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b886d83c | 1 | // SPDX-License-Identifier: GPL-2.0-only |
f381c272 MZ |
2 | /* |
3 | * Copyright (C) 2008 IBM Corporation | |
4 | * | |
5 | * Authors: | |
6 | * Mimi Zohar <zohar@us.ibm.com> | |
7 | * | |
f381c272 MZ |
8 | * File: integrity_iint.c |
9 | * - implements the integrity hooks: integrity_inode_alloc, | |
10 | * integrity_inode_free | |
11 | * - cache integrity information associated with an inode | |
12 | * using a rbtree tree. | |
13 | */ | |
14 | #include <linux/slab.h> | |
876979c9 | 15 | #include <linux/init.h> |
f381c272 MZ |
16 | #include <linux/spinlock.h> |
17 | #include <linux/rbtree.h> | |
e3c4abbf DK |
18 | #include <linux/file.h> |
19 | #include <linux/uaccess.h> | |
0c343af8 | 20 | #include <linux/security.h> |
5b89c1bd | 21 | #include <linux/lsm_hooks.h> |
f381c272 MZ |
22 | #include "integrity.h" |
23 | ||
24 | static struct rb_root integrity_iint_tree = RB_ROOT; | |
a10bf26b | 25 | static DEFINE_RWLOCK(integrity_iint_lock); |
f381c272 MZ |
26 | static struct kmem_cache *iint_cache __read_mostly; |
27 | ||
0c343af8 MG |
28 | struct dentry *integrity_dir; |
29 | ||
f381c272 MZ |
30 | /* |
31 | * __integrity_iint_find - return the iint associated with an inode | |
32 | */ | |
33 | static struct integrity_iint_cache *__integrity_iint_find(struct inode *inode) | |
34 | { | |
35 | struct integrity_iint_cache *iint; | |
36 | struct rb_node *n = integrity_iint_tree.rb_node; | |
37 | ||
f381c272 MZ |
38 | while (n) { |
39 | iint = rb_entry(n, struct integrity_iint_cache, rb_node); | |
40 | ||
41 | if (inode < iint->inode) | |
42 | n = n->rb_left; | |
43 | else if (inode > iint->inode) | |
44 | n = n->rb_right; | |
45 | else | |
46 | break; | |
47 | } | |
48 | if (!n) | |
49 | return NULL; | |
50 | ||
51 | return iint; | |
52 | } | |
53 | ||
54 | /* | |
55 | * integrity_iint_find - return the iint associated with an inode | |
56 | */ | |
57 | struct integrity_iint_cache *integrity_iint_find(struct inode *inode) | |
58 | { | |
59 | struct integrity_iint_cache *iint; | |
60 | ||
61 | if (!IS_IMA(inode)) | |
62 | return NULL; | |
63 | ||
a10bf26b | 64 | read_lock(&integrity_iint_lock); |
f381c272 | 65 | iint = __integrity_iint_find(inode); |
a10bf26b | 66 | read_unlock(&integrity_iint_lock); |
f381c272 MZ |
67 | |
68 | return iint; | |
69 | } | |
70 | ||
71 | static void iint_free(struct integrity_iint_cache *iint) | |
72 | { | |
a35c3fb6 DK |
73 | kfree(iint->ima_hash); |
74 | iint->ima_hash = NULL; | |
f381c272 MZ |
75 | iint->version = 0; |
76 | iint->flags = 0UL; | |
e2598077 | 77 | iint->atomic_flags = 0UL; |
d79d72e0 MZ |
78 | iint->ima_file_status = INTEGRITY_UNKNOWN; |
79 | iint->ima_mmap_status = INTEGRITY_UNKNOWN; | |
80 | iint->ima_bprm_status = INTEGRITY_UNKNOWN; | |
c6af8efe | 81 | iint->ima_read_status = INTEGRITY_UNKNOWN; |
d906c10d | 82 | iint->ima_creds_status = INTEGRITY_UNKNOWN; |
fb788d8b | 83 | iint->evm_status = INTEGRITY_UNKNOWN; |
96d450bb | 84 | iint->measured_pcrs = 0; |
f381c272 MZ |
85 | kmem_cache_free(iint_cache, iint); |
86 | } | |
87 | ||
88 | /** | |
bf2276d1 | 89 | * integrity_inode_get - find or allocate an iint associated with an inode |
f381c272 | 90 | * @inode: pointer to the inode |
bf2276d1 DK |
91 | * @return: allocated iint |
92 | * | |
93 | * Caller must lock i_mutex | |
f381c272 | 94 | */ |
bf2276d1 | 95 | struct integrity_iint_cache *integrity_inode_get(struct inode *inode) |
f381c272 MZ |
96 | { |
97 | struct rb_node **p; | |
bf2276d1 DK |
98 | struct rb_node *node, *parent = NULL; |
99 | struct integrity_iint_cache *iint, *test_iint; | |
f381c272 | 100 | |
520edaee MZ |
101 | /* |
102 | * The integrity's "iint_cache" is initialized at security_init(), | |
103 | * unless it is not included in the ordered list of LSMs enabled | |
104 | * on the boot command line. | |
105 | */ | |
106 | if (!iint_cache) | |
107 | panic("%s: lsm=integrity required.\n", __func__); | |
108 | ||
bf2276d1 DK |
109 | iint = integrity_iint_find(inode); |
110 | if (iint) | |
111 | return iint; | |
f381c272 | 112 | |
bf2276d1 DK |
113 | iint = kmem_cache_alloc(iint_cache, GFP_NOFS); |
114 | if (!iint) | |
115 | return NULL; | |
f381c272 | 116 | |
a10bf26b | 117 | write_lock(&integrity_iint_lock); |
f381c272 MZ |
118 | |
119 | p = &integrity_iint_tree.rb_node; | |
120 | while (*p) { | |
121 | parent = *p; | |
122 | test_iint = rb_entry(parent, struct integrity_iint_cache, | |
123 | rb_node); | |
f381c272 MZ |
124 | if (inode < test_iint->inode) |
125 | p = &(*p)->rb_left; | |
f381c272 | 126 | else |
bf2276d1 | 127 | p = &(*p)->rb_right; |
f381c272 MZ |
128 | } |
129 | ||
bf2276d1 DK |
130 | iint->inode = inode; |
131 | node = &iint->rb_node; | |
f381c272 | 132 | inode->i_flags |= S_IMA; |
bf2276d1 DK |
133 | rb_link_node(node, parent, p); |
134 | rb_insert_color(node, &integrity_iint_tree); | |
f381c272 | 135 | |
a10bf26b | 136 | write_unlock(&integrity_iint_lock); |
bf2276d1 | 137 | return iint; |
f381c272 MZ |
138 | } |
139 | ||
140 | /** | |
141 | * integrity_inode_free - called on security_inode_free | |
142 | * @inode: pointer to the inode | |
143 | * | |
144 | * Free the integrity information(iint) associated with an inode. | |
145 | */ | |
146 | void integrity_inode_free(struct inode *inode) | |
147 | { | |
148 | struct integrity_iint_cache *iint; | |
149 | ||
150 | if (!IS_IMA(inode)) | |
151 | return; | |
152 | ||
a10bf26b | 153 | write_lock(&integrity_iint_lock); |
f381c272 MZ |
154 | iint = __integrity_iint_find(inode); |
155 | rb_erase(&iint->rb_node, &integrity_iint_tree); | |
a10bf26b | 156 | write_unlock(&integrity_iint_lock); |
f381c272 MZ |
157 | |
158 | iint_free(iint); | |
159 | } | |
160 | ||
161 | static void init_once(void *foo) | |
162 | { | |
163 | struct integrity_iint_cache *iint = foo; | |
164 | ||
2bb930ab | 165 | memset(iint, 0, sizeof(*iint)); |
d79d72e0 MZ |
166 | iint->ima_file_status = INTEGRITY_UNKNOWN; |
167 | iint->ima_mmap_status = INTEGRITY_UNKNOWN; | |
168 | iint->ima_bprm_status = INTEGRITY_UNKNOWN; | |
c6af8efe | 169 | iint->ima_read_status = INTEGRITY_UNKNOWN; |
d906c10d | 170 | iint->ima_creds_status = INTEGRITY_UNKNOWN; |
24e0198e | 171 | iint->evm_status = INTEGRITY_UNKNOWN; |
0d73a552 | 172 | mutex_init(&iint->mutex); |
f381c272 MZ |
173 | } |
174 | ||
175 | static int __init integrity_iintcache_init(void) | |
176 | { | |
177 | iint_cache = | |
178 | kmem_cache_create("iint_cache", sizeof(struct integrity_iint_cache), | |
179 | 0, SLAB_PANIC, init_once); | |
f381c272 MZ |
180 | return 0; |
181 | } | |
3d6e5f6d | 182 | DEFINE_LSM(integrity) = { |
07aed2f2 | 183 | .name = "integrity", |
3d6e5f6d KC |
184 | .init = integrity_iintcache_init, |
185 | }; | |
e3c4abbf DK |
186 | |
187 | ||
188 | /* | |
189 | * integrity_kernel_read - read data from the file | |
190 | * | |
191 | * This is a function for reading file content instead of kernel_read(). | |
192 | * It does not perform locking checks to ensure it cannot be blocked. | |
193 | * It does not perform security checks because it is irrelevant for IMA. | |
194 | * | |
195 | */ | |
196 | int integrity_kernel_read(struct file *file, loff_t offset, | |
bb543e39 | 197 | void *addr, unsigned long count) |
e3c4abbf | 198 | { |
a1f9b1c0 | 199 | return __kernel_read(file, addr, count, &offset); |
e3c4abbf DK |
200 | } |
201 | ||
c9cd2ce2 DK |
202 | /* |
203 | * integrity_load_keys - load integrity keys hook | |
204 | * | |
205 | * Hooks is called from init/main.c:kernel_init_freeable() | |
206 | * when rootfs is ready | |
207 | */ | |
208 | void __init integrity_load_keys(void) | |
209 | { | |
210 | ima_load_x509(); | |
2ce523eb | 211 | evm_load_x509(); |
c9cd2ce2 | 212 | } |
0c343af8 MG |
213 | |
214 | static int __init integrity_fs_init(void) | |
215 | { | |
216 | integrity_dir = securityfs_create_dir("integrity", NULL); | |
217 | if (IS_ERR(integrity_dir)) { | |
ac2409a5 SH |
218 | int ret = PTR_ERR(integrity_dir); |
219 | ||
220 | if (ret != -ENODEV) | |
221 | pr_err("Unable to create integrity sysfs dir: %d\n", | |
222 | ret); | |
0c343af8 | 223 | integrity_dir = NULL; |
ac2409a5 | 224 | return ret; |
0c343af8 MG |
225 | } |
226 | ||
227 | return 0; | |
228 | } | |
229 | ||
230 | late_initcall(integrity_fs_init) |