audit: remove unused actx param from audit_rule_match

The audit_rule_match() struct audit_context *actx parameter is not used
by any in-tree consumers (selinux, apparmour, integrity, smack).

The audit context is an internal audit structure that should only be
accessed by audit accessor functions.

It was part of commit 03d37d25e0f9 ("LSM/Audit: Introduce generic
Audit LSM hooks") but appears to have never been used.

Remove it.

Please see the github issue
https://github.com/linux-audit/audit-kernel/issues/107

Signed-off-by: Richard Guy Briggs <[e-mail]>
[PM: fixed the referenced commit title]
Signed-off-by: Paul Moore <[e-mail]>

include/linux/lsm_hooks.h

···
  *	@field contains the field which relates to current LSM.
  *	@op contains the operator that will be used for matching.
  *	@rule points to the audit rule that will be checked against.
- *	@actx points to the audit context associated with the check.
  *	Return 1 if secid matches the rule, 0 if it does not, -ERRNO on failure.
  *
  * @audit_rule_free:
···
 	int (*audit_rule_init)(u32 field, u32 op, char *rulestr,
 				void **lsmrule);
 	int (*audit_rule_known)(struct audit_krule *krule);
-	int (*audit_rule_match)(u32 secid, u32 field, u32 op, void *lsmrule,
-				struct audit_context *actx);
+	int (*audit_rule_match)(u32 secid, u32 field, u32 op, void *lsmrule);
 	void (*audit_rule_free)(void *lsmrule);
 #endif /* CONFIG_AUDIT */
 

include/linux/security.h

···
 #ifdef CONFIG_SECURITY
 int security_audit_rule_init(u32 field, u32 op, char *rulestr, void **lsmrule);
 int security_audit_rule_known(struct audit_krule *krule);
-int security_audit_rule_match(u32 secid, u32 field, u32 op, void *lsmrule,
-			      struct audit_context *actx);
+int security_audit_rule_match(u32 secid, u32 field, u32 op, void *lsmrule);
 void security_audit_rule_free(void *lsmrule);
 
 #else
···
 }
 
 static inline int security_audit_rule_match(u32 secid, u32 field, u32 op,
-				   void *lsmrule, struct audit_context *actx)
+					    void *lsmrule)
 {
 	return 0;
 }

kernel/auditfilter.c

···
 				if (f->lsm_rule) {
 					security_task_getsecid(current, &sid);
 					result = security_audit_rule_match(sid,
-							f->type, f->op, f->lsm_rule, NULL);
+						   f->type, f->op, f->lsm_rule);
 				}
 				break;
 			case AUDIT_EXE:

kernel/auditsc.c

···
 					need_sid = 0;
 				}
 				result = security_audit_rule_match(sid, f->type,
-				                                  f->op,
-				                                  f->lsm_rule,
-				                                  ctx);
+								   f->op,
+								   f->lsm_rule);
 			}
 			break;
 		case AUDIT_OBJ_USER:
···
 				/* Find files that match */
 				if (name) {
 					result = security_audit_rule_match(
-					           name->osid, f->type, f->op,
-					           f->lsm_rule, ctx);
+								name->osid,
+								f->type,
+								f->op,
+								f->lsm_rule);
 				} else if (ctx) {
 					list_for_each_entry(n, &ctx->names_list, list) {
-						if (security_audit_rule_match(n->osid, f->type,
-									      f->op, f->lsm_rule,
-									      ctx)) {
+						if (security_audit_rule_match(
+								n->osid,
+								f->type,
+								f->op,
+								f->lsm_rule)) {
 							++result;
 							break;
 						}
···
 					break;
 				if (security_audit_rule_match(ctx->ipc.osid,
 							      f->type, f->op,
-							      f->lsm_rule, ctx))
+							      f->lsm_rule))
 					++result;
 			}
 			break;

security/apparmor/audit.c

···
 	return 0;
 }
 
-int aa_audit_rule_match(u32 sid, u32 field, u32 op, void *vrule,
-			struct audit_context *actx)
+int aa_audit_rule_match(u32 sid, u32 field, u32 op, void *vrule)
 {
 	struct aa_audit_rule *rule = vrule;
 	struct aa_label *label;

security/apparmor/include/audit.h

···
 void aa_audit_rule_free(void *vrule);
 int aa_audit_rule_init(u32 field, u32 op, char *rulestr, void **vrule);
 int aa_audit_rule_known(struct audit_krule *rule);
-int aa_audit_rule_match(u32 sid, u32 field, u32 op, void *vrule,
-			struct audit_context *actx);
+int aa_audit_rule_match(u32 sid, u32 field, u32 op, void *vrule);
 
 #endif /* __AA_AUDIT_H */

security/integrity/ima/ima.h

···
 }
 
 static inline int security_filter_rule_match(u32 secid, u32 field, u32 op,
-					     void *lsmrule,
-					     struct audit_context *actx)
+					     void *lsmrule)
 {
 	return -EINVAL;
 }

security/integrity/ima/ima_policy.c

···
 			rc = security_filter_rule_match(osid,
 							rule->lsm[i].type,
 							Audit_equal,
-							rule->lsm[i].rule,
-							NULL);
+							rule->lsm[i].rule);
 			break;
 		case LSM_SUBJ_USER:
 		case LSM_SUBJ_ROLE:
···
 			rc = security_filter_rule_match(secid,
 							rule->lsm[i].type,
 							Audit_equal,
-							rule->lsm[i].rule,
-							NULL);
+							rule->lsm[i].rule);
 		default:
 			break;
 		}

security/security.c

···
 	call_void_hook(audit_rule_free, lsmrule);
 }
 
-int security_audit_rule_match(u32 secid, u32 field, u32 op, void *lsmrule,
-			      struct audit_context *actx)
+int security_audit_rule_match(u32 secid, u32 field, u32 op, void *lsmrule)
 {
-	return call_int_hook(audit_rule_match, 0, secid, field, op, lsmrule,
-				actx);
+	return call_int_hook(audit_rule_match, 0, secid, field, op, lsmrule);
 }
 #endif /* CONFIG_AUDIT */
 

security/selinux/include/audit.h

···
  *	@field: the field this rule refers to
  *	@op: the operater the rule uses
  *	@rule: pointer to the audit rule to check against
- *	@actx: the audit context (can be NULL) associated with the check
  *
  *	Returns 1 if the context id matches the rule, 0 if it does not, and
  *	-errno on failure.
  */
-int selinux_audit_rule_match(u32 sid, u32 field, u32 op, void *rule,
-			     struct audit_context *actx);
+int selinux_audit_rule_match(u32 sid, u32 field, u32 op, void *rule);
 
 /**
  *	selinux_audit_rule_known - check to see if rule contains selinux fields.

security/selinux/ss/services.c

···
 	return 0;
 }
 
-int selinux_audit_rule_match(u32 sid, u32 field, u32 op, void *vrule,
-			     struct audit_context *actx)
+int selinux_audit_rule_match(u32 sid, u32 field, u32 op, void *vrule)
 {
 	struct selinux_state *state = &selinux_state;
 	struct context *ctxt;

security/smack/smack_lsm.c

···
  * @field: audit rule flags given from user-space
  * @op: required testing operator
  * @vrule: smack internal rule presentation
- * @actx: audit context associated with the check
  *
  * The core Audit hook. It's used to take the decision of
  * whether to audit or not to audit a given object.
  */
-static int smack_audit_rule_match(u32 secid, u32 field, u32 op, void *vrule,
-				  struct audit_context *actx)
+static int smack_audit_rule_match(u32 secid, u32 field, u32 op, void *vrule)
 {
 	struct smack_known *skp;
 	char *rule = vrule;