// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (c) 2012 The Chromium OS Authors. All rights reserved.
 *
 * Test code for seccomp bpf.
 */

#define _GNU_SOURCE
#include <sys/types.h>

/*
 * glibc 2.26 and later have SIGSYS in siginfo_t. Before that,
 * we need to use the kernel's siginfo.h file and trick glibc
 * into accepting it.
 */
#if !__GLIBC_PREREQ(2, 26)
# include <asm/siginfo.h>
# define __have_siginfo_t 1
# define __have_sigval_t 1
# define __have_sigevent_t 1
#endif

#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 <limits.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>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <linux/kcmp.h>
#include <sys/resource.h>

#include <unistd.h>
#include <sys/syscall.h>
#include <poll.h>

#include "../kselftest_harness.h"
#include "../clone3/clone3_selftests.h"

/* Attempt to de-conflict with the selftests tree. */
#ifndef SKIP
#define SKIP(s, ...)    XFAIL(s, ##__VA_ARGS__)
#endif

#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_ALLOW
struct seccomp_data {
        int nr;
        __u32 arch;
        __u64 instruction_pointer;
        __u64 args[6];
};
#endif

#ifndef SECCOMP_RET_KILL_PROCESS
#define SECCOMP_RET_KILL_PROCESS 0x80000000U /* kill the process */
#define SECCOMP_RET_KILL_THREAD  0x00000000U /* kill the thread */
#endif
#ifndef SECCOMP_RET_KILL
#define SECCOMP_RET_KILL         SECCOMP_RET_KILL_THREAD
#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 */
#endif
#ifndef SECCOMP_RET_LOG
#define SECCOMP_RET_LOG          0x7ffc0000U /* allow after logging */
#endif

#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(__riscv)
#  define __NR_seccomp 277
# elif defined(__csky__)
#  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
# elif defined(__xtensa__)
#  define __NR_seccomp 337
# elif defined(__sh__)
#  define __NR_seccomp 372
# 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_GET_ACTION_AVAIL
#define SECCOMP_GET_ACTION_AVAIL 2
#endif

#ifndef SECCOMP_GET_NOTIF_SIZES
#define SECCOMP_GET_NOTIF_SIZES 3
#endif

#ifndef SECCOMP_FILTER_FLAG_TSYNC
#define SECCOMP_FILTER_FLAG_TSYNC (1UL << 0)
#endif

#ifndef SECCOMP_FILTER_FLAG_LOG
#define SECCOMP_FILTER_FLAG_LOG (1UL << 1)
#endif

#ifndef SECCOMP_FILTER_FLAG_SPEC_ALLOW
#define SECCOMP_FILTER_FLAG_SPEC_ALLOW (1UL << 2)
#endif

#ifndef PTRACE_SECCOMP_GET_METADATA
#define PTRACE_SECCOMP_GET_METADATA     0x420d

struct seccomp_metadata {
        __u64 filter_off;       /* Input: which filter */
        __u64 flags;             /* Output: filter's flags */
};
#endif

#ifndef SECCOMP_FILTER_FLAG_NEW_LISTENER
#define SECCOMP_FILTER_FLAG_NEW_LISTENER        (1UL << 3)
#endif

#ifndef SECCOMP_RET_USER_NOTIF
#define SECCOMP_RET_USER_NOTIF 0x7fc00000U

#define SECCOMP_IOC_MAGIC               '!'
#define SECCOMP_IO(nr)                  _IO(SECCOMP_IOC_MAGIC, nr)
#define SECCOMP_IOR(nr, type)           _IOR(SECCOMP_IOC_MAGIC, nr, type)
#define SECCOMP_IOW(nr, type)           _IOW(SECCOMP_IOC_MAGIC, nr, type)
#define SECCOMP_IOWR(nr, type)          _IOWR(SECCOMP_IOC_MAGIC, nr, type)

/* Flags for seccomp notification fd ioctl. */
#define SECCOMP_IOCTL_NOTIF_RECV        SECCOMP_IOWR(0, struct seccomp_notif)
#define SECCOMP_IOCTL_NOTIF_SEND        SECCOMP_IOWR(1, \
                                                struct seccomp_notif_resp)
#define SECCOMP_IOCTL_NOTIF_ID_VALID    SECCOMP_IOW(2, __u64)

struct seccomp_notif {
        __u64 id;
        __u32 pid;
        __u32 flags;
        struct seccomp_data data;
};

struct seccomp_notif_resp {
        __u64 id;
        __s64 val;
        __s32 error;
        __u32 flags;
};

struct seccomp_notif_sizes {
        __u16 seccomp_notif;
        __u16 seccomp_notif_resp;
        __u16 seccomp_data;
};
#endif

#ifndef SECCOMP_IOCTL_NOTIF_ADDFD
/* On success, the return value is the remote process's added fd number */
#define SECCOMP_IOCTL_NOTIF_ADDFD       SECCOMP_IOW(3,  \
                                                struct seccomp_notif_addfd)

/* valid flags for seccomp_notif_addfd */
#define SECCOMP_ADDFD_FLAG_SETFD        (1UL << 0) /* Specify remote fd */

struct seccomp_notif_addfd {
        __u64 id;
        __u32 flags;
        __u32 srcfd;
        __u32 newfd;
        __u32 newfd_flags;
};
#endif

struct seccomp_notif_addfd_small {
        __u64 id;
        char weird[4];
};
#define SECCOMP_IOCTL_NOTIF_ADDFD_SMALL \
        SECCOMP_IOW(3, struct seccomp_notif_addfd_small)

struct seccomp_notif_addfd_big {
        union {
                struct seccomp_notif_addfd addfd;
                char buf[sizeof(struct seccomp_notif_addfd) + 8];
        };
};
#define SECCOMP_IOCTL_NOTIF_ADDFD_BIG   \
        SECCOMP_IOWR(3, struct seccomp_notif_addfd_big)

#ifndef PTRACE_EVENTMSG_SYSCALL_ENTRY
#define PTRACE_EVENTMSG_SYSCALL_ENTRY   1
#define PTRACE_EVENTMSG_SYSCALL_EXIT    2
#endif

#ifndef SECCOMP_USER_NOTIF_FLAG_CONTINUE
#define SECCOMP_USER_NOTIF_FLAG_CONTINUE 0x00000001
#endif

#ifndef SECCOMP_FILTER_FLAG_TSYNC_ESRCH
#define SECCOMP_FILTER_FLAG_TSYNC_ESRCH (1UL << 4)
#endif

#ifndef seccomp
int seccomp(unsigned int op, unsigned int flags, void *args)
{
        errno = 0;
        return syscall(__NR_seccomp, op, flags, args);
}
#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

static int __filecmp(pid_t pid1, pid_t pid2, int fd1, int fd2)
{
#ifdef __NR_kcmp
        errno = 0;
        return syscall(__NR_kcmp, pid1, pid2, KCMP_FILE, fd1, fd2);
#else
        errno = ENOSYS;
        return -1;
#endif
}

/* Have TH_LOG report actual location filecmp() is used. */
#define filecmp(pid1, pid2, fd1, fd2)   ({              \
        int _ret;                                       \
                                                        \
        _ret = __filecmp(pid1, pid2, fd1, fd2);         \
        if (_ret != 0) {                                \
                if (_ret < 0 && errno == ENOSYS) {      \
                        TH_LOG("kcmp() syscall missing (test is less accurate)");\
                        _ret = 0;                       \
                }                                       \
        }                                               \
        _ret; })

TEST(kcmp)
{
        int ret;

        ret = __filecmp(getpid(), getpid(), 1, 1);
        EXPECT_EQ(ret, 0);
        if (ret != 0 && errno == ENOSYS)
                SKIP(return, "Kernel does not support kcmp() (missing CONFIG_CHECKPOINT_RESTORE?)");
}

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, 0);
}

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(log_all)
{
        struct sock_filter filter[] = {
                BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_LOG),
        };
        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);

        /* getppid() should succeed and be logged (no check for logging) */
        EXPECT_EQ(parent, syscall(__NR_getppid));
}

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);
}

/* This is a thread task to die via seccomp filter violation. */
void *kill_thread(void *data)
{
        bool die = (bool)data;

        if (die) {
                prctl(PR_GET_SECCOMP, 0, 0, 0, 0);
                return (void *)SIBLING_EXIT_FAILURE;
        }

        return (void *)SIBLING_EXIT_UNKILLED;
}

/* Prepare a thread that will kill itself or both of us. */
void kill_thread_or_group(struct __test_metadata *_metadata, bool kill_process)
{
        pthread_t thread;
        void *status;
        /* Kill only when calling __NR_prctl. */
        struct sock_filter filter_thread[] = {
                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_KILL_THREAD),
                BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW),
        };
        struct sock_fprog prog_thread = {
                .len = (unsigned short)ARRAY_SIZE(filter_thread),
                .filter = filter_thread,
        };
        struct sock_filter filter_process[] = {
                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_KILL_PROCESS),
                BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW),
        };
        struct sock_fprog prog_process = {
                .len = (unsigned short)ARRAY_SIZE(filter_process),
                .filter = filter_process,
        };

        ASSERT_EQ(0, prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0)) {
                TH_LOG("Kernel does not support PR_SET_NO_NEW_PRIVS!");
        }

        ASSERT_EQ(0, seccomp(SECCOMP_SET_MODE_FILTER, 0,
                             kill_process ? &prog_process : &prog_thread));

        /*
         * Add the KILL_THREAD rule again to make sure that the KILL_PROCESS
         * flag cannot be downgraded by a new filter.
         */
        ASSERT_EQ(0, seccomp(SECCOMP_SET_MODE_FILTER, 0, &prog_thread));

        /* Start a thread that will exit immediately. */
        ASSERT_EQ(0, pthread_create(&thread, NULL, kill_thread, (void *)false));
        ASSERT_EQ(0, pthread_join(thread, &status));
        ASSERT_EQ(SIBLING_EXIT_UNKILLED, (unsigned long)status);

        /* Start a thread that will die immediately. */
        ASSERT_EQ(0, pthread_create(&thread, NULL, kill_thread, (void *)true));
        ASSERT_EQ(0, pthread_join(thread, &status));
        ASSERT_NE(SIBLING_EXIT_FAILURE, (unsigned long)status);

        /*
         * If we get here, only the spawned thread died. Let the parent know
         * the whole process didn't die (i.e. this thread, the spawner,
         * stayed running).
         */
        exit(42);
}

TEST(KILL_thread)
{
        int status;
        pid_t child_pid;

        child_pid = fork();
        ASSERT_LE(0, child_pid);
        if (child_pid == 0) {
                kill_thread_or_group(_metadata, false);
                _exit(38);
        }

        ASSERT_EQ(child_pid, waitpid(child_pid, &status, 0));

        /* If only the thread was killed, we'll see exit 42. */
        ASSERT_TRUE(WIFEXITED(status));
        ASSERT_EQ(42, WEXITSTATUS(status));
}

TEST(KILL_process)
{
        int status;
        pid_t child_pid;

        child_pid = fork();
        ASSERT_LE(0, child_pid);
        if (child_pid == 0) {
                kill_thread_or_group(_metadata, true);
                _exit(38);
        }

        ASSERT_EQ(child_pid, waitpid(child_pid, &status, 0));

        /* If the entire process was killed, we'll see SIGSYS. */
        ASSERT_TRUE(WIFSIGNALED(status));
        ASSERT_EQ(SIGSYS, WTERMSIG(status));
}

/* 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);
}

#define ERRNO_FILTER(name, errno)                                       \
        struct sock_filter _read_filter_##name[] = {                    \
                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 | errno),     \
                BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW),             \
        };                                                              \
        struct sock_fprog prog_##name = {                               \
                .len = (unsigned short)ARRAY_SIZE(_read_filter_##name), \
                .filter = _read_filter_##name,                          \
        }

/* Make sure basic errno values are correctly passed through a filter. */
TEST(ERRNO_valid)
{
        ERRNO_FILTER(valid, E2BIG);
        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_valid);
        ASSERT_EQ(0, ret);

        EXPECT_EQ(parent, syscall(__NR_getppid));
        EXPECT_EQ(-1, read(0, NULL, 0));
        EXPECT_EQ(E2BIG, errno);
}

/* Make sure an errno of zero is correctly handled by the arch code. */
TEST(ERRNO_zero)
{
        ERRNO_FILTER(zero, 0);
        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_zero);
        ASSERT_EQ(0, ret);

        EXPECT_EQ(parent, syscall(__NR_getppid));
        /* "errno" of 0 is ok. */
        EXPECT_EQ(0, read(0, NULL, 0));
}

/*
 * The SECCOMP_RET_DATA mask is 16 bits wide, but errno is smaller.
 * This tests that the errno value gets capped correctly, fixed by
 * 580c57f10768 ("seccomp: cap SECCOMP_RET_ERRNO data to MAX_ERRNO").
 */
TEST(ERRNO_capped)
{
        ERRNO_FILTER(capped, 4096);
        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_capped);
        ASSERT_EQ(0, ret);

        EXPECT_EQ(parent, syscall(__NR_getppid));
        EXPECT_EQ(-1, read(0, NULL, 0));
        EXPECT_EQ(4095, errno);
}

/*
 * Filters are processed in reverse order: last applied is executed first.
 * Since only the SECCOMP_RET_ACTION mask is tested for return values, the
 * SECCOMP_RET_DATA mask results will follow the most recently applied
 * matching filter return (and not the lowest or highest value).
 */
TEST(ERRNO_order)
{
        ERRNO_FILTER(first,  11);
        ERRNO_FILTER(second, 13);
        ERRNO_FILTER(third,  12);
        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_first);
        ASSERT_EQ(0, ret);

        ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog_second);
        ASSERT_EQ(0, ret);

        ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog_third);
        ASSERT_EQ(0, ret);

        EXPECT_EQ(parent, syscall(__NR_getppid));
        EXPECT_EQ(-1, read(0, NULL, 0));
        EXPECT_EQ(12, errno);
}

FIXTURE(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 siginfo_t 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(precedence) {
        struct sock_fprog allow;
        struct sock_fprog log;
        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 log_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_LOG),
        };
        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(log);
        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(log);
        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->log);
        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->log);
        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->log);
        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->log);
        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->log);
        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->log);
        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->log);
        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->log);
        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);
        ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->log);
        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, log_is_fifth)
{
        pid_t mypid, parent;
        long ret;

        mypid = getpid();
        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->log);
        ASSERT_EQ(0, ret);
        /* Should work just fine. */
        EXPECT_EQ(parent, syscall(__NR_getppid));
        /* Should also work just fine */
        EXPECT_EQ(mypid, syscall(__NR_getpid));
}

TEST_F(precedence, log_is_fifth_in_any_order)
{
        pid_t mypid, parent;
        long ret;

        mypid = getpid();
        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->log);
        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));
        /* Should also work just fine */
        EXPECT_EQ(mypid, 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(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(__riscv) && __riscv_xlen == 64
# define ARCH_REGS      struct user_regs_struct
# define SYSCALL_NUM    a7
# define SYSCALL_RET    a0
#elif defined(__csky__)
# define ARCH_REGS      struct pt_regs
#if defined(__CSKYABIV2__)
# define SYSCALL_NUM    regs[3]
#else
# define SYSCALL_NUM    regs[9]
#endif
# define SYSCALL_RET    a0
#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]
# define SYSCALL_NUM_RET_SHARE_REG
#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
#elif defined(__xtensa__)
# define ARCH_REGS      struct user_pt_regs
# define SYSCALL_NUM    syscall
/*
 * On xtensa syscall return value is in the register
 * a2 of the current window which is not fixed.
 */
#define SYSCALL_RET(reg) a[(reg).windowbase * 4 + 2]
#elif defined(__sh__)
# define ARCH_REGS      struct pt_regs
# define SYSCALL_NUM    gpr[3]
# define SYSCALL_RET    gpr[0]
#else
# error "Do not know how to find your architecture's registers and syscalls"
#endif

/* When the syscall return can't be changed, stub out the tests for it. */
#ifdef SYSCALL_NUM_RET_SHARE_REG
# define EXPECT_SYSCALL_RETURN(val, action)     EXPECT_EQ(-1, action)
#else
# define EXPECT_SYSCALL_RETURN(val, action)             \
        do {                                            \
                errno = 0;                              \
                if (val < 0) {                          \
                        EXPECT_EQ(-1, action);          \
                        EXPECT_EQ(-(val), errno);       \
                } else {                                \
                        EXPECT_EQ(val, action);         \
                }                                       \
        } while (0)
#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 result)
{
        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__) || defined(__riscv) || \
        defined(__xtensa__) || defined(__csky__) || defined(__sh__)
        {
                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");

#elif defined(__xtensa__)
                regs.SYSCALL_RET(regs) = result;
#else
                regs.SYSCALL_RET = result;
#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_seccomp(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, 0);
                break;
        case 0x1003:
                /* skip gettid with valid return code. */
                EXPECT_EQ(__NR_gettid, get_syscall(_metadata, tracee));
                change_syscall(_metadata, tracee, -1, 45000);
                break;
        case 0x1004:
                /* skip openat with error. */
                EXPECT_EQ(__NR_openat, get_syscall(_metadata, tracee));
                change_syscall(_metadata, tracee, -1, -ESRCH);
                break;
        case 0x1005:
                /* 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;

        /*
         * The traditional way to tell PTRACE_SYSCALL entry/exit
         * is by counting.
         */
        entry = !entry;

        /* Make sure we got an appropriate message. */
        ret = ptrace(PTRACE_GETEVENTMSG, tracee, NULL, &msg);
        EXPECT_EQ(0, ret);
        EXPECT_EQ(entry ? PTRACE_EVENTMSG_SYSCALL_ENTRY
                        : PTRACE_EVENTMSG_SYSCALL_EXIT, msg);

        if (!entry)
                return;

        nr = get_syscall(_metadata, tracee);

        if (nr == __NR_getpid)
                change_syscall(_metadata, tracee, __NR_getppid, 0);
        if (nr == __NR_gettid)
                change_syscall(_metadata, tracee, -1, 45000);
        if (nr == __NR_openat)
                change_syscall(_metadata, tracee, -1, -ESRCH);
}

FIXTURE(TRACE_syscall) {
        struct sock_fprog prog;
        pid_t tracer, mytid, mypid, parent;
};

FIXTURE_VARIANT(TRACE_syscall) {
        /*
         * All of the SECCOMP_RET_TRACE behaviors can be tested with either
         * SECCOMP_RET_TRACE+PTRACE_CONT or plain ptrace()+PTRACE_SYSCALL.
         * This indicates if we should use SECCOMP_RET_TRACE (false), or
         * ptrace (true).
         */
        bool use_ptrace;
};

FIXTURE_VARIANT_ADD(TRACE_syscall, ptrace) {
        .use_ptrace = true,
};

FIXTURE_VARIANT_ADD(TRACE_syscall, seccomp) {
        .use_ptrace = false,
};

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_openat, 0, 1),
                BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_TRACE | 0x1004),
                BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_getppid, 0, 1),
                BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_TRACE | 0x1005),
                BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW),
        };
        struct sock_fprog prog = {
                .len = (unsigned short)ARRAY_SIZE(filter),
                .filter = filter,
        };
        long ret;

        /* 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,
                                           variant->use_ptrace ? tracer_ptrace
                                                               : tracer_seccomp,
                                           NULL, variant->use_ptrace);

        ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0);
        ASSERT_EQ(0, ret);

        if (variant->use_ptrace)

                return;

        ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog, 0, 0);
        ASSERT_EQ(0, ret);
}

FIXTURE_TEARDOWN(TRACE_syscall)
{
        teardown_trace_fixture(_metadata, self->tracer);
}

TEST(negative_ENOSYS)
{
        /*
         * There should be no difference between an "internal" skip
         * and userspace asking for syscall "-1".
         */
        errno = 0;
        EXPECT_EQ(-1, syscall(-1));
        EXPECT_EQ(errno, ENOSYS);
        /* And no difference for "still not valid but not -1". */
        errno = 0;
        EXPECT_EQ(-1, syscall(-101));
        EXPECT_EQ(errno, ENOSYS);
}

TEST_F(TRACE_syscall, negative_ENOSYS)
{
        negative_ENOSYS(_metadata);
}

TEST_F(TRACE_syscall, syscall_allowed)
{
        /* 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)
{
        /* 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_errno)
{
        /* Tracer should skip the open syscall, resulting in ESRCH. */
        EXPECT_SYSCALL_RETURN(-ESRCH, syscall(__NR_openat));
}

TEST_F(TRACE_syscall, syscall_faked)
{
        /* Tracer skips the gettid syscall and store altered return value. */
        EXPECT_SYSCALL_RETURN(45000, syscall(__NR_gettid));
}

TEST_F(TRACE_syscall, skip_after)
{
        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;

        /* Install additional "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. */
        errno = 0;
        EXPECT_EQ(-1, syscall(__NR_getpid));
        EXPECT_EQ(EPERM, errno);
}

TEST_F_SIGNAL(TRACE_syscall, kill_after, 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;

        /* Install additional "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(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 detection of known and unknown filter flags. Userspace needs to be able
 * to check if a filter flag is supported by the current kernel and a good way
 * of doing that is by attempting to enter filter mode, with the flag bit in
 * question set, and a NULL pointer for the _args_ parameter. EFAULT indicates
 * that the flag is valid and EINVAL indicates that the flag is invalid.
 */
TEST(detect_seccomp_filter_flags)
{
        unsigned int flags[] = { SECCOMP_FILTER_FLAG_TSYNC,
                                 SECCOMP_FILTER_FLAG_LOG,
                                 SECCOMP_FILTER_FLAG_SPEC_ALLOW,
                                 SECCOMP_FILTER_FLAG_NEW_LISTENER,
                                 SECCOMP_FILTER_FLAG_TSYNC_ESRCH };
        unsigned int exclusive[] = {
                                SECCOMP_FILTER_FLAG_TSYNC,
                                SECCOMP_FILTER_FLAG_NEW_LISTENER };
        unsigned int flag, all_flags, exclusive_mask;
        int i;
        long ret;

        /* Test detection of individual known-good filter flags */
        for (i = 0, all_flags = 0; i < ARRAY_SIZE(flags); i++) {
                int bits = 0;

                flag = flags[i];
                /* Make sure the flag is a single bit! */
                while (flag) {
                        if (flag & 0x1)
                                bits ++;
                        flag >>= 1;
                }
                ASSERT_EQ(1, bits);
                flag = flags[i];

                ret = seccomp(SECCOMP_SET_MODE_FILTER, flag, NULL);
                ASSERT_NE(ENOSYS, errno) {
                        TH_LOG("Kernel does not support seccomp syscall!");
                }
                EXPECT_EQ(-1, ret);
                EXPECT_EQ(EFAULT, errno) {
                        TH_LOG("Failed to detect that a known-good filter flag (0x%X) is supported!",
                               flag);
                }

                all_flags |= flag;
        }

        /*
         * Test detection of all known-good filter flags combined. But
         * for the exclusive flags we need to mask them out and try them
         * individually for the "all flags" testing.
         */
        exclusive_mask = 0;
        for (i = 0; i < ARRAY_SIZE(exclusive); i++)
                exclusive_mask |= exclusive[i];
        for (i = 0; i < ARRAY_SIZE(exclusive); i++) {
                flag = all_flags & ~exclusive_mask;
                flag |= exclusive[i];

                ret = seccomp(SECCOMP_SET_MODE_FILTER, flag, NULL);
                EXPECT_EQ(-1, ret);
                EXPECT_EQ(EFAULT, errno) {
                        TH_LOG("Failed to detect that all known-good filter flags (0x%X) are supported!",
                               flag);
                }
        }

        /* Test detection of an unknown filter flags, without exclusives. */
        flag = -1;
        flag &= ~exclusive_mask;
        ret = seccomp(SECCOMP_SET_MODE_FILTER, flag, NULL);
        EXPECT_EQ(-1, ret);
        EXPECT_EQ(EINVAL, errno) {
                TH_LOG("Failed to detect that an unknown filter flag (0x%X) is unsupported!",
                       flag);
        }

        /*
         * Test detection of an unknown filter flag that may simply need to be
         * added to this test
         */
        flag = flags[ARRAY_SIZE(flags) - 1] << 1;
        ret = seccomp(SECCOMP_SET_MODE_FILTER, flag, NULL);
        EXPECT_EQ(-1, ret);
        EXPECT_EQ(EINVAL, errno) {
                TH_LOG("Failed to detect that an unknown filter flag (0x%X) is unsupported! Does a new flag need to be added to this test?",
                       flag);
        }
}

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;
};

/*
 * To avoid joining joined threads (which is not allowed by Bionic),
 * make sure we both successfully join and clear the tid to skip a
 * later join attempt during fixture teardown. Any remaining threads
 * will be directly killed during teardown.
 */
#define PTHREAD_JOIN(tid, status)                                       \
        do {                                                            \
                int _rc = pthread_join(tid, status);                    \
                if (_rc) {                                              \
                        TH_LOG("pthread_join of tid %u failed: %d\n",   \
                                (unsigned int)tid, _rc);                \
                } else {                                                \
                        tid = 0;                                        \
                }                                                       \
        } while (0)

FIXTURE(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];

                if (!s->tid)
                        continue;
                /*
                 * If a thread is still running, it may be stuck, so hit
                 * it over the head really hard.
                 */
                pthread_kill(s->tid, 9);
        }
        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_with_one_divergence_no_tid_in_err)
{
        long ret, flags;
        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++;
        }

        flags = SECCOMP_FILTER_FLAG_TSYNC | \
                SECCOMP_FILTER_FLAG_TSYNC_ESRCH;
        ret = seccomp(SECCOMP_SET_MODE_FILTER, flags, &self->apply_prog);
        ASSERT_EQ(ESRCH, errno) {
                TH_LOG("Did not return ESRCH for diverged sibling.");
        }
        ASSERT_EQ(-1, 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;
        struct timespec delay = { .tv_nsec = 100000000 };

        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))
                nanosleep(&delay, NULL);
        /* 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))
                nanosleep(&delay, NULL);

        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, 7, 0),
#endif
                BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_read, 6, 0),
                BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_exit, 5, 0),
                BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_rt_sigreturn, 4, 0),
                BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_nanosleep, 5, 0),
                BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_clock_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);
        ret = get_syscall(_metadata, child_pid);
        EXPECT_TRUE(ret == __NR_nanosleep || ret == __NR_clock_nanosleep);

        /* 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));
        ASSERT_EQ(0, ptrace(PTRACE_GETSIGINFO, child_pid, NULL, &info));
        /*
         * There is no siginfo on SIGSTOP any more, so we can't verify
         * signal delivery came from parent now (getpid() == info.si_pid).
         * https://lkml.kernel.org/r/CAGXu5jJaZAOzP1qFz66tYrtbuywqb+UN2SOA1VLHpCCOiYvYeg@mail.gmail.com
         * At least verify the SIGSTOP via PTRACE_GETSIGINFO.
         */
        EXPECT_EQ(SIGSTOP, info.si_signo);

        /* 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;
}

TEST_SIGNAL(filter_flag_log, SIGSYS)
{
        struct sock_filter allow_filter[] = {
                BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW),
        };
        struct sock_filter kill_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 allow_prog = {
                .len = (unsigned short)ARRAY_SIZE(allow_filter),
                .filter = allow_filter,
        };
        struct sock_fprog kill_prog = {
                .len = (unsigned short)ARRAY_SIZE(kill_filter),
                .filter = kill_filter,
        };
        long ret;