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8#include <linux/module.h>
9#include <linux/time.h>
10#include <linux/mm.h>
11#include <linux/string.h>
12#include <linux/smp_lock.h>
13#include <linux/capability.h>
14#include <linux/fsnotify.h>
15#include <linux/fcntl.h>
16#include <linux/quotaops.h>
17#include <linux/security.h>
18
19
20
21
22int inode_change_ok(struct inode *inode, struct iattr *attr)
23{
24 int retval = -EPERM;
25 unsigned int ia_valid = attr->ia_valid;
26
27
28 if (ia_valid & ATTR_FORCE)
29 goto fine;
30
31
32 if ((ia_valid & ATTR_UID) &&
33 (current->fsuid != inode->i_uid ||
34 attr->ia_uid != inode->i_uid) && !capable(CAP_CHOWN))
35 goto error;
36
37
38 if ((ia_valid & ATTR_GID) &&
39 (current->fsuid != inode->i_uid ||
40 (!in_group_p(attr->ia_gid) && attr->ia_gid != inode->i_gid)) &&
41 !capable(CAP_CHOWN))
42 goto error;
43
44
45 if (ia_valid & ATTR_MODE) {
46 if ((current->fsuid != inode->i_uid) && !capable(CAP_FOWNER))
47 goto error;
48
49 if (!in_group_p((ia_valid & ATTR_GID) ? attr->ia_gid :
50 inode->i_gid) && !capable(CAP_FSETID))
51 attr->ia_mode &= ~S_ISGID;
52 }
53
54
55 if (ia_valid & (ATTR_MTIME_SET | ATTR_ATIME_SET)) {
56 if (current->fsuid != inode->i_uid && !capable(CAP_FOWNER))
57 goto error;
58 }
59fine:
60 retval = 0;
61error:
62 return retval;
63}
64
65EXPORT_SYMBOL(inode_change_ok);
66
67int inode_setattr(struct inode * inode, struct iattr * attr)
68{
69 unsigned int ia_valid = attr->ia_valid;
70
71 if (ia_valid & ATTR_SIZE &&
72 attr->ia_size != i_size_read(inode)) {
73 int error = vmtruncate(inode, attr->ia_size);
74 if (error)
75 return error;
76 }
77
78 if (ia_valid & ATTR_UID)
79 inode->i_uid = attr->ia_uid;
80 if (ia_valid & ATTR_GID)
81 inode->i_gid = attr->ia_gid;
82 if (ia_valid & ATTR_ATIME)
83 inode->i_atime = timespec_trunc(attr->ia_atime,
84 inode->i_sb->s_time_gran);
85 if (ia_valid & ATTR_MTIME)
86 inode->i_mtime = timespec_trunc(attr->ia_mtime,
87 inode->i_sb->s_time_gran);
88 if (ia_valid & ATTR_CTIME)
89 inode->i_ctime = timespec_trunc(attr->ia_ctime,
90 inode->i_sb->s_time_gran);
91 if (ia_valid & ATTR_MODE) {
92 umode_t mode = attr->ia_mode;
93
94 if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID))
95 mode &= ~S_ISGID;
96 inode->i_mode = mode;
97 }
98 mark_inode_dirty(inode);
99
100 return 0;
101}
102EXPORT_SYMBOL(inode_setattr);
103
104int notify_change(struct dentry * dentry, struct iattr * attr)
105{
106 struct inode *inode = dentry->d_inode;
107 mode_t mode;
108 int error;
109 struct timespec now;
110 unsigned int ia_valid = attr->ia_valid;
111
112 mode = inode->i_mode;
113 now = current_fs_time(inode->i_sb);
114
115 attr->ia_ctime = now;
116 if (!(ia_valid & ATTR_ATIME_SET))
117 attr->ia_atime = now;
118 if (!(ia_valid & ATTR_MTIME_SET))
119 attr->ia_mtime = now;
120 if (ia_valid & ATTR_KILL_SUID) {
121 attr->ia_valid &= ~ATTR_KILL_SUID;
122 if (mode & S_ISUID) {
123 if (!(ia_valid & ATTR_MODE)) {
124 ia_valid = attr->ia_valid |= ATTR_MODE;
125 attr->ia_mode = inode->i_mode;
126 }
127 attr->ia_mode &= ~S_ISUID;
128 }
129 }
130 if (ia_valid & ATTR_KILL_SGID) {
131 attr->ia_valid &= ~ ATTR_KILL_SGID;
132 if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) {
133 if (!(ia_valid & ATTR_MODE)) {
134 ia_valid = attr->ia_valid |= ATTR_MODE;
135 attr->ia_mode = inode->i_mode;
136 }
137 attr->ia_mode &= ~S_ISGID;
138 }
139 }
140 if (!attr->ia_valid)
141 return 0;
142
143 if (ia_valid & ATTR_SIZE)
144 down_write(&dentry->d_inode->i_alloc_sem);
145
146 if (inode->i_op && inode->i_op->setattr) {
147 error = security_inode_setattr(dentry, attr);
148 if (!error)
149 error = inode->i_op->setattr(dentry, attr);
150 } else {
151 error = inode_change_ok(inode, attr);
152 if (!error)
153 error = security_inode_setattr(dentry, attr);
154 if (!error) {
155 if ((ia_valid & ATTR_UID && attr->ia_uid != inode->i_uid) ||
156 (ia_valid & ATTR_GID && attr->ia_gid != inode->i_gid))
157 error = DQUOT_TRANSFER(inode, attr) ? -EDQUOT : 0;
158 if (!error)
159 error = inode_setattr(inode, attr);
160 }
161 }
162
163 if (ia_valid & ATTR_SIZE)
164 up_write(&dentry->d_inode->i_alloc_sem);
165
166 if (!error)
167 fsnotify_change(dentry, ia_valid);
168
169 return error;
170}
171
172EXPORT_SYMBOL(notify_change);
173
