Re: [PATCH net-next v2] netlink: specs: fix duplicate if/then keys in netlink-raw schema

[Hangbin Liu]

On Mon, Sep 14, 2026 at 09:53:15PM -0400, Taylor Bates wrote:
> Currently netlink-raw.yaml contains two if keys and two then keys in a
> single mapping that enforces a "len" for "pad" members and a "len" or
> "struct" for binary members.
> 
> During validation PyYAML resolves duplicate keys last-wins, so only the
> binary rule survives. Pad has not been validated since commit
> bf08f32c8ced ("tools/net/ynl: Add support for nested structs") added
> the second if/then pair in January 2024.
> 
> None of the current specs violate this rule, but this validation should
> not be parser dependent and unspecified. Strict YAML validators such as
> Red Hat's VS Code YAML extension and Adrien Verge's yamllint will
> reject the netlink-raw.yaml schema:
> 
> Command:
>   $ yamllint Documentation/netlink/netlink-raw.yaml
> 
> Output:
>   185:13    error    duplication of key "if" in mapping  (key-duplicates)
>   189:13    error    duplication of key "then" in mapping  (key-duplicates)
> 
> The following invalid netlink family spec will pass validation in the
> current ynl tooling:
> 
>   # SPDX-License-Identifier: ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)
>   ---
>   name: minimal-raw
>   doc: Minimal netlink-raw family for schema validation testing.
>   protocol: netlink-raw
>   protonum: 0
> 
>   definitions:
>     -
>       name: test-struct
>       type: struct
>       members:
>         -
>           name: reserved
>           type: pad
>           # len intentionally omitted
> 
>   attribute-sets: []
> 
>   operations:
>     list: []
> 
> Signed-off-by: Taylor Bates <tmbates12@xxxxxxxxx>
> ---
> This is a repost of patch 1 from the "netlink: fix ynl spec tooling
> robustness bugs" series, reduced to this single fix as requested.
> 
> The netlink-raw spec for the Bridge VLAN family that motivated the
> original series will be sent separately once this has landed.
> ---
> Changes in v2:
> - Drop patches 2/4, 3/4 and 4/4 from the series; this schema fix stands
>   on its own.
> - Drop the Fixes tag. This is developer tooling only and is not a bug
>   that needs to reach stable. The offending commit is now cited in the
>   commit message instead.
> - Link to v1: https://patch.msgid.link/20260908-ynl-robustness-v1-0-f255214c0f30@xxxxxxxxx
> 
> To: Donald Hunter <donald.hunter@xxxxxxxxx>
> To: Jakub Kicinski <kuba@xxxxxxxxxx>
> To: "David S. Miller" <davem@xxxxxxxxxxxxx>
> To: Eric Dumazet <edumazet@xxxxxxxxxx>
> To: Paolo Abeni <pabeni@xxxxxxxxxx>
> To: Simon Horman <horms@xxxxxxxxxx>
> Cc: netdev@xxxxxxxxxxxxxxx
> Cc: linux-kernel@xxxxxxxxxxxxxxx
> ---
>  Documentation/netlink/netlink-raw.yaml | 31 +++++++++++++++++--------------
>  1 file changed, 17 insertions(+), 14 deletions(-)
> 
> diff --git a/Documentation/netlink/netlink-raw.yaml b/Documentation/netlink/netlink-raw.yaml
> index 4c436b59a34b..18ccfe05048a 100644
> --- a/Documentation/netlink/netlink-raw.yaml
> +++ b/Documentation/netlink/netlink-raw.yaml
> @@ -176,20 +176,23 @@ properties:
>                struct:
>                  description: Name of the nested struct type.
>                  type: string
> -            if:
> -              properties:
> -                type:
> -                  const: pad
> -            then:
> -              required: [ len ]
> -            if:
> -              properties:
> -                type:
> -                  const: binary
> -            then:
> -              oneOf:
> -                - required: [ len ]
> -                - required: [ struct ]
> +            allOf:
> +              -
> +                if:
> +                  properties:
> +                    type:
> +                      const: pad
> +                then:
> +                  required: [ len ]
> +              -
> +                if:
> +                  properties:
> +                    type:
> +                      const: binary
> +                then:
> +                  oneOf:
> +                    - required: [ len ]
> +                    - required: [ struct ]
>          # End genetlink-legacy
>  
>    attribute-sets:
> 
> ---
> base-commit: 043777e948807b5f335f58a0b9f5ed04bba681cf
> change-id: 20260907-ynl-robustness-d62d9693cc12
> 
> Best regards,
> --  
> Taylor Bates <tmbates12@xxxxxxxxx>
> 

Reviewed-by: Hangbin Liu <liuhangbin@xxxxxxxxxx>