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ipaldap does not take into account the possibility of the attribute
encoding returned by python-ldap differing from the attribute
encoding produced by FreeIPA. In particular this can occur with DNs
with special characters that require escaping. For example,
python-ldap (or the underlying LDAP library) escapes special
characters using hex encoding:
CN=Test Sub-CA 201604041620,OU=ftweedal,O=Red Hat\2C Inc.,L=Brisbane,C=AU
Whereas FreeIPA, when encoding the DN, escapes the character
directly:
CN=Test Sub-CA 201604041620,OU=ftweedal,O=Red Hat\, Inc.,L=Brisbane,C=AU
Therefore it is possible to generate an invalid modlist. For
example, during external CA certificate renewal, if the issuer DN
includes a comma in one of the attribute values (as above), an
invalid modlist will be generated:
[ (ldap.MOD_ADD, 'ipacaissuerdn',
[b'CN=Test Sub-CA 201604041620,OU=ftweedal,O=Red Hat\, Inc.,L=Brisbane,C=AU'])
, (ldap.MOD_DELETE, 'ipacaissuerdn',
[b'CN=Test Sub-CA 201604041620,OU=ftweedal,O=Red Hat\2C Inc.,L=Brisbane,C=AU'])
]
Although encoded differently, these are the same value. If this
modification is applied to the object, attributeOrValueExists (error
20) occurs.
To avoid the issue, put deletes before adds in the modlist. If a
value is present (with different encodings) as both an addition and
a deletion, it must be because the original object contained the
value with a different encoding. Therefore it is safe to delete it,
then add it back.
Note that the modlist is not optimal. In the simplest case (like
above example), there should be no modification to perform. It is
considerably more complex (and more computation) to implement this
because the raw attribute values must be decoded before comparison.
Fixes: https://pagure.io/freeipa/issue/7750
Reviewed-By: Christian Heimes <cheimes@redhat.com>
This is a set of libraries common to IPA clients and servers though mostly
geared currently towards command-line tools.
A brief overview:
config.py - identify the IPA server domain and realm. It uses python-dns to
try to detect this information first and will fall back to
/etc/ipa/default.conf if that fails.
ipautil.py - helper functions
entity.py - entity is the main data type. User and Group extend this class
(but don't add anything currently).
ipavalidate.py - basic data validation routines