From 870fdcf92e5991c0bb2e349a951aa8dd93b0e22f Mon Sep 17 00:00:00 2001
From: NIIBE Yutaka <gniibe@fsij.org>
Date: Fri, 4 Nov 2022 19:04:39 +0900
Subject: w32: Support sendfd/recvfd through pipe connection.

* src/assuan-defs.h (w32_fdpass_send, w32_fdpass_recv): New.
* src/assuan-pipe-connect.c [HAVE_W32_SYSTEM] (pipe_connect): Set
w32_fdpass_send.
[!HAVE_W32_SYSTEM] (assuan_pipe_connect): Use socketpair_connect.
* src/assuan-pipe-server.c
[HAVE_W32_SYSTEM] (assuan_init_pipe_server): Set w32_fdpass_recv.
* src/system-w32.c (get_file_handle): New.
(w32_fdpass_send): New, using "SENDFD" internal command.
(w32_fdpass_recv): New, using the result of "SENDFD" internal command.

--

GnuPG-bug-id: 6236
Signed-off-by: NIIBE Yutaka <gniibe@fsij.org>
---
 src/assuan-defs.h         |  2 ++
 src/assuan-pipe-connect.c | 16 +++++-----
 src/assuan-pipe-server.c  |  4 +++
 src/system-w32.c          | 77 +++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 91 insertions(+), 8 deletions(-)

diff --git a/src/assuan-defs.h b/src/assuan-defs.h
index 47ff4ef..68bd983 100644
--- a/src/assuan-defs.h
+++ b/src/assuan-defs.h
@@ -327,6 +327,8 @@ int _assuan_error_is_eagain (assuan_context_t ctx, gpg_error_t err);
 
 #ifdef HAVE_W32_SYSTEM
 char *_assuan_w32_strerror (assuan_context_t ctx, int ec);
+gpg_error_t w32_fdpass_send (assuan_context_t ctx, assuan_fd_t fd);
+gpg_error_t w32_fdpass_recv (assuan_context_t ctx, assuan_fd_t *fd);
 #endif /*HAVE_W32_SYSTEM*/
 
 
diff --git a/src/assuan-pipe-connect.c b/src/assuan-pipe-connect.c
index 1589d79..13ea3de 100644
--- a/src/assuan-pipe-connect.c
+++ b/src/assuan-pipe-connect.c
@@ -209,7 +209,11 @@ pipe_connect (assuan_context_t ctx,
   ctx->engine.release = _assuan_client_release;
   ctx->engine.readfnc = _assuan_simple_read;
   ctx->engine.writefnc = _assuan_simple_write;
+#ifdef HAVE_W32_SYSTEM
+  ctx->engine.sendfd = w32_fdpass_send;
+#else
   ctx->engine.sendfd = NULL;
+#endif
   ctx->engine.receivefd = NULL;
   ctx->finish_handler = _assuan_client_finish;
   ctx->max_accepts = 1;
@@ -413,16 +417,12 @@ assuan_pipe_connect (assuan_context_t ctx,
   TRACE2 (ctx, ASSUAN_LOG_CTX, "assuan_pipe_connect", ctx,
 	  "name=%s, flags=0x%x", name ? name : "(null)", flags);
 
+#ifndef HAVE_W32_SYSTEM
   if (flags & ASSUAN_PIPE_CONNECT_FDPASSING)
-    {
-#ifdef HAVE_W32_SYSTEM
-      return _assuan_error (ctx, GPG_ERR_NOT_IMPLEMENTED);
-#else
-      return socketpair_connect (ctx, name, argv, fd_child_list,
-                                 atfork, atforkvalue);
-#endif
-    }
+    return socketpair_connect (ctx, name, argv, fd_child_list,
+			       atfork, atforkvalue);
   else
+#endif
     return pipe_connect (ctx, name, argv, fd_child_list, atfork, atforkvalue,
                          flags);
 }
diff --git a/src/assuan-pipe-server.c b/src/assuan-pipe-server.c
index db66978..8da54ad 100644
--- a/src/assuan-pipe-server.c
+++ b/src/assuan-pipe-server.c
@@ -115,7 +115,11 @@ assuan_init_pipe_server (assuan_context_t ctx, assuan_fd_t filedes[2])
   ctx->engine.readfnc = _assuan_simple_read;
   ctx->engine.writefnc = _assuan_simple_write;
   ctx->engine.sendfd = NULL;
+#ifdef HAVE_W32_SYSTEM
+  ctx->engine.receivefd = w32_fdpass_recv;
+#else
   ctx->engine.receivefd = NULL;
+#endif
   ctx->max_accepts = 1;
 
   s = getenv ("_assuan_pipe_connect_pid");
diff --git a/src/system-w32.c b/src/system-w32.c
index cfc1d61..76ff2a0 100644
--- a/src/system-w32.c
+++ b/src/system-w32.c
@@ -167,6 +167,83 @@ __assuan_close (assuan_context_t ctx, assuan_fd_t fd)
 
 
 
+/* Get a file HANDLE to send, from POSIX fd.  */
+static gpg_error_t
+get_file_handle (int fd, int server_pid, HANDLE *r_handle)
+{
+  HANDLE prochandle, handle, newhandle;
+
+  handle = (void *)_get_osfhandle (fd);
+
+  prochandle = OpenProcess (PROCESS_DUP_HANDLE, FALSE, server_pid);
+  if (!prochandle)
+    return gpg_error (GPG_ERR_ASS_PARAMETER);/*FIXME: error*/
+
+  if (!DuplicateHandle (GetCurrentProcess (), handle, prochandle, &newhandle,
+                        0, TRUE, DUPLICATE_SAME_ACCESS))
+    {
+      CloseHandle (prochandle);
+      return gpg_error (GPG_ERR_ASS_PARAMETER);/*FIXME: error*/
+    }
+  CloseHandle (prochandle);
+  *r_handle = newhandle;
+  return 0;
+}
+
+
+/* Send a FD (which means POSIX fd) to the peer.  */
+gpg_error_t
+w32_fdpass_send (assuan_context_t ctx, assuan_fd_t fd)
+{
+  char fdpass_msg[256];
+  int res;
+  int fd0;                      /* POSIX fd */
+  intptr_t fd_converted_to_integer;
+  HANDLE file_handle;
+  gpg_error_t err;
+
+  fd_converted_to_integer = (intptr_t)fd;
+  fd0 = (int)fd_converted_to_integer; /* Bit pattern is possibly truncated.  */
+
+  err = get_file_handle (fd0, ctx->pid, &file_handle);
+  if (err)
+    return err;
+
+  res = snprintf (fdpass_msg, sizeof (fdpass_msg), "SENDFD %p", file_handle);
+  if (res < 0)
+    {
+      CloseHandle (file_handle);
+      return gpg_error (GPG_ERR_ASS_PARAMETER);/*FIXME: error*/
+    }
+
+  err = assuan_transact (ctx, fdpass_msg, NULL, NULL, NULL, NULL, NULL, NULL);
+  return err;
+}
+
+
+/* Receive a HANDLE from the peer and turn it into a FD (POSIX fd).  */
+gpg_error_t
+w32_fdpass_recv (assuan_context_t ctx, assuan_fd_t *fd)
+{
+  int i;
+
+  if (!ctx->uds.pendingfdscount)
+    {
+      TRACE0 (ctx, ASSUAN_LOG_SYSIO, "w32_receivefd", ctx,
+	      "no pending file descriptors");
+      return _assuan_error (ctx, GPG_ERR_ASS_GENERAL);
+    }
+
+  *fd = ctx->uds.pendingfds[0];
+  for (i=1; i < ctx->uds.pendingfdscount; i++)
+    ctx->uds.pendingfds[i-1] = ctx->uds.pendingfds[i];
+  ctx->uds.pendingfdscount--;
+
+  TRACE1 (ctx, ASSUAN_LOG_SYSIO, "w32_fdpass_recv", ctx,
+          "received fd: %p", ctx->uds.pendingfds[0]);
+  return 0;
+}
+
 ssize_t
 __assuan_read (assuan_context_t ctx, assuan_fd_t fd, void *buffer, size_t size)
 {
-- 
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