| msg324954 - (view) |
Author: Christian Heimes (christian.heimes) *  |
Date: 2018-09-10 22:47 |
| The pyexpat module calls XML_SetHashSalt(self->itself, (unsigned long)_Py_HashSecret.expat.hashsalt) to initialize the salt for hash randomization of the XML_Parser struct. The _elementree C accelerator doesn't call XML_SetHashSalt(). It's not a security issue with recent versions of libexpat. The library initializes the salt from a good entry source by default. |
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| msg324961 - (view) |
Author: Benjamin Peterson (benjamin.peterson) * |
Date: 2018-09-10 23:48 |
| Note we compile expat with -DXML_POOR_ENTROPY on the assumption that Python always initializes the entropy itself. |
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| msg324963 - (view) |
Author: STINNER Victor (vstinner) * |
Date: 2018-09-11 00:09 |
| > Note we compile expat with -DXML_POOR_ENTROPY on the assumption that Python always initializes the entropy itself. Oh. I forgot this thing. So it seems like we have to backport this change to 2.7, 3.6 and newer versions. What about Python 3.4 and 3.5? Python 3.5 has a copy of libexpat 2.2.0, but setup.py doesn't build expat with XML_POOR_ENTROPY=1. |
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| msg324966 - (view) |
Author: Christian Heimes (christian.heimes) * |
Date: 2018-09-11 00:38 |
| Dang, it's a security bug after all. :( 3.5 has 2.2.4, so it's fine. 2.2.2 had a bug in salt initialization. |
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| msg325633 - (view) |
Author: miss-islington (miss-islington) |
Date: 2018-09-18 12:39 |
| New changeset cb5778f00ce48631c7140f33ba242496aaf7102b by Miss Islington (bot) (Christian Heimes) in branch 'master': bpo-34623: Use XML_SetHashSalt in _elementtree (GH-9146) https://github.com/python/cpython/commit/cb5778f00ce48631c7140f33ba242496aaf7102b |
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| msg325634 - (view) |
Author: Christian Heimes (christian.heimes) * |
Date: 2018-09-18 12:40 |
| Since it's a security fix, the change should land in 3.4 and 3.5, too. |
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| msg325636 - (view) |
Author: miss-islington (miss-islington) |
Date: 2018-09-18 13:11 |
| New changeset 470a435f3b42c9be5fdb7f7b04f3df5663ba7305 by Miss Islington (bot) in branch '3.7': bpo-34623: Use XML_SetHashSalt in _elementtree (GH-9146) https://github.com/python/cpython/commit/470a435f3b42c9be5fdb7f7b04f3df5663ba7305 |
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| msg325637 - (view) |
Author: miss-islington (miss-islington) |
Date: 2018-09-18 13:13 |
| New changeset 18b20bad75b4ff0486940fba4ec680e96e70f3a2 by Miss Islington (bot) (Christian Heimes) in branch '2.7': [2.7] bpo-34623: Use XML_SetHashSalt in _elementtree (GH-9146) (GH-9394) https://github.com/python/cpython/commit/18b20bad75b4ff0486940fba4ec680e96e70f3a2 |
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| msg325638 - (view) |
Author: miss-islington (miss-islington) |
Date: 2018-09-18 13:14 |
| New changeset f7666e828cc3d5873136473ea36ba2013d624fa1 by Miss Islington (bot) in branch '3.6': bpo-34623: Use XML_SetHashSalt in _elementtree (GH-9146) https://github.com/python/cpython/commit/f7666e828cc3d5873136473ea36ba2013d624fa1 |
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| msg325966 - (view) |
Author: Christian Heimes (christian.heimes) * |
Date: 2018-09-21 06:38 |
| The bug affects multiple platforms. libexpat's expat.h uses slightly different autoconf macro names than pyconfig.h. Therefore only platforms that have either HAVE_GETRANDOM or _WIN32 defined, use a proper CSPRNG to seed the hash salt. Since HAVE_SYSCALL_GETRANDOM, HAVE_ARC4RANDOM_BUF, HAVE_ARC4RANDOM, or XML_DEV_URANDOM are never defined by Python's pyconfig.h, older Linux platforms, any BSD, and any other Unix platform with /dev/urandom fall back to a weak Mersenne Twister-like RNG with gettimeofday().tv_usec and getpid() as seed. |
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| msg325967 - (view) |
Author: Christian Heimes (christian.heimes) * |
Date: 2018-09-21 06:47 |
| I have contected Red Hat product security to request a CVE for the issue. |
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| msg326019 - (view) |
Author: Christian Heimes (christian.heimes) * |
Date: 2018-09-21 19:16 |
| CVE-2018-14647 was assigned to this issue. |
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| msg326069 - (view) |
Author: miss-islington (miss-islington) |
Date: 2018-09-22 04:42 |
| New changeset 026337a7101369297c8083047d2f3c6fc9dd1e2b by Miss Islington (bot) (Christian Heimes) in branch 'master': bpo-34623: Mention CVE-2018-14647 in news entry (GH-9482) https://github.com/python/cpython/commit/026337a7101369297c8083047d2f3c6fc9dd1e2b |
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| msg326071 - (view) |
Author: miss-islington (miss-islington) |
Date: 2018-09-22 04:57 |
| New changeset 10be1d3f802b874914b2a13eb41407c7a582d9b3 by Miss Islington (bot) in branch '2.7': [2.7] bpo-34623: Mention CVE-2018-14647 in news entry (GH-9482) (GH-9490) https://github.com/python/cpython/commit/10be1d3f802b874914b2a13eb41407c7a582d9b3 |
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| msg326072 - (view) |
Author: miss-islington (miss-islington) |
Date: 2018-09-22 04:57 |
| New changeset d1b336e530472f316b1d164d04626724c83b16d7 by Miss Islington (bot) in branch '3.6': [3.6] bpo-34623: Mention CVE-2018-14647 in news entry (GH-9482) (GH-9489) https://github.com/python/cpython/commit/d1b336e530472f316b1d164d04626724c83b16d7 |
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| msg326073 - (view) |
Author: miss-islington (miss-islington) |
Date: 2018-09-22 04:57 |
| New changeset 5c3d8b2efda1b99abe09ad925f366c5695bd66fb by Miss Islington (bot) in branch '3.7': [3.7] bpo-34623: Mention CVE-2018-14647 in news entry (GH-9482) (GH-9488) https://github.com/python/cpython/commit/5c3d8b2efda1b99abe09ad925f366c5695bd66fb |
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| msg327758 - (view) |
Author: Charalampos Stratakis (cstratak) * |
Date: 2018-10-15 14:10 |
| Will this change be backported to 3.5 and 3.4? It applied cleanly on both however on 3.4 there is a test failure: ====================================================================== ERROR: test_del_attribute (test.test_xml_etree_c.MiscTests) ---------------------------------------------------------------------- Traceback (most recent call last): File "/builddir/build/BUILD/Python-3.4.9/Lib/test/test_xml_etree_c.py", line 26, in test_del_attribute element = cET.Element('tag') AttributeError: 'NoneType' object has no attribute 'Element' ---------------------------------------------------------------------- |
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| msg334369 - (view) |
Author: Matej Cepl (mcepl) * |
Date: 2019-01-25 21:09 |
| > Will this change be backported to 3.5 and 3.4? It applied cleanly on both however on 3.4 there is a test failure: It actually haven't applied cleanly to me on Python 3.4.6 (SLE-12 package). Apparently self->parser has to be changed into self_xp->parser. Then all tests passed for me. If any Linux maintainer wants to take this patch. |
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| msg336551 - (view) |
Author: Larry Hastings (larry) * |
Date: 2019-02-25 21:02 |
| New changeset d16eaf36795da48b930b80b20d3805bc27820712 by larryhastings (stratakis) in branch '3.4': [3.4] bpo-34623: Use XML_SetHashSalt in _elementtree (#9953) https://github.com/python/cpython/commit/d16eaf36795da48b930b80b20d3805bc27820712 |
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| msg336552 - (view) |
Author: Larry Hastings (larry) * |
Date: 2019-02-25 21:04 |
| New changeset 41b48e71ac8a71f56694b548f118bd20ce203410 by larryhastings (stratakis) in branch '3.5': [3.5] bpo-34623: Use XML_SetHashSalt in _elementtree (#9933) https://github.com/python/cpython/commit/41b48e71ac8a71f56694b548f118bd20ce203410 |
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