[New-bugs-announce] [issue24102] Multiple type confusions in unicode error handlers

[paul]

New submission from paul:

# Breakpoint 1, PyUnicodeEncodeError_GetEnd (exc=<X at remote 0x405730e4>, end=0xbf9e8f7c) at Objects/exceptions.c:1643
# 1643        PyObject *obj = get_unicode(((PyUnicodeErrorObject *)exc)->object,
# (gdb) s
# get_unicode (attr=<unknown at remote 0x8c6a120>, name=0x82765ea "object") at Objects/exceptions.c:1516
# 1516        if (!attr) {
# (gdb) print *attr
# $4 = {_ob_next = 0xfefefefe, _ob_prev = 0xfefefefe, ob_refcnt = -16843010, ob_type = 0xfefefefe}
# (gdb) c
# Continuing.
# 
# Program received signal SIGSEGV, Segmentation fault.
# 0x080bc7d9 in get_unicode (attr=<unknown at remote 0x8cbe250>, name=0x82765ea "object") at Objects/exceptions.c:1521
# 1521        if (!PyUnicode_Check(attr)) {
#
# Type confusion. IsInstance check is ineffective because of custom 
# __getattribute__ method. Contents of string instance is interpreted as
# an exception object.

----------
files: poc_unicode_errors.py
messages: 242319
nosy: pkt
priority: normal
severity: normal
status: open
title: Multiple type confusions in unicode error handlers
type: crash
versions: Python 3.4
Added file: http://bugs.python.org/file39253/poc_unicode_errors.py

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Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue24102>
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