Re: [PATCH v23 19/22] richacl: Add richacl xattr handler

[Jeff Layton]

On Thu, 2016-06-30 at 15:47 +0200, Andreas Gruenbacher wrote:
> Add richacl xattr handler implementing the xattr operations based on the
> get_richacl and set_richacl inode operations.
> 
> Signed-off-by: Andreas Gruenbacher <agruenba@xxxxxxxxxx>
> ---
> Âfs/richacl.cÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ| 22 ++++++++++++++++
> Âfs/richacl_xattr.cÂÂÂÂÂÂÂÂÂÂÂÂ| 61 +++++++++++++++++++++++++++++++++++++++++++
> Âinclude/linux/richacl.hÂÂÂÂÂÂÂ|ÂÂ1 +
> Âinclude/linux/richacl_xattr.h |ÂÂ2 ++
> Â4 files changed, 86 insertions(+)
> 
> diff --git a/fs/richacl.c b/fs/richacl.c
> index 40e4af9..b7d7104 100644
> --- a/fs/richacl.c
> +++ b/fs/richacl.c
> @@ -549,6 +549,28 @@ out:
> ÂEXPORT_SYMBOL_GPL(richacl_permission);
> Â
> Â/**
> + * set_richaclÂÂ-ÂÂset the richacl of an inode
> + * @inode:	inode whose richacl to set
> + * @acl:	access control list
> + */
> +int
> +set_richacl(struct inode *inode, struct richacl *acl)
> +{
> +	if (!IS_RICHACL(inode))
> +		return -EOPNOTSUPP;
> +	if (!inode->i_op->set_richacl)
> +		return -EOPNOTSUPP;
> +
> +	if (!uid_eq(current_fsuid(), inode->i_uid) &&
> +	ÂÂÂÂinode_permission(inode, MAY_CHMOD) &&
> +	ÂÂÂÂ!capable(CAP_FOWNER))
> +		return -EPERM;
> +
> +	return inode->i_op->set_richacl(inode, acl);
> +}
> +EXPORT_SYMBOL(set_richacl);
> +
> +/**
> Â * __richacl_chmodÂÂ-ÂÂupdate the file masks to reflect the new mode
> Â * @acl:	access control list
> Â * @mode:	new file permission bits including the file type
> diff --git a/fs/richacl_xattr.c b/fs/richacl_xattr.c
> index dc1ad36..5eb4aba 100644
> --- a/fs/richacl_xattr.c
> +++ b/fs/richacl_xattr.c
> @@ -18,7 +18,9 @@
> Â#include 
> Â#include 
> Â#include 
> +#include 
> Â#include 
> +#include 
> Â
> Â/**
> Â * richacl_from_xattrÂÂ-ÂÂconvert a richacl xattr into the in-memory representation
> @@ -159,3 +161,62 @@ richacl_to_xattr(struct user_namespace *user_ns,
> Â	return real_size;
> Â}
> ÂEXPORT_SYMBOL_GPL(richacl_to_xattr);
> +
> +static bool
> +richacl_xattr_list(struct dentry *dentry)
> +{
> +	return IS_RICHACL(d_backing_inode(dentry));
> +}
> +
> +static int
> +richacl_xattr_get(const struct xattr_handler *handler,
> +		ÂÂstruct dentry *unused, struct inode *inode,
> +		ÂÂconst char *name, void *buffer, size_t buffer_size)
> +{
> +	struct richacl *acl;
> +	int error;
> +
> +	if (*name)
> +		return -EINVAL;
> +	if (!IS_RICHACL(inode))
> +		return -EOPNOTSUPP;
> +	if (S_ISLNK(inode->i_mode))
> +		return -EOPNOTSUPP;
> +	acl = get_richacl(inode);
> +	if (IS_ERR(acl))
> +		return PTR_ERR(acl);
> +	if (acl == NULL)
> +		return -ENODATA;
> +	error = richacl_to_xattr(current_user_ns(), acl, buffer, buffer_size);
> +	richacl_put(acl);
> +	return error;
> +}
> +
> +static int
> +richacl_xattr_set(const struct xattr_handler *handler,
> +		ÂÂstruct dentry *unused, struct inode *inode,
> +		ÂÂconst char *name, const void *value, size_t size,
> +		ÂÂint flags)
> +{
> +	struct richacl *acl = NULL;
> +	int ret;
> +
> +	if (value) {
> +		acl = richacl_from_xattr(current_user_ns(), value, size,
> +					Â-EINVAL);
> +		if (IS_ERR(acl))
> +			return PTR_ERR(acl);
> +	}
> +
> +	ret = set_richacl(inode, acl);
> +	richacl_put(acl);
> +	return ret;
> +}
> +
> +struct xattr_handler richacl_xattr_handler = {
> +	.name = XATTR_NAME_RICHACL,
> +	.list = richacl_xattr_list,
> +	.get = richacl_xattr_get,
> +	.set = richacl_xattr_set,
> +};
> +EXPORT_SYMBOL(richacl_xattr_handler);
> diff --git a/include/linux/richacl.h b/include/linux/richacl.h
> index a442372..e7db066 100644
> --- a/include/linux/richacl.h
> +++ b/include/linux/richacl.h
> @@ -206,5 +206,6 @@ extern int richacl_chmod(struct inode *, umode_t);
> Âextern int richacl_equiv_mode(const struct richacl *, umode_t *);
> Âextern struct richacl *richacl_inherit(const struct richacl *, int);
> Âextern struct richacl *richacl_create(umode_t *, struct inode *);
> +extern int set_richacl(struct inode *, struct richacl *);
> Â
> Â#endif /* __RICHACL_H */
> diff --git a/include/linux/richacl_xattr.h b/include/linux/richacl_xattr.h
> index 0efa14b..6c6adb1 100644
> --- a/include/linux/richacl_xattr.h
> +++ b/include/linux/richacl_xattr.h
> @@ -26,4 +26,6 @@ extern size_t richacl_xattr_size(const struct richacl *);
> Âextern int richacl_to_xattr(struct user_namespace *, const struct richacl *,
> Â			ÂÂÂÂvoid *, size_t);
> Â
> +extern struct xattr_handler richacl_xattr_handler;
> +
> Â#endif /* __RICHACL_XATTR_H */

Cue same refrain about syscalls vs. xattrs. Otherwise:

Reviewed-by: Jeff Layton <jlayton@xxxxxxxxxx>