Home Home > GIT Browse
summaryrefslogtreecommitdiff
path: root/fs/attr.c
blob: f8dfc2269d85634aa61ebb19a761e986ea0bbc93 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
/*
 *  linux/fs/attr.c
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 *  changes by Thomas Schoebel-Theuer
 */

#include <linux/module.h>
#include <linux/time.h>
#include <linux/mm.h>
#include <linux/string.h>
#include <linux/capability.h>
#include <linux/fsnotify.h>
#include <linux/fcntl.h>
#include <linux/quotaops.h>
#include <linux/security.h>

/* Taken over from the old code... */

/* POSIX UID/GID verification for setting inode attributes. */
int inode_change_ok(struct inode *inode, struct iattr *attr)
{
	int retval = -EPERM;
	unsigned int ia_valid = attr->ia_valid;

	/* If force is set do it anyway. */
	if (ia_valid & ATTR_FORCE)
		goto fine;

	/* Make sure a caller can chown. */
	if ((ia_valid & ATTR_UID) &&
	    (current->fsuid != inode->i_uid ||
	     attr->ia_uid != inode->i_uid) && !capable(CAP_CHOWN))
		goto error;

	/* Make sure caller can chgrp. */
	if ((ia_valid & ATTR_GID) &&
	    (current->fsuid != inode->i_uid ||
	    (!in_group_p(attr->ia_gid) && attr->ia_gid != inode->i_gid)) &&
	    !capable(CAP_CHOWN))
		goto error;

	/* Make sure a caller can chmod. */
	if (ia_valid & ATTR_MODE) {
		if (!is_owner_or_cap(inode))
			goto error;
		/* Also check the setgid bit! */
		if (!in_group_p((ia_valid & ATTR_GID) ? attr->ia_gid :
				inode->i_gid) && !capable(CAP_FSETID))
			attr->ia_mode &= ~S_ISGID;
	}

	/* Check for setting the inode time. */
	if (ia_valid & (ATTR_MTIME_SET | ATTR_ATIME_SET)) {
		if (!is_owner_or_cap(inode))
			goto error;
	}
fine:
	retval = 0;
error:
	return retval;
}

EXPORT_SYMBOL(inode_change_ok);

int inode_setattr(struct inode * inode, struct iattr * attr)
{
	unsigned int ia_valid = attr->ia_valid;

	if (ia_valid & ATTR_SIZE &&
	    attr->ia_size != i_size_read(inode)) {
		int error = vmtruncate(inode, attr->ia_size);
		if (error)
			return error;
	}

	if (ia_valid & ATTR_UID)
		inode->i_uid = attr->ia_uid;
	if (ia_valid & ATTR_GID)
		inode->i_gid = attr->ia_gid;
	if (ia_valid & ATTR_ATIME)
		inode->i_atime = timespec_trunc(attr->ia_atime,
						inode->i_sb->s_time_gran);
	if (ia_valid & ATTR_MTIME)
		inode->i_mtime = timespec_trunc(attr->ia_mtime,
						inode->i_sb->s_time_gran);
	if (ia_valid & ATTR_CTIME)
		inode->i_ctime = timespec_trunc(attr->ia_ctime,
						inode->i_sb->s_time_gran);
	if (ia_valid & ATTR_MODE) {
		umode_t mode = attr->ia_mode;

		if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID))
			mode &= ~S_ISGID;
		inode->i_mode = mode;
	}
	mark_inode_dirty(inode);

	return 0;
}
EXPORT_SYMBOL(inode_setattr);

int notify_change(struct dentry * dentry, struct iattr * attr)
{
	struct inode *inode = dentry->d_inode;
	mode_t mode;
	int error;
	struct timespec now;
	unsigned int ia_valid = attr->ia_valid;

	mode = inode->i_mode;
	now = current_fs_time(inode->i_sb);

	attr->ia_ctime = now;
	if (!(ia_valid & ATTR_ATIME_SET))
		attr->ia_atime = now;
	if (!(ia_valid & ATTR_MTIME_SET))
		attr->ia_mtime = now;
	if (ia_valid & ATTR_KILL_SUID) {
		attr->ia_valid &= ~ATTR_KILL_SUID;
		if (mode & S_ISUID) {
			if (!(ia_valid & ATTR_MODE)) {
				ia_valid = attr->ia_valid |= ATTR_MODE;
				attr->ia_mode = inode->i_mode;
			}
			attr->ia_mode &= ~S_ISUID;
		}
	}
	if (ia_valid & ATTR_KILL_SGID) {
		attr->ia_valid &= ~ ATTR_KILL_SGID;
		if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) {
			if (!(ia_valid & ATTR_MODE)) {
				ia_valid = attr->ia_valid |= ATTR_MODE;
				attr->ia_mode = inode->i_mode;
			}
			attr->ia_mode &= ~S_ISGID;
		}
	}
	if (!attr->ia_valid)
		return 0;

	if (ia_valid & ATTR_SIZE)
		down_write(&dentry->d_inode->i_alloc_sem);

	if (inode->i_op && inode->i_op->setattr) {
		error = security_inode_setattr(dentry, attr);
		if (!error)
			error = inode->i_op->setattr(dentry, attr);
	} else {
		error = inode_change_ok(inode, attr);
		if (!error)
			error = security_inode_setattr(dentry, attr);
		if (!error) {
			if ((ia_valid & ATTR_UID && attr->ia_uid != inode->i_uid) ||
			    (ia_valid & ATTR_GID && attr->ia_gid != inode->i_gid))
				error = DQUOT_TRANSFER(inode, attr) ? -EDQUOT : 0;
			if (!error)
				error = inode_setattr(inode, attr);
		}
	}

	if (ia_valid & ATTR_SIZE)
		up_write(&dentry->d_inode->i_alloc_sem);

	if (!error)
		fsnotify_change(dentry, ia_valid);

	return error;
}

EXPORT_SYMBOL(notify_change);