1 #include <linux/syscalls.h>
2 #include <linux/export.h>
3 #include <linux/fs.h>
4 #include <linux/file.h>
5 #include <linux/mount.h>
6 #include <linux/namei.h>
7 #include <linux/statfs.h>
8 #include <linux/security.h>
9 #include <linux/uaccess.h>
10 #include "internal.h"
11
flags_by_mnt(int mnt_flags)12 static int flags_by_mnt(int mnt_flags)
13 {
14 int flags = 0;
15
16 if (mnt_flags & MNT_READONLY)
17 flags |= ST_RDONLY;
18 if (mnt_flags & MNT_NOSUID)
19 flags |= ST_NOSUID;
20 if (mnt_flags & MNT_NODEV)
21 flags |= ST_NODEV;
22 if (mnt_flags & MNT_NOEXEC)
23 flags |= ST_NOEXEC;
24 if (mnt_flags & MNT_NOATIME)
25 flags |= ST_NOATIME;
26 if (mnt_flags & MNT_NODIRATIME)
27 flags |= ST_NODIRATIME;
28 if (mnt_flags & MNT_RELATIME)
29 flags |= ST_RELATIME;
30 return flags;
31 }
32
flags_by_sb(int s_flags)33 static int flags_by_sb(int s_flags)
34 {
35 int flags = 0;
36 if (s_flags & MS_SYNCHRONOUS)
37 flags |= ST_SYNCHRONOUS;
38 if (s_flags & MS_MANDLOCK)
39 flags |= ST_MANDLOCK;
40 return flags;
41 }
42
calculate_f_flags(struct vfsmount * mnt)43 static int calculate_f_flags(struct vfsmount *mnt)
44 {
45 return ST_VALID | flags_by_mnt(mnt->mnt_flags) |
46 flags_by_sb(mnt->mnt_sb->s_flags);
47 }
48
statfs_by_dentry(struct dentry * dentry,struct kstatfs * buf)49 static int statfs_by_dentry(struct dentry *dentry, struct kstatfs *buf)
50 {
51 int retval;
52
53 if (!dentry->d_sb->s_op->statfs)
54 return -ENOSYS;
55
56 memset(buf, 0, sizeof(*buf));
57 retval = security_sb_statfs(dentry);
58 if (retval)
59 return retval;
60 retval = dentry->d_sb->s_op->statfs(dentry, buf);
61 if (retval == 0 && buf->f_frsize == 0)
62 buf->f_frsize = buf->f_bsize;
63 return retval;
64 }
65
vfs_statfs(struct path * path,struct kstatfs * buf)66 int vfs_statfs(struct path *path, struct kstatfs *buf)
67 {
68 int error;
69
70 error = statfs_by_dentry(path->dentry, buf);
71 if (!error)
72 buf->f_flags = calculate_f_flags(path->mnt);
73 return error;
74 }
75 EXPORT_SYMBOL(vfs_statfs);
76
user_statfs(const char __user * pathname,struct kstatfs * st)77 int user_statfs(const char __user *pathname, struct kstatfs *st)
78 {
79 struct path path;
80 int error = user_path_at(AT_FDCWD, pathname, LOOKUP_FOLLOW|LOOKUP_AUTOMOUNT, &path);
81 if (!error) {
82 error = vfs_statfs(&path, st);
83 path_put(&path);
84 }
85 return error;
86 }
87
fd_statfs(int fd,struct kstatfs * st)88 int fd_statfs(int fd, struct kstatfs *st)
89 {
90 struct file *file = fget_raw(fd);
91 int error = -EBADF;
92 if (file) {
93 error = vfs_statfs(&file->f_path, st);
94 fput(file);
95 }
96 return error;
97 }
98
do_statfs_native(struct kstatfs * st,struct statfs __user * p)99 static int do_statfs_native(struct kstatfs *st, struct statfs __user *p)
100 {
101 struct statfs buf;
102
103 if (sizeof(buf) == sizeof(*st))
104 memcpy(&buf, st, sizeof(*st));
105 else {
106 if (sizeof buf.f_blocks == 4) {
107 if ((st->f_blocks | st->f_bfree | st->f_bavail |
108 st->f_bsize | st->f_frsize) &
109 0xffffffff00000000ULL)
110 return -EOVERFLOW;
111 /*
112 * f_files and f_ffree may be -1; it's okay to stuff
113 * that into 32 bits
114 */
115 if (st->f_files != -1 &&
116 (st->f_files & 0xffffffff00000000ULL))
117 return -EOVERFLOW;
118 if (st->f_ffree != -1 &&
119 (st->f_ffree & 0xffffffff00000000ULL))
120 return -EOVERFLOW;
121 }
122
123 buf.f_type = st->f_type;
124 buf.f_bsize = st->f_bsize;
125 buf.f_blocks = st->f_blocks;
126 buf.f_bfree = st->f_bfree;
127 buf.f_bavail = st->f_bavail;
128 buf.f_files = st->f_files;
129 buf.f_ffree = st->f_ffree;
130 buf.f_fsid = st->f_fsid;
131 buf.f_namelen = st->f_namelen;
132 buf.f_frsize = st->f_frsize;
133 buf.f_flags = st->f_flags;
134 memset(buf.f_spare, 0, sizeof(buf.f_spare));
135 }
136 if (copy_to_user(p, &buf, sizeof(buf)))
137 return -EFAULT;
138 return 0;
139 }
140
do_statfs64(struct kstatfs * st,struct statfs64 __user * p)141 static int do_statfs64(struct kstatfs *st, struct statfs64 __user *p)
142 {
143 struct statfs64 buf;
144 if (sizeof(buf) == sizeof(*st))
145 memcpy(&buf, st, sizeof(*st));
146 else {
147 buf.f_type = st->f_type;
148 buf.f_bsize = st->f_bsize;
149 buf.f_blocks = st->f_blocks;
150 buf.f_bfree = st->f_bfree;
151 buf.f_bavail = st->f_bavail;
152 buf.f_files = st->f_files;
153 buf.f_ffree = st->f_ffree;
154 buf.f_fsid = st->f_fsid;
155 buf.f_namelen = st->f_namelen;
156 buf.f_frsize = st->f_frsize;
157 buf.f_flags = st->f_flags;
158 memset(buf.f_spare, 0, sizeof(buf.f_spare));
159 }
160 if (copy_to_user(p, &buf, sizeof(buf)))
161 return -EFAULT;
162 return 0;
163 }
164
SYSCALL_DEFINE2(statfs,const char __user *,pathname,struct statfs __user *,buf)165 SYSCALL_DEFINE2(statfs, const char __user *, pathname, struct statfs __user *, buf)
166 {
167 struct kstatfs st;
168 int error = user_statfs(pathname, &st);
169 if (!error)
170 error = do_statfs_native(&st, buf);
171 return error;
172 }
173
SYSCALL_DEFINE3(statfs64,const char __user *,pathname,size_t,sz,struct statfs64 __user *,buf)174 SYSCALL_DEFINE3(statfs64, const char __user *, pathname, size_t, sz, struct statfs64 __user *, buf)
175 {
176 struct kstatfs st;
177 int error;
178 if (sz != sizeof(*buf))
179 return -EINVAL;
180 error = user_statfs(pathname, &st);
181 if (!error)
182 error = do_statfs64(&st, buf);
183 return error;
184 }
185
SYSCALL_DEFINE2(fstatfs,unsigned int,fd,struct statfs __user *,buf)186 SYSCALL_DEFINE2(fstatfs, unsigned int, fd, struct statfs __user *, buf)
187 {
188 struct kstatfs st;
189 int error = fd_statfs(fd, &st);
190 if (!error)
191 error = do_statfs_native(&st, buf);
192 return error;
193 }
194
SYSCALL_DEFINE3(fstatfs64,unsigned int,fd,size_t,sz,struct statfs64 __user *,buf)195 SYSCALL_DEFINE3(fstatfs64, unsigned int, fd, size_t, sz, struct statfs64 __user *, buf)
196 {
197 struct kstatfs st;
198 int error;
199
200 if (sz != sizeof(*buf))
201 return -EINVAL;
202
203 error = fd_statfs(fd, &st);
204 if (!error)
205 error = do_statfs64(&st, buf);
206 return error;
207 }
208
vfs_ustat(dev_t dev,struct kstatfs * sbuf)209 int vfs_ustat(dev_t dev, struct kstatfs *sbuf)
210 {
211 struct super_block *s = user_get_super(dev);
212 int err;
213 if (!s)
214 return -EINVAL;
215
216 err = statfs_by_dentry(s->s_root, sbuf);
217 drop_super(s);
218 return err;
219 }
220
SYSCALL_DEFINE2(ustat,unsigned,dev,struct ustat __user *,ubuf)221 SYSCALL_DEFINE2(ustat, unsigned, dev, struct ustat __user *, ubuf)
222 {
223 struct ustat tmp;
224 struct kstatfs sbuf;
225 int err = vfs_ustat(new_decode_dev(dev), &sbuf);
226 if (err)
227 return err;
228
229 memset(&tmp,0,sizeof(struct ustat));
230 tmp.f_tfree = sbuf.f_bfree;
231 tmp.f_tinode = sbuf.f_ffree;
232
233 return copy_to_user(ubuf, &tmp, sizeof(struct ustat)) ? -EFAULT : 0;
234 }
235