bpo-32457: Improves handling of denormalized executable path when launching Python (GH-5756)
(cherry picked from commit 48e8c82fc63d2ddcddce8aa637a892839b551619)
Co-authored-by: Steve Dower <steve.dower@microsoft.com>
diff --git a/PC/getpathp.c b/PC/getpathp.c
index e90a643..9382843 100644
--- a/PC/getpathp.c
+++ b/PC/getpathp.c
@@ -266,6 +266,41 @@
}
}
+static int _PathCchCanonicalizeEx_Initialized = 0;
+typedef HRESULT(__stdcall *PPathCchCanonicalizeEx) (PWSTR pszPathOut, size_t cchPathOut,
+ PCWSTR pszPathIn, unsigned long dwFlags);
+static PPathCchCanonicalizeEx _PathCchCanonicalizeEx;
+
+static _PyInitError canonicalize(wchar_t *buffer, const wchar_t *path)
+{
+ if (buffer == NULL) {
+ return _Py_INIT_NO_MEMORY();
+ }
+
+ if (_PathCchCanonicalizeEx_Initialized == 0) {
+ HMODULE pathapi = LoadLibraryW(L"api-ms-win-core-path-l1-1-0.dll");
+ if (pathapi) {
+ _PathCchCanonicalizeEx = (PPathCchCanonicalizeEx)GetProcAddress(pathapi, "PathCchCanonicalizeEx");
+ }
+ else {
+ _PathCchCanonicalizeEx = NULL;
+ }
+ _PathCchCanonicalizeEx_Initialized = 1;
+ }
+
+ if (_PathCchCanonicalizeEx) {
+ if (FAILED(_PathCchCanonicalizeEx(buffer, MAXPATHLEN + 1, path, 0))) {
+ return _Py_INIT_ERR("buffer overflow in getpathp.c's canonicalize()");
+ }
+ }
+ else {
+ if (!PathCanonicalizeW(buffer, path)) {
+ return _Py_INIT_ERR("buffer overflow in getpathp.c's canonicalize()");
+ }
+ }
+ return _Py_INIT_OK();
+}
+
/* gotlandmark only called by search_for_prefix, which ensures
'prefix' is null terminated in bounds. join() ensures
@@ -504,63 +539,16 @@
wchar_t program_full_path[MAXPATHLEN+1];
memset(program_full_path, 0, sizeof(program_full_path));
- if (GetModuleFileNameW(NULL, program_full_path, MAXPATHLEN)) {
- goto done;
+ if (!GetModuleFileNameW(NULL, program_full_path, MAXPATHLEN)) {
+ /* GetModuleFileName should never fail when passed NULL */
+ return _Py_INIT_ERR("Cannot determine program path");
}
- /* If there is no slash in the argv0 path, then we have to
- * assume python is on the user's $PATH, since there's no
- * other way to find a directory to start the search from. If
- * $PATH isn't exported, you lose.
- */
-#ifdef ALTSEP
- if (wcschr(core_config->program_name, SEP) ||
- wcschr(core_config->program_name, ALTSEP))
-#else
- if (wcschr(core_config->program_name, SEP))
-#endif
- {
- wcsncpy(program_full_path, core_config->program_name, MAXPATHLEN);
- }
- else if (calculate->path_env) {
- const wchar_t *path = calculate->path_env;
- while (1) {
- const wchar_t *delim = wcschr(path, DELIM);
+ config->program_full_path = PyMem_RawMalloc(
+ sizeof(wchar_t) * (MAXPATHLEN + 1));
- if (delim) {
- size_t len = delim - path;
- /* ensure we can't overwrite buffer */
- len = min(MAXPATHLEN,len);
- wcsncpy(program_full_path, path, len);
- program_full_path[len] = '\0';
- }
- else {
- wcsncpy(program_full_path, path, MAXPATHLEN);
- }
-
- /* join() is safe for MAXPATHLEN+1 size buffer */
- join(program_full_path, core_config->program_name);
- if (exists(program_full_path)) {
- break;
- }
-
- if (!delim) {
- program_full_path[0] = '\0';
- break;
- }
- path = delim + 1;
- }
- }
- else {
- program_full_path[0] = '\0';
- }
-
-done:
- config->program_full_path = _PyMem_RawWcsdup(program_full_path);
- if (config->program_full_path == NULL) {
- return _Py_INIT_NO_MEMORY();
- }
- return _Py_INIT_OK();
+ return canonicalize(config->program_full_path,
+ program_full_path);
}