[TOMOYO #16 08/25] TOMOYO: Add number_group keyword support.

[Tetsuo Handa]

This patch contains code for handling numeric values grouping.
To be able to specify value ranges more flexibly, I want to add numeric values
grouping support into TOMOYO 2.3.0.

  number_group UIDS_ALLOWED_TO_EXECUTE_SHELL 100-2000
  number_group UIDS_ALLOWED_TO_EXECUTE_SHELL 10000-20000
              +
  allow_execute /bin/sh if task.uid=@UIDS_ALLOWED_TO_EXECUTE_SHELL

  number_group PERMISSIONS_FOR_CREATE 0644
  number_group PERMISSIONS_FOR_CREATE 0600
              +
  allow_create /tmp/file @PERMISSIONS_FOR_CREATE

Signed-off-by: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
---
 security/tomoyo/number_group.c |  212 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 212 insertions(+)

--- /dev/null
+++ security-testing-2.6/security/tomoyo/number_group.c
@@ -0,0 +1,212 @@
+/*
+ * security/tomoyo/number_group.c
+ *
+ * Copyright (C) 2005-2009  NTT DATA CORPORATION
+ */
+#include "internal.h"
+
+/* The list for "struct tomoyo_number_group". */
+LIST_HEAD(tomoyo_number_group_list);
+
+/**
+ * tomoyo_get_number_group - Allocate memory for "struct tomoyo_number_group".
+ *
+ * @group_name: The name of number group.
+ *
+ * Returns pointer to "struct tomoyo_number_group" on success,
+ * NULL otherwise.
+ */
+struct tomoyo_number_group *tomoyo_get_number_group(const char *group_name)
+{
+	struct tomoyo_number_group *entry = NULL;
+	struct tomoyo_number_group *group;
+	const struct tomoyo_path_info *saved_group_name;
+	int error = -ENOMEM;
+	if (!tomoyo_is_correct_path(group_name, 0, 0, 0) ||
+	    !group_name[0])
+		return NULL;
+	saved_group_name = tomoyo_get_name(group_name);
+	if (!saved_group_name)
+		return NULL;
+	entry = kzalloc(sizeof(*entry), GFP_KERNEL);
+	mutex_lock(&tomoyo_policy_lock);
+	list_for_each_entry_rcu(group, &tomoyo_number_group_list, list) {
+		if (saved_group_name != group->group_name)
+			continue;
+		atomic_inc(&group->users);
+		error = 0;
+		break;
+	}
+	if (error && tomoyo_memory_ok(entry, sizeof(*entry))) {
+		INIT_LIST_HEAD(&entry->member_list);
+		entry->group_name = saved_group_name;
+		saved_group_name = NULL;
+		atomic_set(&entry->users, 1);
+		list_add_tail_rcu(&entry->list, &tomoyo_number_group_list);
+		group = entry;
+		entry = NULL;
+		error = 0;
+	}
+	mutex_unlock(&tomoyo_policy_lock);
+	tomoyo_put_name(saved_group_name);
+	kfree(entry);
+	return !error ? group : NULL;
+}
+
+/**
+ * tomoyo_put_number_group - Delete memory for "struct tomoyo_number_group".
+ *
+ * @group: Pointer to "struct tomoyo_number_group".
+ */
+void tomoyo_put_number_group(struct tomoyo_number_group *group)
+{
+	struct tomoyo_number_group_member *member;
+	struct tomoyo_number_group_member *next_member;
+	LIST_HEAD(q);
+	bool can_delete_group = false;
+	if (!group)
+		return;
+	mutex_lock(&tomoyo_policy_lock);
+	if (atomic_dec_and_test(&group->users)) {
+		list_for_each_entry_safe(member, next_member,
+					 &group->member_list, list) {
+			if (!member->is_deleted)
+				break;
+			list_del(&member->list);
+			list_add(&member->list, &q);
+		}
+		if (list_empty(&group->member_list)) {
+			list_del(&group->list);
+			can_delete_group = true;
+		}
+	}
+	mutex_unlock(&tomoyo_policy_lock);
+	list_for_each_entry_safe(member, next_member, &q, list) {
+		list_del(&member->list);
+		tomoyo_memory_free(member, sizeof(*member));
+	}
+	if (can_delete_group) {
+		tomoyo_put_name(group->group_name);
+		tomoyo_memory_free(group, sizeof(*group));
+	}
+}
+
+/**
+ * tomoyo_write_number_group_policy - Write "struct tomoyo_number_group" list.
+ *
+ * @data:      String to parse.
+ * @is_delete: True if it is a delete request.
+ *
+ * Returns 0 on success, nagative value otherwise.
+ */
+int tomoyo_write_number_group_policy(char *data, const bool is_delete)
+{
+	struct tomoyo_number_group *group;
+	struct tomoyo_number_group_member *entry = NULL;
+	struct tomoyo_number_group_member e = { };
+	struct tomoyo_number_group_member *member;
+	int error = is_delete ? -ENOENT : -ENOMEM;
+	char *w[2];
+	if (!tomoyo_tokenize(data, w, sizeof(w)))
+		return -EINVAL;
+	if (!tomoyo_parse_number_union(w[1], &e.number))
+		return -EINVAL;
+	if (e.number.is_group || e.number.values[0] > e.number.values[1]) {
+		tomoyo_put_number_union(&e.number);
+		return -EINVAL;
+	}
+	group = tomoyo_get_number_group(w[0]);
+	if (!group)
+		return -ENOMEM;
+	if (!is_delete)
+		entry = kmalloc(sizeof(e), GFP_KERNEL);
+	mutex_lock(&tomoyo_policy_lock);
+	list_for_each_entry_rcu(member, &group->member_list, list) {
+		if (memcmp(&member->number, &e.number, sizeof(e.number)))
+			continue;
+		member->is_deleted = is_delete;
+		error = 0;
+		break;
+	}
+	if (!is_delete && error && tomoyo_commit_ok(entry, &e, sizeof(e))) {
+		list_add_tail_rcu(&entry->list, &group->member_list);
+		entry = NULL;
+		error = 0;
+	}
+	mutex_unlock(&tomoyo_policy_lock);
+	tomoyo_put_number_group(group);
+	kfree(entry);
+	return error;
+}
+
+/**
+ * tomoyo_read_number_group_policy - Read "struct tomoyo_number_group" list.
+ *
+ * @head: Pointer to "struct tomoyo_io_buffer".
+ *
+ * Returns true on success, false otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
+ */
+bool tomoyo_read_number_group_policy(struct tomoyo_io_buffer *head)
+{
+	struct list_head *gpos;
+	struct list_head *mpos;
+	bool done = true;
+	list_for_each_cookie(gpos, head->read_var1,
+			     &tomoyo_number_group_list) {
+		struct tomoyo_number_group *group;
+		const char *name;
+		group = list_entry(gpos, struct tomoyo_number_group, list);
+		name = group->group_name->name;
+		list_for_each_cookie(mpos, head->read_var2,
+				     &group->member_list) {
+			int pos;
+			const struct tomoyo_number_group_member *member
+				= list_entry(mpos,
+					     struct tomoyo_number_group_member,
+					     list);
+			if (member->is_deleted)
+				continue;
+			pos = head->read_avail;
+			if (!tomoyo_io_printf(head, TOMOYO_KEYWORD_NUMBER_GROUP
+					      "%s", name) ||
+			    !tomoyo_print_number_union(head, &member->number)
+			    || !tomoyo_io_printf(head, "\n")) {
+				head->read_avail = pos;
+				done = false;
+				break;
+			}
+		}
+	}
+	return done;
+}
+
+/**
+ * tomoyo_number_matches_group - Check whether the given number matches members of the given number group.
+ *
+ * @min:   Min number.
+ * @max:   Max number.
+ * @group: Pointer to "struct tomoyo_number_group".
+ *
+ * Returns true if @min and @max partially overlaps @group, false otherwise.
+ *
+ * Caller holds tomoyo_read_lock().
+ */
+bool tomoyo_number_matches_group(const unsigned long min,
+				 const unsigned long max,
+				 const struct tomoyo_number_group *group)
+{
+	struct tomoyo_number_group_member *member;
+	bool matched = false;
+	list_for_each_entry_rcu(member, &group->member_list, list) {
+		if (member->is_deleted)
+			continue;
+		if (min > member->number.values[1] ||
+		    max < member->number.values[0])
+			continue;
+		matched = true;
+		break;
+	}
+	return matched;
+}

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