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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 | |
bf2276d1 DK |
101 | iint = integrity_iint_find(inode); |
102 | if (iint) | |
103 | return iint; | |
f381c272 | 104 | |
bf2276d1 DK |
105 | iint = kmem_cache_alloc(iint_cache, GFP_NOFS); |
106 | if (!iint) | |
107 | return NULL; | |
f381c272 | 108 | |
a10bf26b | 109 | write_lock(&integrity_iint_lock); |
f381c272 MZ |
110 | |
111 | p = &integrity_iint_tree.rb_node; | |
112 | while (*p) { | |
113 | parent = *p; | |
114 | test_iint = rb_entry(parent, struct integrity_iint_cache, | |
115 | rb_node); | |
f381c272 MZ |
116 | if (inode < test_iint->inode) |
117 | p = &(*p)->rb_left; | |
f381c272 | 118 | else |
bf2276d1 | 119 | p = &(*p)->rb_right; |
f381c272 MZ |
120 | } |
121 | ||
bf2276d1 DK |
122 | iint->inode = inode; |
123 | node = &iint->rb_node; | |
f381c272 | 124 | inode->i_flags |= S_IMA; |
bf2276d1 DK |
125 | rb_link_node(node, parent, p); |
126 | rb_insert_color(node, &integrity_iint_tree); | |
f381c272 | 127 | |
a10bf26b | 128 | write_unlock(&integrity_iint_lock); |
bf2276d1 | 129 | return iint; |
f381c272 MZ |
130 | } |
131 | ||
132 | /** | |
133 | * integrity_inode_free - called on security_inode_free | |
134 | * @inode: pointer to the inode | |
135 | * | |
136 | * Free the integrity information(iint) associated with an inode. | |
137 | */ | |
138 | void integrity_inode_free(struct inode *inode) | |
139 | { | |
140 | struct integrity_iint_cache *iint; | |
141 | ||
142 | if (!IS_IMA(inode)) | |
143 | return; | |
144 | ||
a10bf26b | 145 | write_lock(&integrity_iint_lock); |
f381c272 MZ |
146 | iint = __integrity_iint_find(inode); |
147 | rb_erase(&iint->rb_node, &integrity_iint_tree); | |
a10bf26b | 148 | write_unlock(&integrity_iint_lock); |
f381c272 MZ |
149 | |
150 | iint_free(iint); | |
151 | } | |
152 | ||
153 | static void init_once(void *foo) | |
154 | { | |
155 | struct integrity_iint_cache *iint = foo; | |
156 | ||
2bb930ab | 157 | memset(iint, 0, sizeof(*iint)); |
d79d72e0 MZ |
158 | iint->ima_file_status = INTEGRITY_UNKNOWN; |
159 | iint->ima_mmap_status = INTEGRITY_UNKNOWN; | |
160 | iint->ima_bprm_status = INTEGRITY_UNKNOWN; | |
c6af8efe | 161 | iint->ima_read_status = INTEGRITY_UNKNOWN; |
d906c10d | 162 | iint->ima_creds_status = INTEGRITY_UNKNOWN; |
24e0198e | 163 | iint->evm_status = INTEGRITY_UNKNOWN; |
0d73a552 | 164 | mutex_init(&iint->mutex); |
f381c272 MZ |
165 | } |
166 | ||
167 | static int __init integrity_iintcache_init(void) | |
168 | { | |
169 | iint_cache = | |
170 | kmem_cache_create("iint_cache", sizeof(struct integrity_iint_cache), | |
171 | 0, SLAB_PANIC, init_once); | |
f381c272 MZ |
172 | return 0; |
173 | } | |
3d6e5f6d | 174 | DEFINE_LSM(integrity) = { |
07aed2f2 | 175 | .name = "integrity", |
3d6e5f6d KC |
176 | .init = integrity_iintcache_init, |
177 | }; | |
e3c4abbf DK |
178 | |
179 | ||
180 | /* | |
181 | * integrity_kernel_read - read data from the file | |
182 | * | |
183 | * This is a function for reading file content instead of kernel_read(). | |
184 | * It does not perform locking checks to ensure it cannot be blocked. | |
185 | * It does not perform security checks because it is irrelevant for IMA. | |
186 | * | |
187 | */ | |
188 | int integrity_kernel_read(struct file *file, loff_t offset, | |
bb543e39 | 189 | void *addr, unsigned long count) |
e3c4abbf DK |
190 | { |
191 | mm_segment_t old_fs; | |
192 | char __user *buf = (char __user *)addr; | |
6fb5032e | 193 | ssize_t ret; |
e3c4abbf DK |
194 | |
195 | if (!(file->f_mode & FMODE_READ)) | |
196 | return -EBADF; | |
197 | ||
198 | old_fs = get_fs(); | |
736706be | 199 | set_fs(KERNEL_DS); |
6fb5032e | 200 | ret = __vfs_read(file, buf, count, &offset); |
e3c4abbf | 201 | set_fs(old_fs); |
6fb5032e | 202 | |
e3c4abbf DK |
203 | return ret; |
204 | } | |
205 | ||
c9cd2ce2 DK |
206 | /* |
207 | * integrity_load_keys - load integrity keys hook | |
208 | * | |
209 | * Hooks is called from init/main.c:kernel_init_freeable() | |
210 | * when rootfs is ready | |
211 | */ | |
212 | void __init integrity_load_keys(void) | |
213 | { | |
214 | ima_load_x509(); | |
2ce523eb | 215 | evm_load_x509(); |
c9cd2ce2 | 216 | } |
0c343af8 MG |
217 | |
218 | static int __init integrity_fs_init(void) | |
219 | { | |
220 | integrity_dir = securityfs_create_dir("integrity", NULL); | |
221 | if (IS_ERR(integrity_dir)) { | |
ac2409a5 SH |
222 | int ret = PTR_ERR(integrity_dir); |
223 | ||
224 | if (ret != -ENODEV) | |
225 | pr_err("Unable to create integrity sysfs dir: %d\n", | |
226 | ret); | |
0c343af8 | 227 | integrity_dir = NULL; |
ac2409a5 | 228 | return ret; |
0c343af8 MG |
229 | } |
230 | ||
231 | return 0; | |
232 | } | |
233 | ||
234 | late_initcall(integrity_fs_init) |