TOMOYO: Use callback for updating entries.
[linux-2.6.git] / 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 /* The list for "struct tomoyo_number_group". */
11 LIST_HEAD(tomoyo_number_group_list);
12
13 /**
14  * tomoyo_get_number_group - Allocate memory for "struct tomoyo_number_group".
15  *
16  * @group_name: The name of number group.
17  *
18  * Returns pointer to "struct tomoyo_number_group" on success,
19  * NULL otherwise.
20  */
21 struct tomoyo_number_group *tomoyo_get_number_group(const char *group_name)
22 {
23         struct tomoyo_number_group *entry = NULL;
24         struct tomoyo_number_group *group = NULL;
25         const struct tomoyo_path_info *saved_group_name;
26         int error = -ENOMEM;
27         if (!tomoyo_is_correct_word(group_name))
28                 return NULL;
29         saved_group_name = tomoyo_get_name(group_name);
30         if (!saved_group_name)
31                 return NULL;
32         entry = kzalloc(sizeof(*entry), GFP_NOFS);
33         if (mutex_lock_interruptible(&tomoyo_policy_lock))
34                 goto out;
35         list_for_each_entry_rcu(group, &tomoyo_number_group_list, list) {
36                 if (saved_group_name != group->group_name)
37                         continue;
38                 atomic_inc(&group->users);
39                 error = 0;
40                 break;
41         }
42         if (error && tomoyo_memory_ok(entry)) {
43                 INIT_LIST_HEAD(&entry->member_list);
44                 entry->group_name = saved_group_name;
45                 saved_group_name = NULL;
46                 atomic_set(&entry->users, 1);
47                 list_add_tail_rcu(&entry->list, &tomoyo_number_group_list);
48                 group = entry;
49                 entry = NULL;
50                 error = 0;
51         }
52         mutex_unlock(&tomoyo_policy_lock);
53  out:
54         tomoyo_put_name(saved_group_name);
55         kfree(entry);
56         return !error ? group : NULL;
57 }
58
59 static bool tomoyo_same_number_group(const struct tomoyo_acl_head *a,
60                                      const struct tomoyo_acl_head *b)
61 {
62         return !memcmp(&container_of(a, struct tomoyo_number_group_member,
63                                      head)->number,
64                        &container_of(b, struct tomoyo_number_group_member,
65                                      head)->number,
66                        sizeof(container_of(a,
67                                            struct tomoyo_number_group_member,
68                                            head)->number));
69 }
70
71 /**
72  * tomoyo_write_number_group_policy - Write "struct tomoyo_number_group" list.
73  *
74  * @data:      String to parse.
75  * @is_delete: True if it is a delete request.
76  *
77  * Returns 0 on success, nagative value otherwise.
78  */
79 int tomoyo_write_number_group_policy(char *data, const bool is_delete)
80 {
81         struct tomoyo_number_group *group;
82         struct tomoyo_number_group_member e = { };
83         int error;
84         char *w[2];
85         if (!tomoyo_tokenize(data, w, sizeof(w)))
86                 return -EINVAL;
87         if (w[1][0] == '@' || !tomoyo_parse_number_union(w[1], &e.number) ||
88             e.number.values[0] > e.number.values[1])
89                 return -EINVAL;
90         group = tomoyo_get_number_group(w[0]);
91         if (!group)
92                 return -ENOMEM;
93         error = tomoyo_update_policy(&e.head, sizeof(e), is_delete,
94                                      &group->member_list,
95                                      tomoyo_same_number_group);
96         tomoyo_put_number_group(group);
97         return error;
98 }
99
100 /**
101  * tomoyo_read_number_group_policy - Read "struct tomoyo_number_group" list.
102  *
103  * @head: Pointer to "struct tomoyo_io_buffer".
104  *
105  * Returns true on success, false otherwise.
106  *
107  * Caller holds tomoyo_read_lock().
108  */
109 bool tomoyo_read_number_group_policy(struct tomoyo_io_buffer *head)
110 {
111         struct list_head *gpos;
112         struct list_head *mpos;
113         list_for_each_cookie(gpos, head->read_var1, &tomoyo_number_group_list) {
114                 struct tomoyo_number_group *group;
115                 const char *name;
116                 group = list_entry(gpos, struct tomoyo_number_group, list);
117                 name = group->group_name->name;
118                 list_for_each_cookie(mpos, head->read_var2,
119                                      &group->member_list) {
120                         int pos;
121                         const struct tomoyo_number_group_member *member
122                                 = list_entry(mpos,
123                                              struct tomoyo_number_group_member,
124                                              head.list);
125                         if (member->head.is_deleted)
126                                 continue;
127                         pos = head->read_avail;
128                         if (!tomoyo_io_printf(head, TOMOYO_KEYWORD_NUMBER_GROUP
129                                               "%s", name) ||
130                             !tomoyo_print_number_union(head, &member->number) ||
131                             !tomoyo_io_printf(head, "\n")) {
132                                 head->read_avail = pos;
133                                 return false;
134                         }
135                 }
136         }
137         return true;
138 }
139
140 /**
141  * tomoyo_number_matches_group - Check whether the given number matches members of the given number group.
142  *
143  * @min:   Min number.
144  * @max:   Max number.
145  * @group: Pointer to "struct tomoyo_number_group".
146  *
147  * Returns true if @min and @max partially overlaps @group, false otherwise.
148  *
149  * Caller holds tomoyo_read_lock().
150  */
151 bool tomoyo_number_matches_group(const unsigned long min,
152                                  const unsigned long max,
153                                  const struct tomoyo_number_group *group)
154 {
155         struct tomoyo_number_group_member *member;
156         bool matched = false;
157         list_for_each_entry_rcu(member, &group->member_list, head.list) {
158                 if (member->head.is_deleted)
159                         continue;
160                 if (min > member->number.values[1] ||
161                     max < member->number.values[0])
162                         continue;
163                 matched = true;
164                 break;
165         }
166         return matched;
167 }