1
2
3
4
5
6
7
8#include <linux/export.h>
9#include <linux/time.h>
10#include <linux/mm.h>
11#include <linux/string.h>
12#include <linux/capability.h>
13#include <linux/fsnotify.h>
14#include <linux/fcntl.h>
15#include <linux/security.h>
16#include <linux/evm.h>
17#include <linux/ima.h>
18
19
20
21
22
23
24
25
26
27
28
29
30
31int inode_change_ok(const struct inode *inode, struct iattr *attr)
32{
33 unsigned int ia_valid = attr->ia_valid;
34
35
36
37
38
39 if (ia_valid & ATTR_SIZE) {
40 int error = inode_newsize_ok(inode, attr->ia_size);
41 if (error)
42 return error;
43 }
44
45
46 if (ia_valid & ATTR_FORCE)
47 return 0;
48
49
50 if ((ia_valid & ATTR_UID) &&
51 (!uid_eq(current_fsuid(), inode->i_uid) ||
52 !uid_eq(attr->ia_uid, inode->i_uid)) &&
53 !inode_capable(inode, CAP_CHOWN))
54 return -EPERM;
55
56
57 if ((ia_valid & ATTR_GID) &&
58 (!uid_eq(current_fsuid(), inode->i_uid) ||
59 (!in_group_p(attr->ia_gid) && !gid_eq(attr->ia_gid, inode->i_gid))) &&
60 !inode_capable(inode, CAP_CHOWN))
61 return -EPERM;
62
63
64 if (ia_valid & ATTR_MODE) {
65 if (!inode_owner_or_capable(inode))
66 return -EPERM;
67
68 if (!in_group_p((ia_valid & ATTR_GID) ? attr->ia_gid :
69 inode->i_gid) &&
70 !inode_capable(inode, CAP_FSETID))
71 attr->ia_mode &= ~S_ISGID;
72 }
73
74
75 if (ia_valid & (ATTR_MTIME_SET | ATTR_ATIME_SET | ATTR_TIMES_SET)) {
76 if (!inode_owner_or_capable(inode))
77 return -EPERM;
78 }
79
80 return 0;
81}
82EXPORT_SYMBOL(inode_change_ok);
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99int inode_newsize_ok(const struct inode *inode, loff_t offset)
100{
101 if (inode->i_size < offset) {
102 unsigned long limit;
103
104 limit = rlimit(RLIMIT_FSIZE);
105 if (limit != RLIM_INFINITY && offset > limit)
106 goto out_sig;
107 if (offset > inode->i_sb->s_maxbytes)
108 goto out_big;
109 } else {
110
111
112
113
114
115 if (IS_SWAPFILE(inode))
116 return -ETXTBSY;
117 }
118
119 return 0;
120out_sig:
121 send_sig(SIGXFSZ, current, 0);
122out_big:
123 return -EFBIG;
124}
125EXPORT_SYMBOL(inode_newsize_ok);
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142void setattr_copy(struct inode *inode, const struct iattr *attr)
143{
144 unsigned int ia_valid = attr->ia_valid;
145
146 if (ia_valid & ATTR_UID)
147 inode->i_uid = attr->ia_uid;
148 if (ia_valid & ATTR_GID)
149 inode->i_gid = attr->ia_gid;
150 if (ia_valid & ATTR_ATIME)
151 inode->i_atime = timespec_trunc(attr->ia_atime,
152 inode->i_sb->s_time_gran);
153 if (ia_valid & ATTR_MTIME)
154 inode->i_mtime = timespec_trunc(attr->ia_mtime,
155 inode->i_sb->s_time_gran);
156 if (ia_valid & ATTR_CTIME)
157 inode->i_ctime = timespec_trunc(attr->ia_ctime,
158 inode->i_sb->s_time_gran);
159 if (ia_valid & ATTR_MODE) {
160 umode_t mode = attr->ia_mode;
161
162 if (!in_group_p(inode->i_gid) &&
163 !inode_capable(inode, CAP_FSETID))
164 mode &= ~S_ISGID;
165 inode->i_mode = mode;
166 }
167}
168EXPORT_SYMBOL(setattr_copy);
169
170int notify_change(struct dentry * dentry, struct iattr * attr)
171{
172 struct inode *inode = dentry->d_inode;
173 umode_t mode = inode->i_mode;
174 int error;
175 struct timespec now;
176 unsigned int ia_valid = attr->ia_valid;
177
178 WARN_ON_ONCE(!mutex_is_locked(&inode->i_mutex));
179
180 if (ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID | ATTR_TIMES_SET)) {
181 if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
182 return -EPERM;
183 }
184
185 if ((ia_valid & ATTR_SIZE) && IS_I_VERSION(inode)) {
186 if (attr->ia_size != inode->i_size)
187 inode_inc_iversion(inode);
188 }
189
190 if ((ia_valid & ATTR_MODE)) {
191 umode_t amode = attr->ia_mode;
192
193 if (is_sxid(amode))
194 inode->i_flags &= ~S_NOSEC;
195 }
196
197 now = current_fs_time(inode->i_sb);
198
199 attr->ia_ctime = now;
200 if (!(ia_valid & ATTR_ATIME_SET))
201 attr->ia_atime = now;
202 if (!(ia_valid & ATTR_MTIME_SET))
203 attr->ia_mtime = now;
204 if (ia_valid & ATTR_KILL_PRIV) {
205 attr->ia_valid &= ~ATTR_KILL_PRIV;
206 ia_valid &= ~ATTR_KILL_PRIV;
207 error = security_inode_need_killpriv(dentry);
208 if (error > 0)
209 error = security_inode_killpriv(dentry);
210 if (error)
211 return error;
212 }
213
214
215
216
217
218
219
220
221 if ((ia_valid & (ATTR_KILL_SUID|ATTR_KILL_SGID)) &&
222 (ia_valid & ATTR_MODE))
223 BUG();
224
225 if (ia_valid & ATTR_KILL_SUID) {
226 if (mode & S_ISUID) {
227 ia_valid = attr->ia_valid |= ATTR_MODE;
228 attr->ia_mode = (inode->i_mode & ~S_ISUID);
229 }
230 }
231 if (ia_valid & ATTR_KILL_SGID) {
232 if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) {
233 if (!(ia_valid & ATTR_MODE)) {
234 ia_valid = attr->ia_valid |= ATTR_MODE;
235 attr->ia_mode = inode->i_mode;
236 }
237 attr->ia_mode &= ~S_ISGID;
238 }
239 }
240 if (!(attr->ia_valid & ~(ATTR_KILL_SUID | ATTR_KILL_SGID)))
241 return 0;
242
243 error = security_inode_setattr(dentry, attr);
244 if (error)
245 return error;
246
247 if (inode->i_op->setattr)
248 error = inode->i_op->setattr(dentry, attr);
249 else
250 error = simple_setattr(dentry, attr);
251
252 if (!error) {
253 fsnotify_change(dentry, ia_valid);
254 ima_inode_post_setattr(dentry);
255 evm_inode_post_setattr(dentry, ia_valid);
256 }
257
258 return error;
259}
260EXPORT_SYMBOL(notify_change);
261