8a00ade85166615a67fc768f595e00ac782b0863
[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) 2005-2009  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_alloc_blank(struct cred *new, gfp_t gfp)
18 {
19         new->security = NULL;
20         return 0;
21 }
22
23 static 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
34 static 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
43 static 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
71 static 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 static int tomoyo_path_truncate(struct path *path, loff_t length,
89                                 unsigned int time_attrs)
90 {
91         return tomoyo_check_1path_perm(tomoyo_domain(),
92                                        TOMOYO_TYPE_TRUNCATE_ACL,
93                                        path);
94 }
95
96 static int tomoyo_path_unlink(struct path *parent, struct dentry *dentry)
97 {
98         struct path path = { parent->mnt, dentry };
99         return tomoyo_check_1path_perm(tomoyo_domain(),
100                                        TOMOYO_TYPE_UNLINK_ACL,
101                                        &path);
102 }
103
104 static int tomoyo_path_mkdir(struct path *parent, struct dentry *dentry,
105                              int mode)
106 {
107         struct path path = { parent->mnt, dentry };
108         return tomoyo_check_1path_perm(tomoyo_domain(),
109                                        TOMOYO_TYPE_MKDIR_ACL,
110                                        &path);
111 }
112
113 static int tomoyo_path_rmdir(struct path *parent, struct dentry *dentry)
114 {
115         struct path path = { parent->mnt, dentry };
116         return tomoyo_check_1path_perm(tomoyo_domain(),
117                                        TOMOYO_TYPE_RMDIR_ACL,
118                                        &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_check_1path_perm(tomoyo_domain(),
126                                        TOMOYO_TYPE_SYMLINK_ACL,
127                                        &path);
128 }
129
130 static int tomoyo_path_mknod(struct path *parent, struct dentry *dentry,
131                              int mode, unsigned int dev)
132 {
133         struct path path = { parent->mnt, dentry };
134         int type = TOMOYO_TYPE_CREATE_ACL;
135
136         switch (mode & S_IFMT) {
137         case S_IFCHR:
138                 type = TOMOYO_TYPE_MKCHAR_ACL;
139                 break;
140         case S_IFBLK:
141                 type = TOMOYO_TYPE_MKBLOCK_ACL;
142                 break;
143         case S_IFIFO:
144                 type = TOMOYO_TYPE_MKFIFO_ACL;
145                 break;
146         case S_IFSOCK:
147                 type = TOMOYO_TYPE_MKSOCK_ACL;
148                 break;
149         }
150         return tomoyo_check_1path_perm(tomoyo_domain(),
151                                        type, &path);
152 }
153
154 static int tomoyo_path_link(struct dentry *old_dentry, struct path *new_dir,
155                             struct dentry *new_dentry)
156 {
157         struct path path1 = { new_dir->mnt, old_dentry };
158         struct path path2 = { new_dir->mnt, new_dentry };
159         return tomoyo_check_2path_perm(tomoyo_domain(),
160                                        TOMOYO_TYPE_LINK_ACL,
161                                        &path1, &path2);
162 }
163
164 static int tomoyo_path_rename(struct path *old_parent,
165                               struct dentry *old_dentry,
166                               struct path *new_parent,
167                               struct dentry *new_dentry)
168 {
169         struct path path1 = { old_parent->mnt, old_dentry };
170         struct path path2 = { new_parent->mnt, new_dentry };
171         return tomoyo_check_2path_perm(tomoyo_domain(),
172                                        TOMOYO_TYPE_RENAME_ACL,
173                                        &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_check_rewrite_permission(tomoyo_domain(), file);
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
188         if ((flags + 1) & O_ACCMODE)
189                 flags++;
190         flags |= f->f_flags & (O_APPEND | O_TRUNC);
191         /* Don't check read permission here if called from do_execve(). */
192         if (current->in_execve)
193                 return 0;
194         return tomoyo_check_open_permission(tomoyo_domain(), &f->f_path, flags);
195 }
196
197 /*
198  * tomoyo_security_ops is a "struct security_operations" which is used for
199  * registering TOMOYO.
200  */
201 static struct security_operations tomoyo_security_ops = {
202         .name                = "tomoyo",
203         .cred_alloc_blank    = tomoyo_cred_alloc_blank,
204         .cred_prepare        = tomoyo_cred_prepare,
205         .cred_transfer       = tomoyo_cred_transfer,
206         .bprm_set_creds      = tomoyo_bprm_set_creds,
207         .bprm_check_security = tomoyo_bprm_check_security,
208         .file_fcntl          = tomoyo_file_fcntl,
209         .dentry_open         = tomoyo_dentry_open,
210         .path_truncate       = tomoyo_path_truncate,
211         .path_unlink         = tomoyo_path_unlink,
212         .path_mkdir          = tomoyo_path_mkdir,
213         .path_rmdir          = tomoyo_path_rmdir,
214         .path_symlink        = tomoyo_path_symlink,
215         .path_mknod          = tomoyo_path_mknod,
216         .path_link           = tomoyo_path_link,
217         .path_rename         = tomoyo_path_rename,
218 };
219
220 static int __init tomoyo_init(void)
221 {
222         struct cred *cred = (struct cred *) current_cred();
223
224         if (!security_module_enable(&tomoyo_security_ops))
225                 return 0;
226         /* register ourselves with the security framework */
227         if (register_security(&tomoyo_security_ops))
228                 panic("Failure registering TOMOYO Linux");
229         printk(KERN_INFO "TOMOYO Linux initialized\n");
230         cred->security = &tomoyo_kernel_domain;
231         tomoyo_realpath_init();
232         return 0;
233 }
234
235 security_initcall(tomoyo_init);