security/tomoyo/number_group.c

   1 /*
   2  * security/tomoyo/number_group.c
   3  *
   4  * Copyright (C) 2005-2009  NTT DATA CORPORATION
   5  */
   6
   7 #include <linux/slab.h>
   8 #include "common.h"
   9
  10 /**
  11  * tomoyo_get_group - Allocate memory for "struct tomoyo_number_group".
  12  *
  13  * @group_name: The name of number group.
  14  *
  15  * Returns pointer to "struct tomoyo_number_group" on success,
  16  * NULL otherwise.
  17  */
  18 struct tomoyo_group *tomoyo_get_number_group(const char *group_name)
  19 {
  20         struct tomoyo_group *entry = NULL;
  21         struct tomoyo_group *group = NULL;
  22         const struct tomoyo_path_info *saved_group_name;
  23         int error = -ENOMEM;
  24         if (!tomoyo_correct_word(group_name))
  25                 return NULL;
  26         saved_group_name = tomoyo_get_name(group_name);
  27         if (!saved_group_name)
  28                 return NULL;
  29         entry = kzalloc(sizeof(*entry), GFP_NOFS);
  30         if (mutex_lock_interruptible(&tomoyo_policy_lock))
  31                 goto out;
  32         list_for_each_entry_rcu(group, &tomoyo_group_list[TOMOYO_NUMBER_GROUP],
  33                                 list) {
  34                 if (saved_group_name != group->group_name)
  35                         continue;
  36                 atomic_inc(&group->users);
  37                 error = 0;
  38                 break;
  39         }
  40         if (error && tomoyo_memory_ok(entry)) {
  41                 INIT_LIST_HEAD(&entry->member_list);
  42                 entry->group_name = saved_group_name;
  43                 saved_group_name = NULL;
  44                 atomic_set(&entry->users, 1);
  45                 list_add_tail_rcu(&entry->list,
  46                                   &tomoyo_group_list[TOMOYO_NUMBER_GROUP]);
  47                 group = entry;
  48                 entry = NULL;
  49                 error = 0;
  50         }
  51         mutex_unlock(&tomoyo_policy_lock);
  52  out:
  53         tomoyo_put_name(saved_group_name);
  54         kfree(entry);
  55         return !error ? group : NULL;
  56 }
  57
  58 static bool tomoyo_same_number_group(const struct tomoyo_acl_head *a,
  59                                      const struct tomoyo_acl_head *b)
  60 {
  61         return !memcmp(&container_of(a, struct tomoyo_number_group,
  62                                      head)->number,
  63                        &container_of(b, struct tomoyo_number_group,
  64                                      head)->number,
  65                        sizeof(container_of(a,
  66                                            struct tomoyo_number_group,
  67                                            head)->number));
  68 }
  69
  70 /**
  71  * tomoyo_write_number_group_policy - Write "struct tomoyo_number_group" list.
  72  *
  73  * @data:      String to parse.
  74  * @is_delete: True if it is a delete request.
  75  *
  76  * Returns 0 on success, nagative value otherwise.
  77  */
  78 int tomoyo_write_number_group_policy(char *data, const bool is_delete)
  79 {
  80         struct tomoyo_group *group;
  81         struct tomoyo_number_group e = { };
  82         int error;
  83         char *w[2];
  84         if (!tomoyo_tokenize(data, w, sizeof(w)))
  85                 return -EINVAL;
  86         if (w[1][0] == '@' || !tomoyo_parse_number_union(w[1], &e.number) ||
  87             e.number.values[0] > e.number.values[1])
  88                 return -EINVAL;
  89         group = tomoyo_get_number_group(w[0]);
  90         if (!group)
  91                 return -ENOMEM;
  92         error = tomoyo_update_policy(&e.head, sizeof(e), is_delete,
  93                                      &group->member_list,
  94                                      tomoyo_same_number_group);
  95         tomoyo_put_group(group);
  96         return error;
  97 }
  98
  99 /**
 100  * tomoyo_number_matches_group - Check whether the given number matches members of the given number group.
 101  *
 102  * @min:   Min number.
 103  * @max:   Max number.
 104  * @group: Pointer to "struct tomoyo_number_group".
 105  *
 106  * Returns true if @min and @max partially overlaps @group, false otherwise.
 107  *
 108  * Caller holds tomoyo_read_lock().
 109  */
 110 bool tomoyo_number_matches_group(const unsigned long min,
 111                                  const unsigned long max,
 112                                  const struct tomoyo_group *group)
 113 {
 114         struct tomoyo_number_group *member;
 115         bool matched = false;
 116         list_for_each_entry_rcu(member, &group->member_list, head.list) {
 117                 if (member->head.is_deleted)
 118                         continue;
 119                 if (min > member->number.values[1] ||
 120                     max < member->number.values[0])
 121                         continue;
 122                 matched = true;
 123                 break;
 124         }
 125         return matched;
 126 }