krb5 commit [krb5-1.12]: Fix SAM-2 preauth when password argument is used

[Tom Yu]

https://github.com/krb5/krb5/commit/249562f0371207de31f48beb6cf7431dccd6f420
commit 249562f0371207de31f48beb6cf7431dccd6f420
Author: Greg Hudson <ghudson at mit.edu>
Date:   Tue Feb 11 20:00:51 2014 -0500

    Fix SAM-2 preauth when password argument is used
    
    sam2_process accesses gak_data to get the password, so that it can do
    string-to-key with the etype in the SAM-2 challenge.  When #7642
    changed gic_pwd.c to use struct gak_password instead of krb5_data,
    sam2_process wasn't altered to match.  We don't see a problem when the
    password is read through the prompter (as with kinit), because the
    password winds up in the storage field at the beginning of the
    gak_password structure.  But when a password is supplied as a
    parameter (as with ksu), the storage field is empty and we get the
    wrong answer from sam2_process.
    
    (cherry picked from commit 3bedfe7c3724b0d22c72d1684f1cf76cfb600fdd)
    
    ticket: 7862
    version_fixed: 1.12.2
    status: resolved

 src/lib/krb5/krb/preauth_sam2.c |    5 +++--
 1 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/src/lib/krb5/krb/preauth_sam2.c b/src/lib/krb5/krb/preauth_sam2.c
index 6888e94..c8a3306 100644
--- a/src/lib/krb5/krb/preauth_sam2.c
+++ b/src/lib/krb5/krb/preauth_sam2.c
@@ -95,6 +95,7 @@ sam2_process(krb5_context context, krb5_clpreauth_moddata moddata,
     krb5_prompt kprompt;
     krb5_prompt_type prompt_type;
     krb5_data defsalt, *salt;
+    struct gak_password *gakpw;
     krb5_checksum **cksum;
     krb5_data *scratch = NULL;
     krb5_boolean valid_cksum = 0;
@@ -219,9 +220,9 @@ sam2_process(krb5_context context, krb5_clpreauth_moddata moddata,
         }
 
         /* generate a key using the supplied password */
+        gakpw = ctx->gak_data;
         retval = krb5_c_string_to_key(context, sc2b->sam_etype,
-                                      (krb5_data *)ctx->gak_data, salt,
-                                      &ctx->as_key);
+                                      gakpw->password, salt, &ctx->as_key);
 
         if (retval) {
             krb5_free_sam_challenge_2(context, sc2);