// SPDX-License-Identifier: GPL-2.0

/*
 * Based on Christian Brauner's clone3() example.
 * These tests are assuming to be running in the host's
 * PID namespace.
 */

/* capabilities related code based on selftests/bpf/test_verifier.c */

#define _GNU_SOURCE
#include <errno.h>
#include <linux/types.h>
#include <linux/sched.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <sys/capability.h>
#include <sys/prctl.h>
#include <sys/syscall.h>
#include <sys/types.h>
#include <sys/un.h>
#include <sys/wait.h>
#include <unistd.h>
#include <sched.h>

#include "kselftest_harness.h"
#include "clone3_selftests.h"

static void child_exit(int ret)
{
        fflush(stdout);
        fflush(stderr);
        _exit(ret);
}

static int call_clone3_set_tid(struct __test_metadata *_metadata,
                               pid_t *set_tid, size_t set_tid_size)
{
        int status;
        pid_t pid = -1;

        struct __clone_args args = {
                .exit_signal = SIGCHLD,
                .set_tid = ptr_to_u64(set_tid),
                .set_tid_size = set_tid_size,
        };

        pid = sys_clone3(&args, sizeof(args));
        if (pid < 0) {
                TH_LOG("%s - Failed to create new process", strerror(errno));
                return -errno;
        }

        if (pid == 0) {
                int ret;
                char tmp = 0;

                TH_LOG("I am the child, my PID is %d (expected %d)", getpid(), set_tid[0]);

                if (set_tid[0] != getpid())
                        child_exit(EXIT_FAILURE);
                child_exit(EXIT_SUCCESS);
        }

        TH_LOG("I am the parent (%d). My child's pid is %d", getpid(), pid);

        if (waitpid(pid, &status, 0) < 0) {
                TH_LOG("Child returned %s", strerror(errno));
                return -errno;
        }

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

        return WEXITSTATUS(status);
}

static int test_clone3_set_tid(struct __test_metadata *_metadata,
                               pid_t *set_tid, size_t set_tid_size)
{
        int ret;

        TH_LOG("[%d] Trying clone3() with CLONE_SET_TID to %d", getpid(), set_tid[0]);
        ret = call_clone3_set_tid(_metadata, set_tid, set_tid_size);
        TH_LOG("[%d] clone3() with CLONE_SET_TID %d says:%d", getpid(), set_tid[0], ret);
        return ret;
}

struct libcap {
        struct __user_cap_header_struct hdr;
        struct __user_cap_data_struct data[2];
};

static int set_capability(void)
{
        cap_value_t cap_values[] = { CAP_SETUID, CAP_SETGID };
        struct libcap *cap;
        int ret = -1;
        cap_t caps;

        caps = cap_get_proc();
        if (!caps) {
                perror("cap_get_proc");
                return -1;
        }

        /* Drop all capabilities */
        if (cap_clear(caps)) {
                perror("cap_clear");
                goto out;
        }

        cap_set_flag(caps, CAP_EFFECTIVE, 2, cap_values, CAP_SET);
        cap_set_flag(caps, CAP_PERMITTED, 2, cap_values, CAP_SET);

        cap = (struct libcap *) caps;

        /* 40 -> CAP_CHECKPOINT_RESTORE */
        cap->data[1].effective |= 1 << (40 - 32);
        cap->data[1].permitted |= 1 << (40 - 32);

        if (cap_set_proc(caps)) {
                perror("cap_set_proc");
                goto out;
        }
        ret = 0;
out:
        if (cap_free(caps))
                perror("cap_free");
        return ret;
}

TEST(clone3_cap_checkpoint_restore)
{
        pid_t pid;
        int status;
        int ret = 0;
        pid_t set_tid[1];

        test_clone3_supported();

        EXPECT_EQ(getuid(), 0)
                SKIP(return, "Skipping all tests as non-root");

        memset(&set_tid, 0, sizeof(set_tid));

        /* Find the current active PID */
        pid = fork();
        if (pid == 0) {
                TH_LOG("Child has PID %d", getpid());
                child_exit(EXIT_SUCCESS);
        }
        ASSERT_GT(waitpid(pid, &status, 0), 0)
                TH_LOG("Waiting for child %d failed", pid);

        /* After the child has finished, its PID should be free. */
        set_tid[0] = pid;

        ASSERT_EQ(set_capability(), 0)
                TH_LOG("Could not set CAP_CHECKPOINT_RESTORE");

        ASSERT_EQ(prctl(PR_SET_KEEPCAPS, 1, 0, 0, 0), 0);

        EXPECT_EQ(setgid(65534), 0)
                TH_LOG("Failed to setgid(65534)");
        ASSERT_EQ(setuid(65534), 0);

        set_tid[0] = pid;
        /* This would fail without CAP_CHECKPOINT_RESTORE */
        ASSERT_EQ(test_clone3_set_tid(_metadata, set_tid, 1), -EPERM);
        ASSERT_EQ(set_capability(), 0)
                TH_LOG("Could not set CAP_CHECKPOINT_RESTORE");
        /* This should work as we have CAP_CHECKPOINT_RESTORE as non-root */
        ASSERT_EQ(test_clone3_set_tid(_metadata, set_tid, 1), 0);
}

TEST_HARNESS_MAIN