[PATCH] Cygwin: shared: Fix access permissions setting in open_shared().

Takashi Yano takashi.yano@nifty.ne.jp
Tue Aug 15 23:37:46 GMT 2023


After the commit 93508e5bb841, the access permissions argument passed
to open_shared() is ignored and always replaced with (FILE_MAP_READ |
FILE_MAP_WRITE). This causes the weird behaviour that sshd service
process loses its cygwin PID. This triggers the failure in pty that
transfer_input() does not work properly.

This patch resumes the access permission settings to fix that.

Fixes: 93508e5bb841 ("Cygwin: open_shared: don't reuse shared_locations parameter as output")
Signedd-off-by: Takashi Yano <takashi.yano@nifty.ne.jp>
---
 winsup/cygwin/mm/shared.cc | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/winsup/cygwin/mm/shared.cc b/winsup/cygwin/mm/shared.cc
index 40cdd4722..7977df382 100644
--- a/winsup/cygwin/mm/shared.cc
+++ b/winsup/cygwin/mm/shared.cc
@@ -139,8 +139,7 @@ open_shared (const WCHAR *name, int n, HANDLE& shared_h, DWORD size,
       if (name)
 	mapname = shared_name (map_buf, name, n);
       if (m == SH_JUSTOPEN)
-	shared_h = OpenFileMappingW (FILE_MAP_READ | FILE_MAP_WRITE, FALSE,
-				     mapname);
+	shared_h = OpenFileMappingW (access, FALSE, mapname);
       else
 	{
 	  created = true;
@@ -165,8 +164,7 @@ open_shared (const WCHAR *name, int n, HANDLE& shared_h, DWORD size,
   do
     {
       addr = (void *) next_address;
-      shared = MapViewOfFileEx (shared_h, FILE_MAP_READ | FILE_MAP_WRITE,
-				0, 0, 0, addr);
+      shared = MapViewOfFileEx (shared_h, access, 0, 0, 0, addr);
       next_address += wincap.allocation_granularity ();
       if (next_address >= SHARED_REGIONS_ADDRESS_HIGH)
 	{
-- 
2.39.0



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