Problem: Two issues with COM initialization: Issue #1: Incorrect call order - requester_init() called CoInitializeSecurity first - Per Microsoft documentation, CoInitialize() must be called BEFORE CoInitializeSecurity()
Issue #2: Incorrect call location - CoInitializeSecurity was called from dll instead of the main process - Per Microsoft documentation, CoInitializeSecurity() must be called exactly once per process from the main executable, not from a DLL Reference: https://learn.microsoft.com/en-us/windows/win32/api/combaseapi/nf-combaseapi-coinitializesecurity https://learn.microsoft.com/en-us/windows/win32/api/objbase/nf-objbase-coinitialize This caused incorrect COM initialization, preventing VSS Writers from calling back via IVssWriterCallback (hr = 0x80070005, Access denied, Event ID 8194). Fix: - Initialize COM in main.c for both service and CLI modes - Call CoInitialize() followed by CoInitializeSecurity() in correct order in the main thread before any VSS operations - Add proper CoUninitialize() cleanup Result: VSS Writers can now successfully call back to the agent. Event ID 8194 error is resolved. Signed-off-by: Elizabeth Ashurov <[email protected]> --- qga/main.c | 43 +++++++++++++++++++++++++++++++++++++ qga/vss-win32/requester.cpp | 15 ++----------- 2 files changed, 45 insertions(+), 13 deletions(-) diff --git a/qga/main.c b/qga/main.c index dd1c216f9a..210d9983ab 100644 --- a/qga/main.c +++ b/qga/main.c @@ -32,6 +32,8 @@ #include "qemu/systemd.h" #include "qemu-version.h" #ifdef _WIN32 +#include <windows.h> +#include <objbase.h> #include <dbt.h> #include <pdh.h> #include "qga/service-win32.h" @@ -842,6 +844,24 @@ VOID WINAPI service_main(DWORD argc, TCHAR *argv[]) return; } + /* Initialize COM for VSS operations in the service thread */ + HRESULT hr_com = CoInitialize(NULL); + if (FAILED(hr_com)) { + g_critical("Failed to initialize COM in service thread: 0x%lx", hr_com); + return; + } + + hr_com = CoInitializeSecurity( + NULL, -1, NULL, NULL, + RPC_C_AUTHN_LEVEL_PKT_PRIVACY, + RPC_C_IMP_LEVEL_IDENTIFY, + NULL, EOAC_NONE, NULL); + if (FAILED(hr_com)) { + g_critical("Failed to initialize COM security in service thread: 0x%lx", hr_com); + CoUninitialize(); + return; + } + service->status.dwServiceType = SERVICE_WIN32; service->status.dwCurrentState = SERVICE_RUNNING; service->status.dwControlsAccepted = SERVICE_ACCEPT_STOP | SERVICE_ACCEPT_SHUTDOWN; @@ -866,6 +886,8 @@ VOID WINAPI service_main(DWORD argc, TCHAR *argv[]) run_agent(ga_state); + CoUninitialize(); + UnregisterDeviceNotification(service->device_notification_handle); service->status.dwCurrentState = SERVICE_STOPPED; SetServiceStatus(service->status_handle, &service->status); @@ -1714,12 +1736,33 @@ int main(int argc, char **argv) #ifdef _WIN32 if (config->daemonize) { + /* Service mode */ SERVICE_TABLE_ENTRY service_table[] = { { (char *)QGA_SERVICE_NAME, service_main }, { NULL, NULL } }; StartServiceCtrlDispatcher(service_table); ret = EXIT_SUCCESS; } else { + HRESULT hr_com = CoInitialize(NULL); + if (FAILED(hr_com)) { + g_critical("Failed to initialize COM: 0x%lx", hr_com); + ret = EXIT_FAILURE; + goto end; + } + + hr_com = CoInitializeSecurity( + NULL, -1, NULL, NULL, + RPC_C_AUTHN_LEVEL_PKT_PRIVACY, + RPC_C_IMP_LEVEL_IDENTIFY, + NULL, EOAC_NONE, NULL); + if (FAILED(hr_com)) { + g_critical("Failed to initialize COM security: 0x%lx", hr_com); + CoUninitialize(); + ret = EXIT_FAILURE; + goto end; + } + ret = run_agent(s); + CoUninitialize(); } #else ret = run_agent(s); diff --git a/qga/vss-win32/requester.cpp b/qga/vss-win32/requester.cpp index 74489fcd0a..9d978759f1 100644 --- a/qga/vss-win32/requester.cpp +++ b/qga/vss-win32/requester.cpp @@ -60,15 +60,6 @@ STDAPI requester_init(void) { qga_debug_begin; - COMInitializer initializer; /* to call CoInitializeSecurity */ - HRESULT hr = CoInitializeSecurity( - NULL, -1, NULL, NULL, RPC_C_AUTHN_LEVEL_PKT_PRIVACY, - RPC_C_IMP_LEVEL_IDENTIFY, NULL, EOAC_NONE, NULL); - if (FAILED(hr)) { - qga_debug("failed to CoInitializeSecurity (error %lx)", hr); - return hr; - } - hLib = LoadLibraryA("VSSAPI.DLL"); if (!hLib) { qga_debug("failed to load VSSAPI.DLL"); @@ -320,8 +311,6 @@ void requester_freeze(int *num_vols, void *mountpoints, ErrorSet *errset) return; } - CoInitialize(NULL); - /* Allow unrestricted access to events */ InitializeSecurityDescriptor(&sd, SECURITY_DESCRIPTOR_REVISION); SetSecurityDescriptorDacl(&sd, TRUE, NULL, FALSE); @@ -562,7 +551,7 @@ out: out1: requester_cleanup(); - CoUninitialize(); + /* COM is managed at process level in main.c - don't call CoUninitialize here */ qga_debug_end; } @@ -643,7 +632,7 @@ void requester_thaw(int *num_vols, void *mountpints, ErrorSet *errset) *num_vols = vss_ctx.cFrozenVols; requester_cleanup(); - CoUninitialize(); + /* COM is managed at process level in main.c - don't call CoUninitialize here */ StopService(); qga_debug_end; -- 2.51.0
