1 /*
2 * security/tomoyo/tomoyo.c
3 *
4 * LSM hooks for TOMOYO Linux.
5 *
6 * Copyright (C) 2005-2009 NTT DATA CORPORATION
7 *
8 * Version: 2.2.0 2009/04/01
9 *
10 */
11
12 #include <linux/security.h>
13 #include "common.h"
14 #include "tomoyo.h"
15 #include "realpath.h"
16
17 static int tomoyo_cred_prepare(struct cred *new, const struct cred *old,
18 gfp_t gfp)
19 {
20 /*
21 * Since "struct tomoyo_domain_info *" is a sharable pointer,
22 * we don't need to duplicate.
23 */
24 new->security = old->security;
25 return 0;
26 }
27
28 static int tomoyo_bprm_set_creds(struct linux_binprm *bprm)
29 {
30 int rc;
31
32 rc = cap_bprm_set_creds(bprm);
33 if (rc)
34 return rc;
35
36 /*
37 * Do only if this function is called for the first time of an execve
38 * operation.
39 */
40 if (bprm->cred_prepared)
41 return 0;
42 /*
43 * Load policy if /sbin/tomoyo-init exists and /sbin/init is requested
44 * for the first time.
45 */
46 if (!tomoyo_policy_loaded)
47 tomoyo_load_policy(bprm->filename);
48 /*
49 * Tell tomoyo_bprm_check_security() is called for the first time of an
50 * execve operation.
51 */
52 bprm->cred->security = NULL;
53 return 0;
54 }
55
56 static int tomoyo_bprm_check_security(struct linux_binprm *bprm)
57 {
58 struct tomoyo_domain_info *domain = bprm->cred->security;
59
60 /*
61 * Execute permission is checked against pathname passed to do_execve()
62 * using current domain.
63 */
64 if (!domain) {
65 struct tomoyo_domain_info *next_domain = NULL;
66 int retval = tomoyo_find_next_domain(bprm, &next_domain);
67
68 if (!retval)
69 bprm->cred->security = next_domain;
70 return retval;
71 }
72 /*
73 * Read permission is checked against interpreters using next domain.
74 * '1' is the result of open_to_namei_flags(O_RDONLY).
75 */
76 return tomoyo_check_open_permission(domain, &bprm->file->f_path, 1);
77 }
78
79 #ifdef CONFIG_SYSCTL
80
81 static int tomoyo_prepend(char **buffer, int *buflen, const char *str)
82 {
83 int namelen = strlen(str);
84
85 if (*buflen < namelen)
86 return -ENOMEM;
87 *buflen -= namelen;
88 *buffer -= namelen;
89 memcpy(*buffer, str, namelen);
90 return 0;
91 }
92
93 /**
94 * tomoyo_sysctl_path - return the realpath of a ctl_table.
95 * @table: pointer to "struct ctl_table".
96 *
97 * Returns realpath(3) of the @table on success.
98 * Returns NULL on failure.
99 *
100 * This function uses tomoyo_alloc(), so the caller must call tomoyo_free()
101 * if this function didn't return NULL.
102 */
103 static char *tomoyo_sysctl_path(struct ctl_table *table)
104 {
105 int buflen = TOMOYO_MAX_PATHNAME_LEN;
106 char *buf = tomoyo_alloc(buflen);
107 char *end = buf + buflen;
108 int error = -ENOMEM;
109
110 if (!buf)
111 return NULL;
112
113 *--end = '\0';
114 buflen--;
115 while (table) {
116 char num[32];
117 const char *sp = table->procname;
118
119 if (!sp) {
120 memset(num, 0, sizeof(num));
121 snprintf(num, sizeof(num) - 1, "=%d=", table->ctl_name);
122 sp = num;
123 }
124 if (tomoyo_prepend(&end, &buflen, sp) ||
125 tomoyo_prepend(&end, &buflen, "/"))
126 goto out;
127 table = table->parent;
128 }
129 if (tomoyo_prepend(&end, &buflen, "/proc/sys"))
130 goto out;
131 error = tomoyo_encode(buf, end - buf, end);
132 out:
133 if (!error)
134 return buf;
135 tomoyo_free(buf);
136 return NULL;
137 }
138
139 static int tomoyo_sysctl(struct ctl_table *table, int op)
140 {
141 int error;
142 char *name;
143
144 op &= MAY_READ | MAY_WRITE;
145 if (!op)
146 return 0;
147 name = tomoyo_sysctl_path(table);
148 if (!name)
149 return -ENOMEM;
150 error = tomoyo_check_file_perm(tomoyo_domain(), name, op);
151 tomoyo_free(name);
152 return error;
153 }
154 #endif
155
156 static int tomoyo_path_truncate(struct path *path, loff_t length,
157 unsigned int time_attrs)
158 {
159 return tomoyo_check_1path_perm(tomoyo_domain(),
160 TOMOYO_TYPE_TRUNCATE_ACL,
161 path);
162 }
163
164 static int tomoyo_path_unlink(struct path *parent, struct dentry *dentry)
165 {
166 struct path path = { parent->mnt, dentry };
167 return tomoyo_check_1path_perm(tomoyo_domain(),
168 TOMOYO_TYPE_UNLINK_ACL,
169 &path);
170 }
171
172 static int tomoyo_path_mkdir(struct path *parent, struct dentry *dentry,
173 int mode)
174 {
175 struct path path = { parent->mnt, dentry };
176 return tomoyo_check_1path_perm(tomoyo_domain(),
177 TOMOYO_TYPE_MKDIR_ACL,
178 &path);
179 }
180
181 static int tomoyo_path_rmdir(struct path *parent, struct dentry *dentry)
182 {
183 struct path path = { parent->mnt, dentry };
184 return tomoyo_check_1path_perm(tomoyo_domain(),
185 TOMOYO_TYPE_RMDIR_ACL,
186 &path);
187 }
188
189 static int tomoyo_path_symlink(struct path *parent, struct dentry *dentry,
190 const char *old_name)
191 {
192 struct path path = { parent->mnt, dentry };
193 return tomoyo_check_1path_perm(tomoyo_domain(),
194 TOMOYO_TYPE_SYMLINK_ACL,
195 &path);
196 }
197
198 static int tomoyo_path_mknod(struct path *parent, struct dentry *dentry,
199 int mode, unsigned int dev)
200 {
201 struct path path = { parent->mnt, dentry };
202 int type = TOMOYO_TYPE_CREATE_ACL;
203
204 switch (mode & S_IFMT) {
205 case S_IFCHR:
206 type = TOMOYO_TYPE_MKCHAR_ACL;
207 break;
208 case S_IFBLK:
209 type = TOMOYO_TYPE_MKBLOCK_ACL;
210 break;
211 case S_IFIFO:
212 type = TOMOYO_TYPE_MKFIFO_ACL;
213 break;
214 case S_IFSOCK:
215 type = TOMOYO_TYPE_MKSOCK_ACL;
216 break;
217 }
218 return tomoyo_check_1path_perm(tomoyo_domain(),
219 type, &path);
220 }
221
222 static int tomoyo_path_link(struct dentry *old_dentry, struct path *new_dir,
223 struct dentry *new_dentry)
224 {
225 struct path path1 = { new_dir->mnt, old_dentry };
226 struct path path2 = { new_dir->mnt, new_dentry };
227 return tomoyo_check_2path_perm(tomoyo_domain(),
228 TOMOYO_TYPE_LINK_ACL,
229 &path1, &path2);
230 }
231
232 static int tomoyo_path_rename(struct path *old_parent,
233 struct dentry *old_dentry,
234 struct path *new_parent,
235 struct dentry *new_dentry)
236 {
237 struct path path1 = { old_parent->mnt, old_dentry };
238 struct path path2 = { new_parent->mnt, new_dentry };
239 return tomoyo_check_2path_perm(tomoyo_domain(),
240 TOMOYO_TYPE_RENAME_ACL,
241 &path1, &path2);
242 }
243
244 static int tomoyo_file_fcntl(struct file *file, unsigned int cmd,
245 unsigned long arg)
246 {
247 if (cmd == F_SETFL && ((arg ^ file->f_flags) & O_APPEND))
248 return tomoyo_check_rewrite_permission(tomoyo_domain(), file);
249 return 0;
250 }
251
252 static int tomoyo_dentry_open(struct file *f, const struct cred *cred)
253 {
254 int flags = f->f_flags;
255
256 if ((flags + 1) & O_ACCMODE)
257 flags++;
258 flags |= f->f_flags & (O_APPEND | O_TRUNC);
259 /* Don't check read permission here if called from do_execve(). */
260 if (current->in_execve)
261 return 0;
262 return tomoyo_check_open_permission(tomoyo_domain(), &f->f_path, flags);
263 }
264
265 /*
266 * tomoyo_security_ops is a "struct security_operations" which is used for
267 * registering TOMOYO.
268 */
269 static struct security_operations tomoyo_security_ops = {
270 .name = "tomoyo",
271 .cred_prepare = tomoyo_cred_prepare,
272 .bprm_set_creds = tomoyo_bprm_set_creds,
273 .bprm_check_security = tomoyo_bprm_check_security,
274 #ifdef CONFIG_SYSCTL
275 .sysctl = tomoyo_sysctl,
276 #endif
277 .file_fcntl = tomoyo_file_fcntl,
278 .dentry_open = tomoyo_dentry_open,
279 .path_truncate = tomoyo_path_truncate,
280 .path_unlink = tomoyo_path_unlink,
281 .path_mkdir = tomoyo_path_mkdir,
282 .path_rmdir = tomoyo_path_rmdir,
283 .path_symlink = tomoyo_path_symlink,
284 .path_mknod = tomoyo_path_mknod,
285 .path_link = tomoyo_path_link,
286 .path_rename = tomoyo_path_rename,
287 };
288
289 static int __init tomoyo_init(void)
290 {
291 struct cred *cred = (struct cred *) current_cred();
292
293 if (!security_module_enable(&tomoyo_security_ops))
294 return 0;
295 /* register ourselves with the security framework */
296 if (register_security(&tomoyo_security_ops))
297 panic("Failure registering TOMOYO Linux");
298 printk(KERN_INFO "TOMOYO Linux initialized\n");
299 cred->security = &tomoyo_kernel_domain;
300 tomoyo_realpath_init();
301 return 0;
302 }
303
304 security_initcall(tomoyo_init);
305
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