From 0782240958117692ab9861abb5483c9e64f6bc39 Mon Sep 17 00:00:00 2001 From: Benjamin Kaduk Date: Fri, 13 Dec 2013 03:09:29 +0000 Subject: [PATCH] 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). Approved by: hrs (mentor, src committer) MFC after: 3 days --- crypto/heimdal/lib/gssapi/krb5/prf.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/crypto/heimdal/lib/gssapi/krb5/prf.c b/crypto/heimdal/lib/gssapi/krb5/prf.c index 162a3097099f..671ab2c6d982 100644 --- a/crypto/heimdal/lib/gssapi/krb5/prf.c +++ b/crypto/heimdal/lib/gssapi/krb5/prf.c @@ -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++;