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From: Mimi Zohar <zohar@linux.ibm.com>
To: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>,
	linux-integrity@vger.kernel.org
Cc: eric.snowberg@oracle.com, dhowells@redhat.com,
	matthewgarrett@google.com, sashal@kernel.org,
	jamorris@linux.microsoft.com, linux-kernel@vger.kernel.org,
	keyrings@vger.kernel.org
Subject: Re: [PATCH v9 5/6] IMA: Add support to limit measuring keys
Date: Wed, 27 Nov 2019 13:52:21 -0500
Message-ID: <1574880741.4793.292.camel@linux.ibm.com> (raw)
In-Reply-To: <20191127015654.3744-6-nramas@linux.microsoft.com>

> --- a/security/integrity/ima/ima_policy.c
> +++ b/security/integrity/ima/ima_policy.c
> @@ -79,6 +79,7 @@ struct ima_rule_entry {
>  		int type;	/* audit type */
>  	} lsm[MAX_LSM_RULES];
>  	char *fsname;
> +	char *keyrings; /* Measure keys added to these keyrings */
>  	struct ima_template_desc *template;
>  };
>  
> @@ -356,6 +357,55 @@ int ima_lsm_policy_change(struct notifier_block *nb, unsigned long event,
>  	return NOTIFY_OK;
>  }
>  
> +/**
> + * ima_match_keyring - determine whether the keyring matches the measure rule
> + * @rule: a pointer to a rule
> + * @keyring: name of the keyring to match against the measure rule
> + *
> + * If the measure action for KEY_CHECK does not specify keyrings=
> + * option then return true (Measure all keys).
> + * Else, return true if the given keyring name is present in
> + * the keyrings= option. False, otherwise.

This is suppose to be a comment, not code or pseudo code.  Please
refer to the section "Comments" in Documentation/process/coding-
style.rst.
 
> + */
> +static bool ima_match_keyring(struct ima_rule_entry *rule,
> +			      const char *keyring)
> +{
> +	const char *p;
> +
> +	/* If "keyrings=" is not specified all keys are measured. */
> +	if (!rule->keyrings)
> +		return true;
> +
> +	if (!keyring)
> +		return false;
> +
> +	/*
> +	 * "keyrings=" is specified in the policy in the format below:
> +	 *   keyrings=.builtin_trusted_keys|.ima|.evm
> +	 *
> +	 * Each keyring name in the option is separated by a '|' and
> +	 * the last keyring name is null terminated.
> +	 *
> +	 * The given keyring is considered matched only if
> +	 * the whole keyring name matched a keyring name specified
> +	 * in the "keyrings=" option.
> +	 */
> +	p = strstr(rule->keyrings, keyring);
> +	if (p) {
> +		/*
> +		 * Found a substring match. Check if the character
> +		 * at the end of the keyring name is | (keyring name
> +		 * separator) or is the terminating null character.
> +		 * If yes, we have a whole string match.
> +		 */
> +		p += strlen(keyring);
> +		if (*p == '|' || *p == '\0')
> +			return true;
> +	}
> +

Using "while strsep()" would simplify this code, removing the need for
such a long comment.

Mimi

> +	return false;
> +}
> +


  reply index

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-27  1:56 [PATCH v9 0/6] KEYS: Measure keys when they are created or updated Lakshmi Ramasubramanian
2019-11-27  1:56 ` [PATCH v9 1/6] IMA: Check IMA policy flag Lakshmi Ramasubramanian
2019-11-27  1:56 ` [PATCH v9 2/6] IMA: Add KEY_CHECK func to measure keys Lakshmi Ramasubramanian
2019-11-27  1:56 ` [PATCH v9 3/6] IMA: Define an IMA hook " Lakshmi Ramasubramanian
2019-11-27  1:56 ` [PATCH v9 4/6] KEYS: Call the " Lakshmi Ramasubramanian
2019-11-27  1:56 ` [PATCH v9 5/6] IMA: Add support to limit measuring keys Lakshmi Ramasubramanian
2019-11-27 18:52   ` Mimi Zohar [this message]
2019-11-28  0:44     ` Lakshmi Ramasubramanian
2019-12-02 18:18       ` Mimi Zohar
2019-12-03 12:25   ` Mimi Zohar
2019-12-03 16:13     ` Lakshmi Ramasubramanian
2019-12-03 16:47       ` Mimi Zohar
2019-12-03 19:45     ` Lakshmi Ramasubramanian
2019-12-03 20:06       ` Mimi Zohar
2019-12-03 23:37         ` Lakshmi Ramasubramanian
2019-12-04 11:16           ` Mimi Zohar
2019-12-04 22:43             ` Lakshmi Ramasubramanian
2019-12-04 23:25             ` Mat Martineau
2019-11-27  1:56 ` [PATCH v9 6/6] IMA: Read keyrings= option from the IMA policy Lakshmi Ramasubramanian
2019-11-27 19:32   ` Mimi Zohar
2019-11-27 22:05     ` Lakshmi Ramasubramanian

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