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: 8214
version_fixed: 1.13.3
status: resolved

diff --git a/src/plugins/preauth/pkinit/pkinit_clnt.c b/src/plugins/preauth/pkinit/pkinit_clnt.c
index 5ad735a126d884ced4fea8e903b907931c56b3ad..3139d4be6df56923dcd907256472edb6ff59c82a 100644 (file)
--- a/src/plugins/preauth/pkinit/pkinit_clnt.c
+++ b/src/plugins/preauth/pkinit/pkinit_clnt.c
@@ -464,7 +464,7 @@ 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;
 
@@ -496,8 +496,8 @@ 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);