Fix calloc check in krb5_authdata_context_init

ticket: 7973
target_version: 1.12.2
tags: pullup
Move KKDCP OpenSSL code to an internal plugin

Create an internal pluggable interface "tls" with one in-tree dynamic
plugin module named "k5tls".  Move all of the OpenSSL calls to the
plugin module, and make the libkrb5 code load and invoke the plugin.
This way we do not load or initialize libssl unless an HTTP proxy is
used.

ticket: 7929
Rename --with-proxy-tls-impl to --with-tls-impl

Make the configure option for TLS implementation more generic, in case
we use the k5tls module for something other than KDC proxy support.
Rename all of the associated symbols for consistency.

ticket: 7929
Modernize some LDAP sources

Bring ldap_misc.c up to date with current practices and make limited
changes to other files.  Of note:

* krb5_decode_krbsecretkey was freeing its bvalues argument; make that
  the caller's responsibility.
* Make is_principal_in_realm and has_modify_increment return
  krb5_boolean, reversing the sense of their results.
* Remove broken code path in decode_tl_data when an integer value has
  a length other than 2 (which should never happen).
* Simplify krb5_ldap_readpassword and make it take filename/name
  parameters instead of an LDAP context.
* Make krb5_ldap_bind (renamed to authenticate) responsible for
  setting a useful error message, so that its caller doesn't assume
  knowledge of the bind parameters.
* Make krb5_ldap_initialize (renamed to initialize_server) responsible
  for updating the handle list, and remove the otherwise unused
  krb5_update_ldap_handle.
* Remove remaining skeletal certificate support, including the unused
  has_sasl_external_mech function.
* Remove unused krb5_get_containerdn and KDB_TL_CONTAINERDN.
* Remove kdb_xdr.h; all of its prototypes were for functions that
  don't exist in the module or were duplicated in other headers.
* Remove krb5_ldap_get_strings and use ldap_get_values directly at
  its call sites; there was no need to copy the result.
Add SASL support to LDAP KDB module

Add variables for the SASL mechanism, authcid, authzid, and realm.  If
a SASL mechanism is set, perform an interactive bind with that
mechanism.  If <sasl/sasl.h> is found at build time, provide the
authcid, authzid, and realm in the interaction function, and provide a
SASL secret read from the service password file (under the authcid) if
we found one.

Based on a patch from Zoran Pericic <zpericic@netst.org>.

ticket: 7944 (new)
Add tests for LDAP SASL support

In t_kdb.py, add a test case for EXTERNAL, and a test case for
DIGEST-MD5 if we built with the SASL header file and found the core
schema file.

ticket: 7944
Document LDAP SASL configuration

Document the LDAP SASL profile tags and DB options.  For consistency,
also condense the kdc.conf documentation for the two bind DN variables
into one entry.

ticket: 7944
Fix doc build

Commit 15b7e405ff7b62ab96af45999d1350455948e602 contained an
indentation error which broke the doc build.  Fix it.

ticket: 7944
Fix leak on GSS module symbol resolution error

If krb5int_get_plugin_func fails, errinfo may contain an allocated
error message.  Free it on error when loading GSS modules.

[ghudson@mit.edu: also fix GSS_ADD_DYNAMIC_METHOD; clarify commit
message]

ticket: 7966 (new)
target_version: 1.12.2
tags: pullup
Fix double-free in SPNEGO [CVE-2014-4343]

In commit cd7d6b08 ("Verify acceptor's mech in SPNEGO initiator") the
pointer sc->internal_mech became an alias into sc->mech_set->elements,
which should be considered constant for the duration of the SPNEGO
context.  So don't free it.

CVE-2014-4343:

In MIT krb5 releases 1.10 and newer, an unauthenticated remote
attacker with the ability to spoof packets appearing to be from a
GSSAPI acceptor can cause a double-free condition in GSSAPI initiators
(clients) which are using the SPNEGO mechanism, by returning a
different underlying mechanism than was proposed by the initiator.  At
this stage of the negotiation, the acceptor is unauthenticated, and
the acceptor's response could be spoofed by an attacker with the
ability to inject traffic to the initiator.

Historically, some double-free vulnerabilities can be translated into
remote code execution, though the necessary exploits must be tailored
to the individual application and are usually quite
complicated. Double-frees can also be exploited to cause an
application crash, for a denial of service.  However, most GSSAPI
client applications are not vulnerable, as the SPNEGO mechanism is not
used by default (when GSS_C_NO_OID is passed as the mech_type argument
to gss_init_sec_context()).  The most common use of SPNEGO is for
HTTP-Negotiate, used in web browsers and other web clients.  Most such
clients are believed to not offer HTTP-Negotiate by default, instead
requiring a whitelist of sites for which it may be used to be
configured.  If the whitelist is configured to only allow
HTTP-Negotiate over TLS connections ("https://"), a successful
attacker must also spoof the web server's SSL certificate, due to the
way the WWW-Authenticate header is sent in a 401 (Unauthorized)
response message.  Unfortunately, many instructions for enabling
HTTP-Negotiate in common web browsers do not include a TLS
requirement.

    CVSSv2 Vector: AV:N/AC:H/Au:N/C:C/I:C/A:C/E:POC/RL:OF/RC:C

[kaduk@mit.edu: CVE summary and CVSSv2 vector]

ticket: 7969 (new)
target_version: 1.12.2
tags: pullup
Fix null deref in SPNEGO acceptor [CVE-2014-4344]

When processing a continuation token, acc_ctx_cont was dereferencing
the initial byte of the token without checking the length.  This could
result in a null dereference.

CVE-2014-4344:

In MIT krb5 1.5 and newer, an unauthenticated or partially
authenticated remote attacker can cause a NULL dereference and
application crash during a SPNEGO negotiation by sending an empty
token as the second or later context token from initiator to acceptor.
The attacker must provide at least one valid context token in the
security context negotiation before sending the empty token.  This can
be done by an unauthenticated attacker by forcing SPNEGO to
renegotiate the underlying mechanism, or by using IAKERB to wrap an
unauthenticated AS-REQ as the first token.

    CVSSv2 Vector: AV:N/AC:L/Au:N/C:N/I:N/A:C/E:POC/RL:OF/RC:C

[kaduk@mit.edu: CVE summary, CVSSv2 vector]

ticket: 7970 (new)
subject: NULL dereference in SPNEGO acceptor for continuation tokens [CVE-2014-4344]
target_version: 1.12.2
tags: pullup
Don't equate IAKERB and krb5 in SPNEGO initiator

To work around a historical bug in Samba, the SPNEGO initiator treats
a counterproposal as matching the optimistic token if both are aliases
for the krb5 mech.  When IAKERB support was added (#6712), IAKERB was
unintentionally added to the set of mech OIDs which were considered to
be krb5 aliases for this purpose.

Remove IAKERB from gss_mech_set_krb5_both and create a new internal
mech set, kg_all_mechs, for use by krb5_gss_indicate_mechs.

ticket: 7974 (new)
Add SPNEGO renegotiation test case

Modify t_spnego.c to force a renegotiation in the SPNEGO exchange, by
making the initiator propose IAKERB while the acceptor supports only
krb5.
Fix deleted node handling in libprofile

In profile_find_node, skip deleted nodes when finding the second
match; otherwise, profile_clear_nodes can return an error a node has
some values to clear but the last one is deleted.

In profile_node_iterator, skip deleted nodes when looking up the
section names.  Otherwise we can iterate over a deleted section and/or
ignore its replacement.

ticket: 7971 (new)
target_version: 1.12.2
tags: pullup
Fix creation/rename of top-level profile sections

profile_rename_section should demand only one name.
profile_add_relation should demand only one name if it is creating a
new section; it aso needs to reset state before calling
profile_find_node for the section in case it didn't look up any parent
sections previously.

ticket: 7972 (new)
target_version: 1.12.2
tags: pullup
Add profile tests for deletion bugs

Add three new libprofile tests to prof_test1, two to test for the bugs
in #7971 and one to test a bug which would have been introduced by a
candidate fix.