#include <linux/version.h>
#include <linux/security.h>
#include <linux/lsm_hooks.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/cred.h>
#include <linux/key.h>
#include <linux/string.h>
#include <linux/kernel.h>
#include <linux/uidgid.h>

#include "kernel_compat.h"
#include "ksu.h"

#if LINUX_VERSION_CODE > KERNEL_VERSION(4, 10, 0) && defined(CONFIG_KSU_MANUAL_SU)
#include "manual_su.h"

static int ksu_task_alloc(struct task_struct *task,
                          unsigned long clone_flags)
{
    ksu_try_escalate_for_uid(task_uid(task).val);
    return 0;
}
#endif

// kernel 4.4 and 4.9
#if LINUX_VERSION_CODE < KERNEL_VERSION(4, 10, 0) ||    \
    defined(CONFIG_IS_HW_HISI) ||    \
    defined(CONFIG_KSU_ALLOWLIST_WORKAROUND)
static int ksu_key_permission(key_ref_t key_ref, const struct cred *cred,
                  unsigned perm)
{
    if (init_session_keyring != NULL) {
        return 0;
    }
    if (strcmp(current->comm, "init")) {
        // we are only interested in `init` process
        return 0;
    }
    init_session_keyring = cred->session_keyring;
    pr_info("kernel_compat: got init_session_keyring\n");
    return 0;
}
#endif

static struct security_hook_list ksu_hooks[] = {
#if LINUX_VERSION_CODE > KERNEL_VERSION(4, 10, 0) && defined(CONFIG_KSU_MANUAL_SU)
    LSM_HOOK_INIT(task_alloc, ksu_task_alloc),
#endif
#if LINUX_VERSION_CODE < KERNEL_VERSION(4, 10, 0) || \
    defined(CONFIG_IS_HW_HISI) || defined(CONFIG_KSU_ALLOWLIST_WORKAROUND)
    LSM_HOOK_INIT(key_permission, ksu_key_permission)
#endif
};

#if LINUX_VERSION_CODE >= KERNEL_VERSION(6, 8, 0)
const struct lsm_id ksu_lsmid = {
    .name = "ksu",
    .id = 912,
};
#endif

void __init ksu_lsm_hook_init(void)
{
#if LINUX_VERSION_CODE >= KERNEL_VERSION(6, 8, 0)
    // https://elixir.bootlin.com/linux/v6.8/source/include/linux/lsm_hooks.h#L120
    security_add_hooks(ksu_hooks, ARRAY_SIZE(ksu_hooks), &ksu_lsmid);
#elif LINUX_VERSION_CODE >= KERNEL_VERSION(4, 11, 0)
    security_add_hooks(ksu_hooks, ARRAY_SIZE(ksu_hooks), "ksu");
#else
    // https://elixir.bootlin.com/linux/v4.10.17/source/include/linux/lsm_hooks.h#L1892
    security_add_hooks(ksu_hooks, ARRAY_SIZE(ksu_hooks));
#endif
}