diff options
Diffstat (limited to 'fs/file_attr.c')
| -rw-r--r-- | fs/file_attr.c | 498 |
1 files changed, 498 insertions, 0 deletions
diff --git a/fs/file_attr.c b/fs/file_attr.c new file mode 100644 index 000000000000..12424d4945d0 --- /dev/null +++ b/fs/file_attr.c @@ -0,0 +1,498 @@ +// SPDX-License-Identifier: GPL-2.0 +#include <linux/fs.h> +#include <linux/security.h> +#include <linux/fscrypt.h> +#include <linux/fileattr.h> +#include <linux/export.h> +#include <linux/syscalls.h> +#include <linux/namei.h> + +#include "internal.h" + +/** + * fileattr_fill_xflags - initialize fileattr with xflags + * @fa: fileattr pointer + * @xflags: FS_XFLAG_* flags + * + * Set ->fsx_xflags, ->fsx_valid and ->flags (translated xflags). All + * other fields are zeroed. + */ +void fileattr_fill_xflags(struct file_kattr *fa, u32 xflags) +{ + memset(fa, 0, sizeof(*fa)); + fa->fsx_valid = true; + fa->fsx_xflags = xflags; + if (fa->fsx_xflags & FS_XFLAG_IMMUTABLE) + fa->flags |= FS_IMMUTABLE_FL; + if (fa->fsx_xflags & FS_XFLAG_APPEND) + fa->flags |= FS_APPEND_FL; + if (fa->fsx_xflags & FS_XFLAG_SYNC) + fa->flags |= FS_SYNC_FL; + if (fa->fsx_xflags & FS_XFLAG_NOATIME) + fa->flags |= FS_NOATIME_FL; + if (fa->fsx_xflags & FS_XFLAG_NODUMP) + fa->flags |= FS_NODUMP_FL; + if (fa->fsx_xflags & FS_XFLAG_DAX) + fa->flags |= FS_DAX_FL; + if (fa->fsx_xflags & FS_XFLAG_PROJINHERIT) + fa->flags |= FS_PROJINHERIT_FL; +} +EXPORT_SYMBOL(fileattr_fill_xflags); + +/** + * fileattr_fill_flags - initialize fileattr with flags + * @fa: fileattr pointer + * @flags: FS_*_FL flags + * + * Set ->flags, ->flags_valid and ->fsx_xflags (translated flags). + * All other fields are zeroed. + */ +void fileattr_fill_flags(struct file_kattr *fa, u32 flags) +{ + memset(fa, 0, sizeof(*fa)); + fa->flags_valid = true; + fa->flags = flags; + if (fa->flags & FS_SYNC_FL) + fa->fsx_xflags |= FS_XFLAG_SYNC; + if (fa->flags & FS_IMMUTABLE_FL) + fa->fsx_xflags |= FS_XFLAG_IMMUTABLE; + if (fa->flags & FS_APPEND_FL) + fa->fsx_xflags |= FS_XFLAG_APPEND; + if (fa->flags & FS_NODUMP_FL) + fa->fsx_xflags |= FS_XFLAG_NODUMP; + if (fa->flags & FS_NOATIME_FL) + fa->fsx_xflags |= FS_XFLAG_NOATIME; + if (fa->flags & FS_DAX_FL) + fa->fsx_xflags |= FS_XFLAG_DAX; + if (fa->flags & FS_PROJINHERIT_FL) + fa->fsx_xflags |= FS_XFLAG_PROJINHERIT; +} +EXPORT_SYMBOL(fileattr_fill_flags); + +/** + * vfs_fileattr_get - retrieve miscellaneous file attributes + * @dentry: the object to retrieve from + * @fa: fileattr pointer + * + * Call i_op->fileattr_get() callback, if exists. + * + * Return: 0 on success, or a negative error on failure. + */ +int vfs_fileattr_get(struct dentry *dentry, struct file_kattr *fa) +{ + struct inode *inode = d_inode(dentry); + int error; + + if (!inode->i_op->fileattr_get) + return -EOPNOTSUPP; + + error = security_inode_file_getattr(dentry, fa); + if (error) + return error; + + return inode->i_op->fileattr_get(dentry, fa); +} +EXPORT_SYMBOL(vfs_fileattr_get); + +static void fileattr_to_file_attr(const struct file_kattr *fa, + struct file_attr *fattr) +{ + __u32 mask = FS_XFLAGS_MASK; + + memset(fattr, 0, sizeof(struct file_attr)); + fattr->fa_xflags = fa->fsx_xflags & mask; + fattr->fa_extsize = fa->fsx_extsize; + fattr->fa_nextents = fa->fsx_nextents; + fattr->fa_projid = fa->fsx_projid; + fattr->fa_cowextsize = fa->fsx_cowextsize; +} + +/** + * copy_fsxattr_to_user - copy fsxattr to userspace. + * @fa: fileattr pointer + * @ufa: fsxattr user pointer + * + * Return: 0 on success, or -EFAULT on failure. + */ +int copy_fsxattr_to_user(const struct file_kattr *fa, struct fsxattr __user *ufa) +{ + struct fsxattr xfa; + __u32 mask = FS_XFLAGS_MASK; + + memset(&xfa, 0, sizeof(xfa)); + xfa.fsx_xflags = fa->fsx_xflags & mask; + xfa.fsx_extsize = fa->fsx_extsize; + xfa.fsx_nextents = fa->fsx_nextents; + xfa.fsx_projid = fa->fsx_projid; + xfa.fsx_cowextsize = fa->fsx_cowextsize; + + if (copy_to_user(ufa, &xfa, sizeof(xfa))) + return -EFAULT; + + return 0; +} +EXPORT_SYMBOL(copy_fsxattr_to_user); + +static int file_attr_to_fileattr(const struct file_attr *fattr, + struct file_kattr *fa) +{ + __u64 mask = FS_XFLAGS_MASK; + + if (fattr->fa_xflags & ~mask) + return -EINVAL; + + fileattr_fill_xflags(fa, fattr->fa_xflags); + fa->fsx_xflags &= ~FS_XFLAG_RDONLY_MASK; + fa->fsx_extsize = fattr->fa_extsize; + fa->fsx_projid = fattr->fa_projid; + fa->fsx_cowextsize = fattr->fa_cowextsize; + + return 0; +} + +static int copy_fsxattr_from_user(struct file_kattr *fa, + struct fsxattr __user *ufa) +{ + struct fsxattr xfa; + __u32 mask = FS_XFLAGS_MASK; + + if (copy_from_user(&xfa, ufa, sizeof(xfa))) + return -EFAULT; + + if (xfa.fsx_xflags & ~mask) + return -EOPNOTSUPP; + + fileattr_fill_xflags(fa, xfa.fsx_xflags); + fa->fsx_xflags &= ~FS_XFLAG_RDONLY_MASK; + fa->fsx_extsize = xfa.fsx_extsize; + fa->fsx_nextents = xfa.fsx_nextents; + fa->fsx_projid = xfa.fsx_projid; + fa->fsx_cowextsize = xfa.fsx_cowextsize; + + return 0; +} + +/* + * Generic function to check FS_IOC_FSSETXATTR/FS_IOC_SETFLAGS values and reject + * any invalid configurations. + * + * Note: must be called with inode lock held. + */ +static int fileattr_set_prepare(struct inode *inode, + const struct file_kattr *old_ma, + struct file_kattr *fa) +{ + int err; + + /* + * The IMMUTABLE and APPEND_ONLY flags can only be changed by + * the relevant capability. + */ + if ((fa->flags ^ old_ma->flags) & (FS_APPEND_FL | FS_IMMUTABLE_FL) && + !capable(CAP_LINUX_IMMUTABLE)) + return -EPERM; + + err = fscrypt_prepare_setflags(inode, old_ma->flags, fa->flags); + if (err) + return err; + + /* + * Project Quota ID state is only allowed to change from within the init + * namespace. Enforce that restriction only if we are trying to change + * the quota ID state. Everything else is allowed in user namespaces. + */ + if (current_user_ns() != &init_user_ns) { + if (old_ma->fsx_projid != fa->fsx_projid) + return -EINVAL; + if ((old_ma->fsx_xflags ^ fa->fsx_xflags) & + FS_XFLAG_PROJINHERIT) + return -EINVAL; + } else { + /* + * Caller is allowed to change the project ID. If it is being + * changed, make sure that the new value is valid. + */ + if (old_ma->fsx_projid != fa->fsx_projid && + !projid_valid(make_kprojid(&init_user_ns, fa->fsx_projid))) + return -EINVAL; + } + + /* Check extent size hints. */ + if ((fa->fsx_xflags & FS_XFLAG_EXTSIZE) && !S_ISREG(inode->i_mode)) + return -EINVAL; + + if ((fa->fsx_xflags & FS_XFLAG_EXTSZINHERIT) && + !S_ISDIR(inode->i_mode)) + return -EINVAL; + + if ((fa->fsx_xflags & FS_XFLAG_COWEXTSIZE) && + !S_ISREG(inode->i_mode) && !S_ISDIR(inode->i_mode)) + return -EINVAL; + + /* + * It is only valid to set the DAX flag on regular files and + * directories on filesystems. + */ + if ((fa->fsx_xflags & FS_XFLAG_DAX) && + !(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode))) + return -EINVAL; + + /* Extent size hints of zero turn off the flags. */ + if (fa->fsx_extsize == 0) + fa->fsx_xflags &= ~(FS_XFLAG_EXTSIZE | FS_XFLAG_EXTSZINHERIT); + if (fa->fsx_cowextsize == 0) + fa->fsx_xflags &= ~FS_XFLAG_COWEXTSIZE; + + return 0; +} + +/** + * vfs_fileattr_set - change miscellaneous file attributes + * @idmap: idmap of the mount + * @dentry: the object to change + * @fa: fileattr pointer + * + * After verifying permissions, call i_op->fileattr_set() callback, if + * exists. + * + * Verifying attributes involves retrieving current attributes with + * i_op->fileattr_get(), this also allows initializing attributes that have + * not been set by the caller to current values. Inode lock is held + * thoughout to prevent racing with another instance. + * + * Return: 0 on success, or a negative error on failure. + */ +int vfs_fileattr_set(struct mnt_idmap *idmap, struct dentry *dentry, + struct file_kattr *fa) +{ + struct inode *inode = d_inode(dentry); + struct file_kattr old_ma = {}; + int err; + + if (!inode->i_op->fileattr_set) + return -EOPNOTSUPP; + + if (!inode_owner_or_capable(idmap, inode)) + return -EPERM; + + inode_lock(inode); + err = vfs_fileattr_get(dentry, &old_ma); + if (!err) { + /* initialize missing bits from old_ma */ + if (fa->flags_valid) { + fa->fsx_xflags |= old_ma.fsx_xflags & ~FS_XFLAG_COMMON; + fa->fsx_extsize = old_ma.fsx_extsize; + fa->fsx_nextents = old_ma.fsx_nextents; + fa->fsx_projid = old_ma.fsx_projid; + fa->fsx_cowextsize = old_ma.fsx_cowextsize; + } else { + fa->flags |= old_ma.flags & ~FS_COMMON_FL; + } + + err = fileattr_set_prepare(inode, &old_ma, fa); + if (err) + goto out; + err = security_inode_file_setattr(dentry, fa); + if (err) + goto out; + err = inode->i_op->fileattr_set(idmap, dentry, fa); + if (err) + goto out; + } + +out: + inode_unlock(inode); + return err; +} +EXPORT_SYMBOL(vfs_fileattr_set); + +int ioctl_getflags(struct file *file, unsigned int __user *argp) +{ + struct file_kattr fa = { .flags_valid = true }; /* hint only */ + int err; + + err = vfs_fileattr_get(file->f_path.dentry, &fa); + if (err == -EOPNOTSUPP) + err = -ENOIOCTLCMD; + if (!err) + err = put_user(fa.flags, argp); + return err; +} +EXPORT_SYMBOL(ioctl_getflags); + +int ioctl_setflags(struct file *file, unsigned int __user *argp) +{ + struct mnt_idmap *idmap = file_mnt_idmap(file); + struct dentry *dentry = file->f_path.dentry; + struct file_kattr fa; + unsigned int flags; + int err; + + err = get_user(flags, argp); + if (!err) { + err = mnt_want_write_file(file); + if (!err) { + fileattr_fill_flags(&fa, flags); + err = vfs_fileattr_set(idmap, dentry, &fa); + mnt_drop_write_file(file); + if (err == -EOPNOTSUPP) + err = -ENOIOCTLCMD; + } + } + return err; +} +EXPORT_SYMBOL(ioctl_setflags); + +int ioctl_fsgetxattr(struct file *file, void __user *argp) +{ + struct file_kattr fa = { .fsx_valid = true }; /* hint only */ + int err; + + err = vfs_fileattr_get(file->f_path.dentry, &fa); + if (err == -EOPNOTSUPP) + err = -ENOIOCTLCMD; + if (!err) + err = copy_fsxattr_to_user(&fa, argp); + + return err; +} +EXPORT_SYMBOL(ioctl_fsgetxattr); + +int ioctl_fssetxattr(struct file *file, void __user *argp) +{ + struct mnt_idmap *idmap = file_mnt_idmap(file); + struct dentry *dentry = file->f_path.dentry; + struct file_kattr fa; + int err; + + err = copy_fsxattr_from_user(&fa, argp); + if (!err) { + err = mnt_want_write_file(file); + if (!err) { + err = vfs_fileattr_set(idmap, dentry, &fa); + mnt_drop_write_file(file); + if (err == -EOPNOTSUPP) + err = -ENOIOCTLCMD; + } + } + return err; +} +EXPORT_SYMBOL(ioctl_fssetxattr); + +SYSCALL_DEFINE5(file_getattr, int, dfd, const char __user *, filename, + struct file_attr __user *, ufattr, size_t, usize, + unsigned int, at_flags) +{ + struct path filepath __free(path_put) = {}; + struct filename *name __free(putname) = NULL; + unsigned int lookup_flags = 0; + struct file_attr fattr; + struct file_kattr fa; + int error; + + BUILD_BUG_ON(sizeof(struct file_attr) < FILE_ATTR_SIZE_VER0); + BUILD_BUG_ON(sizeof(struct file_attr) != FILE_ATTR_SIZE_LATEST); + + if ((at_flags & ~(AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH)) != 0) + return -EINVAL; + + if (!(at_flags & AT_SYMLINK_NOFOLLOW)) + lookup_flags |= LOOKUP_FOLLOW; + + if (usize > PAGE_SIZE) + return -E2BIG; + + if (usize < FILE_ATTR_SIZE_VER0) + return -EINVAL; + + name = getname_maybe_null(filename, at_flags); + if (IS_ERR(name)) + return PTR_ERR(name); + + if (!name && dfd >= 0) { + CLASS(fd, f)(dfd); + if (fd_empty(f)) + return -EBADF; + + filepath = fd_file(f)->f_path; + path_get(&filepath); + } else { + error = filename_lookup(dfd, name, lookup_flags, &filepath, + NULL); + if (error) + return error; + } + + error = vfs_fileattr_get(filepath.dentry, &fa); + if (error) + return error; + + fileattr_to_file_attr(&fa, &fattr); + error = copy_struct_to_user(ufattr, usize, &fattr, + sizeof(struct file_attr), NULL); + + return error; +} + +SYSCALL_DEFINE5(file_setattr, int, dfd, const char __user *, filename, + struct file_attr __user *, ufattr, size_t, usize, + unsigned int, at_flags) +{ + struct path filepath __free(path_put) = {}; + struct filename *name __free(putname) = NULL; + unsigned int lookup_flags = 0; + struct file_attr fattr; + struct file_kattr fa; + int error; + + BUILD_BUG_ON(sizeof(struct file_attr) < FILE_ATTR_SIZE_VER0); + BUILD_BUG_ON(sizeof(struct file_attr) != FILE_ATTR_SIZE_LATEST); + + if ((at_flags & ~(AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH)) != 0) + return -EINVAL; + + if (!(at_flags & AT_SYMLINK_NOFOLLOW)) + lookup_flags |= LOOKUP_FOLLOW; + + if (usize > PAGE_SIZE) + return -E2BIG; + + if (usize < FILE_ATTR_SIZE_VER0) + return -EINVAL; + + error = copy_struct_from_user(&fattr, sizeof(struct file_attr), ufattr, + usize); + if (error) + return error; + + error = file_attr_to_fileattr(&fattr, &fa); + if (error) + return error; + + name = getname_maybe_null(filename, at_flags); + if (IS_ERR(name)) + return PTR_ERR(name); + + if (!name && dfd >= 0) { + CLASS(fd, f)(dfd); + if (fd_empty(f)) + return -EBADF; + + filepath = fd_file(f)->f_path; + path_get(&filepath); + } else { + error = filename_lookup(dfd, name, lookup_flags, &filepath, + NULL); + if (error) + return error; + } + + error = mnt_want_write(filepath.mnt); + if (!error) { + error = vfs_fileattr_set(mnt_idmap(filepath.mnt), + filepath.dentry, &fa); + mnt_drop_write(filepath.mnt); + } + + return error; +} |