Update embeded copy of libexpat from 2.2.1 to 2.2.3 #75130

vstinner · 2017-07-17T14:18:16Z

BPO	30947
Nosy	@gpshead, @vstinner, @larryhastings, @tiran, @ned-deily, @serhiy-storchaka
PRs	bpo-30947: Update libexpat from 2.2.1 to 2.2.3 #3106 [3.6] bpo-30947: Update libexpat from 2.2.1 to 2.2.3 (#3106) #3143 [3.5] bpo-30947: Update libexpat from 2.2.1 to 2.2.3 (#3106) #3144 [2.7] bpo-30947: Update libexpat from 2.2.1 to 2.2.3 (#3106) #3145 [3.3] bpo-30947, bpo-31170: Update expat from 2.2.1 to 2.2.4 #3352 [3.4][Security] bpo-30947, bpo-31170: Update expat from 2.2.1 to 2.2.4 #3353 [3.5][Security] bpo-30947, bpo-31170: Update expat from 2.2.1 to 2.2.4 #3354
Files	cpython_rebuild_expat_dir.sh

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = None
closed_at = <Date 2017-09-25.08:26:11.982>
created_at = <Date 2017-07-17.14:18:15.790>
labels = ['type-security', '3.7']
title = 'Update embeded copy of libexpat from 2.2.1 to 2.2.3'
updated_at = <Date 2019-05-10.18:02:34.803>
user = 'https://github.com/vstinner'

bugs.python.org fields:

activity = <Date 2019-05-10.18:02:34.803>
actor = 'ned.deily'
assignee = 'none'
closed = True
closed_date = <Date 2017-09-25.08:26:11.982>
closer = 'vstinner'
components = []
creation = <Date 2017-07-17.14:18:15.790>
creator = 'vstinner'
dependencies = []
files = ['47088']
hgrepos = []
issue_num = 30947
keywords = []
message_count = 22.0
messages = ['298525', '298528', '298529', '300365', '300367', '300368', '300369', '300414', '300437', '300535', '300547', '300548', '301269', '301423', '302834', '302899', '302924', '302929', '325910', '325922', '325925', '325934']
nosy_count = 6.0
nosy_names = ['gregory.p.smith', 'vstinner', 'larry', 'christian.heimes', 'ned.deily', 'serhiy.storchaka']
pr_nums = ['3106', '3143', '3144', '3145', '3352', '3353', '3354']
priority = 'normal'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'security'
url = 'https://bugs.python.org/issue30947'
versions = ['Python 3.7']

vstinner · 2017-07-17T14:18:16Z

libexpat released a new version 2.2.2 which seems to contain 2 or 3 security fixes. I'm not sure that Python is affected by these bugs.

https://github.com/libexpat/libexpat/blob/R_2_2_2/expat/Changes#L5

Release 2.2.2 Wed July 12 2017
Security fixes:
#43 Protect against compilation without any source of high
quality entropy enabled, e.g. with CMake build system;
commit ff0207e6076e9828e536b8d9cd45c9c92069b895
#60 Windows with _UNICODE:
Unintended use of LoadLibraryW with a non-wide string
resulted in failure to load advapi32.dll and degradation
in quality of used entropy when compiled with _UNICODE for
Windows; you can launch existing binaries with
EXPAT_ENTROPY_DEBUG=1 in the environment to inspect the
quality of entropy used during runtime; commits
* 95b95032f907ef1cd17ee7a9a1768010a825d61d
* 73a5a2e9c081f49f2d775cf7ced864158b68dc80
[MOX-006] Fix non-NULL parser parameter validation in XML_Parse;
resulted in NULL dereference, previously;
commit ac256dafdffc9622ab0dc2c62fcecb0dfcfa71fe

    Bug fixes:
         #69  Fix improper use of unsigned long long integer literals

    Other changes:
         #73  Start requiring a C99 compiler
         #49  Fix "==" Bashism in configure script
         #50  Fix too eager getrandom detection for Debian GNU/kFreeBSD
         #52    and macOS
         #51  Address lack of stdint.h in Visual Studio 2003 to 2008
         #58  Address compile warnings
         #68  Fix "./buildconf.sh && ./configure" for some versions
                of Dash for /bin/sh
         #72  CMake: Ease use of Expat in context of a parent project
                with multipe CMakeLists.txt files
         #72  CMake: Resolve mistaken executable permissions
         #76  Address compile warning with -DNDEBUG (not recommended!)
         #77  Address compile warning about macro redefinition

    Special thanks to:
        Alexander Bluhm
        Ben Boeckel
        Cătălin Răceanu
        Kerin Millar
        László Böszörményi
        S. P. Zeidler
        Segev Finer
        Václav Slavík
        Victor Stinner
        Viktor Szakats
             and

Radically Open Security

--

Previous issue for expat 2.2.1: issue bpo-30694.

vstinner · 2017-07-17T14:24:46Z

#51 Address lack of stdint.h in Visual Studio 2003 to 2008

FYI this change only impacts Python 2.7, since Python 3.3 and newer requires Visual Studio 2010 or newer, and I already backported (cherry-picked) this specific commit in Python 2.7:
https://github.com/python/cpython/pull/2312/commits

#58 Address compile warnings

That's my small contribution, so coming from CPython :-)
libexpat/libexpat#58

#76 Address compile warning with -DNDEBUG (not recommended!)

Nice contributions from Segev Finer, coming from CPython ;-)
libexpat/libexpat#76

#77 Address compile warning about macro redefinition

Another contribution of Segev Finer, already fixed downstream (in Python):
libexpat/libexpat#77

vstinner · 2017-07-17T14:28:25Z

About the 3 security fixes (is the last change a security fix?).

"""
#43 Protect against compilation without any source of high
quality entropy enabled, e.g. with CMake build system;
commit ff0207e6076e9828e536b8d9cd45c9c92069b895
"""

Since Python uses its own entropy source, I don't think that this change impacts us.

libexpat/libexpat@ff0207e

"""
#60 Windows with _UNICODE:
Unintended use of LoadLibraryW with a non-wide string
resulted in failure to load advapi32.dll and degradation
in quality of used entropy when compiled with _UNICODE for
Windows; you can launch existing binaries with
EXPAT_ENTROPY_DEBUG=1 in the environment to inspect the
quality of entropy used during runtime; commits
* 95b95032f907ef1cd17ee7a9a1768010a825d61d
* 73a5a2e9c081f49f2d775cf7ced864158b68dc80
"""

I don't understand the consequence of this specific bug.

libexpat/libexpat@95b9503
libexpat/libexpat@73a5a2e

"""
[MOX-006] Fix non-NULL parser parameter validation in XML_Parse;
resulted in NULL dereference, previously;
commit ac256dafdffc9622ab0dc2c62fcecb0dfcfa71fe
"""

I'm not sure that it's possible to call XML_Parse() with NULL in Python.

libexpat/libexpat@ac256da

vstinner · 2017-08-16T14:21:19Z

Expat 2.2.3 was released:

Release 2.2.3 Wed August 2 2017
Security fixes:
#82 CVE-2017-11742 -- Windows: Fix DLL hijacking vulnerability
using Steve Holme's LoadLibrary wrapper for/of cURL

    Bug fixes:
         #85  Fix a dangling pointer issue related to realloc

    Other changes:
              Increase code coverage
         #91  Linux: Allow getrandom to fail if nonblocking pool has not
                yet been initialized and read /dev/urandom then, instead.
                This is in line with what recent Python does.
         #81  Pre-10.7/Lion macOS: Support entropy from arc4random
         #86  Check that a UTF-16 encoding in an XML declaration has the
                right endianness
    #4 #5 #7  Recover correctly when some reallocations fail
              Repair "./configure && make" for systems without any
                provider of high quality entropy
                and try reading /dev/urandom on those
              Ensure that user-defined character encodings have converter
                functions when they are needed
              Fix mis-leading description of argument -c in xmlwf.1
              Rely on macro HAVE_ARC4RANDOM_BUF (rather than __CloudABI__)
                for CloudABI
        #100  Fix use of SIPHASH_MAIN in siphash.h
         #23  Test suite: Fix memory leaks
              Version info bumped from 7:4:6 to 7:5:6

    Special thanks to:
        Chanho Park
        Joe Orton
        Pascal Cuoq
        Rhodri James
        Simon McVittie
        Vadim Zeitlin
        Viktor Szakats
             and

Core Infrastructure Initiative

vstinner · 2017-08-16T14:30:37Z

Previous update: bpo-30694.

vstinner · 2017-08-16T14:35:09Z

cpython_rebuild_expat_dir.sh: Script used to update Modules/expat/ to 2.2.3. The script now uses the libexpat Git repository. Previously, I used tarballs.

vstinner · 2017-08-16T14:38:43Z

#82 CVE-2017-11742 -- Windows: Fix DLL hijacking vulnerability using Steve Holme's LoadLibrary wrapper for/of cURL

libexpat/libexpat#82

I don't think that this bug affects Python since Python sets a hash secret.

serhiy-storchaka · 2017-08-17T12:44:45Z

Could the updating script be added into the CPython repository?

vstinner · 2017-08-17T15:24:56Z

If libexpat is upgraded in Python 2.7, the new Modules/expat/loadlibrary.c should also be added to PC/VS9.0/ project files, as I did for PCbuild.

Note: PC/VS7.1/ and PC/VS8.0/ are likely broken and don't need to be updated, right?

vstinner · 2017-08-18T21:43:57Z

New changeset 93d0cb5 by Victor Stinner in branch 'master':
bpo-30947: Update libexpat from 2.2.1 to 2.2.3 (bpo-3106)
93d0cb5

vstinner · 2017-08-18T23:06:30Z

New changeset 83e37e1 by Victor Stinner in branch '3.6':
bpo-30947: Update libexpat from 2.2.1 to 2.2.3 (bpo-3106) (bpo-3143)
83e37e1

vstinner · 2017-08-18T23:06:47Z

New changeset ec4ab09 by Victor Stinner in branch '2.7':
bpo-30947: Update libexpat from 2.2.1 to 2.2.3 (bpo-3106) (bpo-3145)
ec4ab09

vstinner · 2017-09-04T21:36:27Z

Expat 2.2.3 has a bug: see bpo-31170 :-(

ned-deily · 2017-09-06T00:57:39Z

New changeset 297516e by Ned Deily (Victor Stinner) in branch '3.3':
[3.3] bpo-30947, bpo-31170: Update expat from 2.2.1 to 2.2.4 (bpo-3352)
297516e

larryhastings · 2017-09-24T08:04:57Z

New changeset 86a713c by larryhastings (Victor Stinner) in branch '3.4':
[3.4][Security] bpo-30947, bpo-31170: Update expat from 2.2.1 to 2.2.4 (bpo-3353)
86a713c

larryhastings · 2017-09-25T00:58:36Z

New changeset f2492bb by larryhastings (Victor Stinner) in branch '3.5':
[3.5][Security] bpo-30947, bpo-31170: Update expat from 2.2.1 to 2.2.4 (bpo-3354)
f2492bb

vstinner · 2017-09-25T08:26:12Z

libexpat has been upgraded from 2.2.1 to 2.2.4 in 2.7, 3.4, 3.5, 3.6 and master branches.

serhiy-storchaka · 2017-09-25T08:51:10Z

And in 3.3.

tiran · 2018-09-20T17:16:37Z

Victor, the PR for this BPO has introduced XML_POOR_ENTROPY. Neither the commit message nor the issue explains why. Which platform failed to compile without XML_POOR_ENTROPY?

vstinner · 2018-09-20T19:17:13Z

Christian Heimes <lists@cheimes.de> added the comment:

Victor, the PR for this BPO has introduced XML_POOR_ENTROPY. Neither the commit message nor the issue explains why. Which platform failed to compile without XML_POOR_ENTROPY?

And, maybe:

"Oh, compilation fails on Travis CI at:"
#3106 (comment)

And my rationale is (extract of setup.py):

            # bpo-30947: Python uses best available entropy sources to
            # call XML_SetHashSalt(), expat entropy sources are not needed
            ('XML_POOR_ENTROPY', '1'),

But I'm wrong if I understood what you told me last week.

tiran · 2018-09-20T19:39:14Z

Do you remember which platform failed? It doesn't say on the GH PR either.

See bpo-34623 for security bug. We only set good salt for pyexpat based parsers (sax, dom, pure Python etree), but not for the C-accelerated ElementTree implementation.

vstinner · 2018-09-20T23:29:11Z

Do you remember which platform failed? It doesn't say on the GH PR either.

It was the Linux job of Travis CI, something like an old Ubuntu LTS version.

Since Travis CI prevented me to merge anything and Python already has access to a safe PRNG, I didn't worry about that issue. The disabled code shouldn't be needed on Python.

vstinner added 3.7 (EOL) end of life type-security A security issue labels Jul 17, 2017

vstinner changed the title ~~Update embeded copy of libexpat to 2.2.2~~ Update embeded copy of libexpat from 2.2.1 to 2.2.3 Aug 16, 2017

vstinner closed this as completed Sep 25, 2017

ezio-melotti transferred this issue from another repository Apr 10, 2022

Update embeded copy of libexpat from 2.2.1 to 2.2.3 #75130

Update embeded copy of libexpat from 2.2.1 to 2.2.3 #75130

vstinner commented Jul 17, 2017

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vstinner commented Sep 4, 2017

ned-deily commented Sep 6, 2017

larryhastings commented Sep 24, 2017

larryhastings commented Sep 25, 2017

vstinner commented Sep 25, 2017

serhiy-storchaka commented Sep 25, 2017

tiran commented Sep 20, 2018

vstinner commented Sep 20, 2018

tiran commented Sep 20, 2018

vstinner commented Sep 20, 2018

Update embeded copy of libexpat from 2.2.1 to 2.2.3 #75130

Update embeded copy of libexpat from 2.2.1 to 2.2.3 #75130

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