move compare to frontend (disabled by default, only invoked if backend doesn't...

move compare to frontend (disabled by default, only invoked if backend doesn't provide hook); honor ITS#3472 (disclose access check); fix ITS#3521 as well (check access to hasSubordinates); fix a problem in backend_attribute() with operational attrs; add backend_access() helper

servers/slapd/backend.c

@@ -555,11 +555,11 @@ backend_db_init(
  	/* assign a default depth limit for alias deref */
 	be->be_max_deref_depth = SLAPD_DEFAULT_MAXDEREFDEPTH; 
 
-	if(bi->bi_db_init) {
+	if ( bi->bi_db_init ) {
 		rc = bi->bi_db_init( be );
 	}
 
-	if(rc != 0) {
+	if ( rc != 0 ) {
 		fprintf( stderr, "database init failed (%s)\n", type );
 		nbackends--;
 		return NULL;
@@ -583,6 +583,7 @@ be_db_close( void )
 	if ( frontendDB->bd_info->bi_db_close ) {
 		(*frontendDB->bd_info->bi_db_close)( frontendDB );
 	}
+
 }
 
 Backend *
@@ -1479,13 +1480,21 @@ backend_attribute(
 			BER_BVZERO( &anlist[ 1 ].an_name );
 			rs.sr_attrs = anlist;
 			
-			rs.sr_attr_flags = slap_attr_flags( rs.sr_attrs );
-
-			rc = backend_operational( op, &rs );
+ 			/* NOTE: backend_operational() is also called
+ 			 * when returning results, so it's supposed
+ 			 * to do no harm to entries */
+ 			rs.sr_entry = e;
+  			rc = backend_operational( op, &rs );
+ 			rs.sr_entry = NULL;
+ 
+			if ( rc == LDAP_SUCCESS ) {
+				if ( rs.sr_operational_attrs ) {
+					freeattr = 1;
+					a = rs.sr_operational_attrs;
 
-			if ( rc == LDAP_SUCCESS && rs.sr_operational_attrs ) {
-				freeattr = 1;
-				a = rs.sr_operational_attrs;
+				} else {
+					rc = LDAP_NO_SUCH_ATTRIBUTE;
+				}
 			}
 		}
 
@@ -1567,6 +1576,144 @@ freeit:		if ( e != target ) {
 	return rc;
 }
 
+#ifdef LDAP_SLAPI
+static int backend_compute_output_attr_access(computed_attr_context *c, Slapi_Attr *a, Slapi_Entry *e)
+{
+	struct berval	*nval = (struct berval *)c->cac_private;
+	Operation	*op = NULL;
+
+	slapi_pblock_get( c->cac_pb, SLAPI_OPERATION, &op );
+	if ( op == NULL ) {
+		return 1;
+	}
+
+	return access_allowed( op, e, a->a_desc, nval, ACL_AUTH, NULL ) == 0;
+}
+#endif /* LDAP_SLAPI */
+
+int 
+backend_access(
+	Operation		*op,
+	Entry			*target,
+	struct berval		*edn,
+	AttributeDescription	*entry_at,
+	struct berval		*nval,
+	slap_access_t		access,
+	slap_mask_t		*mask )
+{
+	Entry		*e = NULL;
+	int		rc = LDAP_INSUFFICIENT_ACCESS;
+	Backend		*be = op->o_bd;
+
+	/* pedantic */
+	assert( op );
+	assert( op->o_conn );
+	assert( edn );
+	assert( access > ACL_NONE );
+
+	op->o_bd = select_backend( edn, 0, 0 );
+
+	if ( target && dn_match( &target->e_nname, edn ) ) {
+		e = target;
+
+	} else {
+		rc = be_entry_get_rw( op, edn, NULL, entry_at, 0, &e );
+	} 
+
+	if ( e ) {
+		Attribute	*a = NULL;
+		int		freeattr = 0;
+
+		if ( entry_at == NULL ) {
+			entry_at = slap_schema.si_ad_entry;
+		}
+
+		if ( entry_at == slap_schema.si_ad_entry || entry_at == slap_schema.si_ad_children )
+		{
+			if ( access_allowed_mask( op, e, entry_at,
+					NULL, access, NULL, mask ) == 0 )
+			{
+				rc = LDAP_INSUFFICIENT_ACCESS;
+
+			} else {
+				rc = LDAP_SUCCESS;
+			}
+
+		} else {
+			a = attr_find( e->e_attrs, entry_at );
+			if ( a == NULL ) {
+				SlapReply	rs = { 0 };
+				AttributeName	anlist[ 2 ];
+
+				anlist[ 0 ].an_name = entry_at->ad_cname;
+				anlist[ 0 ].an_desc = entry_at;
+				BER_BVZERO( &anlist[ 1 ].an_name );
+				rs.sr_attrs = anlist;
+			
+				rs.sr_attr_flags = slap_attr_flags( rs.sr_attrs );
+
+				/* NOTE: backend_operational() is also called
+				 * when returning results, so it's supposed
+				 * to do no harm to entries */
+				rs.sr_entry = e;
+				rc = backend_operational( op, &rs );
+				rs.sr_entry = NULL;
+
+				if ( rc == LDAP_SUCCESS ) {
+					if ( rs.sr_operational_attrs ) {
+						freeattr = 1;
+						a = rs.sr_operational_attrs;
+
+					} else {
+						rc = LDAP_NO_SUCH_OBJECT;
+					}
+				}
+			}
+
+			if ( a ) {
+				if ( access_allowed_mask( op, e, entry_at,
+						nval, access, NULL, mask ) == 0 )
+				{
+					rc = LDAP_INSUFFICIENT_ACCESS;
+					goto freeit;
+				}
+				rc = LDAP_SUCCESS;
+			}
+#ifdef LDAP_SLAPI
+			else if ( op->o_pb ) {
+				/* try any computed attributes */
+				computed_attr_context	ctx;
+
+				slapi_int_pblock_set_operation( op->o_pb, op );
+
+				ctx.cac_pb = op->o_pb;
+				ctx.cac_attrs = NULL;
+				ctx.cac_userattrs = 0;
+				ctx.cac_opattrs = 0;
+				ctx.cac_private = (void *)nval;
+
+				rc = compute_evaluator( &ctx, entry_at->ad_cname.bv_val, e, backend_compute_output_attr_access );
+				if ( rc == 1 ) {
+					rc = LDAP_INSUFFICIENT_ACCESS;
+
+				} else {
+					rc = LDAP_SUCCESS;
+				}
+			}
+#endif /* LDAP_SLAPI */
+		}
+freeit:		if ( e != target ) {
+			be_entry_release_r( op, e );
+		}
+		if ( freeattr ) {
+			attr_free( a );
+		}
+	}
+
+	op->o_bd = be;
+	return rc;
+}
+
 int backend_operational(
 	Operation *op,
 	SlapReply *rs )
@@ -1583,15 +1730,15 @@ int backend_operational(
 	 * and the backend supports specific operational attributes, 
 	 * add them to the attribute list
 	 */
-	if ( SLAP_OPATTRS( rs->sr_attr_flags ) || ( op->ors_attrs &&
-		ad_inlist( slap_schema.si_ad_entryDN, op->ors_attrs )))
+	if ( SLAP_OPATTRS( rs->sr_attr_flags ) || ( rs->sr_attrs &&
+		ad_inlist( slap_schema.si_ad_entryDN, rs->sr_attrs )))
 	{
 		*ap = slap_operational_entryDN( rs->sr_entry );
 		ap = &(*ap)->a_next;
 	}
 
-	if ( SLAP_OPATTRS( rs->sr_attr_flags ) || ( op->ors_attrs &&
-		ad_inlist( slap_schema.si_ad_subschemaSubentry, op->ors_attrs )))
+	if ( SLAP_OPATTRS( rs->sr_attr_flags ) || ( rs->sr_attrs &&
+		ad_inlist( slap_schema.si_ad_subschemaSubentry, rs->sr_attrs )))
 	{
 		*ap = slap_operational_subschemaSubentry( op->o_bd );
 		ap = &(*ap)->a_next;
@@ -1602,7 +1749,7 @@ int backend_operational(
 	if ( SLAP_ISOVERLAY( be_orig ))
 		op->o_bd = select_backend( be_orig->be_nsuffix, 0, 0 );
 
-	if (( SLAP_OPATTRS( rs->sr_attr_flags ) || op->ors_attrs ) &&
+	if (( SLAP_OPATTRS( rs->sr_attr_flags ) || rs->sr_attrs ) &&
 		op->o_bd && op->o_bd->be_operational != NULL )
 	{
 		Attribute	*a;

servers/slapd/compare.c

@@ -274,6 +274,7 @@ fe_op_compare( Operation *op, SlapReply *rs )
 		send_ldap_error( op, rs, LDAP_UNWILLING_TO_PERFORM,
 			"subschemaSubentry compare not supported" );
 
+#ifndef SLAP_COMPARE_IN_FRONTEND
 	} else if ( ava.aa_desc == slap_schema.si_ad_hasSubordinates
 		&& op->o_bd->be_has_subordinates )
 	{
@@ -281,9 +282,16 @@ fe_op_compare( Operation *op, SlapReply *rs )
 
 		rc = be_entry_get_rw( op, &op->o_req_ndn, NULL, NULL, 0, &entry );
 		if ( rc == 0 && entry ) {
-			rc = op->o_bd->be_has_subordinates( op, entry,
-				&hasSubordinates );
-			be_entry_release_r( op, entry );
+			if ( ! access_allowed( op, entry,
+				ava.aa_desc, &ava.aa_value, ACL_COMPARE, NULL ) )
+			{	
+				rc = rs->sr_err = LDAP_INSUFFICIENT_ACCESS;
+				
+			} else {
+				rc = rs->sr_err = op->o_bd->be_has_subordinates( op,
+						entry, &hasSubordinates );
+				be_entry_release_r( op, entry );
+			}
 		}
 
 		if ( rc == 0 ) {
@@ -293,20 +301,90 @@ fe_op_compare( Operation *op, SlapReply *rs )
 				? LDAP_COMPARE_TRUE : LDAP_COMPARE_FALSE;
 			if ( hasSubordinates == asserted ) {
 				rs->sr_err = LDAP_COMPARE_TRUE;
+
 			} else {
 				rs->sr_err = LDAP_COMPARE_FALSE;
 			}
+
+		} else {
+#ifdef SLAP_ACL_HONOR_DISCLOSE
+			/* return error only if "disclose"
+			 * is granted on the object */
+			if ( backend_access( op, NULL, &op->o_req_ndn,
+					slap_schema.si_ad_entry,
+					NULL, ACL_DISCLOSE, NULL ) == LDAP_INSUFFICIENT_ACCESS )
+			{
+				rs->sr_err = LDAP_NO_SUCH_OBJECT;
+			}
+#endif /* SLAP_ACL_HONOR_DISCLOSE */
 		}
+
 		send_ldap_result( op, rs );
 
-		if( rc == 0 ) rs->sr_err = LDAP_SUCCESS;
+		if ( rc == 0 ) {
+			rs->sr_err = LDAP_SUCCESS;
+		}
 
 	} else if ( op->o_bd->be_compare ) {
 		op->o_bd->be_compare( op, rs );
 
+#endif /* ! SLAP_COMPARE_IN_FRONTEND */
 	} else {
-		send_ldap_error( op, rs, LDAP_UNWILLING_TO_PERFORM,
-			"operation not supported within namingContext" );
+		/* do our best to compare that AVA
+		 * 
+		 * NOTE: this code is used only
+		 * if SLAP_COMPARE_IN_FRONTEND 
+		 * is #define'd (it's not by default)
+		 * or if op->o_bd->be_compare is NULL.
+		 * 
+		 * FIXME: one potential issue is that
+		 * if SLAP_COMPARE_IN_FRONTEND overlays
+		 * are not executed for compare. */
+		BerVarray	vals = NULL;
+		int		rc = LDAP_OTHER;
+
+		rs->sr_err = backend_attribute( op, NULL, &op->o_req_ndn,
+				ava.aa_desc, &vals, ACL_COMPARE );
+		switch ( rs->sr_err ) {
+		default:
+#ifdef SLAP_ACL_HONOR_DISCLOSE
+			/* return error only if "disclose"
+			 * is granted on the object */
+			if ( backend_access( op, NULL, &op->o_req_ndn,
+					slap_schema.si_ad_entry,
+					NULL, ACL_DISCLOSE, NULL )
+					== LDAP_INSUFFICIENT_ACCESS )
+			{
+				rs->sr_err = LDAP_NO_SUCH_OBJECT;
+			}
+#endif /* SLAP_ACL_HONOR_DISCLOSE */
+			break;
+
+		case LDAP_SUCCESS:
+			if ( value_find_ex( op->oq_compare.rs_ava->aa_desc,
+				SLAP_MR_ATTRIBUTE_VALUE_NORMALIZED_MATCH |
+					SLAP_MR_ASSERTED_VALUE_NORMALIZED_MATCH,
+				vals, &ava.aa_value, op->o_tmpmemctx ) == 0 )
+			{
+				rs->sr_err = LDAP_COMPARE_TRUE;
+				break;
+
+			} else {
+				rs->sr_err = LDAP_COMPARE_FALSE;
+			}
+			rc = LDAP_SUCCESS;
+			break;
+		}
+
+		send_ldap_result( op, rs );
+
+		if ( rc == 0 ) {
+			rs->sr_err = LDAP_SUCCESS;
+		}
+		
+		if ( vals ) {
+			ber_bvarray_free_x( vals, op->o_tmpmemctx );
+		}
 	}
 
 #if defined( LDAP_SLAPI )