python: Fix crash by leaving struct members intact
authorTobias Mueller <muelli@cryptobitch.de>
Tue, 20 Feb 2018 16:34:14 +0000 (17:34 +0100)
committerWerner Koch <wk@gnupg.org>
Tue, 17 Apr 2018 08:20:12 +0000 (10:20 +0200)
* lang/python/setup.py.in: Copy gpgme.h instead of parsing it.
--
The python bindings tried to parse deprecated functions
out of gpgme.h. This fails for the current gpgme.h in
that it removes an entire field in the key sig struct (_obsolete_class).
Hence, the fields were off by an int and the bindings accessed struct
members via the wrong offset. That caused python program to crash.
At least on 32bit platforms, the crash can be easily triggered by
accessing key.uids[0].signatures. On 64bit platforms the compiler
probably aligns the struct so that the missing 4 bytes are not noticed.

With this change, the python bindings will expose all functions
that gpgme exposes, including the deprecated ones.

Credits go to Justus Winter for debugging and identying the issue.

Signed-off-by: Tobias Mueller <muelli@cryptobitch.de>
GnuPG-bug-id: 3892

lang/python/setup.py.in

index f9dda20..2595073 100755 (executable)
@@ -152,25 +152,8 @@ class BuildExtFirstHack(build):
             sink.write(content)
 
     def _generate_gpgme_h(self, source_name, sink_name):
-        if up_to_date(source_name, sink_name):
-            return
-
         print("Using gpgme.h from {}".format(source_name))
-
-        deprec_func = re.compile(r'^(.*typedef.*|.*\(.*\)|[^#]+\s+.+)'
-                                 + r'\s*_GPGME_DEPRECATED(_OUTSIDE_GPGME)?\(.*\);\s*',
-                                 re.S)
-        line_break = re.compile(';|\\$|\\x0c|^\s*#|{')
-
-        with open(sink_name, "w") as sink, open(source_name) as source:
-            text = ''
-            for line in source:
-                text += re.sub(' class ', ' _py_obsolete_class ', line)
-                if line_break.search(line):
-                    if not deprec_func.search(text):
-                        sink.write(text)
-                    text = ''
-            sink.write(text)
+        shutil.copy2(source_name, sink_name)
 
     def _generate_errors_i(self):