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 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 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 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 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 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 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 88 int fd_statfs(int fd, struct kstatfs *st) 89 { 90 int fput_needed; 91 struct file *file = fget_light(fd, &fput_needed); 92 int error = -EBADF; 93 if (file) { 94 error = vfs_statfs(&file->f_path, st); 95 fput_light(file, fput_needed); 96 } 97 return error; 98 } 99 100 static int do_statfs_native(struct kstatfs *st, struct statfs __user *p) 101 { 102 struct statfs buf; 103 104 if (sizeof(buf) == sizeof(*st)) 105 memcpy(&buf, st, sizeof(*st)); 106 else { 107 if (sizeof buf.f_blocks == 4) { 108 if ((st->f_blocks | st->f_bfree | st->f_bavail | 109 st->f_bsize | st->f_frsize) & 110 0xffffffff00000000ULL) 111 return -EOVERFLOW; 112 /* 113 * f_files and f_ffree may be -1; it's okay to stuff 114 * that into 32 bits 115 */ 116 if (st->f_files != -1 && 117 (st->f_files & 0xffffffff00000000ULL)) 118 return -EOVERFLOW; 119 if (st->f_ffree != -1 && 120 (st->f_ffree & 0xffffffff00000000ULL)) 121 return -EOVERFLOW; 122 } 123 124 buf.f_type = st->f_type; 125 buf.f_bsize = st->f_bsize; 126 buf.f_blocks = st->f_blocks; 127 buf.f_bfree = st->f_bfree; 128 buf.f_bavail = st->f_bavail; 129 buf.f_files = st->f_files; 130 buf.f_ffree = st->f_ffree; 131 buf.f_fsid = st->f_fsid; 132 buf.f_namelen = st->f_namelen; 133 buf.f_frsize = st->f_frsize; 134 buf.f_flags = st->f_flags; 135 memset(buf.f_spare, 0, sizeof(buf.f_spare)); 136 } 137 if (copy_to_user(p, &buf, sizeof(buf))) 138 return -EFAULT; 139 return 0; 140 } 141 142 static int do_statfs64(struct kstatfs *st, struct statfs64 __user *p) 143 { 144 struct statfs64 buf; 145 if (sizeof(buf) == sizeof(*st)) 146 memcpy(&buf, st, sizeof(*st)); 147 else { 148 buf.f_type = st->f_type; 149 buf.f_bsize = st->f_bsize; 150 buf.f_blocks = st->f_blocks; 151 buf.f_bfree = st->f_bfree; 152 buf.f_bavail = st->f_bavail; 153 buf.f_files = st->f_files; 154 buf.f_ffree = st->f_ffree; 155 buf.f_fsid = st->f_fsid; 156 buf.f_namelen = st->f_namelen; 157 buf.f_frsize = st->f_frsize; 158 buf.f_flags = st->f_flags; 159 memset(buf.f_spare, 0, sizeof(buf.f_spare)); 160 } 161 if (copy_to_user(p, &buf, sizeof(buf))) 162 return -EFAULT; 163 return 0; 164 } 165 166 SYSCALL_DEFINE2(statfs, const char __user *, pathname, struct statfs __user *, buf) 167 { 168 struct kstatfs st; 169 int error = user_statfs(pathname, &st); 170 if (!error) 171 error = do_statfs_native(&st, buf); 172 return error; 173 } 174 175 SYSCALL_DEFINE3(statfs64, const char __user *, pathname, size_t, sz, struct statfs64 __user *, buf) 176 { 177 struct kstatfs st; 178 int error; 179 if (sz != sizeof(*buf)) 180 return -EINVAL; 181 error = user_statfs(pathname, &st); 182 if (!error) 183 error = do_statfs64(&st, buf); 184 return error; 185 } 186 187 SYSCALL_DEFINE2(fstatfs, unsigned int, fd, struct statfs __user *, buf) 188 { 189 struct kstatfs st; 190 int error = fd_statfs(fd, &st); 191 if (!error) 192 error = do_statfs_native(&st, buf); 193 return error; 194 } 195 196 SYSCALL_DEFINE3(fstatfs64, unsigned int, fd, size_t, sz, struct statfs64 __user *, buf) 197 { 198 struct kstatfs st; 199 int error; 200 201 if (sz != sizeof(*buf)) 202 return -EINVAL; 203 204 error = fd_statfs(fd, &st); 205 if (!error) 206 error = do_statfs64(&st, buf); 207 return error; 208 } 209 210 int vfs_ustat(dev_t dev, struct kstatfs *sbuf) 211 { 212 struct super_block *s = user_get_super(dev); 213 int err; 214 if (!s) 215 return -EINVAL; 216 217 err = statfs_by_dentry(s->s_root, sbuf); 218 drop_super(s); 219 return err; 220 } 221 222 SYSCALL_DEFINE2(ustat, unsigned, dev, struct ustat __user *, ubuf) 223 { 224 struct ustat tmp; 225 struct kstatfs sbuf; 226 int err = vfs_ustat(new_decode_dev(dev), &sbuf); 227 if (err) 228 return err; 229 230 memset(&tmp,0,sizeof(struct ustat)); 231 tmp.f_tfree = sbuf.f_bfree; 232 tmp.f_tinode = sbuf.f_ffree; 233 234 return copy_to_user(ubuf, &tmp, sizeof(struct ustat)) ? -EFAULT : 0; 235 } 236