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

Jeff Layton
2016-07-12T12:13:36Z

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@redhat.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@redhat.com>