freebsd-skq/lib/libcapsicum/capsicum_helpers.h
cem ada5397372 capsicum_helpers: Add LOOKUP flag
Add a helper routine for opening a directory that is restricted to being
used for opening relative files as stdio streams.

I think this will really help basic adaptation of multi-file programs to
Capsicum. Rather than having each program initialize a rights object and
ioctl/fcntl arrays for their root fd for relative opens, consolidate in the
logical place.

Reviewed by:	oshogbo@
Sponsored by:	Dell EMC Isilon
Differential Revision:	https://reviews.freebsd.org/D8743
2016-12-16 01:37:44 +00:00

124 lines
3.2 KiB
C

/*-
* Copyright (c) 2016 Mariusz Zaborski <oshogbo@FreeBSD.org>
* All rights reserved.
*
* 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 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 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.
*
* $FreeBSD$
*/
#ifndef _CAPSICUM_HELPERS_H_
#define _CAPSICUM_HELPERS_H_
#include <sys/param.h>
#include <sys/capsicum.h>
#include <errno.h>
#include <nl_types.h>
#include <termios.h>
#include <time.h>
#include <unistd.h>
#define CAPH_IGNORE_EBADF 0x0001
#define CAPH_READ 0x0002
#define CAPH_WRITE 0x0004
#define CAPH_LOOKUP 0x0008
static __inline int
caph_limit_stream(int fd, int flags)
{
cap_rights_t rights;
unsigned long cmds[] = { TIOCGETA, TIOCGWINSZ };
cap_rights_init(&rights, CAP_FCNTL, CAP_FSTAT, CAP_IOCTL);
if ((flags & CAPH_READ) != 0)
cap_rights_set(&rights, CAP_READ);
if ((flags & CAPH_WRITE) != 0)
cap_rights_set(&rights, CAP_WRITE);
if ((flags & CAPH_LOOKUP) != 0)
cap_rights_set(&rights, CAP_LOOKUP);
if (cap_rights_limit(fd, &rights) < 0 && errno != ENOSYS) {
if (errno == EBADF && (flags & CAPH_IGNORE_EBADF) != 0)
return (0);
return (-1);
}
if (cap_ioctls_limit(fd, cmds, nitems(cmds)) < 0 && errno != ENOSYS)
return (-1);
if (cap_fcntls_limit(fd, CAP_FCNTL_GETFL) < 0 && errno != ENOSYS)
return (-1);
return (0);
}
static __inline int
caph_limit_stdin(void)
{
return (caph_limit_stream(STDIN_FILENO, CAPH_READ));
}
static __inline int
caph_limit_stderr(void)
{
return (caph_limit_stream(STDERR_FILENO, CAPH_WRITE));
}
static __inline int
caph_limit_stdout(void)
{
return (caph_limit_stream(STDOUT_FILENO, CAPH_WRITE));
}
static __inline int
caph_limit_stdio(void)
{
const int iebadf = CAPH_IGNORE_EBADF;
if (caph_limit_stream(STDIN_FILENO, CAPH_READ | iebadf) == -1 ||
caph_limit_stream(STDOUT_FILENO, CAPH_WRITE | iebadf) == -1 ||
caph_limit_stream(STDERR_FILENO, CAPH_WRITE | iebadf) == -1)
return (-1);
return (0);
}
static __inline void
caph_cache_tzdata(void)
{
tzset();
}
static __inline void
caph_cache_catpages(void)
{
(void)catopen("libc", NL_CAT_LOCALE);
}
#endif /* _CAPSICUM_HELPERS_H_ */