diff --git a/Lib/subprocess.py b/Lib/subprocess.py
index 759b59f..e9c9a0e 100644
--- a/Lib/subprocess.py
+++ b/Lib/subprocess.py
@@ -593,14 +593,30 @@
                             c2pread, c2pwrite,
                             errread, errwrite)
 
-        if p2cwrite:
+        # On Windows, you cannot just redirect one or two handles: You
+        # either have to redirect all three or none. If the subprocess
+        # user has only redirected one or two handles, we are
+        # automatically creating PIPEs for the rest. We should close
+        # these after the process is started. See bug #1124861. 
+        if mswindows:
+            if stdin is None and p2cwrite is not None:
+                os.close(p2cwrite)
+                p2cwrite = None
+            if stdout is None and c2pread is not None:
+                os.close(c2pread)
+                c2pread = None
+            if stderr is None and errread is not None:
+                os.close(errread)
+                errread = None
+
+        if p2cwrite is not None:
             self.stdin = os.fdopen(p2cwrite, 'wb', bufsize)
-        if c2pread:
+        if c2pread is not None:
             if universal_newlines:
                 self.stdout = os.fdopen(c2pread, 'rU', bufsize)
             else:
                 self.stdout = os.fdopen(c2pread, 'rb', bufsize)
-        if errread:
+        if errread is not None:
             if universal_newlines:
                 self.stderr = os.fdopen(errread, 'rU', bufsize)
             else:
@@ -669,7 +685,9 @@
 
             if stdin is None:
                 p2cread = GetStdHandle(STD_INPUT_HANDLE)
-            elif stdin == PIPE:
+            if p2cread is not None:
+                pass
+            elif stdin is None or stdin == PIPE:
                 p2cread, p2cwrite = CreatePipe(None, 0)
                 # Detach and turn into fd
                 p2cwrite = p2cwrite.Detach()
@@ -683,7 +701,9 @@
 
             if stdout is None:
                 c2pwrite = GetStdHandle(STD_OUTPUT_HANDLE)
-            elif stdout == PIPE:
+            if c2pwrite is not None:
+                pass
+            elif stdout is None or stdout == PIPE:
                 c2pread, c2pwrite = CreatePipe(None, 0)
                 # Detach and turn into fd
                 c2pread = c2pread.Detach()
@@ -697,7 +717,9 @@
 
             if stderr is None:
                 errwrite = GetStdHandle(STD_ERROR_HANDLE)
-            elif stderr == PIPE:
+            if errwrite is not None:
+                pass
+            elif stderr is None or stderr == PIPE:
                 errread, errwrite = CreatePipe(None, 0)
                 # Detach and turn into fd
                 errread = errread.Detach()
@@ -987,29 +1009,29 @@
                 # Child
                 try:
                     # Close parent's pipe ends
-                    if p2cwrite:
+                    if p2cwrite is not None:
                         os.close(p2cwrite)
-                    if c2pread:
+                    if c2pread is not None:
                         os.close(c2pread)
-                    if errread:
+                    if errread is not None:
                         os.close(errread)
                     os.close(errpipe_read)
 
                     # Dup fds for child
-                    if p2cread:
+                    if p2cread is not None:
                         os.dup2(p2cread, 0)
-                    if c2pwrite:
+                    if c2pwrite is not None:
                         os.dup2(c2pwrite, 1)
-                    if errwrite:
+                    if errwrite is not None:
                         os.dup2(errwrite, 2)
 
                     # Close pipe fds.  Make sure we don't close the same
                     # fd more than once, or standard fds.
-                    if p2cread and p2cread not in (0,):
+                    if p2cread is not None and p2cread not in (0,):
                         os.close(p2cread)
-                    if c2pwrite and c2pwrite not in (p2cread, 1):
+                    if c2pwrite is not None and c2pwrite not in (p2cread, 1):
                         os.close(c2pwrite)
-                    if errwrite and errwrite not in (p2cread, c2pwrite, 2):
+                    if errwrite is not None and errwrite not in (p2cread, c2pwrite, 2):
                         os.close(errwrite)
 
                     # Close all other fds, if asked for
@@ -1042,11 +1064,11 @@
 
             # Parent
             os.close(errpipe_write)
-            if p2cread and p2cwrite:
+            if p2cread is not None and p2cwrite is not None:
                 os.close(p2cread)
-            if c2pwrite and c2pread:
+            if c2pwrite is not None and c2pread is not None:
                 os.close(c2pwrite)
-            if errwrite and errread:
+            if errwrite is not None and errread is not None:
                 os.close(errwrite)
 
             # Wait for exec to fail or succeed; possibly raising exception