[PATCH 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.

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

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

[Trent Waddington]

From: Trent Waddington <[e-mail]>

---
 dlls/kernel32/tests/loader.c | 61 ++++++++++++++++++++++++++++++++++++
 1 file changed, 61 insertions(+)

diff --git a/dlls/kernel32/tests/loader.c b/dlls/kernel32/tests/loader.c
index 529b9de870d..dca4a253abd 100644
--- a/dlls/kernel32/tests/loader.c
+++ b/dlls/kernel32/tests/loader.c
@@ -1552,6 +1552,66 @@ static void test_filenames(void)
     DeleteFileA( long_path );
 }
 
+static void test_getmodulefilename_string_termination(void)
+{
+    WCHAR dll_name[MAX_PATH];
+    int dll_name_len, i;
+
+    dll_name[0] = 0;
+    GetModuleFileNameW(NULL, dll_name, MAX_PATH);
+    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, 0x9, sizeof(dll_name));
+    GetModuleFileNameW(NULL, dll_name, dll_name_len);
+    for (i = 0; i < MAX_PATH && dll_name[i]; i++)
+        ;
+    ok(i > 0, "can't get path for NULL module with short buffer\n");
+    ok(i < MAX_PATH, "unterminated path for NULL module with short buffer\n");
+    if (i < MAX_PATH)
+        ok(i == dll_name_len - 1, "incorrect path termination for NULL module with short buffer\n");
+
+    {
+        IMAGE_NT_HEADERS nt_header = nt_header_template;
+        char dll_name_a[MAX_PATH];
+        HMODULE mod;
+
+        nt_header.FileHeader.NumberOfSections = 1;
+        nt_header.FileHeader.SizeOfOptionalHeader = sizeof(IMAGE_OPTIONAL_HEADER);
+
+        nt_header.OptionalHeader.SectionAlignment = page_size;
+        nt_header.OptionalHeader.DllCharacteristics = IMAGE_DLLCHARACTERISTICS_NX_COMPAT | IMAGE_DLLCHARACTERISTICS_DYNAMIC_BASE;
+        nt_header.OptionalHeader.FileAlignment = page_size;
+        nt_header.OptionalHeader.SizeOfHeaders = sizeof(dos_header) + sizeof(nt_header) + sizeof(IMAGE_SECTION_HEADER);
+        nt_header.OptionalHeader.SizeOfImage = sizeof(dos_header) + sizeof(nt_header) + sizeof(IMAGE_SECTION_HEADER) + page_size;
+
+        create_test_dll( &dos_header, sizeof(dos_header), &nt_header, dll_name_a );
+        mod = LoadLibraryA( dll_name_a );
+        ok(mod, "can't load test dll\n");
+        if (mod)
+        {
+            dll_name[0] = 0;
+            GetModuleFileNameW(mod, dll_name, MAX_PATH);
+            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, 0x9, sizeof(dll_name));
+            GetModuleFileNameW(mod, dll_name, dll_name_len);
+            for (i = 0; i < MAX_PATH && dll_name[i]; i++)
+                ;
+            ok(i > 0, "can't get path for test module with short buffer\n");
+            ok(i < MAX_PATH, "unterminated path for test module with short buffer\n");
+            if (i < MAX_PATH)
+                ok(i == dll_name_len - 1, "incorrect path termination for test module with short buffer\n");
+
+            FreeLibrary( mod );
+        }
+        DeleteFileA(dll_name_a);
+    }
+}
+
 /* Verify linking style of import descriptors */
 static void test_ImportDescriptors(void)
 {
@@ -4859,6 +4919,7 @@ START_TEST(loader)
     }
 
     test_filenames();
+    test_getmodulefilename_string_termination();
     test_ResolveDelayLoadedAPI();
     test_ImportDescriptors();
     test_section_access();
-- 
GitLab


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

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

[Trent Waddington]

From: Trent Waddington <[e-mail]>

---
 dlls/kernelbase/loader.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/dlls/kernelbase/loader.c b/dlls/kernelbase/loader.c
index f4e1ca2e23a..2a2e7fcc35d 100644
--- a/dlls/kernelbase/loader.c
+++ b/dlls/kernelbase/loader.c
@@ -308,7 +308,6 @@ DWORD WINAPI DECLSPEC_HOTPATCH GetModuleFileNameW( HMODULE module, LPWSTR filena
     {
         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 +318,10 @@ DWORD WINAPI DECLSPEC_HOTPATCH GetModuleFileNameW( HMODULE module, LPWSTR filena
     SetLastError( RtlNtStatusToDosError( status ));
 done:
     TRACE( "%s\n", debugstr_wn(filename, len) );
+    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