// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2023 Meta Platforms, Inc. and affiliates. */
#define _GNU_SOURCE
#include <test_progs.h>
#include <bpf/btf.h>
#include "cap_helpers.h"
#include <fcntl.h>
#include <sched.h>
#include <signal.h>
#include <unistd.h>
#include <linux/filter.h>
#include <linux/unistd.h>
#include <linux/mount.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/syscall.h>
#include <sys/un.h>
#include "priv_map.skel.h"
#include "priv_prog.skel.h"
#include "dummy_st_ops_success.skel.h"
#include "token_lsm.skel.h"
#include "priv_freplace_prog.skel.h"

static inline int sys_mount(const char *dev_name, const char *dir_name,
                            const char *type, unsigned long flags,
                            const void *data)
{
        return syscall(__NR_mount, dev_name, dir_name, type, flags, data);
}

static inline int sys_fsopen(const char *fsname, unsigned flags)
{
        return syscall(__NR_fsopen, fsname, flags);
}

static inline int sys_fspick(int dfd, const char *path, unsigned flags)
{
        return syscall(__NR_fspick, dfd, path, flags);
}

static inline int sys_fsconfig(int fs_fd, unsigned cmd, const char *key, const void *val, int aux)
{
        return syscall(__NR_fsconfig, fs_fd, cmd, key, val, aux);
}

static inline int sys_fsmount(int fs_fd, unsigned flags, unsigned ms_flags)
{
        return syscall(__NR_fsmount, fs_fd, flags, ms_flags);
}

static inline int sys_move_mount(int from_dfd, const char *from_path,
                                 int to_dfd, const char *to_path,
                                 unsigned flags)
{
        return syscall(__NR_move_mount, from_dfd, from_path, to_dfd, to_path, flags);
}

static int drop_priv_caps(__u64 *old_caps)
{
        return cap_disable_effective((1ULL << CAP_BPF) |
                                     (1ULL << CAP_PERFMON) |
                                     (1ULL << CAP_NET_ADMIN) |
                                     (1ULL << CAP_SYS_ADMIN), old_caps);
}

static int restore_priv_caps(__u64 old_caps)
{
        return cap_enable_effective(old_caps, NULL);
}

static int set_delegate_mask(int fs_fd, const char *key, __u64 mask, const char *mask_str)
{
        char buf[32];
        int err;

        if (!mask_str) {
                if (mask == ~0ULL) {
                        mask_str = "any";
                } else {
                        snprintf(buf, sizeof(buf), "0x%llx", (unsigned long long)mask);
                        mask_str = buf;
                }
        }

        err = sys_fsconfig(fs_fd, FSCONFIG_SET_STRING, key,
                           mask_str, 0);
        if (err < 0)
                err = -errno;
        return err;
}

#define zclose(fd) do { if (fd >= 0) close(fd); fd = -1; } while (0)

struct bpffs_opts {
        __u64 cmds;
        __u64 maps;
        __u64 progs;
        __u64 attachs;
        const char *cmds_str;
        const char *maps_str;
        const char *progs_str;
        const char *attachs_str;
};

static int create_bpffs_fd(void)
{
        int fs_fd;

        /* create VFS context */
        fs_fd = sys_fsopen("bpf", 0);
        ASSERT_GE(fs_fd, 0, "fs_fd");

        return fs_fd;
}

static int materialize_bpffs_fd(int fs_fd, struct bpffs_opts *opts)
{
        int err;

        /* set up token delegation mount options */
        err = set_delegate_mask(fs_fd, "delegate_cmds", opts->cmds, opts->cmds_str);
        if (!ASSERT_OK(err, "fs_cfg_cmds"))
                return err;
        err = set_delegate_mask(fs_fd, "delegate_maps", opts->maps, opts->maps_str);
        if (!ASSERT_OK(err, "fs_cfg_maps"))
                return err;
        err = set_delegate_mask(fs_fd, "delegate_progs", opts->progs, opts->progs_str);
        if (!ASSERT_OK(err, "fs_cfg_progs"))
                return err;
        err = set_delegate_mask(fs_fd, "delegate_attachs", opts->attachs, opts->attachs_str);
        if (!ASSERT_OK(err, "fs_cfg_attachs"))
                return err;

        /* instantiate FS object */
        err = sys_fsconfig(fs_fd, FSCONFIG_CMD_CREATE, NULL, NULL, 0);
        if (err < 0)
                return -errno;

        return 0;
}

/* send FD over Unix domain (AF_UNIX) socket */
static int sendfd(int sockfd, int fd)
{
        struct msghdr msg = {};
        struct cmsghdr *cmsg;
        int fds[1] = { fd }, err;
        char iobuf[1];
        struct iovec io = {
                .iov_base = iobuf,
                .iov_len = sizeof(iobuf),
        };
        union {
                char buf[CMSG_SPACE(sizeof(fds))];
                struct cmsghdr align;
        } u;

        msg.msg_iov = &io;
        msg.msg_iovlen = 1;
        msg.msg_control = u.buf;
        msg.msg_controllen = sizeof(u.buf);
        cmsg = CMSG_FIRSTHDR(&msg);
        cmsg->cmsg_level = SOL_SOCKET;
        cmsg->cmsg_type = SCM_RIGHTS;
        cmsg->cmsg_len = CMSG_LEN(sizeof(fds));
        memcpy(CMSG_DATA(cmsg), fds, sizeof(fds));

        err = sendmsg(sockfd, &msg, 0);
        if (err < 0)
                err = -errno;
        if (!ASSERT_EQ(err, 1, "sendmsg"))
                return -EINVAL;

        return 0;
}

/* receive FD over Unix domain (AF_UNIX) socket */
static int recvfd(int sockfd, int *fd)
{
        struct msghdr msg = {};
        struct cmsghdr *cmsg;
        int fds[1], err;
        char iobuf[1];
        struct iovec io = {
                .iov_base = iobuf,
                .iov_len = sizeof(iobuf),
        };
        union {
                char buf[CMSG_SPACE(sizeof(fds))];
                struct cmsghdr align;
        } u;

        msg.msg_iov = &io;
        msg.msg_iovlen = 1;
        msg.msg_control = u.buf;
        msg.msg_controllen = sizeof(u.buf);

        err = recvmsg(sockfd, &msg, 0);
        if (err < 0)
                err = -errno;
        if (!ASSERT_EQ(err, 1, "recvmsg"))
                return -EINVAL;

        cmsg = CMSG_FIRSTHDR(&msg);
        if (!ASSERT_OK_PTR(cmsg, "cmsg_null") ||
            !ASSERT_EQ(cmsg->cmsg_len, CMSG_LEN(sizeof(fds)), "cmsg_len") ||
            !ASSERT_EQ(cmsg->cmsg_level, SOL_SOCKET, "cmsg_level") ||
            !ASSERT_EQ(cmsg->cmsg_type, SCM_RIGHTS, "cmsg_type"))
                return -EINVAL;

        memcpy(fds, CMSG_DATA(cmsg), sizeof(fds));
        *fd = fds[0];

        return 0;
}

static ssize_t write_nointr(int fd, const void *buf, size_t count)
{
        ssize_t ret;

        do {
                ret = write(fd, buf, count);
        } while (ret < 0 && errno == EINTR);

        return ret;
}

static int write_file(const char *path, const void *buf, size_t count)
{
        int fd;
        ssize_t ret;

        fd = open(path, O_WRONLY | O_CLOEXEC | O_NOCTTY | O_NOFOLLOW);
        if (fd < 0)
                return -1;

        ret = write_nointr(fd, buf, count);
        close(fd);
        if (ret < 0 || (size_t)ret != count)
                return -1;

        return 0;
}

static int create_and_enter_userns(void)
{
        uid_t uid;
        gid_t gid;
        char map[100];

        uid = getuid();
        gid = getgid();

        if (unshare(CLONE_NEWUSER))
                return -1;

        if (write_file("/proc/self/setgroups", "deny", sizeof("deny") - 1) &&
            errno != ENOENT)
                return -1;

        snprintf(map, sizeof(map), "0 %d 1", uid);
        if (write_file("/proc/self/uid_map", map, strlen(map)))
                return -1;


        snprintf(map, sizeof(map), "0 %d 1", gid);
        if (write_file("/proc/self/gid_map", map, strlen(map)))
                return -1;

        if (setgid(0))
                return -1;

        if (setuid(0))
                return -1;

        return 0;
}

typedef int (*child_callback_fn)(int bpffs_fd, struct token_lsm *lsm_skel);

static void child(int sock_fd, struct bpffs_opts *opts, child_callback_fn callback)
{
        int mnt_fd = -1, fs_fd = -1, err = 0, bpffs_fd = -1, token_fd = -1;
        struct token_lsm *lsm_skel = NULL;
        char one;

        /* load and attach LSM "policy" before we go into unpriv userns */
        lsm_skel = token_lsm__open_and_load();
        if (!ASSERT_OK_PTR(lsm_skel, "lsm_skel_load")) {
                err = -EINVAL;
                goto cleanup;
        }
        lsm_skel->bss->my_pid = getpid();
        err = token_lsm__attach(lsm_skel);
        if (!ASSERT_OK(err, "lsm_skel_attach"))
                goto cleanup;

        /* setup userns with root mappings */
        err = create_and_enter_userns();
        if (!ASSERT_OK(err, "create_and_enter_userns"))
                goto cleanup;

        /* setup mountns to allow creating BPF FS (fsopen("bpf")) from unpriv process */
        err = unshare(CLONE_NEWNS);
        if (!ASSERT_OK(err, "create_mountns"))
                goto cleanup;

        err = sys_mount(NULL, "/", NULL, MS_REC | MS_PRIVATE, 0);
        if (!ASSERT_OK(err, "remount_root"))
                goto cleanup;

        fs_fd = create_bpffs_fd();
        if (!ASSERT_GE(fs_fd, 0, "create_bpffs_fd")) {
                err = -EINVAL;
                goto cleanup;
        }

        /* ensure unprivileged child cannot set delegation options */
        err = set_delegate_mask(fs_fd, "delegate_cmds", 0x1, NULL);
        ASSERT_EQ(err, -EPERM, "delegate_cmd_eperm");
        err = set_delegate_mask(fs_fd, "delegate_maps", 0x1, NULL);
        ASSERT_EQ(err, -EPERM, "delegate_maps_eperm");
        err = set_delegate_mask(fs_fd, "delegate_progs", 0x1, NULL);
        ASSERT_EQ(err, -EPERM, "delegate_progs_eperm");
        err = set_delegate_mask(fs_fd, "delegate_attachs", 0x1, NULL);
        ASSERT_EQ(err, -EPERM, "delegate_attachs_eperm");

        /* pass BPF FS context object to parent */
        err = sendfd(sock_fd, fs_fd);
        if (!ASSERT_OK(err, "send_fs_fd"))
                goto cleanup;

        /* wait that the parent reads the fd, does the fsconfig() calls
         * and send us a signal that it is done
         */
        err = read(sock_fd, &one, sizeof(one));
        if (!ASSERT_GE(err, 0, "read_one"))
                goto cleanup;

        /* avoid mucking around with mount namespaces and mounting at
         * well-known path, just create O_PATH fd for detached mount
         */
        mnt_fd = sys_fsmount(fs_fd, 0, 0);
        if (!ASSERT_OK_FD(mnt_fd, "mnt_fd"))
                goto cleanup;

        /* try to fspick() BPF FS and try to add some delegation options */
        fs_fd = sys_fspick(mnt_fd, "", FSPICK_EMPTY_PATH);
        if (!ASSERT_GE(fs_fd, 0, "bpffs_fspick")) {
                err = -EINVAL;
                goto cleanup;
        }

        /* ensure unprivileged child cannot reconfigure to set delegation options */
        err = set_delegate_mask(fs_fd, "delegate_cmds", 0, "any");
        if (!ASSERT_EQ(err, -EPERM, "delegate_cmd_eperm_reconfig")) {
                err = -EINVAL;
                goto cleanup;
        }
        err = set_delegate_mask(fs_fd, "delegate_maps", 0, "any");
        if (!ASSERT_EQ(err, -EPERM, "delegate_maps_eperm_reconfig")) {
                err = -EINVAL;
                goto cleanup;
        }
        err = set_delegate_mask(fs_fd, "delegate_progs", 0, "any");
        if (!ASSERT_EQ(err, -EPERM, "delegate_progs_eperm_reconfig")) {
                err = -EINVAL;
                goto cleanup;
        }
        err = set_delegate_mask(fs_fd, "delegate_attachs", 0, "any");
        if (!ASSERT_EQ(err, -EPERM, "delegate_attachs_eperm_reconfig")) {
                err = -EINVAL;
                goto cleanup;
        }
        zclose(fs_fd);

        bpffs_fd = openat(mnt_fd, ".", 0, O_RDWR);
        if (!ASSERT_GE(bpffs_fd, 0, "bpffs_open")) {
                err = -EINVAL;
                goto cleanup;
        }

        /* create BPF token FD and pass it to parent for some extra checks */
        token_fd = bpf_token_create(bpffs_fd, NULL);
        if (!ASSERT_GT(token_fd, 0, "child_token_create")) {
                err = -EINVAL;
                goto cleanup;
        }
        err = sendfd(sock_fd, token_fd);
        if (!ASSERT_OK(err, "send_token_fd"))
                goto cleanup;
        zclose(token_fd);

        /* do custom test logic with customly set up BPF FS instance */
        err = callback(bpffs_fd, lsm_skel);
        if (!ASSERT_OK(err, "test_callback"))
                goto cleanup;

        err = 0;
cleanup:
        zclose(sock_fd);
        zclose(mnt_fd);
        zclose(fs_fd);
        zclose(bpffs_fd);
        zclose(token_fd);

        lsm_skel->bss->my_pid = 0;
        token_lsm__destroy(lsm_skel);

        exit(-err);
}

static int wait_for_pid(pid_t pid)
{
        int status, ret;

again:
        ret = waitpid(pid, &status, 0);
        if (ret == -1) {
                if (errno == EINTR)
                        goto again;

                return -1;
        }

        if (!WIFEXITED(status))
                return -1;

        return WEXITSTATUS(status);
}

static void parent(int child_pid, struct bpffs_opts *bpffs_opts, int sock_fd)
{
        int fs_fd = -1, token_fd = -1, err;
        char one = 1;

        err = recvfd(sock_fd, &fs_fd);
        if (!ASSERT_OK(err, "recv_bpffs_fd"))
                goto cleanup;

        err = materialize_bpffs_fd(fs_fd, bpffs_opts);
        if (!ASSERT_GE(err, 0, "materialize_bpffs_fd")) {
                err = -EINVAL;
                goto cleanup;
        }

        /* notify the child that we did the fsconfig() calls and it can proceed. */
        err = write(sock_fd, &one, sizeof(one));
        if (!ASSERT_EQ(err, sizeof(one), "send_one"))
                goto cleanup;
        zclose(fs_fd);

        /* receive BPF token FD back from child for some extra tests */
        err = recvfd(sock_fd, &token_fd);
        if (!ASSERT_OK(err, "recv_token_fd"))
                goto cleanup;

        err = wait_for_pid(child_pid);
        ASSERT_OK(err, "waitpid_child");

cleanup:
        zclose(sock_fd);
        zclose(fs_fd);
        zclose(token_fd);

        if (child_pid > 0)
                (void)kill(child_pid, SIGKILL);
}

static void subtest_userns(struct bpffs_opts *bpffs_opts,
                           child_callback_fn child_cb)
{
        int sock_fds[2] = { -1, -1 };
        int child_pid = 0, err;

        err = socketpair(AF_UNIX, SOCK_STREAM, 0, sock_fds);
        if (!ASSERT_OK(err, "socketpair"))
                goto cleanup;

        child_pid = fork();
        if (!ASSERT_GE(child_pid, 0, "fork"))
                goto cleanup;

        if (child_pid == 0) {
                zclose(sock_fds[0]);
                return child(sock_fds[1], bpffs_opts, child_cb);

        } else {
                zclose(sock_fds[1]);
                return parent(child_pid, bpffs_opts, sock_fds[0]);
        }

cleanup:
        zclose(sock_fds[0]);
        zclose(sock_fds[1]);
        if (child_pid > 0)
                (void)kill(child_pid, SIGKILL);
}

static int userns_map_create(int mnt_fd, struct token_lsm *lsm_skel)
{
        LIBBPF_OPTS(bpf_map_create_opts, map_opts);
        int err, token_fd = -1, map_fd = -1;
        __u64 old_caps = 0;

        /* create BPF token from BPF FS mount */
        token_fd = bpf_token_create(mnt_fd, NULL);
        if (!ASSERT_GT(token_fd, 0, "token_create")) {
                err = -EINVAL;
                goto cleanup;
        }

        /* while inside non-init userns, we need both a BPF token *and*
         * CAP_BPF inside current userns to create privileged map; let's test
         * that neither BPF token alone nor namespaced CAP_BPF is sufficient
         */
        err = drop_priv_caps(&old_caps);
        if (!ASSERT_OK(err, "drop_caps"))
                goto cleanup;

        /* no token, no CAP_BPF -> fail */
        map_opts.map_flags = 0;
        map_opts.token_fd = 0;
        map_fd = bpf_map_create(BPF_MAP_TYPE_STACK, "wo_token_wo_bpf", 0, 8, 1, &map_opts);
        if (!ASSERT_LT(map_fd, 0, "stack_map_wo_token_wo_cap_bpf_should_fail")) {
                err = -EINVAL;
                goto cleanup;
        }

        /* token without CAP_BPF -> fail */
        map_opts.map_flags = BPF_F_TOKEN_FD;
        map_opts.token_fd = token_fd;
        map_fd = bpf_map_create(BPF_MAP_TYPE_STACK, "w_token_wo_bpf", 0, 8, 1, &map_opts);
        if (!ASSERT_LT(map_fd, 0, "stack_map_w_token_wo_cap_bpf_should_fail")) {
                err = -EINVAL;
                goto cleanup;
        }

        /* get back effective local CAP_BPF (and CAP_SYS_ADMIN) */
        err = restore_priv_caps(old_caps);
        if (!ASSERT_OK(err, "restore_caps"))
                goto cleanup;

        /* CAP_BPF without token -> fail */
        map_opts.map_flags = 0;
        map_opts.token_fd = 0;
        map_fd = bpf_map_create(BPF_MAP_TYPE_STACK, "wo_token_w_bpf", 0, 8, 1, &map_opts);
        if (!ASSERT_LT(map_fd, 0, "stack_map_wo_token_w_cap_bpf_should_fail")) {
                err = -EINVAL;
                goto cleanup;
        }

        /* finally, namespaced CAP_BPF + token -> success */
        map_opts.map_flags = BPF_F_TOKEN_FD;
        map_opts.token_fd = token_fd;
        map_fd = bpf_map_create(BPF_MAP_TYPE_STACK, "w_token_w_bpf", 0, 8, 1, &map_opts);
        if (!ASSERT_GT(map_fd, 0, "stack_map_w_token_w_cap_bpf")) {
                err = -EINVAL;
                goto cleanup;
        }

cleanup:
        zclose(token_fd);
        zclose(map_fd);
        return err;
}

static int userns_btf_load(int mnt_fd, struct token_lsm *lsm_skel)
{
        LIBBPF_OPTS(bpf_btf_load_opts, btf_opts);
        int err, token_fd = -1, btf_fd = -1;
        const void *raw_btf_data;
        struct btf *btf = NULL;
        __u32 raw_btf_size;
        __u64 old_caps = 0;

        /* create BPF token from BPF FS mount */
        token_fd = bpf_token_create(mnt_fd, NULL);
        if (!ASSERT_GT(token_fd, 0, "token_create")) {
                err = -EINVAL;
                goto cleanup;
        }

        /* while inside non-init userns, we need both a BPF token *and*
         * CAP_BPF inside current userns to create privileged map; let's test
         * that neither BPF token alone nor namespaced CAP_BPF is sufficient
         */
        err = drop_priv_caps(&old_caps);
        if (!ASSERT_OK(err, "drop_caps"))
                goto cleanup;

        /* setup a trivial BTF data to load to the kernel */
        btf = btf__new_empty();
        if (!ASSERT_OK_PTR(btf, "empty_btf"))
                goto cleanup;

        ASSERT_GT(btf__add_int(btf, "int", 4, 0), 0, "int_type");

        raw_btf_data = btf__raw_data(btf, &raw_btf_size);
        if (!ASSERT_OK_PTR(raw_btf_data, "raw_btf_data"))
                goto cleanup;

        /* no token + no CAP_BPF -> failure */
        btf_opts.btf_flags = 0;
        btf_opts.token_fd = 0;
        btf_fd = bpf_btf_load(raw_btf_data, raw_btf_size, &btf_opts);
        if (!ASSERT_LT(btf_fd, 0, "no_token_no_cap_should_fail"))
                goto cleanup;

        /* token + no CAP_BPF -> failure */
        btf_opts.btf_flags = BPF_F_TOKEN_FD;
        btf_opts.token_fd = token_fd;
        btf_fd = bpf_btf_load(raw_btf_data, raw_btf_size, &btf_opts);
        if (!ASSERT_LT(btf_fd, 0, "token_no_cap_should_fail"))
                goto cleanup;

        /* get back effective local CAP_BPF (and CAP_SYS_ADMIN) */
        err = restore_priv_caps(old_caps);
        if (!ASSERT_OK(err, "restore_caps"))
                goto cleanup;

        /* token + CAP_BPF -> success */
        btf_opts.btf_flags = BPF_F_TOKEN_FD;
        btf_opts.token_fd = token_fd;
        btf_fd = bpf_btf_load(raw_btf_data, raw_btf_size, &btf_opts);
        if (!ASSERT_GT(btf_fd, 0, "token_and_cap_success"))
                goto cleanup;

        err = 0;
cleanup:
        btf__free(btf);
        zclose(btf_fd);
        zclose(token_fd);
        return err;
}

static int userns_prog_load(int mnt_fd, struct token_lsm *lsm_skel)
{
        LIBBPF_OPTS(bpf_prog_load_opts, prog_opts);
        int err, token_fd = -1, prog_fd = -1;
        struct bpf_insn insns[] = {
                /* bpf_jiffies64() requires CAP_BPF */
                BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_jiffies64),
                /* bpf_get_current_task() requires CAP_PERFMON */
                BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_get_current_task),
                /* r0 = 0; exit; */
                BPF_MOV64_IMM(BPF_REG_0, 0),
                BPF_EXIT_INSN(),
        };
        size_t insn_cnt = ARRAY_SIZE(insns);
        __u64 old_caps = 0;

        /* create BPF token from BPF FS mount */
        token_fd = bpf_token_create(mnt_fd, NULL);
        if (!ASSERT_GT(token_fd, 0, "token_create")) {
                err = -EINVAL;
                goto cleanup;
        }

        /* validate we can successfully load BPF program with token; this
         * being XDP program (CAP_NET_ADMIN) using bpf_jiffies64() (CAP_BPF)
         * and bpf_get_current_task() (CAP_PERFMON) helpers validates we have
         * BPF token wired properly in a bunch of places in the kernel
         */
        prog_opts.prog_flags = BPF_F_TOKEN_FD;
        prog_opts.token_fd = token_fd;
        prog_opts.expected_attach_type = BPF_XDP;
        prog_fd = bpf_prog_load(BPF_PROG_TYPE_XDP, "token_prog", "GPL",
                                insns, insn_cnt, &prog_opts);
        if (!ASSERT_GT(prog_fd, 0, "prog_fd")) {
                err = -EPERM;
                goto cleanup;
        }

        /* no token + caps -> failure */
        prog_opts.prog_flags = 0;
        prog_opts.token_fd = 0;
        prog_fd = bpf_prog_load(BPF_PROG_TYPE_XDP, "token_prog", "GPL",
                                insns, insn_cnt, &prog_opts);
        if (!ASSERT_EQ(prog_fd, -EPERM, "prog_fd_eperm")) {
                err = -EPERM;
                goto cleanup;
        }

        err = drop_priv_caps(&old_caps);
        if (!ASSERT_OK(err, "drop_caps"))
                goto cleanup;

        /* no caps + token -> failure */
        prog_opts.prog_flags = BPF_F_TOKEN_FD;
        prog_opts.token_fd = token_fd;
        prog_fd = bpf_prog_load(BPF_PROG_TYPE_XDP, "token_prog", "GPL",
                                insns, insn_cnt, &prog_opts);
        if (!ASSERT_EQ(prog_fd, -EPERM, "prog_fd_eperm")) {
                err = -EPERM;
                goto cleanup;
        }

        /* no caps + no token -> definitely a failure */
        prog_opts.prog_flags = 0;
        prog_opts.token_fd = 0;
        prog_fd = bpf_prog_load(BPF_PROG_TYPE_XDP, "token_prog", "GPL",
                                insns, insn_cnt, &prog_opts);
        if (!ASSERT_EQ(prog_fd, -EPERM, "prog_fd_eperm")) {
                err = -EPERM;
                goto cleanup;
        }

        err = 0;
cleanup:
        zclose(prog_fd);
        zclose(token_fd);
        return err;
}

static int userns_obj_priv_map(int mnt_fd, struct token_lsm *lsm_skel)
{
        LIBBPF_OPTS(bpf_object_open_opts, opts);
        char buf[256];
        struct priv_map *skel;
        int err;

        skel = priv_map__open_and_load();
        if (!ASSERT_ERR_PTR(skel, "obj_tokenless_load")) {
                priv_map__destroy(skel);
                return -EINVAL;
        }

        /* use bpf_token_path to provide BPF FS path */
        snprintf(buf, sizeof(buf), "/proc/self/fd/%d", mnt_fd);
        opts.bpf_token_path = buf;
        skel = priv_map__open_opts(&opts);
        if (!ASSERT_OK_PTR(skel, "obj_token_path_open"))
                return -EINVAL;

        err = priv_map__load(skel);
        priv_map__destroy(skel);
        if (!ASSERT_OK(err, "obj_token_path_load"))
                return -EINVAL;

        return 0;
}

static int userns_obj_priv_prog(int mnt_fd, struct token_lsm *lsm_skel)
{
        LIBBPF_OPTS(bpf_object_open_opts, opts);
        char buf[256];
        struct priv_prog *skel;
        int err;

        skel = priv_prog__open_and_load();
        if (!ASSERT_ERR_PTR(skel, "obj_tokenless_load")) {
                priv_prog__destroy(skel);
                return -EINVAL;
        }

        /* use bpf_token_path to provide BPF FS path */
        snprintf(buf, sizeof(buf), "/proc/self/fd/%d", mnt_fd);
        opts.bpf_token_path = buf;
        skel = priv_prog__open_opts(&opts);
        if (!ASSERT_OK_PTR(skel, "obj_token_path_open"))
                return -EINVAL;
        err = priv_prog__load(skel);
        priv_prog__destroy(skel);
        if (!ASSERT_OK(err, "obj_token_path_load"))
                return -EINVAL;

        /* provide BPF token, but reject bpf_token_capable() with LSM */
        lsm_skel->bss->reject_capable = true;
        lsm_skel->bss->reject_cmd = false;
        skel = priv_prog__open_opts(&opts);
        if (!ASSERT_OK_PTR(skel, "obj_token_lsm_reject_cap_open"))
                return -EINVAL;
        err = priv_prog__load(skel);
        priv_prog__destroy(skel);
        if (!ASSERT_ERR(err, "obj_token_lsm_reject_cap_load"))
                return -EINVAL;

        /* provide BPF token, but reject bpf_token_cmd() with LSM */
        lsm_skel->bss->reject_capable = false;
        lsm_skel->bss->reject_cmd = true;
        skel = priv_prog__open_opts(&opts);
        if (!ASSERT_OK_PTR(skel, "obj_token_lsm_reject_cmd_open"))
                return -EINVAL;
        err = priv_prog__load(skel);
        priv_prog__destroy(skel);
        if (!ASSERT_ERR(err, "obj_token_lsm_reject_cmd_load"))
                return -EINVAL;

        return 0;
}

static int userns_obj_priv_freplace_setup(int mnt_fd, struct priv_freplace_prog **fr_skel,
                                          struct priv_prog **skel, int *tgt_fd)
{
        LIBBPF_OPTS(bpf_object_open_opts, opts);
        int err;
        char buf[256];

        /* use bpf_token_path to provide BPF FS path */
        snprintf(buf, sizeof(buf), "/proc/self/fd/%d", mnt_fd);
        opts.bpf_token_path = buf;
        *skel = priv_prog__open_opts(&opts);
        if (!ASSERT_OK_PTR(*skel, "priv_prog__open_opts"))
                return -EINVAL;
        err = priv_prog__load(*skel);
        if (!ASSERT_OK(err, "priv_prog__load"))
                return -EINVAL;

        *fr_skel = priv_freplace_prog__open_opts(&opts);
        if (!ASSERT_OK_PTR(*skel, "priv_freplace_prog__open_opts"))
                return -EINVAL;

        *tgt_fd = bpf_program__fd((*skel)->progs.xdp_prog1);
        return 0;
}

/* Verify that freplace works from user namespace, because bpf token is loaded
 * in bpf_object__prepare
 */
static int userns_obj_priv_freplace_prog(int mnt_fd, struct token_lsm *lsm_skel)
{
        struct priv_freplace_prog *fr_skel = NULL;
        struct priv_prog *skel = NULL;
        int err, tgt_fd;

        err = userns_obj_priv_freplace_setup(mnt_fd, &fr_skel, &skel, &tgt_fd);
        if (!ASSERT_OK(err, "setup"))
                goto out;

        err = bpf_object__prepare(fr_skel->obj);
        if (!ASSERT_OK(err, "freplace__prepare"))
                goto out;

        err = bpf_program__set_attach_target(fr_skel->progs.new_xdp_prog2, tgt_fd, "xdp_prog1");
        if (!ASSERT_OK(err, "set_attach_target"))
                goto out;

        err = priv_freplace_prog__load(fr_skel);
        ASSERT_OK(err, "priv_freplace_prog__load");

out:
        priv_freplace_prog__destroy(fr_skel);
        priv_prog__destroy(skel);
        return err;
}

/* Verify that replace fails to set attach target from user namespace without bpf token */
static int userns_obj_priv_freplace_prog_fail(int mnt_fd, struct token_lsm *lsm_skel)
{
        struct priv_freplace_prog *fr_skel = NULL;
        struct priv_prog *skel = NULL;
        int err, tgt_fd;

        err = userns_obj_priv_freplace_setup(mnt_fd, &fr_skel, &skel, &tgt_fd);
        if (!ASSERT_OK(err, "setup"))
                goto out;

        err = bpf_program__set_attach_target(fr_skel->progs.new_xdp_prog2, tgt_fd, "xdp_prog1");
        if (ASSERT_ERR(err, "attach fails"))
                err = 0;
        else
                err = -EINVAL;

out:
        priv_freplace_prog__destroy(fr_skel);
        priv_prog__destroy(skel);
        return err;
}

/* this test is called with BPF FS that doesn't delegate BPF_BTF_LOAD command,
 * which should cause struct_ops application to fail, as BTF won't be uploaded
 * into the kernel, even if STRUCT_OPS programs themselves are allowed
 */
static int validate_struct_ops_load(int mnt_fd, bool expect_success)
{
        LIBBPF_OPTS(bpf_object_open_opts, opts);
        char buf[256];
        struct dummy_st_ops_success *skel;
        int err;

        snprintf(buf, sizeof(buf), "/proc/self/fd/%d", mnt_fd);
        opts.bpf_token_path = buf;
        skel = dummy_st_ops_success__open_opts(&opts);
        if (!ASSERT_OK_PTR(skel, "obj_token_path_open"))
                return -EINVAL;

        err = dummy_st_ops_success__load(skel);
        dummy_st_ops_success__destroy(skel);
        if (expect_success) {
                if (!ASSERT_OK(err, "obj_token_path_load"))
                        return -EINVAL;
        } else /* expect failure */ {
                if (!ASSERT_ERR(err, "obj_token_path_load"))
                        return -EINVAL;
        }

        return 0;
}

static int userns_obj_priv_btf_fail(int mnt_fd, struct token_lsm *lsm_skel)
{
        return validate_struct_ops_load(mnt_fd, false /* should fail */);
}

static int userns_obj_priv_btf_success(int mnt_fd, struct token_lsm *lsm_skel)
{
        return validate_struct_ops_load(mnt_fd, true /* should succeed */);
}

static const char *token_bpffs_custom_dir()
{
        return getenv("BPF_SELFTESTS_BPF_TOKEN_DIR") ?: "/tmp/bpf-token-fs";
}

#define TOKEN_ENVVAR "LIBBPF_BPF_TOKEN_PATH"

static int userns_obj_priv_implicit_token(int mnt_fd, struct token_lsm *lsm_skel)
{
        LIBBPF_OPTS(bpf_object_open_opts, opts);
        struct dummy_st_ops_success *skel;
        int err;

        /* before we mount BPF FS with token delegation, struct_ops skeleton
         * should fail to load
         */
        skel = dummy_st_ops_success__open_and_load();
        if (!ASSERT_ERR_PTR(skel, "obj_tokenless_load")) {
                dummy_st_ops_success__destroy(skel);
                return -EINVAL;
        }

        /* mount custom BPF FS over /sys/fs/bpf so that libbpf can create BPF
         * token automatically and implicitly
         */
        err = sys_move_mount(mnt_fd, "", AT_FDCWD, "/sys/fs/bpf", MOVE_MOUNT_F_EMPTY_PATH);
        if (!ASSERT_OK(err, "move_mount_bpffs"))
                return -EINVAL;

        /* disable implicit BPF token creation by setting
         * LIBBPF_BPF_TOKEN_PATH envvar to empty value, load should fail
         */
        err = setenv(TOKEN_ENVVAR, "", 1 /*overwrite*/);
        if (!ASSERT_OK(err, "setenv_token_path"))
                return -EINVAL;
        skel = dummy_st_ops_success__open_and_load();
        if (!ASSERT_ERR_PTR(skel, "obj_token_envvar_disabled_load")) {
                unsetenv(TOKEN_ENVVAR);
                dummy_st_ops_success__destroy(skel);
                return -EINVAL;
        }
        unsetenv(TOKEN_ENVVAR);

        /* now the same struct_ops skeleton should succeed thanks to libbpf
         * creating BPF token from /sys/fs/bpf mount point
         */
        skel = dummy_st_ops_success__open_and_load();
        if (!ASSERT_OK_PTR(skel, "obj_implicit_token_load"))
                return -EINVAL;

        dummy_st_ops_success__destroy(skel);

        /* now disable implicit token through empty bpf_token_path, should fail */
        opts.bpf_token_path = "";
        skel = dummy_st_ops_success__open_opts(&opts);
        if (!ASSERT_OK_PTR(skel, "obj_empty_token_path_open"))
                return -EINVAL;

        err = dummy_st_ops_success__load(skel);
        dummy_st_ops_success__destroy(skel);
        if (!ASSERT_ERR(err, "obj_empty_token_path_load"))
                return -EINVAL;

        return 0;
}

static int userns_obj_priv_implicit_token_envvar(int mnt_fd, struct token_lsm *lsm_skel)
{
        const char *custom_dir = token_bpffs_custom_dir();
        LIBBPF_OPTS(bpf_object_open_opts, opts);
        struct dummy_st_ops_success *skel;
        int err;

        /* before we mount BPF FS with token delegation, struct_ops skeleton
         * should fail to load
         */
        skel = dummy_st_ops_success__open_and_load();
        if (!ASSERT_ERR_PTR(skel, "obj_tokenless_load")) {
                dummy_st_ops_success__destroy(skel);
                return -EINVAL;
        }

        /* mount custom BPF FS over custom location, so libbpf can't create
         * BPF token implicitly, unless pointed to it through
         * LIBBPF_BPF_TOKEN_PATH envvar
         */
        rmdir(custom_dir);
        if (!ASSERT_OK(mkdir(custom_dir, 0777), "mkdir_bpffs_custom"))
                goto err_out;
        err = sys_move_mount(mnt_fd, "", AT_FDCWD, custom_dir, MOVE_MOUNT_F_EMPTY_PATH);
        if (!ASSERT_OK(err, "move_mount_bpffs"))
                goto err_out;

        /* even though we have BPF FS with delegation, it's not at default
         * /sys/fs/bpf location, so we still fail to load until envvar is set up
         */
        skel = dummy_st_ops_success__open_and_load();
        if (!ASSERT_ERR_PTR(skel, "obj_tokenless_load2")) {
                dummy_st_ops_success__destroy(skel);
                goto err_out;
        }

        err = setenv(TOKEN_ENVVAR, custom_dir, 1 /*overwrite*/);
        if (!ASSERT_OK(err, "setenv_token_path"))
                goto err_out;

        /* now the same struct_ops skeleton should succeed thanks to libbpf
         * creating BPF token from custom mount point
         */
        skel = dummy_st_ops_success__open_and_load();
        if (!ASSERT_OK_PTR(skel, "obj_implicit_token_load"))
                goto err_out;

        dummy_st_ops_success__destroy(skel);

        /* now disable implicit token through empty bpf_token_path, envvar
         * will be ignored, should fail
         */
        opts.bpf_token_path = "";
        skel = dummy_st_ops_success__open_opts(&opts);
        if (!ASSERT_OK_PTR(skel, "obj_empty_token_path_open"))
                goto err_out;

        err = dummy_st_ops_success__load(skel);
        dummy_st_ops_success__destroy(skel);
        if (!ASSERT_ERR(err, "obj_empty_token_path_load"))
                goto err_out;

        rmdir(custom_dir);
        unsetenv(TOKEN_ENVVAR);
        return 0;
err_out:
        rmdir(custom_dir);
        unsetenv(TOKEN_ENVVAR);
        return -EINVAL;
}

#define bit(n) (1ULL << (n))

static int userns_bpf_token_info(int mnt_fd, struct token_lsm *lsm_skel)
{
        int err, token_fd = -1;
        struct bpf_token_info info;
        u32 len = sizeof(struct bpf_token_info);

        /* create BPF token from BPF FS mount */
        token_fd = bpf_token_create(mnt_fd, NULL);
        if (!ASSERT_GT(token_fd, 0, "token_create")) {
                err = -EINVAL;
                goto cleanup;
        }

        memset(&info, 0, len);
        err = bpf_obj_get_info_by_fd(token_fd, &info, &len);
        if (!ASSERT_ERR(err, "bpf_obj_get_token_info"))
                goto cleanup;
        if (!ASSERT_EQ(info.allowed_cmds, bit(BPF_MAP_CREATE), "token_info_cmds_map_create")) {
                err = -EINVAL;
                goto cleanup;
        }
        if (!ASSERT_EQ(info.allowed_progs, bit(BPF_PROG_TYPE_XDP), "token_info_progs_xdp")) {
                err = -EINVAL;
                goto cleanup;
        }

        /* The BPF_PROG_TYPE_EXT is not set in token */
        if (ASSERT_EQ(info.allowed_progs, bit(BPF_PROG_TYPE_EXT), "token_info_progs_ext"))
                err = -EINVAL;

cleanup:
        zclose(token_fd);
        return err;
}

void test_token(void)
{
        if (test__start_subtest("map_token")) {
                struct bpffs_opts opts = {
                        .cmds_str = "map_create",
                        .maps_str = "stack",
                };

                subtest_userns(&opts, userns_map_create);
        }
        if (test__start_subtest("btf_token")) {
                struct bpffs_opts opts = {
                        .cmds = 1ULL << BPF_BTF_LOAD,
                };

                subtest_userns(&opts, userns_btf_load);
        }
        if (test__start_subtest("prog_token")) {
                struct bpffs_opts opts = {
                        .cmds_str = "PROG_LOAD",
                        .progs_str = "XDP",
                        .attachs_str = "xdp",
                };

                subtest_userns(&opts, userns_prog_load);
        }
        if (test__start_subtest("obj_priv_map")) {
                struct bpffs_opts opts = {
                        .cmds = bit(BPF_MAP_CREATE),
                        .maps = bit(BPF_MAP_TYPE_QUEUE),
                };

                subtest_userns(&opts, userns_obj_priv_map);
        }
        if (test__start_subtest("obj_priv_prog")) {
                struct bpffs_opts opts = {
                        .cmds = bit(BPF_PROG_LOAD),
                        .progs = bit(BPF_PROG_TYPE_XDP),
                        .attachs = ~0ULL,
                };

                subtest_userns(&opts, userns_obj_priv_prog);
        }
        if (test__start_subtest("obj_priv_freplace_prog")) {
                struct bpffs_opts opts = {
                        .cmds = bit(BPF_BTF_LOAD) | bit(BPF_PROG_LOAD) | bit(BPF_BTF_GET_FD_BY_ID),
                        .progs = bit(BPF_PROG_TYPE_EXT) | bit(BPF_PROG_TYPE_XDP),
                        .attachs = ~0ULL,
                };
                subtest_userns(&opts, userns_obj_priv_freplace_prog);
        }
        if (test__start_subtest("obj_priv_freplace_prog_fail")) {
                struct bpffs_opts opts = {
                        .cmds = bit(BPF_BTF_LOAD) | bit(BPF_PROG_LOAD) | bit(BPF_BTF_GET_FD_BY_ID),
                        .progs = bit(BPF_PROG_TYPE_EXT) | bit(BPF_PROG_TYPE_XDP),
                        .attachs = ~0ULL,
                };
                subtest_userns(&opts, userns_obj_priv_freplace_prog_fail);
        }
        if (test__start_subtest("obj_priv_btf_fail")) {
                struct bpffs_opts opts = {
                        /* disallow BTF loading */
                        .cmds = bit(BPF_MAP_CREATE) | bit(BPF_PROG_LOAD),
                        .maps = bit(BPF_MAP_TYPE_STRUCT_OPS),
                        .progs = bit(BPF_PROG_TYPE_STRUCT_OPS),
                        .attachs = ~0ULL,
                };

                subtest_userns(&opts, userns_obj_priv_btf_fail);
        }
        if (test__start_subtest("obj_priv_btf_success")) {
                struct bpffs_opts opts = {
                        /* allow BTF loading */
                        .cmds = bit(BPF_BTF_LOAD) | bit(BPF_MAP_CREATE) | bit(BPF_PROG_LOAD),
                        .maps = bit(BPF_MAP_TYPE_STRUCT_OPS),
                        .progs = bit(BPF_PROG_TYPE_STRUCT_OPS),
                        .attachs = ~0ULL,
                };

                subtest_userns(&opts, userns_obj_priv_btf_success);
        }
        if (test__start_subtest("obj_priv_implicit_token")) {
                struct bpffs_opts opts = {
                        /* allow BTF loading */
                        .cmds = bit(BPF_BTF_LOAD) | bit(BPF_MAP_CREATE) | bit(BPF_PROG_LOAD),
                        .maps = bit(BPF_MAP_TYPE_STRUCT_OPS),
                        .progs = bit(BPF_PROG_TYPE_STRUCT_OPS),
                        .attachs = ~0ULL,
                };

                subtest_userns(&opts, userns_obj_priv_implicit_token);
        }
        if (test__start_subtest("obj_priv_implicit_token_envvar")) {
                struct bpffs_opts opts = {
                        /* allow BTF loading */
                        .cmds = bit(BPF_BTF_LOAD) | bit(BPF_MAP_CREATE) | bit(BPF_PROG_LOAD),
                        .maps = bit(BPF_MAP_TYPE_STRUCT_OPS),
                        .progs = bit(BPF_PROG_TYPE_STRUCT_OPS),
                        .attachs = ~0ULL,
                };

                subtest_userns(&opts, userns_obj_priv_implicit_token_envvar);
        }
        if (test__start_subtest("bpf_token_info")) {
                struct bpffs_opts opts = {
                        .cmds = bit(BPF_MAP_CREATE),
                        .progs = bit(BPF_PROG_TYPE_XDP),
                        .attachs = ~0ULL,
                };

                subtest_userns(&opts, userns_bpf_token_info);
        }
}