git init failed in case of user have access to a directory but not have "List Directory" access to some of the parent directories of that directory

[skvoboo]

OS/Git version

C:\inetpub\wwwroot>git version
git version 2.7.0.windows.1

C:\inetpub\wwwroot>ver
Microsoft Windows [Version 6.3.9600]

Steps to reproduce

1. Create user
2. Allow full access control on C:\inetpub\wwwroot directory for created user
3. Deny List Directory permission (this folder only) on C:\inetpub directory for created user
4. Login to server by created user and execute:

C:\Users\user1>cd C:\inetpub\wwwroot
C:\inetpub\wwwroot>git init
fatal: unable to get current working directory: No error

Root cause
mingw_getcwd function in compat\mingw.c file uses GetLongPathNameW WinAPI function, GetLongPathName may fail when it is unable to query the parent directory of a path component to determine the long name for that component.

Proposed solution
Get handle of current directory and use GetFinalPathNameByHandleW function to get long path.

The solution proposed for Windows Server 2008/Windows Vista or high.

Patch

 char *mingw_getcwd(char *pointer, int len)
 {
-   int i;
    wchar_t cwd[MAX_PATH], wpointer[MAX_PATH];
+   DECLARE_PROC_ADDR(kernel32.dll, DWORD, GetFinalPathNameByHandleW,
+             HANDLE, LPWSTR, DWORD, DWORD);
    DWORD ret = GetCurrentDirectoryW(ARRAY_SIZE(cwd), cwd);

    if (ret < 0 || ret >= ARRAY_SIZE(cwd))
        return NULL;
-   ret = GetLongPathNameW(cwd, wpointer, ARRAY_SIZE(wpointer));
-   if (!ret || ret >= ARRAY_SIZE(wpointer))
+
+   if (INIT_PROC_ADDR(GetFinalPathNameByHandleW)) {
+       HANDLE hnd = CreateFileW(cwd, 0,
+           FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE, NULL,
+           OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS, NULL);
+       if (hnd == INVALID_HANDLE_VALUE)
+           return NULL;
+       ret = GetFinalPathNameByHandleW(hnd, wpointer, ARRAY_SIZE(wpointer), 0);
+       CloseHandle(hnd);
+   } else {
+       ret = GetLongPathNameW(cwd, wpointer, ARRAY_SIZE(wpointer));
+   }
+
+   if (!ret || ret >= ARRAY_SIZE(wpointer))
        return NULL;
-   if (xwcstoutf(pointer, wpointer, len) < 0)
+   if (xwcstoutf(pointer, normalize_ntpath(wpointer), len) < 0)
        return NULL;
-   for (i = 0; pointer[i]; i++)
-       if (pointer[i] == '\\')
-           pointer[i] = '/';
    return pointer;
 }

[dscho]

@skvoboo could you turn that into a real Pull Request (with a nice commit message), please?

[dscho]

Fixed via #606.