try out @nielsdos suggestion, delaying free object_id at the end of the call.

Author: devnexen

ext/snmp/snmp.c

@@ -626,6 +626,10 @@ static void php_snmp_internal(INTERNAL_FUNCTION_PARAMETERS, int st,
 }
 /* }}} */
 
+static void php_snmp_zend_string_release_from_char_pointer(char *ptr) {
+	zend_string_release((zend_string*) (ptr - XtOffsetOf(zend_string, val)));
+}
+
 /* {{{ php_snmp_parse_oid
 *
 * OID parser (and type, value for SNMP_SET command)
@@ -682,7 +686,6 @@ static bool php_snmp_parse_oid(
 				return false;
 			}
 			objid_query->vars[objid_query->count].oid = ZSTR_VAL(tmp);
-			zend_string_release(tmp);
 			if (st & SNMP_CMD_SET) {
 				if (type_str) {
 					pptr = ZSTR_VAL(type_str);
@@ -706,13 +709,17 @@ static bool php_snmp_parse_oid(
 						}
 					}
 					if (idx_type < type_ht->nNumUsed) {
-						convert_to_string(tmp_type);
-						if (Z_STRLEN_P(tmp_type) != 1) {
+						zend_string *tmp = zval_try_get_string(tmp_type);
+						if (!tmp) {
+							efree(objid_query->vars);
+							return false;
+						}
+						if (ZSTR_LEN(tmp) != 1) {
 							zend_value_error("Type must be a single character");
 							efree(objid_query->vars);
 							return false;
 						}
-						pptr = Z_STRVAL_P(tmp_type);
+						pptr = ZSTR_VAL(tmp);
 						objid_query->vars[objid_query->count].type = *pptr;
 						idx_type++;
 					} else {
@@ -743,8 +750,12 @@ static bool php_snmp_parse_oid(
 						}
 					}
 					if (idx_value < value_ht->nNumUsed) {
-						convert_to_string(tmp_value);
-						objid_query->vars[objid_query->count].value = Z_STRVAL_P(tmp_value);
+						zend_string *tmp = zval_try_get_string(tmp_value);
+						if (!tmp) {
+							efree(objid_query->vars);
+							return false;
+						}
+						objid_query->vars[objid_query->count].value = ZSTR_VAL(tmp);
 						idx_value++;
 					} else {
 						php_error_docref(NULL, E_WARNING, "'%s': no value set", Z_STRVAL_P(tmp_oid));
@@ -761,13 +772,23 @@ static bool php_snmp_parse_oid(
 	if (st & SNMP_CMD_WALK) {
 		if (objid_query->count > 1) {
 			php_snmp_error(object, PHP_SNMP_ERRNO_OID_PARSING_ERROR, "Multi OID walks are not supported!");
+			for (int i = 0; i < objid_query->count; i ++) {
+				snmpobjarg *arg = &objid_query->vars[i];
+				php_snmp_zend_string_release_from_char_pointer(arg->oid);
+			}
+
 			efree(objid_query->vars);
 			return false;
 		}
 		objid_query->vars[0].name_length = MAX_NAME_LEN;
 		if (strlen(objid_query->vars[0].oid)) { /* on a walk, an empty string means top of tree - no error */
 			if (!snmp_parse_oid(objid_query->vars[0].oid, objid_query->vars[0].name, &(objid_query->vars[0].name_length))) {
 				php_snmp_error(object, PHP_SNMP_ERRNO_OID_PARSING_ERROR, "Invalid object identifier: %s", objid_query->vars[0].oid);
+				for (int i = 0; i < objid_query->count; i ++) {
+					snmpobjarg *arg = &objid_query->vars[i];
+					php_snmp_zend_string_release_from_char_pointer(arg->oid);
+				}
+
 				efree(objid_query->vars);
 				return false;
 			}
@@ -780,6 +801,11 @@ static bool php_snmp_parse_oid(
 			objid_query->vars[objid_query->offset].name_length = MAX_OID_LEN;
 			if (!snmp_parse_oid(objid_query->vars[objid_query->offset].oid, objid_query->vars[objid_query->offset].name, &(objid_query->vars[objid_query->offset].name_length))) {
 				php_snmp_error(object, PHP_SNMP_ERRNO_OID_PARSING_ERROR, "Invalid object identifier: %s", objid_query->vars[objid_query->offset].oid);
+				for (int i = 0; i < objid_query->count; i ++) {
+					snmpobjarg *arg = &objid_query->vars[i];
+					php_snmp_zend_string_release_from_char_pointer(arg->oid);
+				}
+
 				efree(objid_query->vars);
 				return false;
 			}
@@ -1257,11 +1283,21 @@ static void php_snmp(INTERNAL_FUNCTION_PARAMETERS, int st, int version)
 
 	if (session_less_mode) {
 		if (!netsnmp_session_init(&session, version, a1, a2, timeout, retries)) {
+			for (int i = 0; i < objid_query.count; i ++) {
+				snmpobjarg *arg = &objid_query.vars[i];
+				php_snmp_zend_string_release_from_char_pointer(arg->oid);
+			}
+
 			efree(objid_query.vars);
 			netsnmp_session_free(&session);
 			RETURN_FALSE;
 		}
 		if (version == SNMP_VERSION_3 && !netsnmp_session_set_security(session, a3, a4, a5, a6, a7, NULL, NULL)) {
+			for (int i = 0; i < objid_query.count; i ++) {
+				snmpobjarg *arg = &objid_query.vars[i];
+				php_snmp_zend_string_release_from_char_pointer(arg->oid);
+			}
+
 			efree(objid_query.vars);
 			netsnmp_session_free(&session);
 			/* Warning message sent already, just bail out */
@@ -1273,6 +1309,11 @@ static void php_snmp(INTERNAL_FUNCTION_PARAMETERS, int st, int version)
 		session = snmp_object->session;
 		if (!session) {
 			zend_throw_error(NULL, "Invalid or uninitialized SNMP object");
+			for (int i = 0; i < objid_query.count; i ++) {
+				snmpobjarg *arg = &objid_query.vars[i];
+				php_snmp_zend_string_release_from_char_pointer(arg->oid);
+			}
+
 			efree(objid_query.vars);
 			RETURN_THROWS();
 		}
@@ -1299,15 +1340,21 @@ static void php_snmp(INTERNAL_FUNCTION_PARAMETERS, int st, int version)
 
 	php_snmp_internal(INTERNAL_FUNCTION_PARAM_PASSTHRU, st, session, &objid_query);
 
-	efree(objid_query.vars);
-
 	if (session_less_mode) {
 		netsnmp_session_free(&session);
 	} else {
 		netsnmp_ds_set_boolean(NETSNMP_DS_LIBRARY_ID, NETSNMP_DS_LIB_PRINT_NUMERIC_ENUM, glob_snmp_object.enum_print);
 		netsnmp_ds_set_boolean(NETSNMP_DS_LIBRARY_ID, NETSNMP_DS_LIB_QUICK_PRINT, glob_snmp_object.quick_print);
 		netsnmp_ds_set_int(NETSNMP_DS_LIBRARY_ID, NETSNMP_DS_LIB_OID_OUTPUT_FORMAT, glob_snmp_object.oid_output_format);
 	}
+
+	for (int i = 0; i < objid_query.count; i ++) {
+		snmpobjarg *arg = &objid_query.vars[i];
+		php_snmp_zend_string_release_from_char_pointer(arg->oid);
+	}
+
+	efree(objid_query.vars);
+
 }
 /* }}} */
 

ext/snmp/tests/gh16959.phpt

@@ -35,7 +35,7 @@ array(4) {
   int(0)
 }
 
-Warning: snmpget(): Invalid object identifier: -229 in %s on line %d
+Warning: snmpget(): Invalid object identifier: -54 in %s on line %d
 bool(true)
 array(4) {
   [63]=>