Re: [PATCH] fhandler_pipe: add sanity limit to handle loops

[Ken Brown]

On 12/23/2021 6:10 PM, Jeremy Drake via Cygwin-patches wrote:
diff --git a/winsup/cygwin/fhandler_pipe.cc
b/winsup/cygwin/fhandler_pipe.cc
index ba6b70f55..48713a38d 100644
--- a/winsup/cygwin/fhandler_pipe.cc
+++ b/winsup/cygwin/fhandler_pipe.cc
@@ -1239,7 +1239,7 @@ fhandler_pipe::get_query_hdl_per_process (WCHAR *name,
        if (!NT_SUCCESS (status))
         goto close_proc;
-      for (ULONG j = 0; j < phi->NumberOfHandles; j++)
+      for (ULONG j = 0; j < min(phi->NumberOfHandles, n_handle); j++)

Reading the preceding code, I don't see how n_handle could be less than 
phi->NumberOfHandles.  Can you explain?

         {
           /* Check for the peculiarity of cygwin read pipe */
           const ULONG access = FILE_READ_DATA | FILE_READ_EA
@@ -1309,7 +1309,7 @@ fhandler_pipe::get_query_hdl_per_system (WCHAR *name,
    if (!NT_SUCCESS (status))
      return NULL;

-  for (LONG i = (LONG) shi->NumberOfHandles - 1; i >= 0; i--)
+  for (LONG i = (LONG) min(shi->NumberOfHandles, n_handle) - 1; i >= 0; i--)

Same comment.

Ken