diff options
Diffstat (limited to 'fs/statfs.c')
| -rw-r--r-- | fs/statfs.c | 406 |
1 files changed, 406 insertions, 0 deletions
diff --git a/fs/statfs.c b/fs/statfs.c new file mode 100644 index 0000000000..96d1c3edf2 --- /dev/null +++ b/fs/statfs.c @@ -0,0 +1,406 @@ +// SPDX-License-Identifier: GPL-2.0 +#include <linux/syscalls.h> +#include <linux/export.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> +#include <linux/compat.h> +#include "internal.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; + if (mnt_flags & MNT_NOSYMFOLLOW) + flags |= ST_NOSYMFOLLOW; + return flags; +} + +static int flags_by_sb(int s_flags) +{ + int flags = 0; + if (s_flags & SB_SYNCHRONOUS) + flags |= ST_SYNCHRONOUS; + if (s_flags & SB_MANDLOCK) + flags |= ST_MANDLOCK; + if (s_flags & SB_RDONLY) + flags |= ST_RDONLY; + 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); +} + +static 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_get_fsid(struct dentry *dentry, __kernel_fsid_t *fsid) +{ + struct kstatfs st; + int error; + + error = statfs_by_dentry(dentry, &st); + if (error) + return error; + + *fsid = st.f_fsid; + return 0; +} +EXPORT_SYMBOL(vfs_get_fsid); + +int vfs_statfs(const 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; + unsigned int lookup_flags = LOOKUP_FOLLOW|LOOKUP_AUTOMOUNT; +retry: + error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path); + if (!error) { + error = vfs_statfs(&path, st); + path_put(&path); + if (retry_estale(error, lookup_flags)) { + lookup_flags |= LOOKUP_REVAL; + goto retry; + } + } + return error; +} + +int fd_statfs(int fd, struct kstatfs *st) +{ + struct fd f = fdget_raw(fd); + int error = -EBADF; + if (f.file) { + error = vfs_statfs(&f.file->f_path, st); + fdput(f); + } + 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 { + memset(&buf, 0, sizeof(buf)); + 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; + } + 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 { + memset(&buf, 0, sizeof(buf)); + 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; + } + 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; +} + +static int vfs_ustat(dev_t dev, struct kstatfs *sbuf) +{ + struct super_block *s = user_get_super(dev, false); + int err; + if (!s) + return -EINVAL; + + err = statfs_by_dentry(s->s_root, sbuf); + drop_super(s); + return err; +} + +SYSCALL_DEFINE2(ustat, unsigned, dev, struct ustat __user *, ubuf) +{ + struct ustat tmp; + struct kstatfs sbuf; + int err = vfs_ustat(new_decode_dev(dev), &sbuf); + if (err) + return err; + + memset(&tmp,0,sizeof(struct ustat)); + tmp.f_tfree = sbuf.f_bfree; + if (IS_ENABLED(CONFIG_ARCH_32BIT_USTAT_F_TINODE)) + tmp.f_tinode = min_t(u64, sbuf.f_ffree, UINT_MAX); + else + tmp.f_tinode = sbuf.f_ffree; + + return copy_to_user(ubuf, &tmp, sizeof(struct ustat)) ? -EFAULT : 0; +} + +#ifdef CONFIG_COMPAT +static int put_compat_statfs(struct compat_statfs __user *ubuf, struct kstatfs *kbuf) +{ + struct compat_statfs buf; + if (sizeof ubuf->f_blocks == 4) { + if ((kbuf->f_blocks | kbuf->f_bfree | kbuf->f_bavail | + kbuf->f_bsize | kbuf->f_frsize) & 0xffffffff00000000ULL) + return -EOVERFLOW; + /* f_files and f_ffree may be -1; it's okay + * to stuff that into 32 bits */ + if (kbuf->f_files != 0xffffffffffffffffULL + && (kbuf->f_files & 0xffffffff00000000ULL)) + return -EOVERFLOW; + if (kbuf->f_ffree != 0xffffffffffffffffULL + && (kbuf->f_ffree & 0xffffffff00000000ULL)) + return -EOVERFLOW; + } + memset(&buf, 0, sizeof(struct compat_statfs)); + buf.f_type = kbuf->f_type; + buf.f_bsize = kbuf->f_bsize; + buf.f_blocks = kbuf->f_blocks; + buf.f_bfree = kbuf->f_bfree; + buf.f_bavail = kbuf->f_bavail; + buf.f_files = kbuf->f_files; + buf.f_ffree = kbuf->f_ffree; + buf.f_namelen = kbuf->f_namelen; + buf.f_fsid.val[0] = kbuf->f_fsid.val[0]; + buf.f_fsid.val[1] = kbuf->f_fsid.val[1]; + buf.f_frsize = kbuf->f_frsize; + buf.f_flags = kbuf->f_flags; + if (copy_to_user(ubuf, &buf, sizeof(struct compat_statfs))) + return -EFAULT; + return 0; +} + +/* + * The following statfs calls are copies of code from fs/statfs.c and + * should be checked against those from time to time + */ +COMPAT_SYSCALL_DEFINE2(statfs, const char __user *, pathname, struct compat_statfs __user *, buf) +{ + struct kstatfs tmp; + int error = user_statfs(pathname, &tmp); + if (!error) + error = put_compat_statfs(buf, &tmp); + return error; +} + +COMPAT_SYSCALL_DEFINE2(fstatfs, unsigned int, fd, struct compat_statfs __user *, buf) +{ + struct kstatfs tmp; + int error = fd_statfs(fd, &tmp); + if (!error) + error = put_compat_statfs(buf, &tmp); + return error; +} + +static int put_compat_statfs64(struct compat_statfs64 __user *ubuf, struct kstatfs *kbuf) +{ + struct compat_statfs64 buf; + + if ((kbuf->f_bsize | kbuf->f_frsize) & 0xffffffff00000000ULL) + return -EOVERFLOW; + + memset(&buf, 0, sizeof(struct compat_statfs64)); + buf.f_type = kbuf->f_type; + buf.f_bsize = kbuf->f_bsize; + buf.f_blocks = kbuf->f_blocks; + buf.f_bfree = kbuf->f_bfree; + buf.f_bavail = kbuf->f_bavail; + buf.f_files = kbuf->f_files; + buf.f_ffree = kbuf->f_ffree; + buf.f_namelen = kbuf->f_namelen; + buf.f_fsid.val[0] = kbuf->f_fsid.val[0]; + buf.f_fsid.val[1] = kbuf->f_fsid.val[1]; + buf.f_frsize = kbuf->f_frsize; + buf.f_flags = kbuf->f_flags; + if (copy_to_user(ubuf, &buf, sizeof(struct compat_statfs64))) + return -EFAULT; + return 0; +} + +int kcompat_sys_statfs64(const char __user * pathname, compat_size_t sz, struct compat_statfs64 __user * buf) +{ + struct kstatfs tmp; + int error; + + if (sz != sizeof(*buf)) + return -EINVAL; + + error = user_statfs(pathname, &tmp); + if (!error) + error = put_compat_statfs64(buf, &tmp); + return error; +} + +COMPAT_SYSCALL_DEFINE3(statfs64, const char __user *, pathname, compat_size_t, sz, struct compat_statfs64 __user *, buf) +{ + return kcompat_sys_statfs64(pathname, sz, buf); +} + +int kcompat_sys_fstatfs64(unsigned int fd, compat_size_t sz, struct compat_statfs64 __user * buf) +{ + struct kstatfs tmp; + int error; + + if (sz != sizeof(*buf)) + return -EINVAL; + + error = fd_statfs(fd, &tmp); + if (!error) + error = put_compat_statfs64(buf, &tmp); + return error; +} + +COMPAT_SYSCALL_DEFINE3(fstatfs64, unsigned int, fd, compat_size_t, sz, struct compat_statfs64 __user *, buf) +{ + return kcompat_sys_fstatfs64(fd, sz, buf); +} + +/* + * This is a copy of sys_ustat, just dealing with a structure layout. + * Given how simple this syscall is that apporach is more maintainable + * than the various conversion hacks. + */ +COMPAT_SYSCALL_DEFINE2(ustat, unsigned, dev, struct compat_ustat __user *, u) +{ + struct compat_ustat tmp; + struct kstatfs sbuf; + int err = vfs_ustat(new_decode_dev(dev), &sbuf); + if (err) + return err; + + memset(&tmp, 0, sizeof(struct compat_ustat)); + tmp.f_tfree = sbuf.f_bfree; + tmp.f_tinode = sbuf.f_ffree; + if (copy_to_user(u, &tmp, sizeof(struct compat_ustat))) + return -EFAULT; + return 0; +} +#endif |