SukiSU-Ultra/kernel/selinux/selinux.c

#include "linux/cred.h"
#include "linux/sched.h"
#include <linux/version.h>
#include "selinux_defs.h"
#include "../klog.h" // IWYU pragma: keep

#define KERNEL_SU_DOMAIN "u:r:su:s0"

#ifdef CONFIG_KSU_SUSFS
#define KERNEL_INIT_DOMAIN "u:r:init:s0"
#define KERNEL_ZYGOTE_DOMAIN "u:r:zygote:s0"
#define KERNEL_KERNEL_DOMAIN "u:r:kernel:s0"
u32 susfs_ksu_sid = 0;
u32 susfs_init_sid = 0;
u32 susfs_zygote_sid = 0;
u32 susfs_kernel_sid = 0;
#endif

static int transive_to_domain(const char *domain)
{
    struct cred *cred;
    struct task_security_struct *tsec;
    u32 sid;
    int error;

    cred = (struct cred *)__task_cred(current);

    tsec = cred->security;
    if (!tsec) {
        pr_err("tsec == NULL!\n");
        return -1;
    }

    error = security_secctx_to_secid(domain, strlen(domain), &sid);
    if (error) {
        pr_info("security_secctx_to_secid %s -> sid: %d, error: %d\n",
            domain, sid, error);
    }

    if (!error) {
        tsec->sid = sid;
        tsec->create_sid = 0;
        tsec->keycreate_sid = 0;
        tsec->sockcreate_sid = 0;
    }

    return error;
}

#if LINUX_VERSION_CODE <= KERNEL_VERSION(4, 19, 0)
bool __maybe_unused is_ksu_transition(const struct task_security_struct *old_tsec,
            const struct task_security_struct *new_tsec)
{
    static u32 ksu_sid;
    char *secdata;
    u32 seclen;
    bool allowed = false;

    if (!ksu_sid)
        security_secctx_to_secid(KERNEL_SU_DOMAIN, strlen(KERNEL_SU_DOMAIN), &ksu_sid);

    if (security_secid_to_secctx(old_tsec->sid, &secdata, &seclen))
        return false;

    allowed = (!strcmp("u:r:init:s0", secdata) && new_tsec->sid == ksu_sid);
    security_release_secctx(secdata, seclen);
    return allowed;
}
#endif

void setup_selinux(const char *domain)
{
    if (transive_to_domain(domain)) {
        pr_err("transive domain failed.\n");
        return;
    }
}

void setenforce(bool enforce)
{
    __setenforce(enforce);
}

bool getenforce(void)
{
    if (is_selinux_disabled()) {
        return false;
    }

    return __is_selinux_enforcing();
}

#if LINUX_VERSION_CODE < KERNEL_VERSION(6, 14, 0)
struct lsm_context {
    char *context;
    u32 len;
};

static int __security_secid_to_secctx(u32 secid, struct lsm_context *cp)
{
    return security_secid_to_secctx(secid, &cp->context, &cp->len);
}
static void __security_release_secctx(struct lsm_context *cp)
{
    return security_release_secctx(cp->context, cp->len);
}
#else
#define __security_secid_to_secctx security_secid_to_secctx
#define __security_release_secctx security_release_secctx
#endif

bool is_task_ksu_domain(const struct cred* cred)
{
    struct lsm_context ctx;
    bool result;
    if (!cred) {
        return false;
    }
    const struct task_security_struct *tsec = selinux_cred(cred);
    if (!tsec) {
        return false;
    }
    int err = __security_secid_to_secctx(tsec->sid, &ctx);
    if (err) {
        return false;
    }
    result = strncmp(KERNEL_SU_DOMAIN, ctx.context, ctx.len) == 0;
    __security_release_secctx(&ctx);
    return result;
}

bool is_ksu_domain()
{
    current_sid();
    return is_task_ksu_domain(current_cred());
}

bool is_zygote(const struct cred* cred)
{
    if (!cred) {
        return false;
    }
    const struct task_security_struct * tsec = selinux_cred(cred);
    if (!tsec) {
        return false;
    }
    struct lsm_context ctx;
    bool result;
    int err = __security_secid_to_secctx(tsec->sid, &ctx);
    if (err) {
        return false;
    }
    result = strncmp("u:r:zygote:s0", ctx.context, ctx.len) == 0;
    __security_release_secctx(&ctx);
    return result;
}

#ifdef CONFIG_KSU_SUSFS
static inline void susfs_set_sid(const char *secctx_name, u32 *out_sid)
{
    int err;
    
    if (!secctx_name || !out_sid) {
        pr_err("secctx_name || out_sid is NULL\n");
        return;
    }

    err = security_secctx_to_secid(secctx_name, strlen(secctx_name),
                       out_sid);
    if (err) {
        pr_err("failed setting sid for '%s', err: %d\n", secctx_name, err);
        return;
    }
    pr_info("sid '%u' is set for secctx_name '%s'\n", *out_sid, secctx_name);
}

bool susfs_is_sid_equal(void *sec, u32 sid2) {
    struct task_security_struct *tsec = (struct task_security_struct *)sec;
    if (!tsec) {
        return false;
    }
    return tsec->sid == sid2;
}

u32 susfs_get_sid_from_name(const char *secctx_name)
{
    u32 out_sid = 0;
    int err;
    
    if (!secctx_name) {
        pr_err("secctx_name is NULL\n");
        return 0;
    }
    err = security_secctx_to_secid(secctx_name, strlen(secctx_name),
                       &out_sid);
    if (err) {
        pr_err("failed getting sid from secctx_name: %s, err: %d\n", secctx_name, err);
        return 0;
    }
    return out_sid;
}

u32 susfs_get_current_sid(void) {
    return current_sid();
}

void susfs_set_zygote_sid(void)
{
    susfs_set_sid(KERNEL_ZYGOTE_DOMAIN, &susfs_zygote_sid);
}

bool susfs_is_current_zygote_domain(void) {
    return unlikely(current_sid() == susfs_zygote_sid);
}

void susfs_set_ksu_sid(void)
{
    susfs_set_sid(KERNEL_SU_DOMAIN, &susfs_ksu_sid);
}

bool susfs_is_current_ksu_domain(void) {
    return unlikely(current_sid() == susfs_ksu_sid);
}

void susfs_set_init_sid(void)
{
    susfs_set_sid(KERNEL_INIT_DOMAIN, &susfs_init_sid);
}

bool susfs_is_current_init_domain(void) {
    return unlikely(current_sid() == susfs_init_sid);
}

void susfs_set_kernel_sid(void)
{
    susfs_set_sid(KERNEL_KERNEL_DOMAIN, &susfs_kernel_sid);
}
#endif

#define KSU_FILE_DOMAIN "u:object_r:ksu_file:s0"

u32 ksu_get_ksu_file_sid()
{
    u32 ksu_file_sid = 0;
    int err = security_secctx_to_secid(KSU_FILE_DOMAIN, strlen(KSU_FILE_DOMAIN),
                       &ksu_file_sid);
    if (err) {
        pr_info("get ksufile sid err %d\n", err);
    }
    return ksu_file_sid;
}