#include <linux/syscalls.h> #include <linux/module.h> #include <linux/fs.h> #include <linux/file.h> #include <linux/mount.h> #include <linux/namei.h> #include <linux/statfs.h> #include <linux/security.h> #include <linux/uaccess.h> static int flags_by_mnt(int mnt_flags) { int flags = 0; if (mnt_flags & MNT_READONLY) flags |= ST_RDONLY; if (mnt_flags & MNT_NOSUID) flags |= ST_NOSUID; if (mnt_flags & MNT_NODEV) flags |= ST_NODEV; if (mnt_flags & MNT_NOEXEC) flags |= ST_NOEXEC; if (mnt_flags & MNT_NOATIME) flags |= ST_NOATIME; if (mnt_flags & MNT_NODIRATIME) flags |= ST_NODIRATIME; if (mnt_flags & MNT_RELATIME) flags |= ST_RELATIME; return flags; } static int flags_by_sb(int s_flags) { int flags = 0; if (s_flags & MS_SYNCHRONOUS) flags |= ST_SYNCHRONOUS; if (s_flags & MS_MANDLOCK) flags |= ST_MANDLOCK; return flags; } static int calculate_f_flags(struct vfsmount *mnt) { return ST_VALID | flags_by_mnt(mnt->mnt_flags) | flags_by_sb(mnt->mnt_sb->s_flags); } int statfs_by_dentry(struct dentry *dentry, struct kstatfs *buf) { int retval; if (!dentry->d_sb->s_op->statfs) return -ENOSYS; memset(buf, 0, sizeof(*buf)); retval = security_sb_statfs(dentry); if (retval) return retval; retval = dentry->d_sb->s_op->statfs(dentry, buf); if (retval == 0 && buf->f_frsize == 0) buf->f_frsize = buf->f_bsize; return retval; } int vfs_statfs(struct path *path, struct kstatfs *buf) { int error; error = statfs_by_dentry(path->dentry, buf); if (!error) buf->f_flags = calculate_f_flags(path->mnt); return error; } EXPORT_SYMBOL(vfs_statfs); int user_statfs(const char __user *pathname, struct kstatfs *st) { struct path path; int error = user_path_at(AT_FDCWD, pathname, LOOKUP_FOLLOW|LOOKUP_AUTOMOUNT, &path); if (!error) { error = vfs_statfs(&path, st); path_put(&path); } return error; } int fd_statfs(int fd, struct kstatfs *st) { struct file *file = fget(fd); int error = -EBADF; if (file) { error = vfs_statfs(&file->f_path, st); fput(file); } return error; } static int do_statfs_native(struct kstatfs *st, struct statfs __user *p) { struct statfs buf; if (sizeof(buf) == sizeof(*st)) memcpy(&buf, st, sizeof(*st)); else { if (sizeof buf.f_blocks == 4) { if ((st->f_blocks | st->f_bfree | st->f_bavail | st->f_bsize | st->f_frsize) & 0xffffffff00000000ULL) return -EOVERFLOW; /* * f_files and f_ffree may be -1; it's okay to stuff * that into 32 bits */ if (st->f_files != -1 && (st->f_files & 0xffffffff00000000ULL)) return -EOVERFLOW; if (st->f_ffree != -1 && (st->f_ffree & 0xffffffff00000000ULL)) return -EOVERFLOW; } buf.f_type = st->f_type; buf.f_bsize = st->f_bsize; buf.f_blocks = st->f_blocks; buf.f_bfree = st->f_bfree; buf.f_bavail = st->f_bavail; buf.f_files = st->f_files; buf.f_ffree = st->f_ffree; buf.f_fsid = st->f_fsid; buf.f_namelen = st->f_namelen; buf.f_frsize = st->f_frsize; buf.f_flags = st->f_flags; memset(buf.f_spare, 0, sizeof(buf.f_spare)); } if (copy_to_user(p, &buf, sizeof(buf))) return -EFAULT; return 0; } static int do_statfs64(struct kstatfs *st, struct statfs64 __user *p) { struct statfs64 buf; if (sizeof(buf) == sizeof(*st)) memcpy(&buf, st, sizeof(*st)); else { buf.f_type = st->f_type; buf.f_bsize = st->f_bsize; buf.f_blocks = st->f_blocks; buf.f_bfree = st->f_bfree; buf.f_bavail = st->f_bavail; buf.f_files = st->f_files; buf.f_ffree = st->f_ffree; buf.f_fsid = st->f_fsid; buf.f_namelen = st->f_namelen; buf.f_frsize = st->f_frsize; buf.f_flags = st->f_flags; memset(buf.f_spare, 0, sizeof(buf.f_spare)); } if (copy_to_user(p, &buf, sizeof(buf))) return -EFAULT; return 0; } SYSCALL_DEFINE2(statfs, const char __user *, pathname, struct statfs __user *, buf) { struct kstatfs st; int error = user_statfs(pathname, &st); if (!error) error = do_statfs_native(&st, buf); return error; } SYSCALL_DEFINE3(statfs64, const char __user *, pathname, size_t, sz, struct statfs64 __user *, buf) { struct kstatfs st; int error; if (sz != sizeof(*buf)) return -EINVAL; error = user_statfs(pathname, &st); if (!error) error = do_statfs64(&st, buf); return error; } SYSCALL_DEFINE2(fstatfs, unsigned int, fd, struct statfs __user *, buf) { struct kstatfs st; int error = fd_statfs(fd, &st); if (!error) error = do_statfs_native(&st, buf); return error; } SYSCALL_DEFINE3(fstatfs64, unsigned int, fd, size_t, sz, struct statfs64 __user *, buf) { struct kstatfs st; int error; if (sz != sizeof(*buf)) return -EINVAL; error = fd_statfs(fd, &st); if (!error) error = do_statfs64(&st, buf); return error; } SYSCALL_DEFINE2(ustat, unsigned, dev, struct ustat __user *, ubuf) { struct super_block *s; struct ustat tmp; struct kstatfs sbuf; int err; s = user_get_super(new_decode_dev(dev)); if (!s) return -EINVAL; err = statfs_by_dentry(s->s_root, &sbuf); drop_super(s); if (err) return err; memset(&tmp,0,sizeof(struct ustat)); tmp.f_tfree = sbuf.f_bfree; tmp.f_tinode = sbuf.f_ffree; return copy_to_user(ubuf, &tmp, sizeof(struct ustat)) ? -EFAULT : 0; }