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1 | /* | |
2 | * security/tomoyo/tomoyo.c | |
3 | * | |
4 | * LSM hooks for TOMOYO Linux. | |
5 | * | |
6 | * Copyright (C) 2005-2010 NTT DATA CORPORATION | |
7 | */ | |
8 | ||
9 | #include <linux/security.h> | |
10 | #include "common.h" | |
11 | ||
12 | static int tomoyo_cred_alloc_blank(struct cred *new, gfp_t gfp) | |
13 | { | |
14 | new->security = NULL; | |
15 | return 0; | |
16 | } | |
17 | ||
18 | static int tomoyo_cred_prepare(struct cred *new, const struct cred *old, | |
19 | gfp_t gfp) | |
20 | { | |
21 | struct tomoyo_domain_info *domain = old->security; | |
22 | new->security = domain; | |
23 | if (domain) | |
24 | atomic_inc(&domain->users); | |
25 | return 0; | |
26 | } | |
27 | ||
28 | static void tomoyo_cred_transfer(struct cred *new, const struct cred *old) | |
29 | { | |
30 | tomoyo_cred_prepare(new, old, 0); | |
31 | } | |
32 | ||
33 | static void tomoyo_cred_free(struct cred *cred) | |
34 | { | |
35 | struct tomoyo_domain_info *domain = cred->security; | |
36 | if (domain) | |
37 | atomic_dec(&domain->users); | |
38 | } | |
39 | ||
40 | static int tomoyo_bprm_set_creds(struct linux_binprm *bprm) | |
41 | { | |
42 | int rc; | |
43 | ||
44 | rc = cap_bprm_set_creds(bprm); | |
45 | if (rc) | |
46 | return rc; | |
47 | ||
48 | /* | |
49 | * Do only if this function is called for the first time of an execve | |
50 | * operation. | |
51 | */ | |
52 | if (bprm->cred_prepared) | |
53 | return 0; | |
54 | /* | |
55 | * Load policy if /sbin/tomoyo-init exists and /sbin/init is requested | |
56 | * for the first time. | |
57 | */ | |
58 | if (!tomoyo_policy_loaded) | |
59 | tomoyo_load_policy(bprm->filename); | |
60 | /* | |
61 | * Release reference to "struct tomoyo_domain_info" stored inside | |
62 | * "bprm->cred->security". New reference to "struct tomoyo_domain_info" | |
63 | * stored inside "bprm->cred->security" will be acquired later inside | |
64 | * tomoyo_find_next_domain(). | |
65 | */ | |
66 | atomic_dec(&((struct tomoyo_domain_info *) | |
67 | bprm->cred->security)->users); | |
68 | /* | |
69 | * Tell tomoyo_bprm_check_security() is called for the first time of an | |
70 | * execve operation. | |
71 | */ | |
72 | bprm->cred->security = NULL; | |
73 | return 0; | |
74 | } | |
75 | ||
76 | static int tomoyo_bprm_check_security(struct linux_binprm *bprm) | |
77 | { | |
78 | struct tomoyo_domain_info *domain = bprm->cred->security; | |
79 | ||
80 | /* | |
81 | * Execute permission is checked against pathname passed to do_execve() | |
82 | * using current domain. | |
83 | */ | |
84 | if (!domain) { | |
85 | const int idx = tomoyo_read_lock(); | |
86 | const int err = tomoyo_find_next_domain(bprm); | |
87 | tomoyo_read_unlock(idx); | |
88 | return err; | |
89 | } | |
90 | /* | |
91 | * Read permission is checked against interpreters using next domain. | |
92 | */ | |
93 | return tomoyo_check_open_permission(domain, &bprm->file->f_path, O_RDONLY); | |
94 | } | |
95 | ||
96 | static int tomoyo_path_truncate(struct path *path) | |
97 | { | |
98 | return tomoyo_path_perm(TOMOYO_TYPE_TRUNCATE, path); | |
99 | } | |
100 | ||
101 | static int tomoyo_path_unlink(struct path *parent, struct dentry *dentry) | |
102 | { | |
103 | struct path path = { parent->mnt, dentry }; | |
104 | return tomoyo_path_perm(TOMOYO_TYPE_UNLINK, &path); | |
105 | } | |
106 | ||
107 | static int tomoyo_path_mkdir(struct path *parent, struct dentry *dentry, | |
108 | int mode) | |
109 | { | |
110 | struct path path = { parent->mnt, dentry }; | |
111 | return tomoyo_path_number_perm(TOMOYO_TYPE_MKDIR, &path, | |
112 | mode & S_IALLUGO); | |
113 | } | |
114 | ||
115 | static int tomoyo_path_rmdir(struct path *parent, struct dentry *dentry) | |
116 | { | |
117 | struct path path = { parent->mnt, dentry }; | |
118 | return tomoyo_path_perm(TOMOYO_TYPE_RMDIR, &path); | |
119 | } | |
120 | ||
121 | static int tomoyo_path_symlink(struct path *parent, struct dentry *dentry, | |
122 | const char *old_name) | |
123 | { | |
124 | struct path path = { parent->mnt, dentry }; | |
125 | return tomoyo_path_perm(TOMOYO_TYPE_SYMLINK, &path); | |
126 | } | |
127 | ||
128 | static int tomoyo_path_mknod(struct path *parent, struct dentry *dentry, | |
129 | int mode, unsigned int dev) | |
130 | { | |
131 | struct path path = { parent->mnt, dentry }; | |
132 | int type = TOMOYO_TYPE_CREATE; | |
133 | const unsigned int perm = mode & S_IALLUGO; | |
134 | ||
135 | switch (mode & S_IFMT) { | |
136 | case S_IFCHR: | |
137 | type = TOMOYO_TYPE_MKCHAR; | |
138 | break; | |
139 | case S_IFBLK: | |
140 | type = TOMOYO_TYPE_MKBLOCK; | |
141 | break; | |
142 | default: | |
143 | goto no_dev; | |
144 | } | |
145 | return tomoyo_mkdev_perm(type, &path, perm, dev); | |
146 | no_dev: | |
147 | switch (mode & S_IFMT) { | |
148 | case S_IFIFO: | |
149 | type = TOMOYO_TYPE_MKFIFO; | |
150 | break; | |
151 | case S_IFSOCK: | |
152 | type = TOMOYO_TYPE_MKSOCK; | |
153 | break; | |
154 | } | |
155 | return tomoyo_path_number_perm(type, &path, perm); | |
156 | } | |
157 | ||
158 | static int tomoyo_path_link(struct dentry *old_dentry, struct path *new_dir, | |
159 | struct dentry *new_dentry) | |
160 | { | |
161 | struct path path1 = { new_dir->mnt, old_dentry }; | |
162 | struct path path2 = { new_dir->mnt, new_dentry }; | |
163 | return tomoyo_path2_perm(TOMOYO_TYPE_LINK, &path1, &path2); | |
164 | } | |
165 | ||
166 | static int tomoyo_path_rename(struct path *old_parent, | |
167 | struct dentry *old_dentry, | |
168 | struct path *new_parent, | |
169 | struct dentry *new_dentry) | |
170 | { | |
171 | struct path path1 = { old_parent->mnt, old_dentry }; | |
172 | struct path path2 = { new_parent->mnt, new_dentry }; | |
173 | return tomoyo_path2_perm(TOMOYO_TYPE_RENAME, &path1, &path2); | |
174 | } | |
175 | ||
176 | static int tomoyo_file_fcntl(struct file *file, unsigned int cmd, | |
177 | unsigned long arg) | |
178 | { | |
179 | if (cmd == F_SETFL && ((arg ^ file->f_flags) & O_APPEND)) | |
180 | return tomoyo_path_perm(TOMOYO_TYPE_REWRITE, &file->f_path); | |
181 | return 0; | |
182 | } | |
183 | ||
184 | static int tomoyo_dentry_open(struct file *f, const struct cred *cred) | |
185 | { | |
186 | int flags = f->f_flags; | |
187 | /* Don't check read permission here if called from do_execve(). */ | |
188 | if (current->in_execve) | |
189 | return 0; | |
190 | return tomoyo_check_open_permission(tomoyo_domain(), &f->f_path, flags); | |
191 | } | |
192 | ||
193 | static int tomoyo_file_ioctl(struct file *file, unsigned int cmd, | |
194 | unsigned long arg) | |
195 | { | |
196 | return tomoyo_path_number_perm(TOMOYO_TYPE_IOCTL, &file->f_path, cmd); | |
197 | } | |
198 | ||
199 | static int tomoyo_path_chmod(struct dentry *dentry, struct vfsmount *mnt, | |
200 | mode_t mode) | |
201 | { | |
202 | struct path path = { mnt, dentry }; | |
203 | return tomoyo_path_number_perm(TOMOYO_TYPE_CHMOD, &path, | |
204 | mode & S_IALLUGO); | |
205 | } | |
206 | ||
207 | static int tomoyo_path_chown(struct path *path, uid_t uid, gid_t gid) | |
208 | { | |
209 | int error = 0; | |
210 | if (uid != (uid_t) -1) | |
211 | error = tomoyo_path_number_perm(TOMOYO_TYPE_CHOWN, path, uid); | |
212 | if (!error && gid != (gid_t) -1) | |
213 | error = tomoyo_path_number_perm(TOMOYO_TYPE_CHGRP, path, gid); | |
214 | return error; | |
215 | } | |
216 | ||
217 | static int tomoyo_path_chroot(struct path *path) | |
218 | { | |
219 | return tomoyo_path_perm(TOMOYO_TYPE_CHROOT, path); | |
220 | } | |
221 | ||
222 | static int tomoyo_sb_mount(char *dev_name, struct path *path, | |
223 | char *type, unsigned long flags, void *data) | |
224 | { | |
225 | return tomoyo_mount_permission(dev_name, path, type, flags, data); | |
226 | } | |
227 | ||
228 | static int tomoyo_sb_umount(struct vfsmount *mnt, int flags) | |
229 | { | |
230 | struct path path = { mnt, mnt->mnt_root }; | |
231 | return tomoyo_path_perm(TOMOYO_TYPE_UMOUNT, &path); | |
232 | } | |
233 | ||
234 | static int tomoyo_sb_pivotroot(struct path *old_path, struct path *new_path) | |
235 | { | |
236 | return tomoyo_path2_perm(TOMOYO_TYPE_PIVOT_ROOT, new_path, old_path); | |
237 | } | |
238 | ||
239 | /* | |
240 | * tomoyo_security_ops is a "struct security_operations" which is used for | |
241 | * registering TOMOYO. | |
242 | */ | |
243 | static struct security_operations tomoyo_security_ops = { | |
244 | .name = "tomoyo", | |
245 | .cred_alloc_blank = tomoyo_cred_alloc_blank, | |
246 | .cred_prepare = tomoyo_cred_prepare, | |
247 | .cred_transfer = tomoyo_cred_transfer, | |
248 | .cred_free = tomoyo_cred_free, | |
249 | .bprm_set_creds = tomoyo_bprm_set_creds, | |
250 | .bprm_check_security = tomoyo_bprm_check_security, | |
251 | .file_fcntl = tomoyo_file_fcntl, | |
252 | .dentry_open = tomoyo_dentry_open, | |
253 | .path_truncate = tomoyo_path_truncate, | |
254 | .path_unlink = tomoyo_path_unlink, | |
255 | .path_mkdir = tomoyo_path_mkdir, | |
256 | .path_rmdir = tomoyo_path_rmdir, | |
257 | .path_symlink = tomoyo_path_symlink, | |
258 | .path_mknod = tomoyo_path_mknod, | |
259 | .path_link = tomoyo_path_link, | |
260 | .path_rename = tomoyo_path_rename, | |
261 | .file_ioctl = tomoyo_file_ioctl, | |
262 | .path_chmod = tomoyo_path_chmod, | |
263 | .path_chown = tomoyo_path_chown, | |
264 | .path_chroot = tomoyo_path_chroot, | |
265 | .sb_mount = tomoyo_sb_mount, | |
266 | .sb_umount = tomoyo_sb_umount, | |
267 | .sb_pivotroot = tomoyo_sb_pivotroot, | |
268 | }; | |
269 | ||
270 | /* Lock for GC. */ | |
271 | struct srcu_struct tomoyo_ss; | |
272 | ||
273 | static int __init tomoyo_init(void) | |
274 | { | |
275 | struct cred *cred = (struct cred *) current_cred(); | |
276 | ||
277 | if (!security_module_enable(&tomoyo_security_ops)) | |
278 | return 0; | |
279 | /* register ourselves with the security framework */ | |
280 | if (register_security(&tomoyo_security_ops) || | |
281 | init_srcu_struct(&tomoyo_ss)) | |
282 | panic("Failure registering TOMOYO Linux"); | |
283 | printk(KERN_INFO "TOMOYO Linux initialized\n"); | |
284 | cred->security = &tomoyo_kernel_domain; | |
285 | tomoyo_mm_init(); | |
286 | return 0; | |
287 | } | |
288 | ||
289 | security_initcall(tomoyo_init); |