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

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Date:	Tue, 12 Jul 2016 08:13:30 -0400
From:	Jeff Layton <jlayton@...hat.com>
To:	Andreas Gruenbacher <agruenba@...hat.com>,
	Alexander Viro <viro@...iv.linux.org.uk>
Cc:	Christoph Hellwig <hch@...radead.org>,
	Theodore Ts'o <tytso@....edu>,
	Andreas Dilger <adilger.kernel@...ger.ca>,
	"J. Bruce Fields" <bfields@...ldses.org>,
	Trond Myklebust <trond.myklebust@...marydata.com>,
	Anna Schumaker <anna.schumaker@...app.com>,
	Dave Chinner <david@...morbit.com>, linux-ext4@...r.kernel.org,
	xfs@....sgi.com, linux-kernel@...r.kernel.org,
	linux-fsdevel@...r.kernel.org, linux-nfs@...r.kernel.org,
	linux-cifs@...r.kernel.org, linux-api@...r.kernel.org
Subject: Re: [PATCH v23 19/22] richacl: Add richacl xattr handler

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@...hat.com>
> ---
>  fs/richacl.c                  | 22 ++++++++++++++++
>  fs/richacl_xattr.c            | 61 +++++++++++++++++++++++++++++++++++++++++++
>  include/linux/richacl.h       |  1 +
>  include/linux/richacl_xattr.h |  2 ++
>  4 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:
>  EXPORT_SYMBOL_GPL(richacl_permission);
>  
>  /**
> + * set_richacl  -  set 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) &&
> +	    inode_permission(inode, MAY_CHMOD) &&
> +	    !capable(CAP_FOWNER))
> +		return -EPERM;
> +
> +	return inode->i_op->set_richacl(inode, acl);
> +}
> +EXPORT_SYMBOL(set_richacl);
> +
> +/**
>   * __richacl_chmod  -  update the file masks to reflect the new mode
>   * @acl:	access control list
>   * @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 @@
>  #include 
>  #include 
>  #include 
> +#include 
>  #include 
> +#include 
>  
>  /**
>   * richacl_from_xattr  -  convert a richacl xattr into the in-memory representation
> @@ -159,3 +161,62 @@ richacl_to_xattr(struct user_namespace *user_ns,
>  	return real_size;
>  }
>  EXPORT_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,
> +		  struct dentry *unused, struct inode *inode,
> +		  const 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,
> +		  struct dentry *unused, struct inode *inode,
> +		  const char *name, const void *value, size_t size,
> +		  int flags)
> +{
> +	struct richacl *acl = NULL;
> +	int ret;
> +
> +	if (value) {
> +		acl = richacl_from_xattr(current_user_ns(), value, size,
> +					 -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);
>  extern int richacl_equiv_mode(const struct richacl *, umode_t *);
>  extern struct richacl *richacl_inherit(const struct richacl *, int);
>  extern struct richacl *richacl_create(umode_t *, struct inode *);
> +extern int set_richacl(struct inode *, struct richacl *);
>  
>  #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 *);
>  extern int richacl_to_xattr(struct user_namespace *, const struct richacl *,
>  			    void *, size_t);
>  
> +extern struct xattr_handler richacl_xattr_handler;
> +
>  #endif /* __RICHACL_XATTR_H */

Cue same refrain about syscalls vs. xattrs. Otherwise:

Reviewed-by: Jeff Layton <jlayton@...hat.com>