freebsd-skq/lib/libcapsicum/libcapsicum.c
pjd 1073fb03ac Please welcome casperd daemon. It (and its services) will be responsible for
giving access to functionality that is not available in capability mode
sandbox. The functionality can be precisely restricted.

Start with the following services:
- system.dns - provides API compatible to:
	- gethostbyname(3),
	- gethostbyname2(3),
	- gethostbyaddr(3),
	- getaddrinfo(3),
	- getnameinfo(3),
- system.grp - provides getgrent(3)-compatible API,
- system.pwd - provides getpwent(3)-compatible API,
- system.random - allows to obtain entropy from /dev/random,
- system.sysctl - provides sysctlbyname(3-compatible API.

Sponsored by:	The FreeBSD Foundation
2013-12-02 08:21:28 +00:00

267 lines
5.7 KiB
C

/*-
* Copyright (c) 2012-2013 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/socket.h>
#include <sys/un.h>
#include <assert.h>
#include <errno.h>
#include <fcntl.h>
#include <stdbool.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "libcapsicum.h"
#include "libcapsicum_impl.h"
#include "nv.h"
/*
* Structure describing communication channel between two separated processes.
*/
#define CAP_CHANNEL_MAGIC 0xcac8a31
struct cap_channel {
/*
* Magic value helps to ensure that a pointer to the right structure is
* passed to our functions.
*/
int cch_magic;
/* Socket descriptor for IPC. */
int cch_sock;
};
bool
fd_is_valid(int fd)
{
return (fcntl(fd, F_GETFL) != -1 || errno != EBADF);
}
cap_channel_t *
cap_init(void)
{
cap_channel_t *chan;
struct sockaddr_un sun;
int serrno, sock;
bzero(&sun, sizeof(sun));
sun.sun_family = AF_UNIX;
strlcpy(sun.sun_path, CASPER_SOCKPATH, sizeof(sun.sun_path));
sun.sun_len = SUN_LEN(&sun);
sock = socket(AF_UNIX, SOCK_STREAM, 0);
if (sock == -1)
return (NULL);
if (connect(sock, (struct sockaddr *)&sun, sizeof(sun)) < 0) {
serrno = errno;
close(sock);
errno = serrno;
return (NULL);
}
chan = cap_wrap(sock);
if (chan == NULL) {
serrno = errno;
close(sock);
errno = serrno;
return (NULL);
}
return (chan);
}
cap_channel_t *
cap_wrap(int sock)
{
cap_channel_t *chan;
if (!fd_is_valid(sock))
return (NULL);
chan = malloc(sizeof(*chan));
if (chan != NULL) {
chan->cch_sock = sock;
chan->cch_magic = CAP_CHANNEL_MAGIC;
}
return (chan);
}
int
cap_unwrap(cap_channel_t *chan)
{
int sock;
assert(chan != NULL);
assert(chan->cch_magic == CAP_CHANNEL_MAGIC);
sock = chan->cch_sock;
chan->cch_magic = 0;
free(chan);
return (sock);
}
cap_channel_t *
cap_clone(const cap_channel_t *chan)
{
cap_channel_t *newchan;
nvlist_t *nvl;
int newsock;
assert(chan != NULL);
assert(chan->cch_magic == CAP_CHANNEL_MAGIC);
nvl = nvlist_create(0);
nvlist_add_string(nvl, "cmd", "clone");
nvl = cap_xfer_nvlist(chan, nvl);
if (nvl == NULL)
return (NULL);
if (nvlist_get_number(nvl, "error") != 0) {
errno = (int)nvlist_get_number(nvl, "error");
nvlist_destroy(nvl);
return (NULL);
}
newsock = nvlist_take_descriptor(nvl, "sock");
nvlist_destroy(nvl);
newchan = cap_wrap(newsock);
if (newchan == NULL) {
int serrno;
serrno = errno;
close(newsock);
errno = serrno;
}
return (newchan);
}
void
cap_close(cap_channel_t *chan)
{
assert(chan != NULL);
assert(chan->cch_magic == CAP_CHANNEL_MAGIC);
chan->cch_magic = 0;
close(chan->cch_sock);
free(chan);
}
int
cap_sock(const cap_channel_t *chan)
{
assert(chan != NULL);
assert(chan->cch_magic == CAP_CHANNEL_MAGIC);
return (chan->cch_sock);
}
int
cap_limit_set(const cap_channel_t *chan, nvlist_t *limits)
{
nvlist_t *nvlmsg;
int error;
nvlmsg = nvlist_create(0);
nvlist_add_string(nvlmsg, "cmd", "limit_set");
nvlist_add_nvlist(nvlmsg, "limits", limits);
nvlmsg = cap_xfer_nvlist(chan, nvlmsg);
if (nvlmsg == NULL) {
nvlist_destroy(limits);
return (-1);
}
error = (int)nvlist_get_number(nvlmsg, "error");
nvlist_destroy(nvlmsg);
nvlist_destroy(limits);
if (error != 0) {
errno = error;
return (-1);
}
return (0);
}
int
cap_limit_get(const cap_channel_t *chan, nvlist_t **limitsp)
{
nvlist_t *nvlmsg;
int error;
nvlmsg = nvlist_create(0);
nvlist_add_string(nvlmsg, "cmd", "limit_get");
nvlmsg = cap_xfer_nvlist(chan, nvlmsg);
if (nvlmsg == NULL)
return (-1);
error = (int)nvlist_get_number(nvlmsg, "error");
if (error != 0) {
nvlist_destroy(nvlmsg);
errno = error;
return (-1);
}
if (nvlist_exists_null(nvlmsg, "limits"))
*limitsp = NULL;
else
*limitsp = nvlist_take_nvlist(nvlmsg, "limits");
nvlist_destroy(nvlmsg);
return (0);
}
int
cap_send_nvlist(const cap_channel_t *chan, const nvlist_t *nvl)
{
assert(chan != NULL);
assert(chan->cch_magic == CAP_CHANNEL_MAGIC);
return (nvlist_send(chan->cch_sock, nvl));
}
nvlist_t *
cap_recv_nvlist(const cap_channel_t *chan)
{
assert(chan != NULL);
assert(chan->cch_magic == CAP_CHANNEL_MAGIC);
return (nvlist_recv(chan->cch_sock));
}
nvlist_t *
cap_xfer_nvlist(const cap_channel_t *chan, nvlist_t *nvl)
{
assert(chan != NULL);
assert(chan->cch_magic == CAP_CHANNEL_MAGIC);
return (nvlist_xfer(chan->cch_sock, nvl));
}