linux-kernel - Re: [PATCH v4 01/10] IMA: Defined an IMA hook to measure keys on key create or update

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Message-Id: <1573080189.5028.313.camel@linux.ibm.com>
Date:   Wed, 06 Nov 2019 17:43:09 -0500
From:   Mimi Zohar <zohar@...ux.ibm.com>
To:     Lakshmi Ramasubramanian <nramas@...ux.microsoft.com>,
        dhowells@...hat.com, matthewgarrett@...gle.com, sashal@...nel.org,
        jamorris@...ux.microsoft.com, linux-integrity@...r.kernel.org,
        linux-security-module@...r.kernel.org, keyrings@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4 01/10] IMA: Defined an IMA hook to measure keys on
 key create or update

On Wed, 2019-11-06 at 11:01 -0800, Lakshmi Ramasubramanian wrote:
> Asymmetric keys used for verifying file signatures or certificates
> are currently not included in the IMA measurement list.
> 
> This patch defines a new IMA hook namely ima_post_key_create_or_update()
> to measure asymmetric keys.
> 
> Signed-off-by: Lakshmi Ramasubramanian <nramas@...ux.microsoft.com>
> ---
>  security/integrity/ima/ima_main.c | 16 ++++++++++++++++
>  1 file changed, 16 insertions(+)
> 
> diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
> index d7e987baf127..a0e233afe876 100644
> --- a/security/integrity/ima/ima_main.c
> +++ b/security/integrity/ima/ima_main.c
> @@ -721,6 +721,22 @@ void ima_kexec_cmdline(const void *buf, int size)
>  					   KEXEC_CMDLINE, 0);
>  }
>  
> +/**
> + * ima_post_key_create_or_update - measure asymmetric keys
> + * @keyring: keyring to which the key is linked to
> + * @key: created or updated key
> + * @flags: key flags
> + * @create: flag indicating whether the key was created or updated
> + *
> + * Keys can only be measured, not appraised.
> + */
> +void ima_post_key_create_or_update(struct key *keyring, struct key *key,
> +				   unsigned long flags, bool create)
> +{
> +	if ((keyring != NULL) && (key != NULL))
> +		return;

I would move the patch that defines the "keyring=" policy option prior
to this one.  Include the call to process_buffer_measurement() in this
patch.  A subsequent patch would add support to defer measuring the
key, by calling a function named something like
ima_queue_key_measurement().

Mimi

> +}
> +
>  static int __init init_ima(void)
>  {
>  	int error;