Include autoconf.h (either directly or via proxy) before system
headers, so that feature test macros defined there can affect the
system namespace.  Where include order was changed, eliminate some
redundant or unnecessary includes.

ticket: 7961

Detect the following cases which would otherwise cause invalid memory
accesses and/or integer underflow:

* An RFC 1964 token being processed by an RFC 4121-only context
  [CVE-2014-4342]

* A header with fewer than 22 bytes after the token ID or an
  incomplete checksum [CVE-2014-4341 CVE-2014-4342]

* A ciphertext shorter than the confounder [CVE-2014-4341]

* A declared padding length longer than the plaintext [CVE-2014-4341]

If we detect a bad pad byte, continue on to compute the checksum to
avoid creating a padding oracle, but treat the checksum as invalid
even if it compares equal.

CVE-2014-4341:

In MIT krb5, an unauthenticated remote attacker with the ability to
inject packets into a legitimately established GSSAPI application
session can cause a program crash due to invalid memory references
when attempting to read beyond the end of a buffer.

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

CVE-2014-4342:

In MIT krb5 releases krb5-1.7 and later, an unauthenticated remote
attacker with the ability to inject packets into a legitimately
established GSSAPI application session can cause a program crash due
to invalid memory references when reading beyond the end of a buffer
or by causing a null pointer dereference.

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

[tlyu@mit.edu: CVE summaries, CVSS]

ticket: 7949 (new)
subject: Handle invalid RFC 1964 tokens [CVE-2014-4341 CVE-2014-4342]
taget_version: 1.12.2
tags: pullup

After krb5_rd_req_decoded or krb5_rd_req_decoded_anyflag, the ticket
(with enc_part2 if we could decrypt it) is accessible via
request->ticket; there is no need to copy it.  Stop using the ticket
parameter of those functions.  Where we need to save the ticket beyond
the lifetime of the krb5_ap_req, steal the pointer before freeing the
request.

Replace most calls to krb5_set_error_message with k5_setmsg for
brevity.  Leave alone plugin sources where we don't include k5-int.h
(mostly PKINIT).

GSSAPI functions are responsible for setting their output parameters
on failure.  Take greater care to do so in krb5_gss_display_name.

The mechglue is generally defensive about initializing variables used
as outputs, and not assuming that mechs will set them on failure.
Make gssint_convert_name_to_union_name initialize
union_name->external_name before calling mech->gss_display_name, so
that if the mech's gss_display_name doesn't touch it, we don't free an
uninitialized pointer.

Either one of these changes prevents an unlikely memory bug which
could occur if krb5_gss_init_context fails within
krb5_gss_display_name when called from
gssint_convert_name_to_union_name.

ticket: 7915 (new)
target_version: 1.12.2

If the GSSAPI context has an unrecognized proto field (which should
never happen), free the context we allocated before returning EINVAL.

[ghudson@mit.edu: clarify commit message]

Simplify acquire_accept_cred using the new helper function.

Use an opaque structure type instead of a void pointer for the
sequence number state.  Rename all functions to use a g_seqstate
prefix rather than a mix of g_order and g_queue.  Remove the
unneccessary indirection from the state object parameter in
g_seqstate_check and g_seqstate_free.  Return OM_uint32 where we
return a GSS major code, long where we return an errno value, and void
where we can't fail.

Don't delete gssapi_krb5.h now that it is not generated.

[ghudson@mit.edu: also remove from generate-files-mac rule and from
.gitignore]

Revert r16428 now that gssapi_krb5.h is in the source tree.