const char *chname, uint64_t choperation)
{
uint64_t operation;
const char *name;
void *cookie;
int type;
if (limits == NULL)
return (true);
cookie = NULL;
while ((name = nvlist_next(limits, &type, &cookie)) != NULL) {
PJDLOG_ASSERT(type == NV_TYPE_NUMBER);
operation = nvlist_get_number(limits, name);
if ((operation & choperation) != choperation)
continue;
if ((operation & CAP_SYSCTL_RECURSIVE) == 0) {
if (strcmp(name, chname) != 0)
continue;
} else {
size_t namelen;
namelen = strlen(name);
if (strncmp(name, chname, namelen) != 0)
continue;
if (chname[namelen] != '.' && chname[namelen] != '\0')
continue;
}
return (true);
}
return (false);
}
static int
sysctl_limit(const nvlist_t *oldlimits, const nvlist_t *newlimits)
{
const nvlist_t *nvl;
const char *name;
void *cookie;
uint64_t operation;
int error, type;
cookie = NULL;
while ((name = nvlist_next(newlimits, &type, &cookie)) != NULL) {
if (type != NV_TYPE_NUMBER)
return (EINVAL);
operation = nvlist_get_number(newlimits, name);
if ((operation & ~(CAP_SYSCTL_RDWR | CAP_SYSCTL_RECURSIVE)) != 0)
return (EINVAL);
if ((operation & (CAP_SYSCTL_RDWR | CAP_SYSCTL_RECURSIVE)) == 0)
return (EINVAL);
if (!sysctl_allowed(oldlimits, name, operation))
return (ENOTCAPABLE);
}
return (0);
}
static int
sysctl_command(const char *cmd, const nvlist_t *limits, nvlist_t *nvlin,
nvlist_t *nvlout)
{
const char *name;
const void *newp;
void *oldp;
uint64_t operation;
size_t oldlen, newlen;
size_t *oldlenp;
int error;
if (strcmp(cmd, "sysctl") != 0)
return (EINVAL);
error = sysctl_check_one(nvlin, false);
if (error != 0)
return (error);
name = nvlist_get_string(nvlin, "name");
operation = nvlist_get_number(nvlin, "operation");
if (!sysctl_allowed(limits, name, operation))
return (ENOTCAPABLE);
if ((operation & CAP_SYSCTL_WRITE) != 0) {
if (!nvlist_exists_binary(nvlin, "newp"))
return (EINVAL);
newp = nvlist_get_binary(nvlin, "newp", &newlen);
PJDLOG_ASSERT(newp != NULL && newlen > 0);
} else {
newp = NULL;
newlen = 0;
}
if ((operation & CAP_SYSCTL_READ) != 0) {
if (nvlist_exists_null(nvlin, "justsize")) {
oldp = NULL;
oldlen = 0;
oldlenp = &oldlen;
} else {
if (!nvlist_exists_number(nvlin, "oldlen"))
return (EINVAL);
oldlen = (size_t)nvlist_get_number(nvlin, "oldlen");
if (oldlen == 0)
return (EINVAL);
oldp = calloc(1, oldlen);
if (oldp == NULL)
return (ENOMEM);
oldlenp = &oldlen;
}
} else {
oldp = NULL;
oldlen = 0;
oldlenp = NULL;
}
if (sysctlbyname(name, oldp, oldlenp, newp, newlen) == -1) {
error = errno;
free(oldp);
return (error);
}
if ((operation & CAP_SYSCTL_READ) != 0) {
if (nvlist_exists_null(nvlin, "justsize"))
nvlist_add_number(nvlout, "oldlen", (uint64_t)oldlen);
else
nvlist_move_binary(nvlout, "oldp", oldp, oldlen);
}
return (0);
}
int
main(int argc, char *argv[])
{
return (service_start("system.sysctl", PARENT_FILENO, sysctl_limit,
sysctl_command, argc, argv));
}
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