Re: Possible issue with linux xattr support?

On Mon, Sep 04, 2023 at 04:03:54PM +0200, Felix Palmen wrote:
> * Felix Palmen <zirias@freebsd.org> [20230904 15:39]:
> > For some reason (I still have to try to get more information about it,
> > will do soon), something else is broken now. While install from GNU
> > coreutils works fine, some build systems use 'cp -p' to install files
> > instead, which now fails with:
> > 
> > | cp: preserving permissions for [...]: Operation not permitted
> 
> The issue seems to be with listing attributes:
> 
> | root@15-default:/wrkdirs/usr/ports/x11/linuxsrc-libxcb/work/libxcb-1.15/doc # truss /compat/linux/bin/cp -pR ./tutorial '/wrkdirs/usr/ports/x11/linuxsrc-libxcb/work/stage/compat/linux/usr/share/doc/libxcb/' 2>&1 | grep xattr
> | linux_flistxattr(0x4,0x0,0x0)                    ERR#-1 'Operation not permitted'
> | linux_flistxattr(0x4,0x0,0x0)                    ERR#-1 'Operation not permitted'
> | linux_llistxattr(0xffffffffcdd9,0x0,0x0)         ERR#-1 'Operation not permitted'
> 
> The following q&d patch makes it work again:
> 
> #v+
> diff --git a/sys/compat/linux/linux_xattr.c b/sys/compat/linux/linux_xattr.c
> index 74b47f1cbaec..0b5af084b1b1 100644
> --- a/sys/compat/linux/linux_xattr.c
> +++ b/sys/compat/linux/linux_xattr.c
> @@ -198,7 +198,7 @@ listxattr(struct thread *td, struct listxattr_args *args)
>         if (error == 0)
>                 td->td_retval[0] = cnt;
>         free(data, M_LINUX);
> -       return (error_to_xattrerror(attrnamespace, error));
> +       return (error_to_xattrerror(EXTATTR_NAMESPACE_SYSTEM, error));
>  }
>  
>  int
> #v-
> 
> I think this makes sense, because listxattr iterates over all
> namespaces, so there's no sane way to know whether the EPERM was caused
> by trying to access "system" or something else.

Thanks for the report,
please, try this: https://people.freebsd.org/~dchagin/lxattr.patch
Don't be surprised, there 2 fixes


> 
> Cheers, Felix
> 
> -- 
>  Felix Palmen <zirias@FreeBSD.org>     {private}   felix@palmen-it.de
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