1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2020-2024 Microsoft Corporation. All rights reserved.
4 */
5
6#include <linux/dcache.h>
7#include <linux/security.h>
8
9#include "ipe.h"
10#include "fs.h"
11#include "eval.h"
12#include "policy.h"
13#include "audit.h"
14
15static struct dentry *root __ro_after_init;
16struct dentry *policy_root __ro_after_init;
17
18/**
19 * setaudit() - Write handler for the securityfs node, "ipe/success_audit"
20 * @f: Supplies a file structure representing the securityfs node.
21 * @data: Supplies a buffer passed to the write syscall.
22 * @len: Supplies the length of @data.
23 * @offset: unused.
24 *
25 * Return:
26 * * Length of buffer written - Success
27 * * %-EPERM - Insufficient permission
28 */
29static ssize_t setaudit(struct file *f, const char __user *data,
30 size_t len, loff_t *offset)
31{
32 int rc = 0;
33 bool value;
34
35 if (!file_ns_capable(file: f, ns: &init_user_ns, CAP_MAC_ADMIN))
36 return -EPERM;
37
38 rc = kstrtobool_from_user(s: data, count: len, res: &value);
39 if (rc)
40 return rc;
41
42 WRITE_ONCE(success_audit, value);
43
44 return len;
45}
46
47/**
48 * getaudit() - Read handler for the securityfs node, "ipe/success_audit"
49 * @f: Supplies a file structure representing the securityfs node.
50 * @data: Supplies a buffer passed to the read syscall.
51 * @len: Supplies the length of @data.
52 * @offset: unused.
53 *
54 * Return: Length of buffer written
55 */
56static ssize_t getaudit(struct file *f, char __user *data,
57 size_t len, loff_t *offset)
58{
59 const char *result;
60
61 result = ((READ_ONCE(success_audit)) ? "1" : "0");
62
63 return simple_read_from_buffer(to: data, count: len, ppos: offset, from: result, available: 1);
64}
65
66/**
67 * setenforce() - Write handler for the securityfs node, "ipe/enforce"
68 * @f: Supplies a file structure representing the securityfs node.
69 * @data: Supplies a buffer passed to the write syscall.
70 * @len: Supplies the length of @data.
71 * @offset: unused.
72 *
73 * Return:
74 * * Length of buffer written - Success
75 * * %-EPERM - Insufficient permission
76 */
77static ssize_t setenforce(struct file *f, const char __user *data,
78 size_t len, loff_t *offset)
79{
80 int rc = 0;
81 bool new_value, old_value;
82
83 if (!file_ns_capable(file: f, ns: &init_user_ns, CAP_MAC_ADMIN))
84 return -EPERM;
85
86 old_value = READ_ONCE(enforce);
87 rc = kstrtobool_from_user(s: data, count: len, res: &new_value);
88 if (rc)
89 return rc;
90
91 if (new_value != old_value) {
92 ipe_audit_enforce(new_enforce: new_value, old_enforce: old_value);
93 WRITE_ONCE(enforce, new_value);
94 }
95
96 return len;
97}
98
99/**
100 * getenforce() - Read handler for the securityfs node, "ipe/enforce"
101 * @f: Supplies a file structure representing the securityfs node.
102 * @data: Supplies a buffer passed to the read syscall.
103 * @len: Supplies the length of @data.
104 * @offset: unused.
105 *
106 * Return: Length of buffer written
107 */
108static ssize_t getenforce(struct file *f, char __user *data,
109 size_t len, loff_t *offset)
110{
111 const char *result;
112
113 result = ((READ_ONCE(enforce)) ? "1" : "0");
114
115 return simple_read_from_buffer(to: data, count: len, ppos: offset, from: result, available: 1);
116}
117
118/**
119 * new_policy() - Write handler for the securityfs node, "ipe/new_policy".
120 * @f: Supplies a file structure representing the securityfs node.
121 * @data: Supplies a buffer passed to the write syscall.
122 * @len: Supplies the length of @data.
123 * @offset: unused.
124 *
125 * Return:
126 * * Length of buffer written - Success
127 * * %-EPERM - Insufficient permission
128 * * %-ENOMEM - Out of memory (OOM)
129 * * %-EBADMSG - Policy is invalid
130 * * %-ERANGE - Policy version number overflow
131 * * %-EINVAL - Policy version parsing error
132 * * %-EEXIST - Same name policy already deployed
133 * * %-ENOKEY - Policy signing key not found
134 * * %-EKEYREJECTED - Policy signature verification failed
135 */
136static ssize_t new_policy(struct file *f, const char __user *data,
137 size_t len, loff_t *offset)
138{
139 struct ipe_policy *p = NULL;
140 char *copy = NULL;
141 int rc = 0;
142
143 if (!file_ns_capable(file: f, ns: &init_user_ns, CAP_MAC_ADMIN)) {
144 rc = -EPERM;
145 goto out;
146 }
147
148 copy = memdup_user_nul(data, len);
149 if (IS_ERR(ptr: copy)) {
150 rc = PTR_ERR(ptr: copy);
151 copy = NULL;
152 goto out;
153 }
154
155 p = ipe_new_policy(NULL, textlen: 0, pkcs7: copy, pkcs7len: len);
156 if (IS_ERR(ptr: p)) {
157 rc = PTR_ERR(ptr: p);
158 goto out;
159 }
160
161 rc = ipe_new_policyfs_node(p);
162 if (rc)
163 goto out;
164
165out:
166 kfree(objp: copy);
167 if (rc < 0) {
168 ipe_free_policy(pol: p);
169 ipe_audit_policy_load(p: ERR_PTR(error: rc));
170 } else {
171 ipe_audit_policy_load(p);
172 }
173 return (rc < 0) ? rc : len;
174}
175
176static const struct file_operations np_fops = {
177 .write = new_policy,
178};
179
180static const struct file_operations audit_fops = {
181 .write = setaudit,
182 .read = getaudit,
183};
184
185static const struct file_operations enforce_fops = {
186 .write = setenforce,
187 .read = getenforce,
188};
189
190/**
191 * ipe_init_securityfs() - Initialize IPE's securityfs tree at fsinit.
192 *
193 * Return: %0 on success. If an error occurs, the function will return
194 * the -errno.
195 */
196int __init ipe_init_securityfs(void)
197{
198 int rc = 0;
199 struct ipe_policy *ap;
200 struct dentry *dentry;
201
202 if (!ipe_enabled)
203 return -EOPNOTSUPP;
204
205 root = securityfs_create_dir(name: "ipe", NULL);
206 if (IS_ERR(ptr: root))
207 return PTR_ERR(ptr: root);
208
209 dentry = securityfs_create_file(name: "success_audit", mode: 0600, parent: root,
210 NULL, fops: &audit_fops);
211 if (IS_ERR(ptr: dentry)) {
212 rc = PTR_ERR(ptr: dentry);
213 goto err;
214 }
215
216 dentry = securityfs_create_file(name: "enforce", mode: 0600, parent: root, NULL,
217 fops: &enforce_fops);
218 if (IS_ERR(ptr: dentry)) {
219 rc = PTR_ERR(ptr: dentry);
220 goto err;
221 }
222
223 policy_root = securityfs_create_dir(name: "policies", parent: root);
224 if (IS_ERR(ptr: policy_root)) {
225 rc = PTR_ERR(ptr: policy_root);
226 goto err;
227 }
228
229 ap = rcu_access_pointer(ipe_active_policy);
230 if (ap) {
231 rc = ipe_new_policyfs_node(p: ap);
232 if (rc)
233 goto err;
234 }
235
236 dentry = securityfs_create_file(name: "new_policy", mode: 0200, parent: root, NULL, fops: &np_fops);
237 if (IS_ERR(ptr: dentry)) {
238 rc = PTR_ERR(ptr: dentry);
239 goto err;
240 }
241
242 return 0;
243err:
244 securityfs_remove(dentry: root);
245 return rc;
246}
247

source code of linux/security/ipe/fs.c