Use a webserver-wide session id instead of per fork

Author: bwoebi

Cargo.lock

@@ -11,6 +11,10 @@ struct _zend_string;
 
 extern ddog_Uuid ddtrace_runtime_id;
 
+extern ddog_Uuid ddtrace_session_id;
+
+extern uint8_t ddtrace_formatted_session_id[36];
+
 extern void (*ddog_log_callback)(ddog_CharSlice);
 
 extern ddog_VecRemoteConfigProduct DDTRACE_REMOTE_CONFIG_PRODUCTS;
@@ -25,6 +29,12 @@ extern const uint8_t *DDOG_PHP_FUNCTION;
  */
 void ddtrace_generate_runtime_id(void);
 
+/**
+ * # Safety
+ * Must be called from a single-threaded context, such as MINIT.
+ */
+void ddtrace_generate_session_id(void);
+
 void ddtrace_format_runtime_id(uint8_t (*buf)[36]);
 
 ddog_CharSlice ddtrace_get_container_id(void);

appsec/tests/extension/rinit_rshutdown_basic.phpt

@@ -32,13 +32,29 @@ pub use libdd_telemetry_ffi::*;
 #[allow(non_upper_case_globals)]
 pub static mut ddtrace_runtime_id: Uuid = Uuid::nil();
 
+#[no_mangle]
+#[allow(non_upper_case_globals)]
+pub static mut ddtrace_session_id: Uuid = Uuid::nil();
+
+#[no_mangle]
+#[allow(non_upper_case_globals)]
+pub static mut ddtrace_formatted_session_id: [u8; 36] = [0u8; 36];
+
 /// # Safety
 /// Must be called from a single-threaded context, such as MINIT.
 #[no_mangle]
 pub unsafe extern "C" fn ddtrace_generate_runtime_id() {
     ddtrace_runtime_id = Uuid::new_v4();
 }
 
+/// # Safety
+/// Must be called from a single-threaded context, such as MINIT.
+#[no_mangle]
+pub unsafe extern "C" fn ddtrace_generate_session_id() {
+    ddtrace_session_id = Uuid::new_v4();
+    ddtrace_session_id.as_hyphenated().encode_lower(&mut ddtrace_formatted_session_id);
+}
+
 #[no_mangle]
 pub extern "C" fn ddtrace_format_runtime_id(buf: &mut [u8; 36]) {
     // Safety: ddtrace_runtime_id is only supposed to be mutated from single-

components-rs/ddtrace.h

@@ -148,6 +148,8 @@ TSRM_TLS void *TSRMLS_CACHE = NULL;
 #endif
 #endif
 
+static int dd_main_pid;
+
 int ddtrace_disable = 0; // 0 = enabled, 1 = disabled via INI, 2 = disabled, but MINIT was fully executed
 static ZEND_INI_MH(dd_OnUpdateDisabled) {
     UNUSED(entry, mh_arg1, mh_arg2, mh_arg3, stage);
@@ -430,7 +432,9 @@ bool ddtrace_alter_dd_version(zval *old_value, zval *new_value, zend_string *new
 
 static void dd_activate_once(void) {
     ddtrace_config_first_rinit();
-    ddtrace_generate_runtime_id();
+    if (dd_main_pid != getpid()) { // equal to session id if not a fork
+        ddtrace_generate_runtime_id();
+    }
 
     // must run before the first zai_hook_activate as ddtrace_telemetry_setup installs a global hook
     if (!ddtrace_disable) {
@@ -1466,6 +1470,9 @@ static PHP_MINIT_FUNCTION(ddtrace) {
         ddtrace_module = Z_PTR_P(ddtrace_module_zv);
     }
 
+    dd_main_pid = getpid();
+    ddtrace_generate_session_id();
+
     // Make sure it's available for appsec, before any early returns
     dd_ip_extraction_startup();
 

components-rs/lib.rs

@@ -27,7 +27,6 @@ ZEND_EXTERN_MODULE_GLOBALS(ddtrace);
 ddog_Endpoint *ddtrace_endpoint;
 ddog_Endpoint *dogstatsd_endpoint; // always set when ddtrace_endpoint is set
 struct ddog_InstanceId *ddtrace_sidecar_instance_id;
-static uint8_t dd_sidecar_formatted_session_id[36];
 
 // Best-effort pointer for the signal handler (SIGTERM/SIGINT). Set to the first
 // per-thread connection; never cleared until MSHUTDOWN. Not atomic: concurrent
@@ -51,7 +50,6 @@ static inline void dd_set_endpoint_test_token(ddog_Endpoint *endpoint) {
 
 // Set the globals that stay unchanged in case of fork
 static void ddtrace_set_non_resettable_sidecar_globals(void) {
-    ddtrace_format_runtime_id(&dd_sidecar_formatted_session_id);
     ddtrace_endpoint = ddtrace_sidecar_agent_endpoint();
 
     if (get_global_DD_TRACE_AGENTLESS() && ZSTR_LEN(get_global_DD_API_KEY())) {
@@ -68,7 +66,7 @@ static void ddtrace_set_resettable_sidecar_globals(void) {
     uint8_t formatted_run_time_id[36];
     ddtrace_format_runtime_id(&formatted_run_time_id);
     ddog_CharSlice runtime_id = (ddog_CharSlice) {.ptr = (char *) formatted_run_time_id, .len = sizeof(formatted_run_time_id)};
-    ddog_CharSlice session_id = (ddog_CharSlice) {.ptr = (char *) dd_sidecar_formatted_session_id, .len = sizeof(dd_sidecar_formatted_session_id)};
+    ddog_CharSlice session_id = (ddog_CharSlice) {.ptr = (char *) ddtrace_formatted_session_id, .len = sizeof(ddtrace_formatted_session_id)};
     ddtrace_sidecar_instance_id = ddog_sidecar_instanceId_build(session_id, runtime_id);
 }
 
@@ -80,10 +78,10 @@ static void dd_free_endpoints(void) {
 }
 
 DDTRACE_PUBLIC const uint8_t *ddtrace_get_formatted_session_id(void) {
-    if (memcmp(dd_sidecar_formatted_session_id, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0", 36) == 0) {
+    if (memcmp(ddtrace_formatted_session_id, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0", 36) == 0) {
         return NULL;
     }
-    return dd_sidecar_formatted_session_id;
+    return ddtrace_formatted_session_id;
 }
 
 DDTRACE_PUBLIC struct telemetry_rc_info ddtrace_get_telemetry_rc_info(void) {
@@ -103,7 +101,7 @@ DDTRACE_PUBLIC uint64_t ddtrace_get_sidecar_queue_id(void) {
 }
 
 static void dd_sidecar_post_connect(ddog_SidecarTransport **transport, bool is_fork, const char *logpath) {
-    ddog_CharSlice session_id = (ddog_CharSlice) {.ptr = (char *) dd_sidecar_formatted_session_id, .len = sizeof(dd_sidecar_formatted_session_id)};
+    ddog_CharSlice session_id = (ddog_CharSlice) {.ptr = (char *) ddtrace_formatted_session_id, .len = sizeof(ddtrace_formatted_session_id)};
     const ddog_Vec_Tag *process_tags = ddtrace_process_tags_get_vec();
     ddog_sidecar_session_set_config(transport, session_id, ddtrace_endpoint, dogstatsd_endpoint,
                                     DDOG_CHARSLICE_C("php"),
@@ -912,7 +910,7 @@ ddog_crasht_Metadata ddtrace_setup_crashtracking_metadata(ddog_Vec_Tag *tags) {
     ddtrace_sidecar_push_tag(tags, DDOG_CHARSLICE_C("library_version"), DDOG_CHARSLICE_C(PHP_DDTRACE_VERSION));
     ddtrace_sidecar_push_tag(tags, DDOG_CHARSLICE_C("language"), DDOG_CHARSLICE_C("php"));
     ddtrace_sidecar_push_tag(tags, DDOG_CHARSLICE_C("runtime"), DDOG_CHARSLICE_C("php"));
-    ddtrace_sidecar_push_tag(tags, DDOG_CHARSLICE_C("runtime-id"), (ddog_CharSlice) {.ptr = (char *) dd_sidecar_formatted_session_id, .len = sizeof(dd_sidecar_formatted_session_id)});
+    ddtrace_sidecar_push_tag(tags, DDOG_CHARSLICE_C("runtime-id"), (ddog_CharSlice) {.ptr = (char *) ddtrace_formatted_session_id, .len = sizeof(ddtrace_formatted_session_id)});
 
     const char *runtime_version = zend_get_module_version("Reflection");
     ddtrace_sidecar_push_tag(tags, DDOG_CHARSLICE_C("runtime_version"), (ddog_CharSlice) {.ptr = (char *) runtime_version, .len = strlen(runtime_version)});