From ffcfbf4b66904529635d0b85687a1be48392ca15 Mon Sep 17 00:00:00 2001 From: Corinna Vinschen Date: Mon, 24 Apr 2017 17:17:29 +0200 Subject: [PATCH] cygwin: try unprivileged symlink creation on W10 1703 and later Add new SYMBOLIC_LINK_FLAG_ALLOW_UNPRIVILEGED_CREATE flag to CreateSymbolicLinkW call when running on W10 1703 or later. Don't do that on older versions to avoid ERROR_INVALID_PARAMETER. Preliminary, needs testing. There's an off-chance that the flag results in the same ERROR_INVALID_PARAMETER on 1703 if the developer settings are not enabled. Signed-off-by: Corinna Vinschen --- winsup/cygwin/path.cc | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/winsup/cygwin/path.cc b/winsup/cygwin/path.cc index 16de025b6..7d1d23d72 100644 --- a/winsup/cygwin/path.cc +++ b/winsup/cygwin/path.cc @@ -1621,6 +1621,10 @@ cnt_bs (PWCHAR s, PWCHAR e) return num; } +#ifndef SYMBOLIC_LINK_FLAG_ALLOW_UNPRIVILEGED_CREATE +#define SYMBOLIC_LINK_FLAG_ALLOW_UNPRIVILEGED_CREATE 2 +#endif + static int symlink_native (const char *oldpath, path_conv &win32_newpath) { @@ -1628,6 +1632,7 @@ symlink_native (const char *oldpath, path_conv &win32_newpath) path_conv win32_oldpath; PUNICODE_STRING final_oldpath, final_newpath; UNICODE_STRING final_oldpath_buf; + DWORD flags; if (isabspath (oldpath)) { @@ -1724,9 +1729,11 @@ symlink_native (const char *oldpath, path_conv &win32_newpath) final_oldpath->Buffer[1] = L'\\'; } /* Try to create native symlink. */ + flags = win32_oldpath.isdir () ? SYMBOLIC_LINK_FLAG_DIRECTORY : 0; + if (wincap.has_unprivileged_createsymlink ()) + flags |= SYMBOLIC_LINK_FLAG_ALLOW_UNPRIVILEGED_CREATE; if (!CreateSymbolicLinkW (final_newpath->Buffer, final_oldpath->Buffer, - win32_oldpath.isdir () - ? SYMBOLIC_LINK_FLAG_DIRECTORY : 0)) + flags)) { /* Repair native newpath, we still need it. */ final_newpath->Buffer[1] = L'?';