1 files changed, 52 insertions, 12 deletions

diff --git a/compat/mingw.c b/compat/mingw.c
index f524c54d06..8a9972a1ca 100644
--- a/compat/mingw.c
+++ b/compat/mingw.c
@@ -21,6 +21,9 @@
 #include "gettext.h"
 #define SECURITY_WIN32
 #include <sspi.h>
+#include <winternl.h>
+
+#define STATUS_DELETE_PENDING ((NTSTATUS) 0xC0000056)
 
 #define HCAST(type, handle) ((type)(intptr_t)handle)
 
@@ -302,7 +305,7 @@ static wchar_t *normalize_ntpath(wchar_t *wbuf)
 	return wbuf;
 }
 
-int mingw_unlink(const char *pathname)
+int mingw_unlink(const char *pathname, int handle_in_use_error)
 {
 	int ret, tries = 0;
 	wchar_t wpathname[MAX_PATH];
@@ -317,6 +320,9 @@ int mingw_unlink(const char *pathname)
 	while ((ret = _wunlink(wpathname)) == -1 && tries < ARRAY_SIZE(delay)) {
 		if (!is_file_in_use_error(GetLastError()))
 			break;
+		if (!handle_in_use_error)
+			return ret;
+
 		/*
 		 * We assume that some other process had the source or
 		 * destination file open at the wrong moment and retry.
@@ -621,6 +627,8 @@ int mingw_open (const char *filename, int oflags, ...)
 	wchar_t wfilename[MAX_PATH];
 	open_fn_t open_fn;
 
+	DECLARE_PROC_ADDR(ntdll.dll, NTSTATUS, NTAPI, RtlGetLastNtStatus, void);
+
 	va_start(args, oflags);
 	mode = va_arg(args, int);
 	va_end(args);
@@ -644,6 +652,21 @@ int mingw_open (const char *filename, int oflags, ...)
 
 	fd = open_fn(wfilename, oflags, mode);
 
+	/*
+	 * Internally, `_wopen()` uses the `CreateFile()` API with CREATE_NEW,
+	 * which may error out with ERROR_ACCESS_DENIED and an NtStatus of
+	 * STATUS_DELETE_PENDING when the file is scheduled for deletion via
+	 * `DeleteFileW()`. The file essentially exists, so we map errno to
+	 * EEXIST instead of EACCESS so that callers don't have to special-case
+	 * this.
+	 *
+	 * This fixes issues for example with the lockfile interface when one
+	 * process has a lock that it is about to commit or release while
+	 * another process wants to acquire it.
+	 */
+	if (fd < 0 && create && GetLastError() == ERROR_ACCESS_DENIED &&
+	    INIT_PROC_ADDR(RtlGetLastNtStatus) && RtlGetLastNtStatus() == STATUS_DELETE_PENDING)
+		errno = EEXIST;
 	if (fd < 0 && (oflags & O_ACCMODE) != O_RDONLY && errno == EACCES) {
 		DWORD attrs = GetFileAttributesW(wfilename);
 		if (attrs != INVALID_FILE_ATTRIBUTES && (attrs & FILE_ATTRIBUTE_DIRECTORY))
@@ -2826,31 +2849,44 @@ static void setup_windows_environment(void)
 	}
 }
 
-static PSID get_current_user_sid(void)
+static void get_current_user_sid(PSID *sid, HANDLE *linked_token)
 {
 	HANDLE token;
 	DWORD len = 0;
-	PSID result = NULL;
+	TOKEN_ELEVATION_TYPE elevationType;
+	DWORD size;
+
+	*sid = NULL;
+	*linked_token = NULL;
 
 	if (!OpenProcessToken(GetCurrentProcess(), TOKEN_QUERY, &token))
-		return NULL;
+		return;
 
 	if (!GetTokenInformation(token, TokenUser, NULL, 0, &len)) {
 		TOKEN_USER *info = xmalloc((size_t)len);
 		if (GetTokenInformation(token, TokenUser, info, len, &len)) {
 			len = GetLengthSid(info->User.Sid);
-			result = xmalloc(len);
-			if (!CopySid(len, result, info->User.Sid)) {
+			*sid = xmalloc(len);
+			if (!CopySid(len, *sid, info->User.Sid)) {
 				error(_("failed to copy SID (%ld)"),
 				      GetLastError());
-				FREE_AND_NULL(result);
+				FREE_AND_NULL(*sid);
 			}
 		}
 		FREE_AND_NULL(info);
 	}
-	CloseHandle(token);
 
-	return result;
+	if (GetTokenInformation(token, TokenElevationType, &elevationType, sizeof(elevationType), &size) &&
+	    elevationType == TokenElevationTypeLimited) {
+		/*
+		 * The current process is run by a member of the Administrators
+		 * group, but is not running elevated.
+		 */
+		if (!GetTokenInformation(token, TokenLinkedToken, linked_token, sizeof(*linked_token), &size))
+			linked_token = NULL; /* there is no linked token */
+	}
+
+	CloseHandle(token);
 }
 
 static BOOL user_sid_to_user_name(PSID sid, LPSTR *str)
@@ -2931,18 +2967,22 @@ int is_path_owned_by_current_sid(const char *path, struct strbuf *report)
 	else if (sid && IsValidSid(sid)) {
 		/* Now, verify that the SID matches the current user's */
 		static PSID current_user_sid;
+		static HANDLE linked_token;
 		BOOL is_member;
 
 		if (!current_user_sid)
-			current_user_sid = get_current_user_sid();
+			get_current_user_sid(&current_user_sid, &linked_token);
 
 		if (current_user_sid &&
 		    IsValidSid(current_user_sid) &&
 		    EqualSid(sid, current_user_sid))
 			result = 1;
 		else if (IsWellKnownSid(sid, WinBuiltinAdministratorsSid) &&
-			 CheckTokenMembership(NULL, sid, &is_member) &&
-			 is_member)
+			 ((CheckTokenMembership(NULL, sid, &is_member) &&
+			   is_member) ||
+			  (linked_token &&
+			   CheckTokenMembership(linked_token, sid, &is_member) &&
+			   is_member)))
 			/*
 			 * If owned by the Administrators group, and the
 			 * current user is an administrator, we consider that