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 struct fd f = fdget(fd); 91 int error = -EBADF; 92 if (f.file) { 93 error = vfs_statfs(&f.file->f_path, st); 94 fdput(f); 95 } 96 return error; 97 } 98 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 } 140 141 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 } 164 165 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 } 173 174 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 } 185 186 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 } 194 195 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 } 208 209 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 } 220 221 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