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Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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
17static int tomoyo_cred_alloc_blank(struct cred *new, gfp_t gfp)
18{
19 new->security = NULL;
20 return 0;
21}
22
23static int tomoyo_cred_prepare(struct cred *new, const struct cred *old,
24 gfp_t gfp)
25{
26 /*
27 * Since "struct tomoyo_domain_info *" is a sharable pointer,
28 * we don't need to duplicate.
29 */
30 new->security = old->security;
31 return 0;
32}
33
34static void tomoyo_cred_transfer(struct cred *new, const struct cred *old)
35{
36 /*
37 * Since "struct tomoyo_domain_info *" is a sharable pointer,
38 * we don't need to duplicate.
39 */
40 new->security = old->security;
41}
42
43static int tomoyo_bprm_set_creds(struct linux_binprm *bprm)
44{
45 int rc;
46
47 rc = cap_bprm_set_creds(bprm);
48 if (rc)
49 return rc;
50
51 /*
52 * Do only if this function is called for the first time of an execve
53 * operation.
54 */
55 if (bprm->cred_prepared)
56 return 0;
57 /*
58 * Load policy if /sbin/tomoyo-init exists and /sbin/init is requested
59 * for the first time.
60 */
61 if (!tomoyo_policy_loaded)
62 tomoyo_load_policy(bprm->filename);
63 /*
64 * Tell tomoyo_bprm_check_security() is called for the first time of an
65 * execve operation.
66 */
67 bprm->cred->security = NULL;
68 return 0;
69}
70
71static int tomoyo_bprm_check_security(struct linux_binprm *bprm)
72{
73 struct tomoyo_domain_info *domain = bprm->cred->security;
74
75 /*
76 * Execute permission is checked against pathname passed to do_execve()
77 * using current domain.
78 */
79 if (!domain)
80 return tomoyo_find_next_domain(bprm);
81 /*
82 * Read permission is checked against interpreters using next domain.
83 * '1' is the result of open_to_namei_flags(O_RDONLY).
84 */
85 return tomoyo_check_open_permission(domain, &bprm->file->f_path, 1);
86}
87
88#ifdef CONFIG_SYSCTL
89
90static int tomoyo_prepend(char **buffer, int *buflen, const char *str)
91{
92 int namelen = strlen(str);
93
94 if (*buflen < namelen)
95 return -ENOMEM;
96 *buflen -= namelen;
97 *buffer -= namelen;
98 memcpy(*buffer, str, namelen);
99 return 0;
100}
101
102/**
103 * tomoyo_sysctl_path - return the realpath of a ctl_table.
104 * @table: pointer to "struct ctl_table".
105 *
106 * Returns realpath(3) of the @table on success.
107 * Returns NULL on failure.
108 *
109 * This function uses tomoyo_alloc(), so the caller must call tomoyo_free()
110 * if this function didn't return NULL.
111 */
112static char *tomoyo_sysctl_path(struct ctl_table *table)
113{
114 int buflen = TOMOYO_MAX_PATHNAME_LEN;
115 char *buf = tomoyo_alloc(buflen);
116 char *end = buf + buflen;
117 int error = -ENOMEM;
118
119 if (!buf)
120 return NULL;
121
122 *--end = '\0';
123 buflen--;
124 while (table) {
125 char num[32];
126 const char *sp = table->procname;
127
128 if (!sp) {
129 memset(num, 0, sizeof(num));
130 snprintf(num, sizeof(num) - 1, "=%d=", table->ctl_name);
131 sp = num;
132 }
133 if (tomoyo_prepend(&end, &buflen, sp) ||
134 tomoyo_prepend(&end, &buflen, "/"))
135 goto out;
136 table = table->parent;
137 }
138 if (tomoyo_prepend(&end, &buflen, "/proc/sys"))
139 goto out;
140 error = tomoyo_encode(buf, end - buf, end);
141 out:
142 if (!error)
143 return buf;
144 tomoyo_free(buf);
145 return NULL;
146}
147
148static int tomoyo_sysctl(struct ctl_table *table, int op)
149{
150 int error;
151 char *name;
152
153 op &= MAY_READ | MAY_WRITE;
154 if (!op)
155 return 0;
156 name = tomoyo_sysctl_path(table);
157 if (!name)
158 return -ENOMEM;
159 error = tomoyo_check_file_perm(tomoyo_domain(), name, op);
160 tomoyo_free(name);
161 return error;
162}
163#endif
164
165static int tomoyo_path_truncate(struct path *path, loff_t length,
166 unsigned int time_attrs)
167{
168 return tomoyo_check_1path_perm(tomoyo_domain(),
169 TOMOYO_TYPE_TRUNCATE_ACL,
170 path);
171}
172
173static int tomoyo_path_unlink(struct path *parent, struct dentry *dentry)
174{
175 struct path path = { parent->mnt, dentry };
176 return tomoyo_check_1path_perm(tomoyo_domain(),
177 TOMOYO_TYPE_UNLINK_ACL,
178 &path);
179}
180
181static int tomoyo_path_mkdir(struct path *parent, struct dentry *dentry,
182 int mode)
183{
184 struct path path = { parent->mnt, dentry };
185 return tomoyo_check_1path_perm(tomoyo_domain(),
186 TOMOYO_TYPE_MKDIR_ACL,
187 &path);
188}
189
190static int tomoyo_path_rmdir(struct path *parent, struct dentry *dentry)
191{
192 struct path path = { parent->mnt, dentry };
193 return tomoyo_check_1path_perm(tomoyo_domain(),
194 TOMOYO_TYPE_RMDIR_ACL,
195 &path);
196}
197
198static int tomoyo_path_symlink(struct path *parent, struct dentry *dentry,
199 const char *old_name)
200{
201 struct path path = { parent->mnt, dentry };
202 return tomoyo_check_1path_perm(tomoyo_domain(),
203 TOMOYO_TYPE_SYMLINK_ACL,
204 &path);
205}
206
207static int tomoyo_path_mknod(struct path *parent, struct dentry *dentry,
208 int mode, unsigned int dev)
209{
210 struct path path = { parent->mnt, dentry };
211 int type = TOMOYO_TYPE_CREATE_ACL;
212
213 switch (mode & S_IFMT) {
214 case S_IFCHR:
215 type = TOMOYO_TYPE_MKCHAR_ACL;
216 break;
217 case S_IFBLK:
218 type = TOMOYO_TYPE_MKBLOCK_ACL;
219 break;
220 case S_IFIFO:
221 type = TOMOYO_TYPE_MKFIFO_ACL;
222 break;
223 case S_IFSOCK:
224 type = TOMOYO_TYPE_MKSOCK_ACL;
225 break;
226 }
227 return tomoyo_check_1path_perm(tomoyo_domain(),
228 type, &path);
229}
230
231static int tomoyo_path_link(struct dentry *old_dentry, struct path *new_dir,
232 struct dentry *new_dentry)
233{
234 struct path path1 = { new_dir->mnt, old_dentry };
235 struct path path2 = { new_dir->mnt, new_dentry };
236 return tomoyo_check_2path_perm(tomoyo_domain(),
237 TOMOYO_TYPE_LINK_ACL,
238 &path1, &path2);
239}
240
241static int tomoyo_path_rename(struct path *old_parent,
242 struct dentry *old_dentry,
243 struct path *new_parent,
244 struct dentry *new_dentry)
245{
246 struct path path1 = { old_parent->mnt, old_dentry };
247 struct path path2 = { new_parent->mnt, new_dentry };
248 return tomoyo_check_2path_perm(tomoyo_domain(),
249 TOMOYO_TYPE_RENAME_ACL,
250 &path1, &path2);
251}
252
253static int tomoyo_file_fcntl(struct file *file, unsigned int cmd,
254 unsigned long arg)
255{
256 if (cmd == F_SETFL && ((arg ^ file->f_flags) & O_APPEND))
257 return tomoyo_check_rewrite_permission(tomoyo_domain(), file);
258 return 0;
259}
260
261static int tomoyo_dentry_open(struct file *f, const struct cred *cred)
262{
263 int flags = f->f_flags;
264
265 if ((flags + 1) & O_ACCMODE)
266 flags++;
267 flags |= f->f_flags & (O_APPEND | O_TRUNC);
268 /* Don't check read permission here if called from do_execve(). */
269 if (current->in_execve)
270 return 0;
271 return tomoyo_check_open_permission(tomoyo_domain(), &f->f_path, flags);
272}
273
274/*
275 * tomoyo_security_ops is a "struct security_operations" which is used for
276 * registering TOMOYO.
277 */
278static struct security_operations tomoyo_security_ops = {
279 .name = "tomoyo",
280 .cred_alloc_blank = tomoyo_cred_alloc_blank,
281 .cred_prepare = tomoyo_cred_prepare,
282 .cred_transfer = tomoyo_cred_transfer,
283 .bprm_set_creds = tomoyo_bprm_set_creds,
284 .bprm_check_security = tomoyo_bprm_check_security,
285#ifdef CONFIG_SYSCTL
286 .sysctl = tomoyo_sysctl,
287#endif
288 .file_fcntl = tomoyo_file_fcntl,
289 .dentry_open = tomoyo_dentry_open,
290 .path_truncate = tomoyo_path_truncate,
291 .path_unlink = tomoyo_path_unlink,
292 .path_mkdir = tomoyo_path_mkdir,
293 .path_rmdir = tomoyo_path_rmdir,
294 .path_symlink = tomoyo_path_symlink,
295 .path_mknod = tomoyo_path_mknod,
296 .path_link = tomoyo_path_link,
297 .path_rename = tomoyo_path_rename,
298};
299
300static int __init tomoyo_init(void)
301{
302 struct cred *cred = (struct cred *) current_cred();
303
304 if (!security_module_enable(&tomoyo_security_ops))
305 return 0;
306 /* register ourselves with the security framework */
307 if (register_security(&tomoyo_security_ops))
308 panic("Failure registering TOMOYO Linux");
309 printk(KERN_INFO "TOMOYO Linux initialized\n");
310 cred->security = &tomoyo_kernel_domain;
311 tomoyo_realpath_init();
312 return 0;
313}
314
315security_initcall(tomoyo_init);