Dmitry V. Levin
6ba947f36e
Always print struct sock_fprog.len. Fix printing of unfetchable elements in sock_filter array. Fix printing of large sock_filter arrays. * seccomp.c (decode_fprog): Rewrite into decode_seccomp_fprog and print_seccomp_fprog. (print_seccomp_filter): Replace decode_fprog with print_seccomp_fprog. * tests/prctl-seccomp-filter-v.c (main): Update. * tests/seccomp-filter-v.c: New file. * tests/seccomp-filter-v.test: New test. * tests/.gitignore: Add seccomp-filter-v. * tests/Makefile.am (check_PROGRAMS): Likewise. (DECODER_TESTS): Add seccomp-filter-v.test.
146 lines
4.3 KiB
C
146 lines
4.3 KiB
C
/*
|
|
* Check verbose decoding of prctl PR_SET_SECCOMP SECCOMP_MODE_FILTER.
|
|
*
|
|
* Copyright (c) 2015-2016 Dmitry V. Levin <ldv@altlinux.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.
|
|
* 3. The name of the author may not be used to endorse or promote products
|
|
* derived from this software without specific prior written permission.
|
|
*
|
|
* 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 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 "tests.h"
|
|
#include <stddef.h>
|
|
#include <unistd.h>
|
|
#include <stdio.h>
|
|
#include <errno.h>
|
|
#include <sys/syscall.h>
|
|
|
|
#ifdef HAVE_PRCTL
|
|
# include <sys/prctl.h>
|
|
#endif
|
|
#ifdef HAVE_LINUX_SECCOMP_H
|
|
# include <linux/seccomp.h>
|
|
#endif
|
|
#ifdef HAVE_LINUX_FILTER_H
|
|
# include <linux/filter.h>
|
|
#endif
|
|
|
|
#if defined HAVE_PRCTL \
|
|
&& defined PR_SET_NO_NEW_PRIVS \
|
|
&& defined PR_SET_SECCOMP \
|
|
&& defined SECCOMP_MODE_FILTER \
|
|
&& defined SECCOMP_RET_ERRNO \
|
|
&& defined BPF_JUMP \
|
|
&& defined BPF_STMT
|
|
|
|
#define SOCK_FILTER_ALLOW_SYSCALL(nr) \
|
|
BPF_JUMP(BPF_JMP|BPF_K|BPF_JEQ, __NR_ ## nr, 0, 1), \
|
|
BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW)
|
|
|
|
#define SOCK_FILTER_DENY_SYSCALL(nr, err) \
|
|
BPF_JUMP(BPF_JMP|BPF_K|BPF_JEQ, __NR_ ## nr, 0, 1), \
|
|
BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ERRNO|(SECCOMP_RET_DATA & (err)))
|
|
|
|
#define SOCK_FILTER_KILL_PROCESS \
|
|
BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_KILL)
|
|
|
|
#define PRINT_ALLOW_SYSCALL(nr) \
|
|
printf("BPF_JUMP(BPF_JMP|BPF_K|BPF_JEQ, %#x, 0, 0x1), " \
|
|
"BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), ", \
|
|
__NR_ ## nr)
|
|
|
|
#define PRINT_DENY_SYSCALL(nr, err) \
|
|
printf("BPF_JUMP(BPF_JMP|BPF_K|BPF_JEQ, %#x, 0, 0x1), " \
|
|
"BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ERRNO|%#x), ", \
|
|
__NR_ ## nr, err)
|
|
|
|
static const struct sock_filter filter[] = {
|
|
/* load syscall number */
|
|
BPF_STMT(BPF_LD|BPF_W|BPF_ABS, offsetof(struct seccomp_data, nr)),
|
|
|
|
/* allow syscalls */
|
|
SOCK_FILTER_ALLOW_SYSCALL(close),
|
|
SOCK_FILTER_ALLOW_SYSCALL(exit),
|
|
SOCK_FILTER_ALLOW_SYSCALL(exit_group),
|
|
|
|
/* deny syscalls */
|
|
SOCK_FILTER_DENY_SYSCALL(sync, EBUSY),
|
|
SOCK_FILTER_DENY_SYSCALL(setsid, EPERM),
|
|
|
|
/* kill process */
|
|
SOCK_FILTER_KILL_PROCESS
|
|
};
|
|
|
|
static const struct sock_fprog prog = {
|
|
.len = ARRAY_SIZE(filter),
|
|
.filter = (struct sock_filter *) filter,
|
|
};
|
|
|
|
int
|
|
main(void)
|
|
{
|
|
int fds[2];
|
|
|
|
puts("prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0) = 0");
|
|
|
|
printf("prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, {len=%u, filter=[",
|
|
prog.len);
|
|
|
|
printf("BPF_STMT(BPF_LD|BPF_W|BPF_ABS, %#x), ",
|
|
(unsigned) offsetof(struct seccomp_data, nr));
|
|
|
|
PRINT_ALLOW_SYSCALL(close);
|
|
PRINT_ALLOW_SYSCALL(exit);
|
|
PRINT_ALLOW_SYSCALL(exit_group);
|
|
|
|
PRINT_DENY_SYSCALL(sync, EBUSY),
|
|
PRINT_DENY_SYSCALL(setsid, EPERM),
|
|
|
|
printf("BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_KILL)");
|
|
|
|
puts("]}) = 0");
|
|
puts("+++ exited with 0 +++");
|
|
|
|
fflush(stdout);
|
|
close(0);
|
|
close(1);
|
|
|
|
if (pipe(fds))
|
|
perror_msg_and_fail("pipe");
|
|
if (prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0))
|
|
perror_msg_and_skip("PR_SET_NO_NEW_PRIVS");
|
|
if (prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog))
|
|
perror_msg_and_skip("PR_SET_SECCOMP");
|
|
if (close(0) || close(1))
|
|
_exit(77);
|
|
|
|
_exit(0);
|
|
}
|
|
|
|
#else
|
|
|
|
SKIP_MAIN_UNDEFINED("HAVE_PRCTL && PR_SET_NO_NEW_PRIVS && PR_SET_SECCOMP"
|
|
" && SECCOMP_MODE_FILTER && SECCOMP_RET_ERRNO"
|
|
" && BPF_JUMP && BPF_STMT")
|
|
|
|
#endif
|