LXR linux/security/selinux/ss/context.c

   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * Implementations of the security context functions.
   4 *
   5 * Author: Ondrej Mosnacek <omosnacek@gmail.com>
   6 * Copyright (C) 2020 Red Hat, Inc.
   7 */
   8
   9#include <linux/jhash.h>
  10
  11#include "context.h"
  12#include "mls.h"
  13
  14u32 context_compute_hash(const struct context *c)
  15{
  16        u32 hash = 0;
  17
  18        /*
  19         * If a context is invalid, it will always be represented by a
  20         * context struct with only the len & str set (and vice versa)
  21         * under a given policy. Since context structs from different
  22         * policies should never meet, it is safe to hash valid and
  23         * invalid contexts differently. The context_cmp() function
  24         * already operates under the same assumption.
  25         */
  26        if (c->len)
  27                return full_name_hash(NULL, c->str, c->len);
  28
  29        hash = jhash_3words(c->user, c->role, c->type, hash);
  30        hash = mls_range_hash(&c->range, hash);
  31        return hash;
  32}
  33