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[linux-2.6.git] / security / tomoyo / tomoyo.c
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);