[PATCH v15 02/23] LSM: Create and manage the lsmblob data structure.

[Mimi Zohar]

[Cc'ing Janne Karhunen]

On Fri, 2020-02-14 at 15:41 -0800, Casey Schaufler wrote:
<snip>
> diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
> index 453427048999..624ed1a34842 100644
> --- a/security/integrity/ima/ima_policy.c
> +++ b/security/integrity/ima/ima_policy.c
> @@ -75,7 +75,7 @@ struct ima_rule_entry {
>  	bool (*fowner_op)(kuid_t, kuid_t); /* uid_eq(), uid_gt(), uid_lt() */
>  	int pcr;
>  	struct {
> -		void *rule;	/* LSM file metadata specific */
> +		void *rules[LSMBLOB_ENTRIES];
>  		void *args_p;	/* audit value */
>  		int type;	/* audit type */
>  	} lsm[MAX_LSM_RULES];
> @@ -84,6 +84,16 @@ struct ima_rule_entry {
>  	struct ima_template_desc *template;
>  };
> 
> +static inline bool ima_lsm_isset(void *rules[])
> +{
> +	int i;
> +
> +	for (i = 0; i < LSMBLOB_ENTRIES; i++)
> +		if (rules[i])
> +			return true;
> +	return false;
> +}
> +

Even though ima_lsm_isset() is static, it should really be commented.

>  /*
>   * Without LSM specific knowledge, the default policy can only be
>   * written in terms of .action, .func, .mask, .fsmagic, .uid, and .fowner
> @@ -258,9 +268,11 @@ __setup("ima_appraise_tcb", default_appraise_policy_setup);
>  static void ima_lsm_free_rule(struct ima_rule_entry *entry)
>  {
>  	int i;
> +	int r;
> 
>  	for (i = 0; i < MAX_LSM_RULES; i++) {
> -		kfree(entry->lsm[i].rule);
> +		for (r = 0; r < LSMBLOB_ENTRIES; r++)
> +			kfree(entry->lsm[i].rules[r]);
>  		kfree(entry->lsm[i].args_p);
>  	}
>  	kfree(entry);
> @@ -295,8 +307,8 @@ static struct ima_rule_entry *ima_lsm_copy_rule(struct ima_rule_entry *entry)
>  		security_filter_rule_init(nentry->lsm[i].type,
>  					  Audit_equal,
>  					  nentry->lsm[i].args_p,
> -					  &nentry->lsm[i].rule);
> -		if (!nentry->lsm[i].rule)
> +					  nentry->lsm[i].rules);
> +		if (!ima_lsm_isset(nentry->lsm[i].rules))
>  			pr_warn("rule for LSM \'%s\' is undefined\n",
>  				(char *)entry->lsm[i].args_p);

Janne, the generic LSM message looks fine, but should there also be an
LSM specific warning the first time it changes?

Mimi