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systemd/src/test/test-seccomp.c
Zbigniew Jędrzejewski-Szmek da1921a5c3 seccomp: enable RestrictAddressFamilies on ppc64, autodetect SECCOMP_RESTRICT_ADDRESS_FAMILIES_BROKEN
We expect that if socket() syscall is available, seccomp works for that
architecture.  So instead of explicitly listing all architectures where we know
it is not available, just assume it is broken if the number is not defined.
This should have the same effect, except that other architectures where it is
also broken will pass tests without further changes. (Architectures where the
filter should work, but does not work because of missing entries in
seccomp-util.c, will still fail.)

i386, s390, s390x are the exception — setting the filter fails, even though
socket() is available, so it needs to be special-cased
(https://github.com/systemd/systemd/issues/5215#issuecomment-277241488).

This remove the last define in seccomp-util.h that was only used in test-seccomp.c. Porting
the seccomp filter to new architectures should be simpler because now only two places need
to be modified.

RestrictAddressFamilies seems to work on ppc64[bl]e, so enable it (the tests pass).
2017-05-10 09:21:16 -04:00

575 lines
19 KiB
C

/***
This file is part of systemd.
Copyright 2016 Lennart Poettering
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <sched.h>
#include <stdlib.h>
#include <sys/eventfd.h>
#include <sys/mman.h>
#include <sys/poll.h>
#include <sys/shm.h>
#include <sys/types.h>
#include <unistd.h>
#include "alloc-util.h"
#include "fd-util.h"
#include "macro.h"
#include "missing.h"
#include "nsflags.h"
#include "process-util.h"
#include "raw-clone.h"
#include "seccomp-util.h"
#include "set.h"
#include "string-util.h"
#include "util.h"
#include "virt.h"
#if SCMP_SYS(socket) < 0 || defined(__i386__) || defined(__s390x__) || defined(__s390__)
/* On these archs, socket() is implemented via the socketcall() syscall multiplexer,
* and we can't restrict it hence via seccomp. */
# define SECCOMP_RESTRICT_ADDRESS_FAMILIES_BROKEN 1
#else
# define SECCOMP_RESTRICT_ADDRESS_FAMILIES_BROKEN 0
#endif
static void test_seccomp_arch_to_string(void) {
uint32_t a, b;
const char *name;
a = seccomp_arch_native();
assert_se(a > 0);
name = seccomp_arch_to_string(a);
assert_se(name);
assert_se(seccomp_arch_from_string(name, &b) >= 0);
assert_se(a == b);
}
static void test_architecture_table(void) {
const char *n, *n2;
NULSTR_FOREACH(n,
"native\0"
"x86\0"
"x86-64\0"
"x32\0"
"arm\0"
"arm64\0"
"mips\0"
"mips64\0"
"mips64-n32\0"
"mips-le\0"
"mips64-le\0"
"mips64-le-n32\0"
"ppc\0"
"ppc64\0"
"ppc64-le\0"
"s390\0"
"s390x\0") {
uint32_t c;
assert_se(seccomp_arch_from_string(n, &c) >= 0);
n2 = seccomp_arch_to_string(c);
log_info("seccomp-arch: %s → 0x%"PRIx32" → %s", n, c, n2);
assert_se(streq_ptr(n, n2));
}
}
static void test_syscall_filter_set_find(void) {
assert_se(!syscall_filter_set_find(NULL));
assert_se(!syscall_filter_set_find(""));
assert_se(!syscall_filter_set_find("quux"));
assert_se(!syscall_filter_set_find("@quux"));
assert_se(syscall_filter_set_find("@clock") == syscall_filter_sets + SYSCALL_FILTER_SET_CLOCK);
assert_se(syscall_filter_set_find("@default") == syscall_filter_sets + SYSCALL_FILTER_SET_DEFAULT);
assert_se(syscall_filter_set_find("@raw-io") == syscall_filter_sets + SYSCALL_FILTER_SET_RAW_IO);
}
static void test_filter_sets(void) {
unsigned i;
int r;
if (!is_seccomp_available())
return;
if (geteuid() != 0)
return;
for (i = 0; i < _SYSCALL_FILTER_SET_MAX; i++) {
pid_t pid;
log_info("Testing %s", syscall_filter_sets[i].name);
pid = fork();
assert_se(pid >= 0);
if (pid == 0) { /* Child? */
int fd;
if (i == SYSCALL_FILTER_SET_DEFAULT) /* if we look at the default set, whitelist instead of blacklist */
r = seccomp_load_syscall_filter_set(SCMP_ACT_ERRNO(EUCLEAN), syscall_filter_sets + i, SCMP_ACT_ALLOW);
else
r = seccomp_load_syscall_filter_set(SCMP_ACT_ALLOW, syscall_filter_sets + i, SCMP_ACT_ERRNO(EUCLEAN));
if (r < 0)
_exit(EXIT_FAILURE);
/* Test the sycall filter with one random system call */
fd = eventfd(0, EFD_NONBLOCK|EFD_CLOEXEC);
if (IN_SET(i, SYSCALL_FILTER_SET_IO_EVENT, SYSCALL_FILTER_SET_DEFAULT))
assert_se(fd < 0 && errno == EUCLEAN);
else {
assert_se(fd >= 0);
safe_close(fd);
}
_exit(EXIT_SUCCESS);
}
assert_se(wait_for_terminate_and_warn(syscall_filter_sets[i].name, pid, true) == EXIT_SUCCESS);
}
}
static void test_restrict_namespace(void) {
_cleanup_free_ char *s = NULL;
unsigned long ul;
pid_t pid;
assert_se(namespace_flag_to_string(0) == NULL);
assert_se(streq(namespace_flag_to_string(CLONE_NEWNS), "mnt"));
assert_se(namespace_flag_to_string(CLONE_NEWNS|CLONE_NEWIPC) == NULL);
assert_se(streq(namespace_flag_to_string(CLONE_NEWCGROUP), "cgroup"));
assert_se(namespace_flag_from_string("mnt") == CLONE_NEWNS);
assert_se(namespace_flag_from_string(NULL) == 0);
assert_se(namespace_flag_from_string("") == 0);
assert_se(namespace_flag_from_string("uts") == CLONE_NEWUTS);
assert_se(namespace_flag_from_string(namespace_flag_to_string(CLONE_NEWUTS)) == CLONE_NEWUTS);
assert_se(streq(namespace_flag_to_string(namespace_flag_from_string("ipc")), "ipc"));
assert_se(namespace_flag_from_string_many(NULL, &ul) == 0 && ul == 0);
assert_se(namespace_flag_from_string_many("", &ul) == 0 && ul == 0);
assert_se(namespace_flag_from_string_many("mnt uts ipc", &ul) == 0 && ul == (CLONE_NEWNS|CLONE_NEWUTS|CLONE_NEWIPC));
assert_se(namespace_flag_to_string_many(NAMESPACE_FLAGS_ALL, &s) == 0);
assert_se(streq(s, "cgroup ipc net mnt pid user uts"));
assert_se(namespace_flag_from_string_many(s, &ul) == 0 && ul == NAMESPACE_FLAGS_ALL);
if (!is_seccomp_available())
return;
if (geteuid() != 0)
return;
pid = fork();
assert_se(pid >= 0);
if (pid == 0) {
assert_se(seccomp_restrict_namespaces(CLONE_NEWNS|CLONE_NEWNET) >= 0);
assert_se(unshare(CLONE_NEWNS) == 0);
assert_se(unshare(CLONE_NEWNET) == 0);
assert_se(unshare(CLONE_NEWUTS) == -1);
assert_se(errno == EPERM);
assert_se(unshare(CLONE_NEWIPC) == -1);
assert_se(errno == EPERM);
assert_se(unshare(CLONE_NEWNET|CLONE_NEWUTS) == -1);
assert_se(errno == EPERM);
/* We use fd 0 (stdin) here, which of course will fail with EINVAL on setns(). Except of course our
* seccomp filter worked, and hits first and makes it return EPERM */
assert_se(setns(0, CLONE_NEWNS) == -1);
assert_se(errno == EINVAL);
assert_se(setns(0, CLONE_NEWNET) == -1);
assert_se(errno == EINVAL);
assert_se(setns(0, CLONE_NEWUTS) == -1);
assert_se(errno == EPERM);
assert_se(setns(0, CLONE_NEWIPC) == -1);
assert_se(errno == EPERM);
assert_se(setns(0, CLONE_NEWNET|CLONE_NEWUTS) == -1);
assert_se(errno == EPERM);
assert_se(setns(0, 0) == -1);
assert_se(errno == EPERM);
pid = raw_clone(CLONE_NEWNS);
assert_se(pid >= 0);
if (pid == 0)
_exit(EXIT_SUCCESS);
pid = raw_clone(CLONE_NEWNET);
assert_se(pid >= 0);
if (pid == 0)
_exit(EXIT_SUCCESS);
pid = raw_clone(CLONE_NEWUTS);
assert_se(pid < 0);
assert_se(errno == EPERM);
pid = raw_clone(CLONE_NEWIPC);
assert_se(pid < 0);
assert_se(errno == EPERM);
pid = raw_clone(CLONE_NEWNET|CLONE_NEWUTS);
assert_se(pid < 0);
assert_se(errno == EPERM);
_exit(EXIT_SUCCESS);
}
assert_se(wait_for_terminate_and_warn("nsseccomp", pid, true) == EXIT_SUCCESS);
}
static void test_protect_sysctl(void) {
pid_t pid;
if (!is_seccomp_available())
return;
if (geteuid() != 0)
return;
if (detect_container() > 0) /* in containers _sysctl() is likely missing anyway */
return;
pid = fork();
assert_se(pid >= 0);
if (pid == 0) {
assert_se(syscall(__NR__sysctl, NULL) < 0);
assert_se(errno == EFAULT);
assert_se(seccomp_protect_sysctl() >= 0);
assert_se(syscall(__NR__sysctl, 0, 0, 0) < 0);
assert_se(errno == EPERM);
_exit(EXIT_SUCCESS);
}
assert_se(wait_for_terminate_and_warn("sysctlseccomp", pid, true) == EXIT_SUCCESS);
}
static void test_restrict_address_families(void) {
pid_t pid;
if (!is_seccomp_available())
return;
if (geteuid() != 0)
return;
pid = fork();
assert_se(pid >= 0);
if (pid == 0) {
int fd;
Set *s;
fd = socket(AF_INET, SOCK_DGRAM, 0);
assert_se(fd >= 0);
safe_close(fd);
fd = socket(AF_UNIX, SOCK_DGRAM, 0);
assert_se(fd >= 0);
safe_close(fd);
fd = socket(AF_NETLINK, SOCK_DGRAM, 0);
assert_se(fd >= 0);
safe_close(fd);
assert_se(s = set_new(NULL));
assert_se(set_put(s, INT_TO_PTR(AF_UNIX)) >= 0);
assert_se(seccomp_restrict_address_families(s, false) >= 0);
fd = socket(AF_INET, SOCK_DGRAM, 0);
assert_se(fd >= 0);
safe_close(fd);
fd = socket(AF_UNIX, SOCK_DGRAM, 0);
#if SECCOMP_RESTRICT_ADDRESS_FAMILIES_BROKEN
assert_se(fd >= 0);
safe_close(fd);
#else
assert_se(fd < 0);
assert_se(errno == EAFNOSUPPORT);
#endif
fd = socket(AF_NETLINK, SOCK_DGRAM, 0);
assert_se(fd >= 0);
safe_close(fd);
set_clear(s);
assert_se(set_put(s, INT_TO_PTR(AF_INET)) >= 0);
assert_se(seccomp_restrict_address_families(s, true) >= 0);
fd = socket(AF_INET, SOCK_DGRAM, 0);
assert_se(fd >= 0);
safe_close(fd);
fd = socket(AF_UNIX, SOCK_DGRAM, 0);
#if SECCOMP_RESTRICT_ADDRESS_FAMILIES_BROKEN
assert_se(fd >= 0);
safe_close(fd);
#else
assert_se(fd < 0);
assert_se(errno == EAFNOSUPPORT);
#endif
fd = socket(AF_NETLINK, SOCK_DGRAM, 0);
#if SECCOMP_RESTRICT_ADDRESS_FAMILIES_BROKEN
assert_se(fd >= 0);
safe_close(fd);
#else
assert_se(fd < 0);
assert_se(errno == EAFNOSUPPORT);
#endif
_exit(EXIT_SUCCESS);
}
assert_se(wait_for_terminate_and_warn("socketseccomp", pid, true) == EXIT_SUCCESS);
}
static void test_restrict_realtime(void) {
pid_t pid;
if (!is_seccomp_available())
return;
if (geteuid() != 0)
return;
if (detect_container() > 0) /* in containers RT privs are likely missing anyway */
return;
pid = fork();
assert_se(pid >= 0);
if (pid == 0) {
assert_se(sched_setscheduler(0, SCHED_FIFO, &(struct sched_param) { .sched_priority = 1 }) >= 0);
assert_se(sched_setscheduler(0, SCHED_RR, &(struct sched_param) { .sched_priority = 1 }) >= 0);
assert_se(sched_setscheduler(0, SCHED_IDLE, &(struct sched_param) { .sched_priority = 0 }) >= 0);
assert_se(sched_setscheduler(0, SCHED_BATCH, &(struct sched_param) { .sched_priority = 0 }) >= 0);
assert_se(sched_setscheduler(0, SCHED_OTHER, &(struct sched_param) {}) >= 0);
assert_se(seccomp_restrict_realtime() >= 0);
assert_se(sched_setscheduler(0, SCHED_IDLE, &(struct sched_param) { .sched_priority = 0 }) >= 0);
assert_se(sched_setscheduler(0, SCHED_BATCH, &(struct sched_param) { .sched_priority = 0 }) >= 0);
assert_se(sched_setscheduler(0, SCHED_OTHER, &(struct sched_param) {}) >= 0);
assert_se(sched_setscheduler(0, SCHED_FIFO, &(struct sched_param) { .sched_priority = 1 }) < 0);
assert_se(errno == EPERM);
assert_se(sched_setscheduler(0, SCHED_RR, &(struct sched_param) { .sched_priority = 1 }) < 0);
assert_se(errno == EPERM);
_exit(EXIT_SUCCESS);
}
assert_se(wait_for_terminate_and_warn("realtimeseccomp", pid, true) == EXIT_SUCCESS);
}
static void test_memory_deny_write_execute_mmap(void) {
pid_t pid;
if (!is_seccomp_available())
return;
if (geteuid() != 0)
return;
pid = fork();
assert_se(pid >= 0);
if (pid == 0) {
void *p;
p = mmap(NULL, page_size(), PROT_WRITE|PROT_EXEC, MAP_PRIVATE|MAP_ANONYMOUS, -1,0);
assert_se(p != MAP_FAILED);
assert_se(munmap(p, page_size()) >= 0);
p = mmap(NULL, page_size(), PROT_WRITE|PROT_READ, MAP_PRIVATE|MAP_ANONYMOUS, -1,0);
assert_se(p != MAP_FAILED);
assert_se(munmap(p, page_size()) >= 0);
assert_se(seccomp_memory_deny_write_execute() >= 0);
p = mmap(NULL, page_size(), PROT_WRITE|PROT_EXEC, MAP_PRIVATE|MAP_ANONYMOUS, -1,0);
#if defined(__x86_64__) || defined(__i386__) || defined(__powerpc64__) || defined(__arm__) || defined(__aarch64__)
assert_se(p == MAP_FAILED);
assert_se(errno == EPERM);
#else /* unknown architectures */
assert_se(p != MAP_FAILED);
assert_se(munmap(p, page_size()) >= 0);
#endif
p = mmap(NULL, page_size(), PROT_WRITE|PROT_READ, MAP_PRIVATE|MAP_ANONYMOUS, -1,0);
assert_se(p != MAP_FAILED);
assert_se(munmap(p, page_size()) >= 0);
_exit(EXIT_SUCCESS);
}
assert_se(wait_for_terminate_and_warn("memoryseccomp-mmap", pid, true) == EXIT_SUCCESS);
}
static void test_memory_deny_write_execute_shmat(void) {
int shmid;
pid_t pid;
if (!is_seccomp_available())
return;
if (geteuid() != 0)
return;
shmid = shmget(IPC_PRIVATE, page_size(), 0);
assert_se(shmid >= 0);
pid = fork();
assert_se(pid >= 0);
if (pid == 0) {
void *p;
p = shmat(shmid, NULL, 0);
assert_se(p != MAP_FAILED);
assert_se(shmdt(p) == 0);
p = shmat(shmid, NULL, SHM_EXEC);
assert_se(p != MAP_FAILED);
assert_se(shmdt(p) == 0);
assert_se(seccomp_memory_deny_write_execute() >= 0);
p = shmat(shmid, NULL, SHM_EXEC);
#if defined(__x86_64__) || defined(__arm__) || defined(__aarch64__)
assert_se(p == MAP_FAILED);
assert_se(errno == EPERM);
#else /* __i386__, __powerpc64__, and "unknown" architectures */
assert_se(p != MAP_FAILED);
assert_se(shmdt(p) == 0);
#endif
p = shmat(shmid, NULL, 0);
assert_se(p != MAP_FAILED);
assert_se(shmdt(p) == 0);
_exit(EXIT_SUCCESS);
}
assert_se(wait_for_terminate_and_warn("memoryseccomp-shmat", pid, true) == EXIT_SUCCESS);
}
static void test_restrict_archs(void) {
pid_t pid;
if (!is_seccomp_available())
return;
if (geteuid() != 0)
return;
pid = fork();
assert_se(pid >= 0);
if (pid == 0) {
_cleanup_set_free_ Set *s = NULL;
assert_se(access("/", F_OK) >= 0);
assert_se(s = set_new(NULL));
#ifdef __x86_64__
assert_se(set_put(s, UINT32_TO_PTR(SCMP_ARCH_X86+1)) >= 0);
#endif
assert_se(seccomp_restrict_archs(s) >= 0);
assert_se(access("/", F_OK) >= 0);
assert_se(seccomp_restrict_archs(NULL) >= 0);
assert_se(access("/", F_OK) >= 0);
_exit(EXIT_SUCCESS);
}
assert_se(wait_for_terminate_and_warn("archseccomp", pid, true) == EXIT_SUCCESS);
}
static void test_load_syscall_filter_set_raw(void) {
pid_t pid;
if (!is_seccomp_available())
return;
if (geteuid() != 0)
return;
pid = fork();
assert_se(pid >= 0);
if (pid == 0) {
_cleanup_set_free_ Set *s = NULL;
assert_se(access("/", F_OK) >= 0);
assert_se(poll(NULL, 0, 0) == 0);
assert_se(seccomp_load_syscall_filter_set_raw(SCMP_ACT_ALLOW, NULL, SCMP_ACT_KILL) >= 0);
assert_se(access("/", F_OK) >= 0);
assert_se(poll(NULL, 0, 0) == 0);
assert_se(s = set_new(NULL));
assert_se(set_put(s, UINT32_TO_PTR(__NR_access + 1)) >= 0);
assert_se(seccomp_load_syscall_filter_set_raw(SCMP_ACT_ALLOW, s, SCMP_ACT_ERRNO(EUCLEAN)) >= 0);
assert_se(access("/", F_OK) < 0);
assert_se(errno == EUCLEAN);
assert_se(poll(NULL, 0, 0) == 0);
s = set_free(s);
assert_se(s = set_new(NULL));
assert_se(set_put(s, UINT32_TO_PTR(__NR_poll + 1)) >= 0);
assert_se(seccomp_load_syscall_filter_set_raw(SCMP_ACT_ALLOW, s, SCMP_ACT_ERRNO(EUNATCH)) >= 0);
assert_se(access("/", F_OK) < 0);
assert_se(errno == EUCLEAN);
assert_se(poll(NULL, 0, 0) < 0);
assert_se(errno == EUNATCH);
_exit(EXIT_SUCCESS);
}
assert_se(wait_for_terminate_and_warn("syscallrawseccomp", pid, true) == EXIT_SUCCESS);
}
int main(int argc, char *argv[]) {
log_set_max_level(LOG_DEBUG);
test_seccomp_arch_to_string();
test_architecture_table();
test_syscall_filter_set_find();
test_filter_sets();
test_restrict_namespace();
test_protect_sysctl();
test_restrict_address_families();
test_restrict_realtime();
test_memory_deny_write_execute_mmap();
test_memory_deny_write_execute_shmat();
test_restrict_archs();
test_load_syscall_filter_set_raw();
return 0;
}