Re: [PATCH nfs-utils] exportfs: make "insecure" the default for all exports

[Chuck Lever <chuck.lever@oracle.com>]

On 5/13/25 9:50 AM, Jeff Layton wrote:
> Back in the 80's someone thought it was a good idea to carve out a set
> of ports that only privileged users could use. When NFS was originally
> conceived, Sun made its server require that clients use low ports.
> Since Linux was following suit with Sun in those days, exportfs has
> always defaulted to requiring connections from low ports.
> 
> These days, anyone can be root on their laptop, so limiting connections
> to low source ports is of little value.
> 
> Make the default be "insecure" when creating exports.
> 
> Signed-off-by: Jeff Layton <jlayton@kernel.org>

Reviewed-by: Chuck Lever <chuck.lever@oracle.com>


> ---
> In discussion at the Bake-a-thon, we decided to just go for making
> "insecure" the default for all exports.
> ---
>  support/nfs/exports.c      | 7 +++++--
>  utils/exportfs/exports.man | 4 ++--
>  2 files changed, 7 insertions(+), 4 deletions(-)
> 
> diff --git a/support/nfs/exports.c b/support/nfs/exports.c
> index 21ec6486ba3d3945df0800972ba1dfd03bd65375..69f8ca8b5e2ed50b837ef287ca0685af3e70ed0b 100644
> --- a/support/nfs/exports.c
> +++ b/support/nfs/exports.c
> @@ -34,8 +34,11 @@
>  #include "reexport.h"
>  #include "nfsd_path.h"
>  
> -#define EXPORT_DEFAULT_FLAGS	\
> -  (NFSEXP_READONLY|NFSEXP_ROOTSQUASH|NFSEXP_GATHERED_WRITES|NFSEXP_NOSUBTREECHECK)
> +#define EXPORT_DEFAULT_FLAGS	(NFSEXP_READONLY |	\
> +				 NFSEXP_ROOTSQUASH |	\
> +				 NFSEXP_GATHERED_WRITES |\
> +				 NFSEXP_NOSUBTREECHECK | \
> +				 NFSEXP_INSECURE_PORT)
>  
>  struct flav_info flav_map[] = {
>  	{ "krb5",	RPC_AUTH_GSS_KRB5,	1},
> diff --git a/utils/exportfs/exports.man b/utils/exportfs/exports.man
> index 39dc30fb8290213990ca7a14b1b3971140b0d120..0b62bb3a82b0e74bc2a7eb84301c4ec97b14d003 100644
> --- a/utils/exportfs/exports.man
> +++ b/utils/exportfs/exports.man
> @@ -180,8 +180,8 @@ understands the following export options:
>  .TP
>  .IR secure
>  This option requires that requests not using gss originate on an
> -Internet port less than IPPORT_RESERVED (1024). This option is on by default.
> -To turn it off, specify
> +Internet port less than IPPORT_RESERVED (1024). This option is off by default
> +but can be explicitly disabled by specifying
>  .IR insecure .
>  (NOTE: older kernels (before upstream kernel version 4.17) enforced this
>  requirement on gss requests as well.)
> 
> ---
> base-commit: 2cf015ea4312f37598efe9733fef3232ab67f784
> change-id: 20250513-master-89974087bb04
> 
> Best regards,


-- 
Chuck Lever