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1 | /* audit_fsnotify.c -- tracking inodes |
2 | * | |
3 | * Copyright 2003-2009,2014-2015 Red Hat, Inc. | |
4 | * Copyright 2005 Hewlett-Packard Development Company, L.P. | |
5 | * Copyright 2005 IBM Corporation | |
6 | * | |
7 | * This program is free software; you can redistribute it and/or modify | |
8 | * it under the terms of the GNU General Public License as published by | |
9 | * the Free Software Foundation; either version 2 of the License, or | |
10 | * (at your option) any later version. | |
11 | * | |
12 | * This program is distributed in the hope that it will be useful, | |
13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 | * GNU General Public License for more details. | |
16 | */ | |
17 | ||
18 | #include <linux/kernel.h> | |
19 | #include <linux/audit.h> | |
20 | #include <linux/kthread.h> | |
21 | #include <linux/mutex.h> | |
22 | #include <linux/fs.h> | |
23 | #include <linux/fsnotify_backend.h> | |
24 | #include <linux/namei.h> | |
25 | #include <linux/netlink.h> | |
26 | #include <linux/sched.h> | |
27 | #include <linux/slab.h> | |
28 | #include <linux/security.h> | |
29 | #include "audit.h" | |
30 | ||
31 | /* | |
32 | * this mark lives on the parent directory of the inode in question. | |
33 | * but dev, ino, and path are about the child | |
34 | */ | |
35 | struct audit_fsnotify_mark { | |
36 | dev_t dev; /* associated superblock device */ | |
37 | unsigned long ino; /* associated inode number */ | |
38 | char *path; /* insertion path */ | |
39 | struct fsnotify_mark mark; /* fsnotify mark on the inode */ | |
40 | struct audit_krule *rule; | |
41 | }; | |
42 | ||
43 | /* fsnotify handle. */ | |
44 | static struct fsnotify_group *audit_fsnotify_group; | |
45 | ||
46 | /* fsnotify events we care about. */ | |
47 | #define AUDIT_FS_EVENTS (FS_MOVE | FS_CREATE | FS_DELETE | FS_DELETE_SELF |\ | |
48 | FS_MOVE_SELF | FS_EVENT_ON_CHILD) | |
49 | ||
50 | static void audit_fsnotify_mark_free(struct audit_fsnotify_mark *audit_mark) | |
51 | { | |
52 | kfree(audit_mark->path); | |
53 | kfree(audit_mark); | |
54 | } | |
55 | ||
56 | static void audit_fsnotify_free_mark(struct fsnotify_mark *mark) | |
57 | { | |
58 | struct audit_fsnotify_mark *audit_mark; | |
59 | ||
60 | audit_mark = container_of(mark, struct audit_fsnotify_mark, mark); | |
61 | audit_fsnotify_mark_free(audit_mark); | |
62 | } | |
63 | ||
64 | char *audit_mark_path(struct audit_fsnotify_mark *mark) | |
65 | { | |
66 | return mark->path; | |
67 | } | |
68 | ||
69 | int audit_mark_compare(struct audit_fsnotify_mark *mark, unsigned long ino, dev_t dev) | |
70 | { | |
71 | if (mark->ino == AUDIT_INO_UNSET) | |
72 | return 0; | |
73 | return (mark->ino == ino) && (mark->dev == dev); | |
74 | } | |
75 | ||
76 | static void audit_update_mark(struct audit_fsnotify_mark *audit_mark, | |
3cd5eca8 | 77 | const struct inode *inode) |
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78 | { |
79 | audit_mark->dev = inode ? inode->i_sb->s_dev : AUDIT_DEV_UNSET; | |
80 | audit_mark->ino = inode ? inode->i_ino : AUDIT_INO_UNSET; | |
81 | } | |
82 | ||
83 | struct audit_fsnotify_mark *audit_alloc_mark(struct audit_krule *krule, char *pathname, int len) | |
84 | { | |
85 | struct audit_fsnotify_mark *audit_mark; | |
86 | struct path path; | |
87 | struct dentry *dentry; | |
88 | struct inode *inode; | |
89 | int ret; | |
90 | ||
91 | if (pathname[0] != '/' || pathname[len-1] == '/') | |
92 | return ERR_PTR(-EINVAL); | |
93 | ||
94 | dentry = kern_path_locked(pathname, &path); | |
95 | if (IS_ERR(dentry)) | |
96 | return (void *)dentry; /* returning an error */ | |
97 | inode = path.dentry->d_inode; | |
5955102c | 98 | inode_unlock(inode); |
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99 | |
100 | audit_mark = kzalloc(sizeof(*audit_mark), GFP_KERNEL); | |
101 | if (unlikely(!audit_mark)) { | |
102 | audit_mark = ERR_PTR(-ENOMEM); | |
103 | goto out; | |
104 | } | |
105 | ||
7b129323 JK |
106 | fsnotify_init_mark(&audit_mark->mark, audit_fsnotify_group, |
107 | audit_fsnotify_free_mark); | |
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108 | audit_mark->mark.mask = AUDIT_FS_EVENTS; |
109 | audit_mark->path = pathname; | |
110 | audit_update_mark(audit_mark, dentry->d_inode); | |
111 | audit_mark->rule = krule; | |
112 | ||
7b129323 | 113 | ret = fsnotify_add_mark(&audit_mark->mark, inode, NULL, true); |
7f492942 | 114 | if (ret < 0) { |
7b129323 | 115 | fsnotify_put_mark(&audit_mark->mark); |
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116 | audit_mark = ERR_PTR(ret); |
117 | } | |
118 | out: | |
119 | dput(dentry); | |
120 | path_put(&path); | |
121 | return audit_mark; | |
122 | } | |
123 | ||
124 | static void audit_mark_log_rule_change(struct audit_fsnotify_mark *audit_mark, char *op) | |
125 | { | |
126 | struct audit_buffer *ab; | |
127 | struct audit_krule *rule = audit_mark->rule; | |
128 | ||
129 | if (!audit_enabled) | |
130 | return; | |
131 | ab = audit_log_start(NULL, GFP_NOFS, AUDIT_CONFIG_CHANGE); | |
132 | if (unlikely(!ab)) | |
133 | return; | |
c1e8f06d | 134 | audit_log_format(ab, "auid=%u ses=%u op=%s", |
7f492942 | 135 | from_kuid(&init_user_ns, audit_get_loginuid(current)), |
c1e8f06d | 136 | audit_get_sessionid(current), op); |
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137 | audit_log_format(ab, " path="); |
138 | audit_log_untrustedstring(ab, audit_mark->path); | |
139 | audit_log_key(ab, rule->filterkey); | |
140 | audit_log_format(ab, " list=%d res=1", rule->listnr); | |
141 | audit_log_end(ab); | |
142 | } | |
143 | ||
144 | void audit_remove_mark(struct audit_fsnotify_mark *audit_mark) | |
145 | { | |
146 | fsnotify_destroy_mark(&audit_mark->mark, audit_fsnotify_group); | |
147 | fsnotify_put_mark(&audit_mark->mark); | |
148 | } | |
149 | ||
150 | void audit_remove_mark_rule(struct audit_krule *krule) | |
151 | { | |
152 | struct audit_fsnotify_mark *mark = krule->exe; | |
153 | ||
154 | audit_remove_mark(mark); | |
155 | } | |
156 | ||
157 | static void audit_autoremove_mark_rule(struct audit_fsnotify_mark *audit_mark) | |
158 | { | |
159 | struct audit_krule *rule = audit_mark->rule; | |
160 | struct audit_entry *entry = container_of(rule, struct audit_entry, rule); | |
161 | ||
162 | audit_mark_log_rule_change(audit_mark, "autoremove_rule"); | |
163 | audit_del_rule(entry); | |
164 | } | |
165 | ||
166 | /* Update mark data in audit rules based on fsnotify events. */ | |
167 | static int audit_mark_handle_event(struct fsnotify_group *group, | |
168 | struct inode *to_tell, | |
169 | struct fsnotify_mark *inode_mark, | |
170 | struct fsnotify_mark *vfsmount_mark, | |
3cd5eca8 | 171 | u32 mask, const void *data, int data_type, |
9385a84d JK |
172 | const unsigned char *dname, u32 cookie, |
173 | struct fsnotify_iter_info *iter_info) | |
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174 | { |
175 | struct audit_fsnotify_mark *audit_mark; | |
3cd5eca8 | 176 | const struct inode *inode = NULL; |
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177 | |
178 | audit_mark = container_of(inode_mark, struct audit_fsnotify_mark, mark); | |
179 | ||
180 | BUG_ON(group != audit_fsnotify_group); | |
181 | ||
182 | switch (data_type) { | |
183 | case (FSNOTIFY_EVENT_PATH): | |
3cd5eca8 | 184 | inode = ((const struct path *)data)->dentry->d_inode; |
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185 | break; |
186 | case (FSNOTIFY_EVENT_INODE): | |
3cd5eca8 | 187 | inode = (const struct inode *)data; |
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188 | break; |
189 | default: | |
190 | BUG(); | |
191 | return 0; | |
192 | }; | |
193 | ||
194 | if (mask & (FS_CREATE|FS_MOVED_TO|FS_DELETE|FS_MOVED_FROM)) { | |
195 | if (audit_compare_dname_path(dname, audit_mark->path, AUDIT_NAME_FULL)) | |
196 | return 0; | |
197 | audit_update_mark(audit_mark, inode); | |
198 | } else if (mask & (FS_DELETE_SELF|FS_UNMOUNT|FS_MOVE_SELF)) | |
199 | audit_autoremove_mark_rule(audit_mark); | |
200 | ||
201 | return 0; | |
202 | } | |
203 | ||
204 | static const struct fsnotify_ops audit_mark_fsnotify_ops = { | |
205 | .handle_event = audit_mark_handle_event, | |
206 | }; | |
207 | ||
208 | static int __init audit_fsnotify_init(void) | |
209 | { | |
210 | audit_fsnotify_group = fsnotify_alloc_group(&audit_mark_fsnotify_ops); | |
211 | if (IS_ERR(audit_fsnotify_group)) { | |
212 | audit_fsnotify_group = NULL; | |
213 | audit_panic("cannot create audit fsnotify group"); | |
214 | } | |
215 | return 0; | |
216 | } | |
217 | device_initcall(audit_fsnotify_init); |