Re: [PATCH] ima: Rename internal audit rule functions

[Casey Schaufler]

On 6/29/2020 8:30 AM, Tyler Hicks wrote:
> Rename IMA's internal audit rule functions from security_filter_rule_*()
> to ima_audit_rule_*(). This avoids polluting the security_* namespace,
> which is typically reserved for general security subsystem
> infrastructure, and better aligns the IMA function names with the names
> of the LSM hooks.
>
> Signed-off-by: Tyler Hicks <tyhicks@xxxxxxxxxxxxxxxxxxx>
> Suggested-by: Casey Schaufler <casey@xxxxxxxxxxxxxxxx>

Reviewed-by: Casey Schaufler <casey@xxxxxxxxxxxxxxxx>

> ---
>
> Developed on top of next-integrity-testing, commit cd1d8603df60 ("IMA:
> Add audit log for failure conditions"), plus this patch series:
>
>  [PATCH v2 00/11] ima: Fix rule parsing bugs and extend KEXEC_CMDLINE rule support
>  https://lore.kernel.org/linux-integrity/20200626223900.253615-1-tyhicks@xxxxxxxxxxxxxxxxxxx/T/#t
>
> This patch has dependencies on the above patch series.
>
> Tested with and without CONFIG_IMA_LSM_RULES enabled by attempting to
> load IMA policy with rules containing the subj_role=foo conditional.
> Build logs are clean in both configurations. The IMA policy was first
> loaded without and then with a valid AppArmor profile named "foo". The
> behavior is the same before and after this patch is applied:
>
>                   | CONFIG_IMA_LSM_RULES=n   | CONFIG_IMA_LSM_RULES=y
> -----------------------------------------------------------------------
>  Without Profile  |  IMA policy load fails   | IMA policy load fails
>  With Profile     |  IMA policy load fails   | IMA policy load succeeds
>
>  security/integrity/ima/ima.h        | 16 +++++++--------
>  security/integrity/ima/ima_policy.c | 30 +++++++++++++----------------
>  2 files changed, 21 insertions(+), 25 deletions(-)
>
> diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
> index ff2bf57ff0c7..5d62ee8319f4 100644
> --- a/security/integrity/ima/ima.h
> +++ b/security/integrity/ima/ima.h
> @@ -419,24 +419,24 @@ static inline void ima_free_modsig(struct modsig *modsig)
>  /* LSM based policy rules require audit */
>  #ifdef CONFIG_IMA_LSM_RULES
>  
> -#define security_filter_rule_init security_audit_rule_init
> -#define security_filter_rule_free security_audit_rule_free
> -#define security_filter_rule_match security_audit_rule_match
> +#define ima_audit_rule_init security_audit_rule_init
> +#define ima_audit_rule_free security_audit_rule_free
> +#define ima_audit_rule_match security_audit_rule_match
>  
>  #else
>  
> -static inline int security_filter_rule_init(u32 field, u32 op, char *rulestr,
> -					    void **lsmrule)
> +static inline int ima_audit_rule_init(u32 field, u32 op, char *rulestr,
> +				      void **lsmrule)
>  {
>  	return -EINVAL;
>  }
>  
> -static inline void security_filter_rule_free(void *lsmrule)
> +static inline void ima_audit_rule_free(void *lsmrule)
>  {
>  }
>  
> -static inline int security_filter_rule_match(u32 secid, u32 field, u32 op,
> -					     void *lsmrule)
> +static inline int ima_audit_rule_match(u32 secid, u32 field, u32 op,
> +				       void *lsmrule)
>  {
>  	return -EINVAL;
>  }
> diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
> index 294323b36d06..60894656a4b7 100644
> --- a/security/integrity/ima/ima_policy.c
> +++ b/security/integrity/ima/ima_policy.c
> @@ -258,7 +258,7 @@ static void ima_lsm_free_rule(struct ima_rule_entry *entry)
>  	int i;
>  
>  	for (i = 0; i < MAX_LSM_RULES; i++) {
> -		security_filter_rule_free(entry->lsm[i].rule);
> +		ima_audit_rule_free(entry->lsm[i].rule);
>  		kfree(entry->lsm[i].args_p);
>  	}
>  }
> @@ -308,10 +308,9 @@ static struct ima_rule_entry *ima_lsm_copy_rule(struct ima_rule_entry *entry)
>  		 */
>  		entry->lsm[i].args_p = NULL;
>  
> -		security_filter_rule_init(nentry->lsm[i].type,
> -					  Audit_equal,
> -					  nentry->lsm[i].args_p,
> -					  &nentry->lsm[i].rule);
> +		ima_audit_rule_init(nentry->lsm[i].type, Audit_equal,
> +				    nentry->lsm[i].args_p,
> +				    &nentry->lsm[i].rule);
>  		if (!nentry->lsm[i].rule)
>  			pr_warn("rule for LSM \'%s\' is undefined\n",
>  				entry->lsm[i].args_p);
> @@ -495,18 +494,16 @@ static bool ima_match_rules(struct ima_rule_entry *rule, struct inode *inode,
>  		case LSM_OBJ_ROLE:
>  		case LSM_OBJ_TYPE:
>  			security_inode_getsecid(inode, &osid);
> -			rc = security_filter_rule_match(osid,
> -							rule->lsm[i].type,
> -							Audit_equal,
> -							rule->lsm[i].rule);
> +			rc = ima_audit_rule_match(osid, rule->lsm[i].type,
> +						  Audit_equal,
> +						  rule->lsm[i].rule);
>  			break;
>  		case LSM_SUBJ_USER:
>  		case LSM_SUBJ_ROLE:
>  		case LSM_SUBJ_TYPE:
> -			rc = security_filter_rule_match(secid,
> -							rule->lsm[i].type,
> -							Audit_equal,
> -							rule->lsm[i].rule);
> +			rc = ima_audit_rule_match(secid, rule->lsm[i].type,
> +						  Audit_equal,
> +						  rule->lsm[i].rule);
>  		default:
>  			break;
>  		}
> @@ -901,10 +898,9 @@ static int ima_lsm_rule_init(struct ima_rule_entry *entry,
>  		return -ENOMEM;
>  
>  	entry->lsm[lsm_rule].type = audit_type;
> -	result = security_filter_rule_init(entry->lsm[lsm_rule].type,
> -					   Audit_equal,
> -					   entry->lsm[lsm_rule].args_p,
> -					   &entry->lsm[lsm_rule].rule);
> +	result = ima_audit_rule_init(entry->lsm[lsm_rule].type, Audit_equal,
> +				     entry->lsm[lsm_rule].args_p,
> +				     &entry->lsm[lsm_rule].rule);
>  	if (!entry->lsm[lsm_rule].rule) {
>  		pr_warn("rule for LSM \'%s\' is undefined\n",
>  			entry->lsm[lsm_rule].args_p);