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linux_dsm_epyc7002/tools/testing/selftests/seccomp/seccomp_bpf.c
Kees Cook 58d0a862f5 seccomp: add tests for ptrace hole 
One problem with seccomp was that ptrace could be used to change a
syscall after seccomp filtering had completed. This was a well documented
limitation, and it was recommended to block ptrace when defining a filter
to avoid this problem. This can be quite a limitation for containers or
other places where ptrace is desired even under seccomp filters.

This adds tests for both SECCOMP_RET_TRACE and PTRACE_SYSCALL manipulations.

Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Andy Lutomirski <luto@kernel.org>
2016-06-14 10:54:38 -07:00

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62 KiB
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/*
* Copyright (c) 2012 The Chromium OS Authors. All rights reserved.
* Use of this source code is governed by the GPLv2 license.
*
* Test code for seccomp bpf.
*/
#include <sys/types.h>
#include <asm/siginfo.h>
#define __have_siginfo_t 1
#define __have_sigval_t 1
#define __have_sigevent_t 1
#include <errno.h>
#include <linux/filter.h>
#include <sys/prctl.h>
#include <sys/ptrace.h>
#include <sys/user.h>
#include <linux/prctl.h>
#include <linux/ptrace.h>
#include <linux/seccomp.h>
#include <pthread.h>
#include <semaphore.h>
#include <signal.h>
#include <stddef.h>
#include <stdbool.h>
#include <string.h>
#include <time.h>
#include <linux/elf.h>
#include <sys/uio.h>
#include <sys/utsname.h>
#include <sys/fcntl.h>
#include <sys/mman.h>
#include <sys/times.h>
#define _GNU_SOURCE
#include <unistd.h>
#include <sys/syscall.h>
#include "test_harness.h"
#ifndef PR_SET_PTRACER
# define PR_SET_PTRACER 0x59616d61
#endif
#ifndef PR_SET_NO_NEW_PRIVS
#define PR_SET_NO_NEW_PRIVS 38
#define PR_GET_NO_NEW_PRIVS 39
#endif
#ifndef PR_SECCOMP_EXT
#define PR_SECCOMP_EXT 43
#endif
#ifndef SECCOMP_EXT_ACT
#define SECCOMP_EXT_ACT 1
#endif
#ifndef SECCOMP_EXT_ACT_TSYNC
#define SECCOMP_EXT_ACT_TSYNC 1
#endif
#ifndef SECCOMP_MODE_STRICT
#define SECCOMP_MODE_STRICT 1
#endif
#ifndef SECCOMP_MODE_FILTER
#define SECCOMP_MODE_FILTER 2
#endif
#ifndef SECCOMP_RET_KILL
#define SECCOMP_RET_KILL 0x00000000U /* kill the task immediately */
#define SECCOMP_RET_TRAP 0x00030000U /* disallow and force a SIGSYS */
#define SECCOMP_RET_ERRNO 0x00050000U /* returns an errno */
#define SECCOMP_RET_TRACE 0x7ff00000U /* pass to a tracer or disallow */
#define SECCOMP_RET_ALLOW 0x7fff0000U /* allow */
/* Masks for the return value sections. */
#define SECCOMP_RET_ACTION 0x7fff0000U
#define SECCOMP_RET_DATA 0x0000ffffU
struct seccomp_data {
int nr;
__u32 arch;
__u64 instruction_pointer;
__u64 args[6];
};
#endif
#if __BYTE_ORDER == __LITTLE_ENDIAN
#define syscall_arg(_n) (offsetof(struct seccomp_data, args[_n]))
#elif __BYTE_ORDER == __BIG_ENDIAN
#define syscall_arg(_n) (offsetof(struct seccomp_data, args[_n]) + sizeof(__u32))
#else
#error "wut? Unknown __BYTE_ORDER?!"
#endif
#define SIBLING_EXIT_UNKILLED 0xbadbeef
#define SIBLING_EXIT_FAILURE 0xbadface
#define SIBLING_EXIT_NEWPRIVS 0xbadfeed
TEST(mode_strict_support)
{
long ret;
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_STRICT, NULL, NULL, NULL);
ASSERT_EQ(0, ret) {
TH_LOG("Kernel does not support CONFIG_SECCOMP");
}
syscall(__NR_exit, 1);
}
TEST_SIGNAL(mode_strict_cannot_call_prctl, SIGKILL)
{
long ret;
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_STRICT, NULL, NULL, NULL);
ASSERT_EQ(0, ret) {
TH_LOG("Kernel does not support CONFIG_SECCOMP");
}
syscall(__NR_prctl, PR_SET_SECCOMP, SECCOMP_MODE_FILTER,
NULL, NULL, NULL);
EXPECT_FALSE(true) {
TH_LOG("Unreachable!");
}
}
/* Note! This doesn't test no new privs behavior */
TEST(no_new_privs_support)
{
long ret;
ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0);
EXPECT_EQ(0, ret) {
TH_LOG("Kernel does not support PR_SET_NO_NEW_PRIVS!");
}
}
/* Tests kernel support by checking for a copy_from_user() fault on * NULL. */
TEST(mode_filter_support)
{
long ret;
ret = prctl(PR_SET_NO_NEW_PRIVS, 1, NULL, 0, 0);
ASSERT_EQ(0, ret) {
TH_LOG("Kernel does not support PR_SET_NO_NEW_PRIVS!");
}
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, NULL, NULL, NULL);
EXPECT_EQ(-1, ret);
EXPECT_EQ(EFAULT, errno) {
TH_LOG("Kernel does not support CONFIG_SECCOMP_FILTER!");
}
}
TEST(mode_filter_without_nnp)
{
struct sock_filter filter[] = {
BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW),
};
struct sock_fprog prog = {
.len = (unsigned short)ARRAY_SIZE(filter),
.filter = filter,
};
long ret;
ret = prctl(PR_GET_NO_NEW_PRIVS, 0, NULL, 0, 0);
ASSERT_LE(0, ret) {
TH_LOG("Expected 0 or unsupported for NO_NEW_PRIVS");
}
errno = 0;
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog, 0, 0);
/* Succeeds with CAP_SYS_ADMIN, fails without */
/* TODO(wad) check caps not euid */
if (geteuid()) {
EXPECT_EQ(-1, ret);
EXPECT_EQ(EACCES, errno);
} else {
EXPECT_EQ(0, ret);
}
}
#define MAX_INSNS_PER_PATH 32768
TEST(filter_size_limits)
{
int i;
int count = BPF_MAXINSNS + 1;
struct sock_filter allow[] = {
BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW),
};
struct sock_filter *filter;
struct sock_fprog prog = { };
long ret;
filter = calloc(count, sizeof(*filter));
ASSERT_NE(NULL, filter);
for (i = 0; i < count; i++)
filter[i] = allow[0];
ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0);
ASSERT_EQ(0, ret);
prog.filter = filter;
prog.len = count;
/* Too many filter instructions in a single filter. */
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog, 0, 0);
ASSERT_NE(0, ret) {
TH_LOG("Installing %d insn filter was allowed", prog.len);
}
/* One less is okay, though. */
prog.len -= 1;
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog, 0, 0);
ASSERT_EQ(0, ret) {
TH_LOG("Installing %d insn filter wasn't allowed", prog.len);
}
}
TEST(filter_chain_limits)
{
int i;
int count = BPF_MAXINSNS;
struct sock_filter allow[] = {
BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW),
};
struct sock_filter *filter;
struct sock_fprog prog = { };
long ret;
filter = calloc(count, sizeof(*filter));
ASSERT_NE(NULL, filter);
for (i = 0; i < count; i++)
filter[i] = allow[0];
ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0);
ASSERT_EQ(0, ret);
prog.filter = filter;
prog.len = 1;
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog, 0, 0);
ASSERT_EQ(0, ret);
prog.len = count;
/* Too many total filter instructions. */
for (i = 0; i < MAX_INSNS_PER_PATH; i++) {
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog, 0, 0);
if (ret != 0)
break;
}
ASSERT_NE(0, ret) {
TH_LOG("Allowed %d %d-insn filters (total with penalties:%d)",
i, count, i * (count + 4));
}
}
TEST(mode_filter_cannot_move_to_strict)
{
struct sock_filter filter[] = {
BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW),
};
struct sock_fprog prog = {
.len = (unsigned short)ARRAY_SIZE(filter),
.filter = filter,
};
long ret;
ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0);
ASSERT_EQ(0, ret);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog, 0, 0);
ASSERT_EQ(0, ret);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_STRICT, NULL, 0, 0);
EXPECT_EQ(-1, ret);
EXPECT_EQ(EINVAL, errno);
}
TEST(mode_filter_get_seccomp)
{
struct sock_filter filter[] = {
BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW),
};
struct sock_fprog prog = {
.len = (unsigned short)ARRAY_SIZE(filter),
.filter = filter,
};
long ret;
ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0);
ASSERT_EQ(0, ret);
ret = prctl(PR_GET_SECCOMP, 0, 0, 0, 0);
EXPECT_EQ(0, ret);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog, 0, 0);
ASSERT_EQ(0, ret);
ret = prctl(PR_GET_SECCOMP, 0, 0, 0, 0);
EXPECT_EQ(2, ret);
}
TEST(ALLOW_all)
{
struct sock_filter filter[] = {
BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW),
};
struct sock_fprog prog = {
.len = (unsigned short)ARRAY_SIZE(filter),
.filter = filter,
};
long ret;
ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0);
ASSERT_EQ(0, ret);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog);
ASSERT_EQ(0, ret);
}
TEST(empty_prog)
{
struct sock_filter filter[] = {
};
struct sock_fprog prog = {
.len = (unsigned short)ARRAY_SIZE(filter),
.filter = filter,
};
long ret;
ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0);
ASSERT_EQ(0, ret);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog);
EXPECT_EQ(-1, ret);
EXPECT_EQ(EINVAL, errno);
}
TEST_SIGNAL(unknown_ret_is_kill_inside, SIGSYS)
{
struct sock_filter filter[] = {
BPF_STMT(BPF_RET|BPF_K, 0x10000000U),
};
struct sock_fprog prog = {
.len = (unsigned short)ARRAY_SIZE(filter),
.filter = filter,
};
long ret;
ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0);
ASSERT_EQ(0, ret);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog);
ASSERT_EQ(0, ret);
EXPECT_EQ(0, syscall(__NR_getpid)) {
TH_LOG("getpid() shouldn't ever return");
}
}
/* return code >= 0x80000000 is unused. */
TEST_SIGNAL(unknown_ret_is_kill_above_allow, SIGSYS)
{
struct sock_filter filter[] = {
BPF_STMT(BPF_RET|BPF_K, 0x90000000U),
};
struct sock_fprog prog = {
.len = (unsigned short)ARRAY_SIZE(filter),
.filter = filter,
};
long ret;
ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0);
ASSERT_EQ(0, ret);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog);
ASSERT_EQ(0, ret);
EXPECT_EQ(0, syscall(__NR_getpid)) {
TH_LOG("getpid() shouldn't ever return");
}
}
TEST_SIGNAL(KILL_all, SIGSYS)
{
struct sock_filter filter[] = {
BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_KILL),
};
struct sock_fprog prog = {
.len = (unsigned short)ARRAY_SIZE(filter),
.filter = filter,
};
long ret;
ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0);
ASSERT_EQ(0, ret);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog);
ASSERT_EQ(0, ret);
}
TEST_SIGNAL(KILL_one, SIGSYS)
{
struct sock_filter filter[] = {
BPF_STMT(BPF_LD|BPF_W|BPF_ABS,
offsetof(struct seccomp_data, nr)),
BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_getpid, 0, 1),
BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_KILL),
BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW),
};
struct sock_fprog prog = {
.len = (unsigned short)ARRAY_SIZE(filter),
.filter = filter,
};
long ret;
pid_t parent = getppid();
ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0);
ASSERT_EQ(0, ret);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog);
ASSERT_EQ(0, ret);
EXPECT_EQ(parent, syscall(__NR_getppid));
/* getpid() should never return. */
EXPECT_EQ(0, syscall(__NR_getpid));
}
TEST_SIGNAL(KILL_one_arg_one, SIGSYS)
{
void *fatal_address;
struct sock_filter filter[] = {
BPF_STMT(BPF_LD|BPF_W|BPF_ABS,
offsetof(struct seccomp_data, nr)),
BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_times, 1, 0),
BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW),
/* Only both with lower 32-bit for now. */
BPF_STMT(BPF_LD|BPF_W|BPF_ABS, syscall_arg(0)),
BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K,
(unsigned long)&fatal_address, 0, 1),
BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_KILL),
BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW),
};
struct sock_fprog prog = {
.len = (unsigned short)ARRAY_SIZE(filter),
.filter = filter,
};
long ret;
pid_t parent = getppid();
struct tms timebuf;
clock_t clock = times(&timebuf);
ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0);
ASSERT_EQ(0, ret);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog);
ASSERT_EQ(0, ret);
EXPECT_EQ(parent, syscall(__NR_getppid));
EXPECT_LE(clock, syscall(__NR_times, &timebuf));
/* times() should never return. */
EXPECT_EQ(0, syscall(__NR_times, &fatal_address));
}
TEST_SIGNAL(KILL_one_arg_six, SIGSYS)
{
#ifndef __NR_mmap2
int sysno = __NR_mmap;
#else
int sysno = __NR_mmap2;
#endif
struct sock_filter filter[] = {
BPF_STMT(BPF_LD|BPF_W|BPF_ABS,
offsetof(struct seccomp_data, nr)),
BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, sysno, 1, 0),
BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW),
/* Only both with lower 32-bit for now. */
BPF_STMT(BPF_LD|BPF_W|BPF_ABS, syscall_arg(5)),
BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, 0x0C0FFEE, 0, 1),
BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_KILL),
BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW),
};
struct sock_fprog prog = {
.len = (unsigned short)ARRAY_SIZE(filter),
.filter = filter,
};
long ret;
pid_t parent = getppid();
int fd;
void *map1, *map2;
int page_size = sysconf(_SC_PAGESIZE);
ASSERT_LT(0, page_size);
ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0);
ASSERT_EQ(0, ret);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog);
ASSERT_EQ(0, ret);
fd = open("/dev/zero", O_RDONLY);
ASSERT_NE(-1, fd);
EXPECT_EQ(parent, syscall(__NR_getppid));
map1 = (void *)syscall(sysno,
NULL, page_size, PROT_READ, MAP_PRIVATE, fd, page_size);
EXPECT_NE(MAP_FAILED, map1);
/* mmap2() should never return. */
map2 = (void *)syscall(sysno,
NULL, page_size, PROT_READ, MAP_PRIVATE, fd, 0x0C0FFEE);
EXPECT_EQ(MAP_FAILED, map2);
/* The test failed, so clean up the resources. */
munmap(map1, page_size);
munmap(map2, page_size);
close(fd);
}
/* TODO(wad) add 64-bit versus 32-bit arg tests. */
TEST(arg_out_of_range)
{
struct sock_filter filter[] = {
BPF_STMT(BPF_LD|BPF_W|BPF_ABS, syscall_arg(6)),
BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW),
};
struct sock_fprog prog = {
.len = (unsigned short)ARRAY_SIZE(filter),
.filter = filter,
};
long ret;
ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0);
ASSERT_EQ(0, ret);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog);
EXPECT_EQ(-1, ret);
EXPECT_EQ(EINVAL, errno);
}
TEST(ERRNO_valid)
{
struct sock_filter filter[] = {
BPF_STMT(BPF_LD|BPF_W|BPF_ABS,
offsetof(struct seccomp_data, nr)),
BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_read, 0, 1),
BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ERRNO | E2BIG),
BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW),
};
struct sock_fprog prog = {
.len = (unsigned short)ARRAY_SIZE(filter),
.filter = filter,
};
long ret;
pid_t parent = getppid();
ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0);
ASSERT_EQ(0, ret);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog);
ASSERT_EQ(0, ret);
EXPECT_EQ(parent, syscall(__NR_getppid));
EXPECT_EQ(-1, read(0, NULL, 0));
EXPECT_EQ(E2BIG, errno);
}
TEST(ERRNO_zero)
{
struct sock_filter filter[] = {
BPF_STMT(BPF_LD|BPF_W|BPF_ABS,
offsetof(struct seccomp_data, nr)),
BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_read, 0, 1),
BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ERRNO | 0),
BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW),
};
struct sock_fprog prog = {
.len = (unsigned short)ARRAY_SIZE(filter),
.filter = filter,
};
long ret;
pid_t parent = getppid();
ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0);
ASSERT_EQ(0, ret);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog);
ASSERT_EQ(0, ret);
EXPECT_EQ(parent, syscall(__NR_getppid));
/* "errno" of 0 is ok. */
EXPECT_EQ(0, read(0, NULL, 0));
}
TEST(ERRNO_capped)
{
struct sock_filter filter[] = {
BPF_STMT(BPF_LD|BPF_W|BPF_ABS,
offsetof(struct seccomp_data, nr)),
BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_read, 0, 1),
BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ERRNO | 4096),
BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW),
};
struct sock_fprog prog = {
.len = (unsigned short)ARRAY_SIZE(filter),
.filter = filter,
};
long ret;
pid_t parent = getppid();
ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0);
ASSERT_EQ(0, ret);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog);
ASSERT_EQ(0, ret);
EXPECT_EQ(parent, syscall(__NR_getppid));
EXPECT_EQ(-1, read(0, NULL, 0));
EXPECT_EQ(4095, errno);
}
FIXTURE_DATA(TRAP) {
struct sock_fprog prog;
};
FIXTURE_SETUP(TRAP)
{
struct sock_filter filter[] = {
BPF_STMT(BPF_LD|BPF_W|BPF_ABS,
offsetof(struct seccomp_data, nr)),
BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_getpid, 0, 1),
BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_TRAP),
BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW),
};
memset(&self->prog, 0, sizeof(self->prog));
self->prog.filter = malloc(sizeof(filter));
ASSERT_NE(NULL, self->prog.filter);
memcpy(self->prog.filter, filter, sizeof(filter));
self->prog.len = (unsigned short)ARRAY_SIZE(filter);
}
FIXTURE_TEARDOWN(TRAP)
{
if (self->prog.filter)
free(self->prog.filter);
}
TEST_F_SIGNAL(TRAP, dfl, SIGSYS)
{
long ret;
ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0);
ASSERT_EQ(0, ret);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->prog);
ASSERT_EQ(0, ret);
syscall(__NR_getpid);
}
/* Ensure that SIGSYS overrides SIG_IGN */
TEST_F_SIGNAL(TRAP, ign, SIGSYS)
{
long ret;
ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0);
ASSERT_EQ(0, ret);
signal(SIGSYS, SIG_IGN);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->prog);
ASSERT_EQ(0, ret);
syscall(__NR_getpid);
}
static struct siginfo TRAP_info;
static volatile int TRAP_nr;
static void TRAP_action(int nr, siginfo_t *info, void *void_context)
{
memcpy(&TRAP_info, info, sizeof(TRAP_info));
TRAP_nr = nr;
}
TEST_F(TRAP, handler)
{
int ret, test;
struct sigaction act;
sigset_t mask;
memset(&act, 0, sizeof(act));
sigemptyset(&mask);
sigaddset(&mask, SIGSYS);
act.sa_sigaction = &TRAP_action;
act.sa_flags = SA_SIGINFO;
ret = sigaction(SIGSYS, &act, NULL);
ASSERT_EQ(0, ret) {
TH_LOG("sigaction failed");
}
ret = sigprocmask(SIG_UNBLOCK, &mask, NULL);
ASSERT_EQ(0, ret) {
TH_LOG("sigprocmask failed");
}
ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0);
ASSERT_EQ(0, ret);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->prog);
ASSERT_EQ(0, ret);
TRAP_nr = 0;
memset(&TRAP_info, 0, sizeof(TRAP_info));
/* Expect the registers to be rolled back. (nr = error) may vary
* based on arch. */
ret = syscall(__NR_getpid);
/* Silence gcc warning about volatile. */
test = TRAP_nr;
EXPECT_EQ(SIGSYS, test);
struct local_sigsys {
void *_call_addr; /* calling user insn */
int _syscall; /* triggering system call number */
unsigned int _arch; /* AUDIT_ARCH_* of syscall */
} *sigsys = (struct local_sigsys *)
#ifdef si_syscall
&(TRAP_info.si_call_addr);
#else
&TRAP_info.si_pid;
#endif
EXPECT_EQ(__NR_getpid, sigsys->_syscall);
/* Make sure arch is non-zero. */
EXPECT_NE(0, sigsys->_arch);
EXPECT_NE(0, (unsigned long)sigsys->_call_addr);
}
FIXTURE_DATA(precedence) {
struct sock_fprog allow;
struct sock_fprog trace;
struct sock_fprog error;
struct sock_fprog trap;
struct sock_fprog kill;
};
FIXTURE_SETUP(precedence)
{
struct sock_filter allow_insns[] = {
BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW),
};
struct sock_filter trace_insns[] = {
BPF_STMT(BPF_LD|BPF_W|BPF_ABS,
offsetof(struct seccomp_data, nr)),
BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_getpid, 1, 0),
BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW),
BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_TRACE),
};
struct sock_filter error_insns[] = {
BPF_STMT(BPF_LD|BPF_W|BPF_ABS,
offsetof(struct seccomp_data, nr)),
BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_getpid, 1, 0),
BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW),
BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ERRNO),
};
struct sock_filter trap_insns[] = {
BPF_STMT(BPF_LD|BPF_W|BPF_ABS,
offsetof(struct seccomp_data, nr)),
BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_getpid, 1, 0),
BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW),
BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_TRAP),
};
struct sock_filter kill_insns[] = {
BPF_STMT(BPF_LD|BPF_W|BPF_ABS,
offsetof(struct seccomp_data, nr)),
BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_getpid, 1, 0),
BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW),
BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_KILL),
};
memset(self, 0, sizeof(*self));
#define FILTER_ALLOC(_x) \
self->_x.filter = malloc(sizeof(_x##_insns)); \
ASSERT_NE(NULL, self->_x.filter); \
memcpy(self->_x.filter, &_x##_insns, sizeof(_x##_insns)); \
self->_x.len = (unsigned short)ARRAY_SIZE(_x##_insns)
FILTER_ALLOC(allow);
FILTER_ALLOC(trace);
FILTER_ALLOC(error);
FILTER_ALLOC(trap);
FILTER_ALLOC(kill);
}
FIXTURE_TEARDOWN(precedence)
{
#define FILTER_FREE(_x) if (self->_x.filter) free(self->_x.filter)
FILTER_FREE(allow);
FILTER_FREE(trace);
FILTER_FREE(error);
FILTER_FREE(trap);
FILTER_FREE(kill);
}
TEST_F(precedence, allow_ok)
{
pid_t parent, res = 0;
long ret;
parent = getppid();
ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0);
ASSERT_EQ(0, ret);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->allow);
ASSERT_EQ(0, ret);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->trace);
ASSERT_EQ(0, ret);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->error);
ASSERT_EQ(0, ret);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->trap);
ASSERT_EQ(0, ret);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->kill);
ASSERT_EQ(0, ret);
/* Should work just fine. */
res = syscall(__NR_getppid);
EXPECT_EQ(parent, res);
}
TEST_F_SIGNAL(precedence, kill_is_highest, SIGSYS)
{
pid_t parent, res = 0;
long ret;
parent = getppid();
ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0);
ASSERT_EQ(0, ret);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->allow);
ASSERT_EQ(0, ret);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->trace);
ASSERT_EQ(0, ret);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->error);
ASSERT_EQ(0, ret);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->trap);
ASSERT_EQ(0, ret);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->kill);
ASSERT_EQ(0, ret);
/* Should work just fine. */
res = syscall(__NR_getppid);
EXPECT_EQ(parent, res);
/* getpid() should never return. */
res = syscall(__NR_getpid);
EXPECT_EQ(0, res);
}
TEST_F_SIGNAL(precedence, kill_is_highest_in_any_order, SIGSYS)
{
pid_t parent;
long ret;
parent = getppid();
ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0);
ASSERT_EQ(0, ret);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->allow);
ASSERT_EQ(0, ret);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->kill);
ASSERT_EQ(0, ret);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->error);
ASSERT_EQ(0, ret);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->trace);
ASSERT_EQ(0, ret);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->trap);
ASSERT_EQ(0, ret);
/* Should work just fine. */
EXPECT_EQ(parent, syscall(__NR_getppid));
/* getpid() should never return. */
EXPECT_EQ(0, syscall(__NR_getpid));
}
TEST_F_SIGNAL(precedence, trap_is_second, SIGSYS)
{
pid_t parent;
long ret;
parent = getppid();
ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0);
ASSERT_EQ(0, ret);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->allow);
ASSERT_EQ(0, ret);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->trace);
ASSERT_EQ(0, ret);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->error);
ASSERT_EQ(0, ret);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->trap);
ASSERT_EQ(0, ret);
/* Should work just fine. */
EXPECT_EQ(parent, syscall(__NR_getppid));
/* getpid() should never return. */
EXPECT_EQ(0, syscall(__NR_getpid));
}
TEST_F_SIGNAL(precedence, trap_is_second_in_any_order, SIGSYS)
{
pid_t parent;
long ret;
parent = getppid();
ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0);
ASSERT_EQ(0, ret);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->allow);
ASSERT_EQ(0, ret);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->trap);
ASSERT_EQ(0, ret);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->trace);
ASSERT_EQ(0, ret);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->error);
ASSERT_EQ(0, ret);
/* Should work just fine. */
EXPECT_EQ(parent, syscall(__NR_getppid));
/* getpid() should never return. */
EXPECT_EQ(0, syscall(__NR_getpid));
}
TEST_F(precedence, errno_is_third)
{
pid_t parent;
long ret;
parent = getppid();
ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0);
ASSERT_EQ(0, ret);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->allow);
ASSERT_EQ(0, ret);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->trace);
ASSERT_EQ(0, ret);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->error);
ASSERT_EQ(0, ret);
/* Should work just fine. */
EXPECT_EQ(parent, syscall(__NR_getppid));
EXPECT_EQ(0, syscall(__NR_getpid));
}
TEST_F(precedence, errno_is_third_in_any_order)
{
pid_t parent;
long ret;
parent = getppid();
ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0);
ASSERT_EQ(0, ret);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->error);
ASSERT_EQ(0, ret);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->trace);
ASSERT_EQ(0, ret);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->allow);
ASSERT_EQ(0, ret);
/* Should work just fine. */
EXPECT_EQ(parent, syscall(__NR_getppid));
EXPECT_EQ(0, syscall(__NR_getpid));
}
TEST_F(precedence, trace_is_fourth)
{
pid_t parent;
long ret;
parent = getppid();
ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0);
ASSERT_EQ(0, ret);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->allow);
ASSERT_EQ(0, ret);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->trace);
ASSERT_EQ(0, ret);
/* Should work just fine. */
EXPECT_EQ(parent, syscall(__NR_getppid));
/* No ptracer */
EXPECT_EQ(-1, syscall(__NR_getpid));
}
TEST_F(precedence, trace_is_fourth_in_any_order)
{
pid_t parent;
long ret;
parent = getppid();
ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0);
ASSERT_EQ(0, ret);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->trace);
ASSERT_EQ(0, ret);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->allow);
ASSERT_EQ(0, ret);
/* Should work just fine. */
EXPECT_EQ(parent, syscall(__NR_getppid));
/* No ptracer */
EXPECT_EQ(-1, syscall(__NR_getpid));
}
#ifndef PTRACE_O_TRACESECCOMP
#define PTRACE_O_TRACESECCOMP 0x00000080
#endif
/* Catch the Ubuntu 12.04 value error. */
#if PTRACE_EVENT_SECCOMP != 7
#undef PTRACE_EVENT_SECCOMP
#endif
#ifndef PTRACE_EVENT_SECCOMP
#define PTRACE_EVENT_SECCOMP 7
#endif
#define IS_SECCOMP_EVENT(status) ((status >> 16) == PTRACE_EVENT_SECCOMP)
bool tracer_running;
void tracer_stop(int sig)
{
tracer_running = false;
}
typedef void tracer_func_t(struct __test_metadata *_metadata,
pid_t tracee, int status, void *args);
void start_tracer(struct __test_metadata *_metadata, int fd, pid_t tracee,
tracer_func_t tracer_func, void *args, bool ptrace_syscall)
{
int ret = -1;
struct sigaction action = {
.sa_handler = tracer_stop,
};
/* Allow external shutdown. */
tracer_running = true;
ASSERT_EQ(0, sigaction(SIGUSR1, &action, NULL));
errno = 0;
while (ret == -1 && errno != EINVAL)
ret = ptrace(PTRACE_ATTACH, tracee, NULL, 0);
ASSERT_EQ(0, ret) {
kill(tracee, SIGKILL);
}
/* Wait for attach stop */
wait(NULL);
ret = ptrace(PTRACE_SETOPTIONS, tracee, NULL, ptrace_syscall ?
PTRACE_O_TRACESYSGOOD :
PTRACE_O_TRACESECCOMP);
ASSERT_EQ(0, ret) {
TH_LOG("Failed to set PTRACE_O_TRACESECCOMP");
kill(tracee, SIGKILL);
}
ret = ptrace(ptrace_syscall ? PTRACE_SYSCALL : PTRACE_CONT,
tracee, NULL, 0);
ASSERT_EQ(0, ret);
/* Unblock the tracee */
ASSERT_EQ(1, write(fd, "A", 1));
ASSERT_EQ(0, close(fd));
/* Run until we're shut down. Must assert to stop execution. */
while (tracer_running) {
int status;
if (wait(&status) != tracee)
continue;
if (WIFSIGNALED(status) || WIFEXITED(status))
/* Child is dead. Time to go. */
return;
/* Check if this is a seccomp event. */
ASSERT_EQ(!ptrace_syscall, IS_SECCOMP_EVENT(status));
tracer_func(_metadata, tracee, status, args);
ret = ptrace(ptrace_syscall ? PTRACE_SYSCALL : PTRACE_CONT,
tracee, NULL, 0);
ASSERT_EQ(0, ret);
}
/* Directly report the status of our test harness results. */
syscall(__NR_exit, _metadata->passed ? EXIT_SUCCESS : EXIT_FAILURE);
}
/* Common tracer setup/teardown functions. */
void cont_handler(int num)
{ }
pid_t setup_trace_fixture(struct __test_metadata *_metadata,
tracer_func_t func, void *args, bool ptrace_syscall)
{
char sync;
int pipefd[2];
pid_t tracer_pid;
pid_t tracee = getpid();
/* Setup a pipe for clean synchronization. */
ASSERT_EQ(0, pipe(pipefd));
/* Fork a child which we'll promote to tracer */
tracer_pid = fork();
ASSERT_LE(0, tracer_pid);
signal(SIGALRM, cont_handler);
if (tracer_pid == 0) {
close(pipefd[0]);
start_tracer(_metadata, pipefd[1], tracee, func, args,
ptrace_syscall);
syscall(__NR_exit, 0);
}
close(pipefd[1]);
prctl(PR_SET_PTRACER, tracer_pid, 0, 0, 0);
read(pipefd[0], &sync, 1);
close(pipefd[0]);
return tracer_pid;
}
void teardown_trace_fixture(struct __test_metadata *_metadata,
pid_t tracer)
{
if (tracer) {
int status;
/*
* Extract the exit code from the other process and
* adopt it for ourselves in case its asserts failed.
*/
ASSERT_EQ(0, kill(tracer, SIGUSR1));
ASSERT_EQ(tracer, waitpid(tracer, &status, 0));
if (WEXITSTATUS(status))
_metadata->passed = 0;
}
}
/* "poke" tracer arguments and function. */
struct tracer_args_poke_t {
unsigned long poke_addr;
};
void tracer_poke(struct __test_metadata *_metadata, pid_t tracee, int status,
void *args)
{
int ret;
unsigned long msg;
struct tracer_args_poke_t *info = (struct tracer_args_poke_t *)args;
ret = ptrace(PTRACE_GETEVENTMSG, tracee, NULL, &msg);
EXPECT_EQ(0, ret);
/* If this fails, don't try to recover. */
ASSERT_EQ(0x1001, msg) {
kill(tracee, SIGKILL);
}
/*
* Poke in the message.
* Registers are not touched to try to keep this relatively arch
* agnostic.
*/
ret = ptrace(PTRACE_POKEDATA, tracee, info->poke_addr, 0x1001);
EXPECT_EQ(0, ret);
}
FIXTURE_DATA(TRACE_poke) {
struct sock_fprog prog;
pid_t tracer;
long poked;
struct tracer_args_poke_t tracer_args;
};
FIXTURE_SETUP(TRACE_poke)
{
struct sock_filter filter[] = {
BPF_STMT(BPF_LD|BPF_W|BPF_ABS,
offsetof(struct seccomp_data, nr)),
BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_read, 0, 1),
BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_TRACE | 0x1001),
BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW),
};
self->poked = 0;
memset(&self->prog, 0, sizeof(self->prog));
self->prog.filter = malloc(sizeof(filter));
ASSERT_NE(NULL, self->prog.filter);
memcpy(self->prog.filter, filter, sizeof(filter));
self->prog.len = (unsigned short)ARRAY_SIZE(filter);
/* Set up tracer args. */
self->tracer_args.poke_addr = (unsigned long)&self->poked;
/* Launch tracer. */
self->tracer = setup_trace_fixture(_metadata, tracer_poke,
&self->tracer_args, false);
}
FIXTURE_TEARDOWN(TRACE_poke)
{
teardown_trace_fixture(_metadata, self->tracer);
if (self->prog.filter)
free(self->prog.filter);
}
TEST_F(TRACE_poke, read_has_side_effects)
{
ssize_t ret;
ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0);
ASSERT_EQ(0, ret);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->prog, 0, 0);
ASSERT_EQ(0, ret);
EXPECT_EQ(0, self->poked);
ret = read(-1, NULL, 0);
EXPECT_EQ(-1, ret);
EXPECT_EQ(0x1001, self->poked);
}
TEST_F(TRACE_poke, getpid_runs_normally)
{
long ret;
ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0);
ASSERT_EQ(0, ret);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->prog, 0, 0);
ASSERT_EQ(0, ret);
EXPECT_EQ(0, self->poked);
EXPECT_NE(0, syscall(__NR_getpid));
EXPECT_EQ(0, self->poked);
}
#if defined(__x86_64__)
# define ARCH_REGS struct user_regs_struct
# define SYSCALL_NUM orig_rax
# define SYSCALL_RET rax
#elif defined(__i386__)
# define ARCH_REGS struct user_regs_struct
# define SYSCALL_NUM orig_eax
# define SYSCALL_RET eax
#elif defined(__arm__)
# define ARCH_REGS struct pt_regs
# define SYSCALL_NUM ARM_r7
# define SYSCALL_RET ARM_r0
#elif defined(__aarch64__)
# define ARCH_REGS struct user_pt_regs
# define SYSCALL_NUM regs[8]
# define SYSCALL_RET regs[0]
#elif defined(__hppa__)
# define ARCH_REGS struct user_regs_struct
# define SYSCALL_NUM gr[20]
# define SYSCALL_RET gr[28]
#elif defined(__powerpc__)
# define ARCH_REGS struct pt_regs
# define SYSCALL_NUM gpr[0]
# define SYSCALL_RET gpr[3]
#elif defined(__s390__)
# define ARCH_REGS s390_regs
# define SYSCALL_NUM gprs[2]
# define SYSCALL_RET gprs[2]
#elif defined(__mips__)
# define ARCH_REGS struct pt_regs
# define SYSCALL_NUM regs[2]
# define SYSCALL_SYSCALL_NUM regs[4]
# define SYSCALL_RET regs[2]
# define SYSCALL_NUM_RET_SHARE_REG
#else
# error "Do not know how to find your architecture's registers and syscalls"
#endif
/* Use PTRACE_GETREGS and PTRACE_SETREGS when available. This is useful for
* architectures without HAVE_ARCH_TRACEHOOK (e.g. User-mode Linux).
*/
#if defined(__x86_64__) || defined(__i386__) || defined(__mips__)
#define HAVE_GETREGS
#endif
/* Architecture-specific syscall fetching routine. */
int get_syscall(struct __test_metadata *_metadata, pid_t tracee)
{
ARCH_REGS regs;
#ifdef HAVE_GETREGS
EXPECT_EQ(0, ptrace(PTRACE_GETREGS, tracee, 0, &regs)) {
TH_LOG("PTRACE_GETREGS failed");
return -1;
}
#else
struct iovec iov;
iov.iov_base = &regs;
iov.iov_len = sizeof(regs);
EXPECT_EQ(0, ptrace(PTRACE_GETREGSET, tracee, NT_PRSTATUS, &iov)) {
TH_LOG("PTRACE_GETREGSET failed");
return -1;
}
#endif
#if defined(__mips__)
if (regs.SYSCALL_NUM == __NR_O32_Linux)
return regs.SYSCALL_SYSCALL_NUM;
#endif
return regs.SYSCALL_NUM;
}
/* Architecture-specific syscall changing routine. */
void change_syscall(struct __test_metadata *_metadata,
pid_t tracee, int syscall)
{
int ret;
ARCH_REGS regs;
#ifdef HAVE_GETREGS
ret = ptrace(PTRACE_GETREGS, tracee, 0, &regs);
#else
struct iovec iov;
iov.iov_base = &regs;
iov.iov_len = sizeof(regs);
ret = ptrace(PTRACE_GETREGSET, tracee, NT_PRSTATUS, &iov);
#endif
EXPECT_EQ(0, ret);
#if defined(__x86_64__) || defined(__i386__) || defined(__powerpc__) || \
defined(__s390__) || defined(__hppa__)
{
regs.SYSCALL_NUM = syscall;
}
#elif defined(__mips__)
{
if (regs.SYSCALL_NUM == __NR_O32_Linux)
regs.SYSCALL_SYSCALL_NUM = syscall;
else
regs.SYSCALL_NUM = syscall;
}
#elif defined(__arm__)
# ifndef PTRACE_SET_SYSCALL
# define PTRACE_SET_SYSCALL 23
# endif
{
ret = ptrace(PTRACE_SET_SYSCALL, tracee, NULL, syscall);
EXPECT_EQ(0, ret);
}
#elif defined(__aarch64__)
# ifndef NT_ARM_SYSTEM_CALL
# define NT_ARM_SYSTEM_CALL 0x404
# endif
{
iov.iov_base = &syscall;
iov.iov_len = sizeof(syscall);
ret = ptrace(PTRACE_SETREGSET, tracee, NT_ARM_SYSTEM_CALL,
&iov);
EXPECT_EQ(0, ret);
}
#else
ASSERT_EQ(1, 0) {
TH_LOG("How is the syscall changed on this architecture?");
}
#endif
/* If syscall is skipped, change return value. */
if (syscall == -1)
#ifdef SYSCALL_NUM_RET_SHARE_REG
TH_LOG("Can't modify syscall return on this architecture");
#else
regs.SYSCALL_RET = 1;
#endif
#ifdef HAVE_GETREGS
ret = ptrace(PTRACE_SETREGS, tracee, 0, &regs);
#else
iov.iov_base = &regs;
iov.iov_len = sizeof(regs);
ret = ptrace(PTRACE_SETREGSET, tracee, NT_PRSTATUS, &iov);
#endif
EXPECT_EQ(0, ret);
}
void tracer_syscall(struct __test_metadata *_metadata, pid_t tracee,
int status, void *args)
{
int ret;
unsigned long msg;
/* Make sure we got the right message. */
ret = ptrace(PTRACE_GETEVENTMSG, tracee, NULL, &msg);
EXPECT_EQ(0, ret);
/* Validate and take action on expected syscalls. */
switch (msg) {
case 0x1002:
/* change getpid to getppid. */
EXPECT_EQ(__NR_getpid, get_syscall(_metadata, tracee));
change_syscall(_metadata, tracee, __NR_getppid);
break;
case 0x1003:
/* skip gettid. */
EXPECT_EQ(__NR_gettid, get_syscall(_metadata, tracee));
change_syscall(_metadata, tracee, -1);
break;
case 0x1004:
/* do nothing (allow getppid) */
EXPECT_EQ(__NR_getppid, get_syscall(_metadata, tracee));
break;
default:
EXPECT_EQ(0, msg) {
TH_LOG("Unknown PTRACE_GETEVENTMSG: 0x%lx", msg);
kill(tracee, SIGKILL);
}
}
}
void tracer_ptrace(struct __test_metadata *_metadata, pid_t tracee,
int status, void *args)
{
int ret, nr;
unsigned long msg;
static bool entry;
/* Make sure we got an empty message. */
ret = ptrace(PTRACE_GETEVENTMSG, tracee, NULL, &msg);
EXPECT_EQ(0, ret);
EXPECT_EQ(0, msg);
/* The only way to tell PTRACE_SYSCALL entry/exit is by counting. */
entry = !entry;
if (!entry)
return;
nr = get_syscall(_metadata, tracee);
if (nr == __NR_getpid)
change_syscall(_metadata, tracee, __NR_getppid);
}
FIXTURE_DATA(TRACE_syscall) {
struct sock_fprog prog;
pid_t tracer, mytid, mypid, parent;
};
FIXTURE_SETUP(TRACE_syscall)
{
struct sock_filter filter[] = {
BPF_STMT(BPF_LD|BPF_W|BPF_ABS,
offsetof(struct seccomp_data, nr)),
BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_getpid, 0, 1),
BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_TRACE | 0x1002),
BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_gettid, 0, 1),
BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_TRACE | 0x1003),
BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_getppid, 0, 1),
BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_TRACE | 0x1004),
BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW),
};
memset(&self->prog, 0, sizeof(self->prog));
self->prog.filter = malloc(sizeof(filter));
ASSERT_NE(NULL, self->prog.filter);
memcpy(self->prog.filter, filter, sizeof(filter));
self->prog.len = (unsigned short)ARRAY_SIZE(filter);
/* Prepare some testable syscall results. */
self->mytid = syscall(__NR_gettid);
ASSERT_GT(self->mytid, 0);
ASSERT_NE(self->mytid, 1) {
TH_LOG("Running this test as init is not supported. :)");
}
self->mypid = getpid();
ASSERT_GT(self->mypid, 0);
ASSERT_EQ(self->mytid, self->mypid);
self->parent = getppid();
ASSERT_GT(self->parent, 0);
ASSERT_NE(self->parent, self->mypid);
/* Launch tracer. */
self->tracer = setup_trace_fixture(_metadata, tracer_syscall, NULL,
false);
}
FIXTURE_TEARDOWN(TRACE_syscall)
{
teardown_trace_fixture(_metadata, self->tracer);
if (self->prog.filter)
free(self->prog.filter);
}
TEST_F(TRACE_syscall, syscall_allowed)
{
long ret;
ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0);
ASSERT_EQ(0, ret);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->prog, 0, 0);
ASSERT_EQ(0, ret);
/* getppid works as expected (no changes). */
EXPECT_EQ(self->parent, syscall(__NR_getppid));
EXPECT_NE(self->mypid, syscall(__NR_getppid));
}
TEST_F(TRACE_syscall, syscall_redirected)
{
long ret;
ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0);
ASSERT_EQ(0, ret);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->prog, 0, 0);
ASSERT_EQ(0, ret);
/* getpid has been redirected to getppid as expected. */
EXPECT_EQ(self->parent, syscall(__NR_getpid));
EXPECT_NE(self->mypid, syscall(__NR_getpid));
}
TEST_F(TRACE_syscall, syscall_dropped)
{
long ret;
ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0);
ASSERT_EQ(0, ret);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->prog, 0, 0);
ASSERT_EQ(0, ret);
#ifdef SYSCALL_NUM_RET_SHARE_REG
/* gettid has been skipped */
EXPECT_EQ(-1, syscall(__NR_gettid));
#else
/* gettid has been skipped and an altered return value stored. */
EXPECT_EQ(1, syscall(__NR_gettid));
#endif
EXPECT_NE(self->mytid, syscall(__NR_gettid));
}
TEST_F(TRACE_syscall, skip_after_RET_TRACE)
{
struct sock_filter filter[] = {
BPF_STMT(BPF_LD|BPF_W|BPF_ABS,
offsetof(struct seccomp_data, nr)),
BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_getppid, 0, 1),
BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ERRNO | EPERM),
BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW),
};
struct sock_fprog prog = {
.len = (unsigned short)ARRAY_SIZE(filter),
.filter = filter,
};
long ret;
ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0);
ASSERT_EQ(0, ret);
/* Install fixture filter. */
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->prog, 0, 0);
ASSERT_EQ(0, ret);
/* Install "errno on getppid" filter. */
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog, 0, 0);
ASSERT_EQ(0, ret);
/* Tracer will redirect getpid to getppid, and we should see EPERM. */
EXPECT_EQ(-1, syscall(__NR_getpid));
EXPECT_EQ(EPERM, errno);
}
TEST_F_SIGNAL(TRACE_syscall, kill_after_RET_TRACE, SIGSYS)
{
struct sock_filter filter[] = {
BPF_STMT(BPF_LD|BPF_W|BPF_ABS,
offsetof(struct seccomp_data, nr)),
BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_getppid, 0, 1),
BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_KILL),
BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW),
};
struct sock_fprog prog = {
.len = (unsigned short)ARRAY_SIZE(filter),
.filter = filter,
};
long ret;
ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0);
ASSERT_EQ(0, ret);
/* Install fixture filter. */
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->prog, 0, 0);
ASSERT_EQ(0, ret);
/* Install "death on getppid" filter. */
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog, 0, 0);
ASSERT_EQ(0, ret);
/* Tracer will redirect getpid to getppid, and we should die. */
EXPECT_NE(self->mypid, syscall(__NR_getpid));
}
TEST_F(TRACE_syscall, skip_after_ptrace)
{
struct sock_filter filter[] = {
BPF_STMT(BPF_LD|BPF_W|BPF_ABS,
offsetof(struct seccomp_data, nr)),
BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_getppid, 0, 1),
BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ERRNO | EPERM),
BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW),
};
struct sock_fprog prog = {
.len = (unsigned short)ARRAY_SIZE(filter),
.filter = filter,
};
long ret;
/* Swap SECCOMP_RET_TRACE tracer for PTRACE_SYSCALL tracer. */
teardown_trace_fixture(_metadata, self->tracer);
self->tracer = setup_trace_fixture(_metadata, tracer_ptrace, NULL,
true);
ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0);
ASSERT_EQ(0, ret);
/* Install "errno on getppid" filter. */
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog, 0, 0);
ASSERT_EQ(0, ret);
/* Tracer will redirect getpid to getppid, and we should see EPERM. */
EXPECT_EQ(-1, syscall(__NR_getpid));
EXPECT_EQ(EPERM, errno);
}
TEST_F_SIGNAL(TRACE_syscall, kill_after_ptrace, SIGSYS)
{
struct sock_filter filter[] = {
BPF_STMT(BPF_LD|BPF_W|BPF_ABS,
offsetof(struct seccomp_data, nr)),
BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_getppid, 0, 1),
BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_KILL),
BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW),
};
struct sock_fprog prog = {
.len = (unsigned short)ARRAY_SIZE(filter),
.filter = filter,
};
long ret;
/* Swap SECCOMP_RET_TRACE tracer for PTRACE_SYSCALL tracer. */
teardown_trace_fixture(_metadata, self->tracer);
self->tracer = setup_trace_fixture(_metadata, tracer_ptrace, NULL,
true);
ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0);
ASSERT_EQ(0, ret);
/* Install "death on getppid" filter. */
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog, 0, 0);
ASSERT_EQ(0, ret);
/* Tracer will redirect getpid to getppid, and we should die. */
EXPECT_NE(self->mypid, syscall(__NR_getpid));
}
#ifndef __NR_seccomp
# if defined(__i386__)
# define __NR_seccomp 354
# elif defined(__x86_64__)
# define __NR_seccomp 317
# elif defined(__arm__)
# define __NR_seccomp 383
# elif defined(__aarch64__)
# define __NR_seccomp 277
# elif defined(__hppa__)
# define __NR_seccomp 338
# elif defined(__powerpc__)
# define __NR_seccomp 358
# elif defined(__s390__)
# define __NR_seccomp 348
# else
# warning "seccomp syscall number unknown for this architecture"
# define __NR_seccomp 0xffff
# endif
#endif
#ifndef SECCOMP_SET_MODE_STRICT
#define SECCOMP_SET_MODE_STRICT 0
#endif
#ifndef SECCOMP_SET_MODE_FILTER
#define SECCOMP_SET_MODE_FILTER 1
#endif
#ifndef SECCOMP_FILTER_FLAG_TSYNC
#define SECCOMP_FILTER_FLAG_TSYNC 1
#endif
#ifndef seccomp
int seccomp(unsigned int op, unsigned int flags, void *args)
{
errno = 0;
return syscall(__NR_seccomp, op, flags, args);
}
#endif
TEST(seccomp_syscall)
{
struct sock_filter filter[] = {
BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW),
};
struct sock_fprog prog = {
.len = (unsigned short)ARRAY_SIZE(filter),
.filter = filter,
};
long ret;
ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0);
ASSERT_EQ(0, ret) {
TH_LOG("Kernel does not support PR_SET_NO_NEW_PRIVS!");
}
/* Reject insane operation. */
ret = seccomp(-1, 0, &prog);
ASSERT_NE(ENOSYS, errno) {
TH_LOG("Kernel does not support seccomp syscall!");
}
EXPECT_EQ(EINVAL, errno) {
TH_LOG("Did not reject crazy op value!");
}
/* Reject strict with flags or pointer. */
ret = seccomp(SECCOMP_SET_MODE_STRICT, -1, NULL);
EXPECT_EQ(EINVAL, errno) {
TH_LOG("Did not reject mode strict with flags!");
}
ret = seccomp(SECCOMP_SET_MODE_STRICT, 0, &prog);
EXPECT_EQ(EINVAL, errno) {
TH_LOG("Did not reject mode strict with uargs!");
}
/* Reject insane args for filter. */
ret = seccomp(SECCOMP_SET_MODE_FILTER, -1, &prog);
EXPECT_EQ(EINVAL, errno) {
TH_LOG("Did not reject crazy filter flags!");
}
ret = seccomp(SECCOMP_SET_MODE_FILTER, 0, NULL);
EXPECT_EQ(EFAULT, errno) {
TH_LOG("Did not reject NULL filter!");
}
ret = seccomp(SECCOMP_SET_MODE_FILTER, 0, &prog);
EXPECT_EQ(0, errno) {
TH_LOG("Kernel does not support SECCOMP_SET_MODE_FILTER: %s",
strerror(errno));
}
}
TEST(seccomp_syscall_mode_lock)
{
struct sock_filter filter[] = {
BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW),
};
struct sock_fprog prog = {
.len = (unsigned short)ARRAY_SIZE(filter),
.filter = filter,
};
long ret;
ret = prctl(PR_SET_NO_NEW_PRIVS, 1, NULL, 0, 0);
ASSERT_EQ(0, ret) {
TH_LOG("Kernel does not support PR_SET_NO_NEW_PRIVS!");
}
ret = seccomp(SECCOMP_SET_MODE_FILTER, 0, &prog);
ASSERT_NE(ENOSYS, errno) {
TH_LOG("Kernel does not support seccomp syscall!");
}
EXPECT_EQ(0, ret) {
TH_LOG("Could not install filter!");
}
/* Make sure neither entry point will switch to strict. */
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_STRICT, 0, 0, 0);
EXPECT_EQ(EINVAL, errno) {
TH_LOG("Switched to mode strict!");
}
ret = seccomp(SECCOMP_SET_MODE_STRICT, 0, NULL);
EXPECT_EQ(EINVAL, errno) {
TH_LOG("Switched to mode strict!");
}
}
TEST(TSYNC_first)
{
struct sock_filter filter[] = {
BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW),
};
struct sock_fprog prog = {
.len = (unsigned short)ARRAY_SIZE(filter),
.filter = filter,
};
long ret;
ret = prctl(PR_SET_NO_NEW_PRIVS, 1, NULL, 0, 0);
ASSERT_EQ(0, ret) {
TH_LOG("Kernel does not support PR_SET_NO_NEW_PRIVS!");
}
ret = seccomp(SECCOMP_SET_MODE_FILTER, SECCOMP_FILTER_FLAG_TSYNC,
&prog);
ASSERT_NE(ENOSYS, errno) {
TH_LOG("Kernel does not support seccomp syscall!");
}
EXPECT_EQ(0, ret) {
TH_LOG("Could not install initial filter with TSYNC!");
}
}
#define TSYNC_SIBLINGS 2
struct tsync_sibling {
pthread_t tid;
pid_t system_tid;
sem_t *started;
pthread_cond_t *cond;
pthread_mutex_t *mutex;
int diverge;
int num_waits;
struct sock_fprog *prog;
struct __test_metadata *metadata;
};
FIXTURE_DATA(TSYNC) {
struct sock_fprog root_prog, apply_prog;
struct tsync_sibling sibling[TSYNC_SIBLINGS];
sem_t started;
pthread_cond_t cond;
pthread_mutex_t mutex;
int sibling_count;
};
FIXTURE_SETUP(TSYNC)
{
struct sock_filter root_filter[] = {
BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW),
};
struct sock_filter apply_filter[] = {
BPF_STMT(BPF_LD|BPF_W|BPF_ABS,
offsetof(struct seccomp_data, nr)),
BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_read, 0, 1),
BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_KILL),
BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW),
};
memset(&self->root_prog, 0, sizeof(self->root_prog));
memset(&self->apply_prog, 0, sizeof(self->apply_prog));
memset(&self->sibling, 0, sizeof(self->sibling));
self->root_prog.filter = malloc(sizeof(root_filter));
ASSERT_NE(NULL, self->root_prog.filter);
memcpy(self->root_prog.filter, &root_filter, sizeof(root_filter));
self->root_prog.len = (unsigned short)ARRAY_SIZE(root_filter);
self->apply_prog.filter = malloc(sizeof(apply_filter));
ASSERT_NE(NULL, self->apply_prog.filter);
memcpy(self->apply_prog.filter, &apply_filter, sizeof(apply_filter));
self->apply_prog.len = (unsigned short)ARRAY_SIZE(apply_filter);
self->sibling_count = 0;
pthread_mutex_init(&self->mutex, NULL);
pthread_cond_init(&self->cond, NULL);
sem_init(&self->started, 0, 0);
self->sibling[0].tid = 0;
self->sibling[0].cond = &self->cond;
self->sibling[0].started = &self->started;
self->sibling[0].mutex = &self->mutex;
self->sibling[0].diverge = 0;
self->sibling[0].num_waits = 1;
self->sibling[0].prog = &self->root_prog;
self->sibling[0].metadata = _metadata;
self->sibling[1].tid = 0;
self->sibling[1].cond = &self->cond;
self->sibling[1].started = &self->started;
self->sibling[1].mutex = &self->mutex;
self->sibling[1].diverge = 0;
self->sibling[1].prog = &self->root_prog;
self->sibling[1].num_waits = 1;
self->sibling[1].metadata = _metadata;
}
FIXTURE_TEARDOWN(TSYNC)
{
int sib = 0;
if (self->root_prog.filter)
free(self->root_prog.filter);
if (self->apply_prog.filter)
free(self->apply_prog.filter);
for ( ; sib < self->sibling_count; ++sib) {
struct tsync_sibling *s = &self->sibling[sib];
void *status;
if (!s->tid)
continue;
if (pthread_kill(s->tid, 0)) {
pthread_cancel(s->tid);
pthread_join(s->tid, &status);
}
}
pthread_mutex_destroy(&self->mutex);
pthread_cond_destroy(&self->cond);
sem_destroy(&self->started);
}
void *tsync_sibling(void *data)
{
long ret = 0;
struct tsync_sibling *me = data;
me->system_tid = syscall(__NR_gettid);
pthread_mutex_lock(me->mutex);
if (me->diverge) {
/* Just re-apply the root prog to fork the tree */
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER,
me->prog, 0, 0);
}
sem_post(me->started);
/* Return outside of started so parent notices failures. */
if (ret) {
pthread_mutex_unlock(me->mutex);
return (void *)SIBLING_EXIT_FAILURE;
}
do {
pthread_cond_wait(me->cond, me->mutex);
me->num_waits = me->num_waits - 1;
} while (me->num_waits);
pthread_mutex_unlock(me->mutex);
ret = prctl(PR_GET_NO_NEW_PRIVS, 0, 0, 0, 0);
if (!ret)
return (void *)SIBLING_EXIT_NEWPRIVS;
read(0, NULL, 0);
return (void *)SIBLING_EXIT_UNKILLED;
}
void tsync_start_sibling(struct tsync_sibling *sibling)
{
pthread_create(&sibling->tid, NULL, tsync_sibling, (void *)sibling);
}
TEST_F(TSYNC, siblings_fail_prctl)
{
long ret;
void *status;
struct sock_filter filter[] = {
BPF_STMT(BPF_LD|BPF_W|BPF_ABS,
offsetof(struct seccomp_data, nr)),
BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_prctl, 0, 1),
BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ERRNO | EINVAL),
BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW),
};
struct sock_fprog prog = {
.len = (unsigned short)ARRAY_SIZE(filter),
.filter = filter,
};
ASSERT_EQ(0, prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0)) {
TH_LOG("Kernel does not support PR_SET_NO_NEW_PRIVS!");
}
/* Check prctl failure detection by requesting sib 0 diverge. */
ret = seccomp(SECCOMP_SET_MODE_FILTER, 0, &prog);
ASSERT_NE(ENOSYS, errno) {
TH_LOG("Kernel does not support seccomp syscall!");
}
ASSERT_EQ(0, ret) {
TH_LOG("setting filter failed");
}
self->sibling[0].diverge = 1;
tsync_start_sibling(&self->sibling[0]);
tsync_start_sibling(&self->sibling[1]);
while (self->sibling_count < TSYNC_SIBLINGS) {
sem_wait(&self->started);
self->sibling_count++;
}
/* Signal the threads to clean up*/
pthread_mutex_lock(&self->mutex);
ASSERT_EQ(0, pthread_cond_broadcast(&self->cond)) {
TH_LOG("cond broadcast non-zero");
}
pthread_mutex_unlock(&self->mutex);
/* Ensure diverging sibling failed to call prctl. */
pthread_join(self->sibling[0].tid, &status);
EXPECT_EQ(SIBLING_EXIT_FAILURE, (long)status);
pthread_join(self->sibling[1].tid, &status);
EXPECT_EQ(SIBLING_EXIT_UNKILLED, (long)status);
}
TEST_F(TSYNC, two_siblings_with_ancestor)
{
long ret;
void *status;
ASSERT_EQ(0, prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0)) {
TH_LOG("Kernel does not support PR_SET_NO_NEW_PRIVS!");
}
ret = seccomp(SECCOMP_SET_MODE_FILTER, 0, &self->root_prog);
ASSERT_NE(ENOSYS, errno) {
TH_LOG("Kernel does not support seccomp syscall!");
}
ASSERT_EQ(0, ret) {
TH_LOG("Kernel does not support SECCOMP_SET_MODE_FILTER!");
}
tsync_start_sibling(&self->sibling[0]);
tsync_start_sibling(&self->sibling[1]);
while (self->sibling_count < TSYNC_SIBLINGS) {
sem_wait(&self->started);
self->sibling_count++;
}
ret = seccomp(SECCOMP_SET_MODE_FILTER, SECCOMP_FILTER_FLAG_TSYNC,
&self->apply_prog);
ASSERT_EQ(0, ret) {
TH_LOG("Could install filter on all threads!");
}
/* Tell the siblings to test the policy */
pthread_mutex_lock(&self->mutex);
ASSERT_EQ(0, pthread_cond_broadcast(&self->cond)) {
TH_LOG("cond broadcast non-zero");
}
pthread_mutex_unlock(&self->mutex);
/* Ensure they are both killed and don't exit cleanly. */
pthread_join(self->sibling[0].tid, &status);
EXPECT_EQ(0x0, (long)status);
pthread_join(self->sibling[1].tid, &status);
EXPECT_EQ(0x0, (long)status);
}
TEST_F(TSYNC, two_sibling_want_nnp)
{
void *status;
/* start siblings before any prctl() operations */
tsync_start_sibling(&self->sibling[0]);
tsync_start_sibling(&self->sibling[1]);
while (self->sibling_count < TSYNC_SIBLINGS) {
sem_wait(&self->started);
self->sibling_count++;
}
/* Tell the siblings to test no policy */
pthread_mutex_lock(&self->mutex);
ASSERT_EQ(0, pthread_cond_broadcast(&self->cond)) {
TH_LOG("cond broadcast non-zero");
}
pthread_mutex_unlock(&self->mutex);
/* Ensure they are both upset about lacking nnp. */
pthread_join(self->sibling[0].tid, &status);
EXPECT_EQ(SIBLING_EXIT_NEWPRIVS, (long)status);
pthread_join(self->sibling[1].tid, &status);
EXPECT_EQ(SIBLING_EXIT_NEWPRIVS, (long)status);
}
TEST_F(TSYNC, two_siblings_with_no_filter)
{
long ret;
void *status;
/* start siblings before any prctl() operations */
tsync_start_sibling(&self->sibling[0]);
tsync_start_sibling(&self->sibling[1]);
while (self->sibling_count < TSYNC_SIBLINGS) {
sem_wait(&self->started);
self->sibling_count++;
}
ASSERT_EQ(0, prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0)) {
TH_LOG("Kernel does not support PR_SET_NO_NEW_PRIVS!");
}
ret = seccomp(SECCOMP_SET_MODE_FILTER, SECCOMP_FILTER_FLAG_TSYNC,
&self->apply_prog);
ASSERT_NE(ENOSYS, errno) {
TH_LOG("Kernel does not support seccomp syscall!");
}
ASSERT_EQ(0, ret) {
TH_LOG("Could install filter on all threads!");
}
/* Tell the siblings to test the policy */
pthread_mutex_lock(&self->mutex);
ASSERT_EQ(0, pthread_cond_broadcast(&self->cond)) {
TH_LOG("cond broadcast non-zero");
}
pthread_mutex_unlock(&self->mutex);
/* Ensure they are both killed and don't exit cleanly. */
pthread_join(self->sibling[0].tid, &status);
EXPECT_EQ(0x0, (long)status);
pthread_join(self->sibling[1].tid, &status);
EXPECT_EQ(0x0, (long)status);
}
TEST_F(TSYNC, two_siblings_with_one_divergence)
{
long ret;
void *status;
ASSERT_EQ(0, prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0)) {
TH_LOG("Kernel does not support PR_SET_NO_NEW_PRIVS!");
}
ret = seccomp(SECCOMP_SET_MODE_FILTER, 0, &self->root_prog);
ASSERT_NE(ENOSYS, errno) {
TH_LOG("Kernel does not support seccomp syscall!");
}
ASSERT_EQ(0, ret) {
TH_LOG("Kernel does not support SECCOMP_SET_MODE_FILTER!");
}
self->sibling[0].diverge = 1;
tsync_start_sibling(&self->sibling[0]);
tsync_start_sibling(&self->sibling[1]);
while (self->sibling_count < TSYNC_SIBLINGS) {
sem_wait(&self->started);
self->sibling_count++;
}
ret = seccomp(SECCOMP_SET_MODE_FILTER, SECCOMP_FILTER_FLAG_TSYNC,
&self->apply_prog);
ASSERT_EQ(self->sibling[0].system_tid, ret) {
TH_LOG("Did not fail on diverged sibling.");
}
/* Wake the threads */
pthread_mutex_lock(&self->mutex);
ASSERT_EQ(0, pthread_cond_broadcast(&self->cond)) {
TH_LOG("cond broadcast non-zero");
}
pthread_mutex_unlock(&self->mutex);
/* Ensure they are both unkilled. */
pthread_join(self->sibling[0].tid, &status);
EXPECT_EQ(SIBLING_EXIT_UNKILLED, (long)status);
pthread_join(self->sibling[1].tid, &status);
EXPECT_EQ(SIBLING_EXIT_UNKILLED, (long)status);
}
TEST_F(TSYNC, two_siblings_not_under_filter)
{
long ret, sib;
void *status;
ASSERT_EQ(0, prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0)) {
TH_LOG("Kernel does not support PR_SET_NO_NEW_PRIVS!");
}
/*
* Sibling 0 will have its own seccomp policy
* and Sibling 1 will not be under seccomp at
* all. Sibling 1 will enter seccomp and 0
* will cause failure.
*/
self->sibling[0].diverge = 1;
tsync_start_sibling(&self->sibling[0]);
tsync_start_sibling(&self->sibling[1]);
while (self->sibling_count < TSYNC_SIBLINGS) {
sem_wait(&self->started);
self->sibling_count++;
}
ret = seccomp(SECCOMP_SET_MODE_FILTER, 0, &self->root_prog);
ASSERT_NE(ENOSYS, errno) {
TH_LOG("Kernel does not support seccomp syscall!");
}
ASSERT_EQ(0, ret) {
TH_LOG("Kernel does not support SECCOMP_SET_MODE_FILTER!");
}
ret = seccomp(SECCOMP_SET_MODE_FILTER, SECCOMP_FILTER_FLAG_TSYNC,
&self->apply_prog);
ASSERT_EQ(ret, self->sibling[0].system_tid) {
TH_LOG("Did not fail on diverged sibling.");
}
sib = 1;
if (ret == self->sibling[0].system_tid)
sib = 0;
pthread_mutex_lock(&self->mutex);
/* Increment the other siblings num_waits so we can clean up
* the one we just saw.
*/
self->sibling[!sib].num_waits += 1;
/* Signal the thread to clean up*/
ASSERT_EQ(0, pthread_cond_broadcast(&self->cond)) {
TH_LOG("cond broadcast non-zero");
}
pthread_mutex_unlock(&self->mutex);
pthread_join(self->sibling[sib].tid, &status);
EXPECT_EQ(SIBLING_EXIT_UNKILLED, (long)status);
/* Poll for actual task death. pthread_join doesn't guarantee it. */
while (!kill(self->sibling[sib].system_tid, 0))
sleep(0.1);
/* Switch to the remaining sibling */
sib = !sib;
ret = seccomp(SECCOMP_SET_MODE_FILTER, SECCOMP_FILTER_FLAG_TSYNC,
&self->apply_prog);
ASSERT_EQ(0, ret) {
TH_LOG("Expected the remaining sibling to sync");
};
pthread_mutex_lock(&self->mutex);
/* If remaining sibling didn't have a chance to wake up during
* the first broadcast, manually reduce the num_waits now.
*/
if (self->sibling[sib].num_waits > 1)
self->sibling[sib].num_waits = 1;
ASSERT_EQ(0, pthread_cond_broadcast(&self->cond)) {
TH_LOG("cond broadcast non-zero");
}
pthread_mutex_unlock(&self->mutex);
pthread_join(self->sibling[sib].tid, &status);
EXPECT_EQ(0, (long)status);
/* Poll for actual task death. pthread_join doesn't guarantee it. */
while (!kill(self->sibling[sib].system_tid, 0))
sleep(0.1);
ret = seccomp(SECCOMP_SET_MODE_FILTER, SECCOMP_FILTER_FLAG_TSYNC,
&self->apply_prog);
ASSERT_EQ(0, ret); /* just us chickens */
}
/* Make sure restarted syscalls are seen directly as "restart_syscall". */
TEST(syscall_restart)
{
long ret;
unsigned long msg;
pid_t child_pid;
int pipefd[2];
int status;
siginfo_t info = { };
struct sock_filter filter[] = {
BPF_STMT(BPF_LD|BPF_W|BPF_ABS,
offsetof(struct seccomp_data, nr)),
#ifdef __NR_sigreturn
BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_sigreturn, 6, 0),
#endif
BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_read, 5, 0),
BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_exit, 4, 0),
BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_rt_sigreturn, 3, 0),
BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_nanosleep, 4, 0),
BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_restart_syscall, 4, 0),
/* Allow __NR_write for easy logging. */
BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_write, 0, 1),
BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW),
BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_KILL),
/* The nanosleep jump target. */
BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_TRACE|0x100),
/* The restart_syscall jump target. */
BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_TRACE|0x200),
};
struct sock_fprog prog = {
.len = (unsigned short)ARRAY_SIZE(filter),
.filter = filter,
};
#if defined(__arm__)
struct utsname utsbuf;
#endif
ASSERT_EQ(0, pipe(pipefd));
child_pid = fork();
ASSERT_LE(0, child_pid);
if (child_pid == 0) {
/* Child uses EXPECT not ASSERT to deliver status correctly. */
char buf = ' ';
struct timespec timeout = { };
/* Attach parent as tracer and stop. */
EXPECT_EQ(0, ptrace(PTRACE_TRACEME));
EXPECT_EQ(0, raise(SIGSTOP));
EXPECT_EQ(0, close(pipefd[1]));
EXPECT_EQ(0, prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0)) {
TH_LOG("Kernel does not support PR_SET_NO_NEW_PRIVS!");
}
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog, 0, 0);
EXPECT_EQ(0, ret) {
TH_LOG("Failed to install filter!");
}
EXPECT_EQ(1, read(pipefd[0], &buf, 1)) {
TH_LOG("Failed to read() sync from parent");
}
EXPECT_EQ('.', buf) {
TH_LOG("Failed to get sync data from read()");
}
/* Start nanosleep to be interrupted. */
timeout.tv_sec = 1;
errno = 0;
EXPECT_EQ(0, nanosleep(&timeout, NULL)) {
TH_LOG("Call to nanosleep() failed (errno %d)", errno);
}
/* Read final sync from parent. */
EXPECT_EQ(1, read(pipefd[0], &buf, 1)) {
TH_LOG("Failed final read() from parent");
}
EXPECT_EQ('!', buf) {
TH_LOG("Failed to get final data from read()");
}
/* Directly report the status of our test harness results. */
syscall(__NR_exit, _metadata->passed ? EXIT_SUCCESS
: EXIT_FAILURE);
}
EXPECT_EQ(0, close(pipefd[0]));
/* Attach to child, setup options, and release. */
ASSERT_EQ(child_pid, waitpid(child_pid, &status, 0));
ASSERT_EQ(true, WIFSTOPPED(status));
ASSERT_EQ(0, ptrace(PTRACE_SETOPTIONS, child_pid, NULL,
PTRACE_O_TRACESECCOMP));
ASSERT_EQ(0, ptrace(PTRACE_CONT, child_pid, NULL, 0));
ASSERT_EQ(1, write(pipefd[1], ".", 1));
/* Wait for nanosleep() to start. */
ASSERT_EQ(child_pid, waitpid(child_pid, &status, 0));
ASSERT_EQ(true, WIFSTOPPED(status));
ASSERT_EQ(SIGTRAP, WSTOPSIG(status));
ASSERT_EQ(PTRACE_EVENT_SECCOMP, (status >> 16));
ASSERT_EQ(0, ptrace(PTRACE_GETEVENTMSG, child_pid, NULL, &msg));
ASSERT_EQ(0x100, msg);
EXPECT_EQ(__NR_nanosleep, get_syscall(_metadata, child_pid));
/* Might as well check siginfo for sanity while we're here. */
ASSERT_EQ(0, ptrace(PTRACE_GETSIGINFO, child_pid, NULL, &info));
ASSERT_EQ(SIGTRAP, info.si_signo);
ASSERT_EQ(SIGTRAP | (PTRACE_EVENT_SECCOMP << 8), info.si_code);
EXPECT_EQ(0, info.si_errno);
EXPECT_EQ(getuid(), info.si_uid);
/* Verify signal delivery came from child (seccomp-triggered). */
EXPECT_EQ(child_pid, info.si_pid);
/* Interrupt nanosleep with SIGSTOP (which we'll need to handle). */
ASSERT_EQ(0, kill(child_pid, SIGSTOP));
ASSERT_EQ(0, ptrace(PTRACE_CONT, child_pid, NULL, 0));
ASSERT_EQ(child_pid, waitpid(child_pid, &status, 0));
ASSERT_EQ(true, WIFSTOPPED(status));
ASSERT_EQ(SIGSTOP, WSTOPSIG(status));
/* Verify signal delivery came from parent now. */
ASSERT_EQ(0, ptrace(PTRACE_GETSIGINFO, child_pid, NULL, &info));
EXPECT_EQ(getpid(), info.si_pid);
/* Restart nanosleep with SIGCONT, which triggers restart_syscall. */
ASSERT_EQ(0, kill(child_pid, SIGCONT));
ASSERT_EQ(0, ptrace(PTRACE_CONT, child_pid, NULL, 0));
ASSERT_EQ(child_pid, waitpid(child_pid, &status, 0));
ASSERT_EQ(true, WIFSTOPPED(status));
ASSERT_EQ(SIGCONT, WSTOPSIG(status));
ASSERT_EQ(0, ptrace(PTRACE_CONT, child_pid, NULL, 0));
/* Wait for restart_syscall() to start. */
ASSERT_EQ(child_pid, waitpid(child_pid, &status, 0));
ASSERT_EQ(true, WIFSTOPPED(status));
ASSERT_EQ(SIGTRAP, WSTOPSIG(status));
ASSERT_EQ(PTRACE_EVENT_SECCOMP, (status >> 16));
ASSERT_EQ(0, ptrace(PTRACE_GETEVENTMSG, child_pid, NULL, &msg));
ASSERT_EQ(0x200, msg);
ret = get_syscall(_metadata, child_pid);
#if defined(__arm__)
/*
* FIXME:
* - native ARM registers do NOT expose true syscall.
* - compat ARM registers on ARM64 DO expose true syscall.
*/
ASSERT_EQ(0, uname(&utsbuf));
if (strncmp(utsbuf.machine, "arm", 3) == 0) {
EXPECT_EQ(__NR_nanosleep, ret);
} else
#endif
{
EXPECT_EQ(__NR_restart_syscall, ret);
}
/* Write again to end test. */
ASSERT_EQ(0, ptrace(PTRACE_CONT, child_pid, NULL, 0));
ASSERT_EQ(1, write(pipefd[1], "!", 1));
EXPECT_EQ(0, close(pipefd[1]));
ASSERT_EQ(child_pid, waitpid(child_pid, &status, 0));
if (WIFSIGNALED(status) || WEXITSTATUS(status))
_metadata->passed = 0;
}
/*
* TODO:
* - add microbenchmarks
* - expand NNP testing
* - better arch-specific TRACE and TRAP handlers.
* - endianness checking when appropriate
* - 64-bit arg prodding
* - arch value testing (x86 modes especially)
* - ...
*/
TEST_HARNESS_MAIN
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