From 30a7bb833cbd848b1814f18b91dfdafba4e86839 Mon Sep 17 00:00:00 2001
From: Tom Tromey <tom@tromey.com>
Date: Mon, 31 Oct 2016 11:10:35 -0600
Subject: [PATCH] Fix some error-handling bugs in python frame filters

While writing a Python frame filter, I found a few bugs in the current
frame filter code.  In particular:

* One spot converts a Python long to a CORE_ADDR using PyLong_AsLong.
  However, this can fail on overflow.  I changed this to use
  get_addr_from_python.

* Another spot is doing the same but with PyLong_AsUnsignedLongLong; I
  changed this as well just for consistency.

* Converting line numbers can print "-1" if conversion from long
  fails.  This isn't fatal but just a bit ugly.

I've included a test case for the first issue.  The line number one
didn't seem important enough to bother with.

2016-11-08  Tom Tromey  <tom@tromey.com>

	* python/py-framefilter.c (py_print_frame): Use
	get_addr_from_python.  Check for errors when getting line number.

2016-11-08  Tom Tromey  <tom@tromey.com>

	* gdb.python/py-framefilter.py (ElidingFrameDecorator.address):
	New method.
---
 gdb/python/py-framefilter.c                | 18 +++++++++++++++---
 gdb/testsuite/ChangeLog                    |  5 +++++
 gdb/testsuite/gdb.python/py-framefilter.py |  6 ++++++
 4 files changed, 31 insertions(+), 3 deletions(-)

diff --git a/gdb/python/py-framefilter.c b/gdb/python/py-framefilter.c
index 6692ac5..4c7757c 100644
--- a/gdb/python/py-framefilter.c
+++ b/gdb/python/py-framefilter.c
@@ -1116,7 +1116,13 @@ py_print_frame (PyObject *filter, int flags,
 
 	  if (paddr != Py_None)
 	    {
-	      address = PyLong_AsLong (paddr);
+	      if (get_addr_from_python (paddr, &address) < 0)
+		{
+		  Py_DECREF (paddr);
+		  do_cleanups (cleanup_stack);
+		  return EXT_LANG_BT_ERROR;
+		}
+
 	      has_addr = 1;
 	    }
 	  Py_DECREF (paddr);
@@ -1213,10 +1219,10 @@ py_print_frame (PyObject *filter, int flags,
 	    }
 	  else if (PyLong_Check (py_func))
 	    {
-	      CORE_ADDR addr = PyLong_AsUnsignedLongLong (py_func);
+	      CORE_ADDR addr;
 	      struct bound_minimal_symbol msymbol;
 
-	      if (PyErr_Occurred ())
+	      if (get_addr_from_python (py_func, &addr) < 0)
 		{
 		  do_cleanups (cleanup_stack);
 		  return EXT_LANG_BT_ERROR;
@@ -1340,6 +1346,12 @@ py_print_frame (PyObject *filter, int flags,
 	  if (py_line != Py_None)
 	    {
 	      line = PyLong_AsLong (py_line);
+	      if (PyErr_Occurred ())
+		{
+		  do_cleanups (cleanup_stack);
+		  return EXT_LANG_BT_ERROR;
+		}
+
 	      TRY
 		{
 		  ui_out_text (out, ":");
diff --git a/gdb/testsuite/gdb.python/py-framefilter.py b/gdb/testsuite/gdb.python/py-framefilter.py
index 8fdff84..2580911 100644
--- a/gdb/testsuite/gdb.python/py-framefilter.py
+++ b/gdb/testsuite/gdb.python/py-framefilter.py
@@ -92,6 +92,12 @@ class ElidingFrameDecorator(FrameDecorator):
     def elided(self):
         return iter(self.elided_frames)
 
+    def address (self):
+        # Regression test for an overflow in the python layer.
+        bitsize = 8 * gdb.lookup_type('void').pointer().sizeof
+        mask = (1 << bitsize) - 1
+        return 0xffffffffffffffff & mask
+
 class ElidingIterator:
     def __init__(self, ii):
         self.input_iterator = ii
-- 
2.9.3