[PATCH v29 0/2] MR10291: Fix GetModuleFileName string termination

[Trent Waddington (＠trent.waddington)]

After Windows XP the string termination behavior of GetModuleFileName was changed to always terminate the path returned, even if  the buffer is insufficient to contain the null terminator.

--
  v29: kernel32: Fix string termination of GetModuleFileName.
 
https://gitlab.winehq.org/wine/wine/-/merge_requests/10291

[PATCH v29 1/2] Add tests for GetModuleFileName string termination.

[Trent Waddington]

From: Trent Waddington <[e-mail]>

---
 dlls/kernel32/tests/loader.c | 90 ++++++++++++++++++++++++++++++++++++
 1 file changed, 90 insertions(+)

diff --git a/dlls/kernel32/tests/loader.c b/dlls/kernel32/tests/loader.c
index 529b9de870d..8547e79bf26 100644
--- a/dlls/kernel32/tests/loader.c
+++ b/dlls/kernel32/tests/loader.c
@@ -1552,6 +1552,94 @@ static void test_filenames(void)
     DeleteFileA( long_path );
 }
 
+static void test_getmodulefilenamew_string_termination(void)
+{
+    WCHAR dll_name[MAX_PATH];
+    int dll_name_len, dll_name_term;
+    DWORD rv, err;
+    HMODULE mod;
+
+    GetModuleFileNameW(NULL, dll_name, MAX_PATH);
+    err = GetLastError();
+    ok(err == ERROR_SUCCESS, "error getting path for NULL module: %d\n", (int)err);
+    dll_name_len = wcslen(dll_name);
+    ok(dll_name_len > 0, "can't get path for NULL module\n");
+    ok(dll_name_len < MAX_PATH, "unterminated path for NULL module\n");
+
+    memset(dll_name, '*', sizeof(dll_name));
+    rv = GetModuleFileNameW(NULL, dll_name, dll_name_len);
+    err = GetLastError();
+    ok(err == ERROR_INSUFFICIENT_BUFFER, "didn't get expected error getting path for NULL module with short buffer: %d\n", (int)err);
+    dll_name_term = wcsnlen(dll_name, MAX_PATH);
+    ok(dll_name_term > 0, "can't get path for NULL module with short buffer, dll_name_term=%d\n", dll_name_term);
+    ok(dll_name_term < MAX_PATH, "unterminated path for NULL module with short buffer, dll_name_term=%d\n", dll_name_term);
+    ok(dll_name_term == dll_name_len - 1, "incorrect path termination for NULL module with short buffer. Expected %d got %d. rv=%d\n", dll_name_len - 1, dll_name_term, (int)rv);
+
+    mod = LoadLibraryW( L"user32.dll" );
+    ok(mod != NULL, "can't load test dll\n");
+    GetModuleFileNameW(mod, dll_name, MAX_PATH);
+    err = GetLastError();
+    ok(err == ERROR_SUCCESS, "error getting path for test module: %d\n", (int)err);
+    dll_name_len = wcslen(dll_name);
+    ok(dll_name_len > 0, "can't get path for test module\n");
+    ok(dll_name_len < MAX_PATH, "unterminated path for test module\n");
+
+    memset(dll_name, '*', sizeof(dll_name));
+    GetModuleFileNameW(mod, dll_name, dll_name_len);
+    err = GetLastError();
+    ok(err == ERROR_INSUFFICIENT_BUFFER, "didn't get expected error getting path for test module with short buffer: %d\n", (int)err);
+    dll_name_term = wcsnlen(dll_name, MAX_PATH);
+    ok(dll_name_term > 0, "can't get path for test module with short buffer, dll_name_term=%d\n", dll_name_term);
+    ok(dll_name_term < MAX_PATH, "unterminated path for test module with short buffer, dll_name_term=%d\n", dll_name_term);
+    ok(dll_name_term == dll_name_len - 1, "incorrect path termination for test module with short buffer. Expected %d got %d\n", dll_name_len - 1, dll_name_term);
+
+    FreeLibrary( mod );
+}
+
+static void test_getmodulefilenamea_string_termination(void)
+{
+    char dll_name[MAX_PATH];
+    int dll_name_len, dll_name_term;
+    DWORD rv, err;
+    HMODULE mod;
+
+    GetModuleFileNameA(NULL, dll_name, MAX_PATH);
+    err = GetLastError();
+    ok(err == ERROR_SUCCESS, "error getting path for NULL module: %d\n", (int)err);
+    dll_name_len = strlen(dll_name);
+    ok(dll_name_len > 0, "can't get path for NULL module\n");
+    ok(dll_name_len < MAX_PATH, "unterminated path for NULL module\n");
+
+    memset(dll_name, '*', sizeof(dll_name));
+    rv = GetModuleFileNameA(NULL, dll_name, dll_name_len);
+    err = GetLastError();
+    ok(err == ERROR_INSUFFICIENT_BUFFER, "didn't get expected error getting path for NULL module with short buffer: %d\n", (int)err);
+    dll_name_term = strnlen(dll_name, MAX_PATH);
+    ok(dll_name_term > 0, "can't get path for NULL module with short buffer, dll_name_term=%d\n", dll_name_term);
+    ok(dll_name_term < MAX_PATH, "unterminated path for NULL module with short buffer, dll_name_term=%d\n", dll_name_term);
+    ok(dll_name_term == dll_name_len - 1, "incorrect path termination for NULL module with short buffer. Expected %d got %d. rv=%d\n", dll_name_len - 1, dll_name_term, (int)rv);
+
+    mod = LoadLibraryA( "user32.dll" );
+    ok(mod != NULL, "can't load test dll\n");
+    GetModuleFileNameA(mod, dll_name, MAX_PATH);
+    err = GetLastError();
+    ok(err == ERROR_SUCCESS, "error getting path for test module: %d\n", (int)err);
+    dll_name_len = strlen(dll_name);
+    ok(dll_name_len > 0, "can't get path for test module\n");
+    ok(dll_name_len < MAX_PATH, "unterminated path for test module\n");
+
+    memset(dll_name, '*', sizeof(dll_name));
+    GetModuleFileNameA(mod, dll_name, dll_name_len);
+    err = GetLastError();
+    ok(err == ERROR_INSUFFICIENT_BUFFER, "didn't get expected error getting path for test module with short buffer: %d\n", (int)err);
+    dll_name_term = strnlen(dll_name, MAX_PATH);
+    ok(dll_name_term > 0, "can't get path for test module with short buffer, dll_name_term=%d\n", dll_name_term);
+    ok(dll_name_term < MAX_PATH, "unterminated path for test module with short buffer, dll_name_term=%d\n", dll_name_term);
+    ok(dll_name_term == dll_name_len - 1, "incorrect path termination for test module with short buffer. Expected %d got %d\n", dll_name_len - 1, dll_name_term);
+
+    FreeLibrary( mod );
+}
+
 /* Verify linking style of import descriptors */
 static void test_ImportDescriptors(void)
 {
@@ -4859,6 +4947,8 @@ START_TEST(loader)
     }
 
     test_filenames();
+    test_getmodulefilenamew_string_termination();
+    test_getmodulefilenamea_string_termination();
     test_ResolveDelayLoadedAPI();
     test_ImportDescriptors();
     test_section_access();
-- 
GitLab


https://gitlab.winehq.org/wine/wine/-/merge_requests/10291

[PATCH v29 2/2] kernel32: Fix string termination of GetModuleFileName.

[Trent Waddington]

From: Trent Waddington <[e-mail]>

---
 dlls/kernelbase/loader.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/dlls/kernelbase/loader.c b/dlls/kernelbase/loader.c
index f4e1ca2e23a..e26a08ccca5 100644
--- a/dlls/kernelbase/loader.c
+++ b/dlls/kernelbase/loader.c
@@ -302,13 +302,12 @@ DWORD WINAPI DECLSPEC_HOTPATCH GetModuleFileNameW( HMODULE module, LPWSTR filena
     ULONG len = 0;
     WIN16_SUBSYSTEM_TIB *win16_tib;
     UNICODE_STRING name;
-    NTSTATUS status;
+    NTSTATUS status = 0;
 
     if (!module && ((win16_tib = NtCurrentTeb()->Tib.SubSystemTib)) && win16_tib->exe_name)
     {
         len = min( size, win16_tib->exe_name->Length / sizeof(WCHAR) );
         memcpy( filename, win16_tib->exe_name->Buffer, len * sizeof(WCHAR) );
-        if (len < size) filename[len] = 0;
         goto done;
     }
 
@@ -319,6 +318,13 @@ DWORD WINAPI DECLSPEC_HOTPATCH GetModuleFileNameW( HMODULE module, LPWSTR filena
     SetLastError( RtlNtStatusToDosError( status ));
 done:
     TRACE( "%s\n", debugstr_wn(filename, len) );
+    if (!status || status == STATUS_BUFFER_TOO_SMALL)
+    {
+        if (len < size)
+            filename[len] = 0;
+        else if (size > 0)
+            filename[size - 1] = 0;
+    }
     return len;
 }
 
-- 
GitLab

https://gitlab.winehq.org/wine/wine/-/merge_requests/10291