krb5 commit [krb5-1.12]: Fix uncommon null dereference in PKINIT client

[Tom Yu]

https://github.com/krb5/krb5/commit/a2acda434a9b7f8285964079e4e242fea14ef164
commit a2acda434a9b7f8285964079e4e242fea14ef164
Author: Greg Hudson <ghudson at mit.edu>
Date:   Fri Jul 3 19:34:46 2015 -0400

    Fix uncommon null dereference in PKINIT client
    
    crypto_retrieve_cert_sans() is allowed to set its princs output to
    NULL, although the OpenSSL implementation rarely does.  Fix the
    TRACE_PKINIT_CLIENT_SAN_KDCCERT_PRINC for loop to allow this like other
    parts of the function do, and also get rid of the unnecessary princptr
    variable by using an integer index like other parts of the function.
    
    Based on a patch from Daniel Deptula.
    
    (cherry picked from commit 47b37b9e13ca1456ba6710f31bc41012d050dd07)
    
    ticket: 8305 (new)
    version_fixed: 1.12.5
    status: resolved

 src/plugins/preauth/pkinit/pkinit_clnt.c |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/plugins/preauth/pkinit/pkinit_clnt.c b/src/plugins/preauth/pkinit/pkinit_clnt.c
index cfef5b9..3724cef 100644
--- a/src/plugins/preauth/pkinit/pkinit_clnt.c
+++ b/src/plugins/preauth/pkinit/pkinit_clnt.c
@@ -515,7 +515,7 @@ verify_kdc_san(krb5_context context,
 {
     krb5_error_code retval;
     char **certhosts = NULL, **cfghosts = NULL, **hostptr;
-    krb5_principal *princs = NULL, *princptr;
+    krb5_principal *princs = NULL;
     unsigned char ***get_dns;
     int i, j;
 
@@ -547,8 +547,8 @@ verify_kdc_san(krb5_context context,
         retval = KRB5KDC_ERR_KDC_NAME_MISMATCH;
         goto out;
     }
-    for (princptr = princs; *princptr != NULL; princptr++)
-        TRACE_PKINIT_CLIENT_SAN_KDCCERT_PRINC(context, *princptr);
+    for (i = 0; princs != NULL && princs[i] != NULL; i++)
+        TRACE_PKINIT_CLIENT_SAN_KDCCERT_PRINC(context, princs[i]);
     if (certhosts != NULL) {
         for (hostptr = certhosts; *hostptr != NULL; hostptr++)
             TRACE_PKINIT_CLIENT_SAN_KDCCERT_DNSNAME(context, *hostptr);