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MFC r259286,259424,259425:

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Apply patch from upstream Heimdal for encoding fix

  RFC 4402 specifies the implementation of the gss_pseudo_random()
  function for the krb5 mechanism (and the C bindings therein).
  The implementation uses a PRF+ function that concatenates the output
  of individual krb5 pseudo-random operations produced with a counter
  and seed.  The original implementation of this function in Heimdal
  incorrectly encoded the counter as a little-endian integer, but the
  RFC specifies the counter encoding as big-endian.  The implementation
  initializes the counter to zero, so the first block of output (16 octets,
  for the modern AES enctypes 17 and 18) is unchanged.  (RFC 4402 specifies
  that the counter should begin at 1, but both existing implementations
  begin with zero and it looks like the standard will be re-issued, with
  test vectors, to begin at zero.)

  This is upstream's commit f85652af868e64811f2b32b815d4198e7f9017f6,
  from 13 October, 2013:
  % Fix krb5's gss_pseudo_random() (n is big-endian)
  %
  % The first enctype RFC3961 prf output length's bytes are correct because
  % the little- and big-endian representations of unsigned zero are the
  % same.  The second block of output was wrong because the counter was not
  % being encoded as big-endian.
  %
  % This change could break applications.  But those applications would not
  % have been interoperating with other implementations anyways (in
  % particular: MIT's).

Bump __FreeBSD_version accordingly and add a note in UPDATING.

Approved by:	hrs (mentor, src committer)
This commit is contained in:
bjk 2013-12-16 02:04:28 +00:00
parent 607f8e622d
commit 638d19cdfc
3 changed files with 14 additions and 3 deletions
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11
UPDATING
View File

@ -16,6 +16,17 @@ from older versions of FreeBSD, try WITHOUT_CLANG to bootstrap to the tip of
stable/10, and then rebuild without this option. The bootstrap process from
older version of current is a bit fragile.
20131216:
The behavior of gss_pseudo_random() for the krb5 mechanism
has changed, for applications requesting a longer random string
than produced by the underlying enctype's pseudo-random() function.
In particular, the random string produced from a session key of
enctype aes256-cts-hmac-sha1-96 or aes256-cts-hmac-sha1-96 will
be different at the 17th octet and later, after this change.
The counter used in the PRF+ construction is now encoded as a
big-endian integer in accordance with RFC 4402.
__FreeBSD_version is bumped to 1000701.
20131031:
The default version of mtree is nmtree which is obtained from
NetBSD. The output is generally the same, but may vary

4
crypto/heimdal/lib/gssapi/krb5/prf.c
View File

@ -119,7 +119,7 @@ _gsskrb5_pseudo_random(OM_uint32 *minor_status,
while(dol > 0) {
size_t tsize;
_gsskrb5_encode_om_uint32(num, input.data);
_gsskrb5_encode_be_om_uint32(num, input.data);
ret = krb5_crypto_prf(context, crypto, &input, &output);
if (ret) {
@ -133,7 +133,7 @@ _gsskrb5_pseudo_random(OM_uint32 *minor_status,
tsize = min(dol, output.length);
memcpy(p, output.data, tsize);
p += output.length;
p += tsize;
dol -= tsize;
krb5_data_free(&output);
num++;

2
sys/sys/param.h
View File

@ -58,7 +58,7 @@
* in the range 5 to 9.
*/
#undef __FreeBSD_version
#define __FreeBSD_version 1000700 /* Master, propagated to newvers */
#define __FreeBSD_version 1000701 /* Master, propagated to newvers */
/*
* __FreeBSD_kernel__ indicates that this system uses the kernel of FreeBSD,