Re: [PATCH v15 19/22] richacl: Add richacl xattr handler

[Andreas Gruenbacher]

On Mon, Nov 9, 2015 at 12:09 PM, Andreas Gruenbacher
<agruenba@xxxxxxxxxx> 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>
> ---
>  fs/richacl_xattr.c            | 78 +++++++++++++++++++++++++++++++++++++++++++
>  include/linux/richacl_xattr.h |  2 ++
>  2 files changed, 80 insertions(+)
>
> diff --git a/fs/richacl_xattr.c b/fs/richacl_xattr.c
> index 38473b6..767c1f7 100644
> --- a/fs/richacl_xattr.c
> +++ b/fs/richacl_xattr.c
> @@ -18,7 +18,9 @@
>  #include <linux/fs.h>
>  #include <linux/slab.h>
>  #include <linux/module.h>
> +#include <linux/xattr.h>
>  #include <linux/richacl_xattr.h>
> +#include <uapi/linux/xattr.h>
>
>  MODULE_LICENSE("GPL");
>
> @@ -161,6 +163,82 @@ richacl_to_xattr(struct user_namespace *user_ns,
>  }
>  EXPORT_SYMBOL_GPL(richacl_to_xattr);
>
> +static size_t
> +richacl_xattr_list(struct dentry *dentry, char *list, size_t list_len,
> +                  const char *name, size_t name_len, int handler_flags)
> +{
> +       const size_t size = sizeof(XATTR_NAME_RICHACL);
> +
> +       if (!IS_RICHACL(d_backing_inode(dentry)))
> +               return 0;
> +       if (list && size <= list_len)
> +               memcpy(list, XATTR_NAME_RICHACL, size);
> +       return size;
> +}
> +
> +static int
> +richacl_xattr_get(struct dentry *dentry, const char *name, void *buffer,
> +                 size_t buffer_size, int handler_flags)
> +{
> +       struct inode *inode = d_backing_inode(dentry);
> +       struct richacl *acl;
> +       int error;
> +
> +       if (strcmp(name, "") != 0)
> +               return -EINVAL;
> +       if (!IS_RICHACL(inode))
> +               return EOPNOTSUPP;

This should have been -EOPNOTSUPP instead.

> +       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(&init_user_ns, acl, buffer, buffer_size);
> +       richacl_put(acl);
> +       return error;
> +}
> +
> +static int
> +richacl_xattr_set(struct dentry *dentry, const char *name,
> +                 const void *value, size_t size, int flags, int handler_flags)
> +{
> +       struct inode *inode = d_backing_inode(dentry);
> +       struct richacl *acl = NULL;
> +       int ret;
> +
> +       if (strcmp(name, "") != 0)
> +               return -EINVAL;
> +       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;
> +
> +       if (value) {
> +               acl = richacl_from_xattr(&init_user_ns, value, size);
> +               if (IS_ERR(acl))
> +                       return PTR_ERR(acl);
> +       }
> +
> +       ret = inode->i_op->set_richacl(inode, acl);
> +       richacl_put(acl);
> +       return ret;
> +}
> +
> +struct xattr_handler richacl_xattr_handler = {
> +       .prefix = XATTR_NAME_RICHACL,
> +       .list = richacl_xattr_list,
> +       .get = richacl_xattr_get,
> +       .set = richacl_xattr_set,
> +};
> +EXPORT_SYMBOL(richacl_xattr_handler);
> +
>  /*
>   * Fix up the uids and gids in richacl extended attributes in place.
>   */
> diff --git a/include/linux/richacl_xattr.h b/include/linux/richacl_xattr.h
> index 7fc5ca8..45ec27a 100644
> --- a/include/linux/richacl_xattr.h
> +++ b/include/linux/richacl_xattr.h
> @@ -39,4 +39,6 @@ static inline void richacl_fix_xattr_to_user(void *value, size_t size)
>  }
>  #endif
>
> +extern struct xattr_handler richacl_xattr_handler;
> +
>  #endif /* __RICHACL_XATTR_H */
> --
> 2.5.0
>
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