函数源码

Linux Kernel

v5.5.9

Brick Technologies Co., Ltd

Source File:security\yama\yama_lsm.c Create Date:2022-07-27 21:49:15
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/**
 * yama_task_prctl - check for Yama-specific prctl operations
 * @option: operation
 * @arg2: argument
 * @arg3: argument
 * @arg4: argument
 * @arg5: argument
 *
 * Return 0 on success, -ve on error.  -ENOSYS is returned when Yama
 * does not handle the given option.
 */
static int yama_task_prctl(int option, unsigned long arg2, unsigned long arg3,
               unsigned long arg4, unsigned long arg5)
{
    int rc = -ENOSYS;
    struct task_struct *myself = current;
 
    switch (option) {
    case PR_SET_PTRACER:
        /* Since a thread can call prctl(), find the group leader
         * before calling _add() or _del() on it, since we want
         * process-level granularity of control. The tracer group
         * leader checking is handled later when walking the ancestry
         * at the time of PTRACE_ATTACH check.
         */
        rcu_read_lock();
        if (!thread_group_leader(myself))
            myself = rcu_dereference(myself->group_leader);
        get_task_struct(myself);
        rcu_read_unlock();
 
        if (arg2 == 0) {
            yama_ptracer_del(NULL, myself);
            rc = 0;
        } else if (arg2 == PR_SET_PTRACER_ANY || (int)arg2 == -1) {
            rc = yama_ptracer_add(NULL, myself);
        } else {
            struct task_struct *tracer;
 
            tracer = find_get_task_by_vpid(arg2);
            if (!tracer) {
                rc = -EINVAL;
            } else {
                rc = yama_ptracer_add(tracer, myself);
                put_task_struct(tracer);
            }
        }
 
        put_task_struct(myself);
        break;
    }
 
    return rc;
}