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

From: Roberto Sassu <roberto.sassu@huaweicloud.com>
To: ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org,
	martin.lau@linux.dev, song@kernel.org, yhs@fb.com,
	john.fastabend@gmail.com, kpsingh@kernel.org, sdf@google.com,
	haoluo@google.com, jolsa@kernel.org, mykolal@fb.com,
	corbet@lwn.net, dhowells@redhat.com, jarkko@kernel.org,
	rostedt@goodmis.org, mingo@redhat.com, paul@paul-moore.com,
	jmorris@namei.org, serge@hallyn.com, shuah@kernel.org
Cc: bpf@vger.kernel.org, linux-doc@vger.kernel.org,
	keyrings@vger.kernel.org, linux-security-module@vger.kernel.org,
	linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org,
	deso@posteo.net, Roberto Sassu <roberto.sassu@huawei.com>
Subject: Re: [PATCH v14 04/10] KEYS: Move KEY_LOOKUP_ to include/linux/key.h and add flags check function
Date: Fri, 26 Aug 2022 11:22:54 +0200	[thread overview]
Message-ID: <6d85d7b1f0c2341698e88bad025bd6e0b34c7666.camel@huaweicloud.com> (raw)
In-Reply-To: <20220826091228.1701185-1-roberto.sassu@huaweicloud.com>

On Fri, 2022-08-26 at 11:12 +0200, Roberto Sassu wrote:
> From: Roberto Sassu <roberto.sassu@huawei.com>
> 
> 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@huawei.com>
> Reviewed-by: KP Singh <kpsingh@kernel.org>

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);