Re: [PATCH v14 04/10] KEYS: Move KEY_LOOKUP_ to include/linux/key.h and add flags check function

[Roberto Sassu]

On Fri, 2022-08-26 at 11:12 +0200, Roberto Sassu wrote:
> From: Roberto Sassu <roberto.sassu@xxxxxxxxxx>
> 
> In preparation for the patch that introduces the
> bpf_lookup_user_key() eBPF
> kfunc, move KEY_LOOKUP_ definitions to include/linux/key.h, to be
> able to
> validate the kfunc parameters.
> 
> Also, introduce key_lookup_flags_valid() to check if the caller set
> in the
> argument only defined flags. Introduce it directly in
> include/linux/key.h,
> to reduce the risk that the check is not in sync with currently
> defined
> flags.
> 
> Signed-off-by: Roberto Sassu <roberto.sassu@xxxxxxxxxx>
> Reviewed-by: KP Singh <kpsingh@xxxxxxxxxx>

Jarkko, could you please ack it if it is fine?

Thanks

Roberto

> ---
>  include/linux/key.h      | 16 ++++++++++++++++
>  security/keys/internal.h |  2 --
>  2 files changed, 16 insertions(+), 2 deletions(-)
> 
> diff --git a/include/linux/key.h b/include/linux/key.h
> index 7febc4881363..e679dbf0c940 100644
> --- a/include/linux/key.h
> +++ b/include/linux/key.h
> @@ -88,6 +88,22 @@ enum key_need_perm {
>  	KEY_DEFER_PERM_CHECK,	/* Special: permission check is
> deferred */
>  };
>  
> +#define KEY_LOOKUP_CREATE	0x01
> +#define KEY_LOOKUP_PARTIAL	0x02
> +
> +/**
> + * key_lookup_flags_valid - detect if provided key lookup flags are
> valid
> + * @flags: key lookup flags.
> + *
> + * Verify whether or not the caller set in the argument only defined
> flags.
> + *
> + * Return: true if flags are valid, false if not.
> + */
> +static inline bool key_lookup_flags_valid(u64 flags)
> +{
> +	return !(flags & ~(KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL));
> +}
> +
>  struct seq_file;
>  struct user_struct;
>  struct signal_struct;
> diff --git a/security/keys/internal.h b/security/keys/internal.h
> index 9b9cf3b6fcbb..3c1e7122076b 100644
> --- a/security/keys/internal.h
> +++ b/security/keys/internal.h
> @@ -165,8 +165,6 @@ extern struct key *request_key_and_link(struct
> key_type *type,
>  
>  extern bool lookup_user_key_possessed(const struct key *key,
>  				      const struct key_match_data
> *match_data);
> -#define KEY_LOOKUP_CREATE	0x01
> -#define KEY_LOOKUP_PARTIAL	0x02
>  
>  extern long join_session_keyring(const char *name);
>  extern void key_change_session_keyring(struct callback_head *twork);