krb5 commit: Avoid another null dereference in krb5_rd_cred()

[ghudson at mit.edu]

https://github.com/krb5/krb5/commit/5031b854ad8ba6cce20cdd8c991f81dbc3f924bd
commit 5031b854ad8ba6cce20cdd8c991f81dbc3f924bd
Author: Rahul Hoysala <rahulhoysala07 at gmail.com>
Date:   Thu Jun 4 13:14:45 2026 +0530

    Avoid another null dereference in krb5_rd_cred()
    
    In RFC 4120, the ticket client and server principal names are optional
    in KrbCredInfo, but we have always required them to be present.  Add
    checks to prevent null dereferences in krb5_rd_cred() if either name
    is not specified.
    
    [ghudson at mit.edu: folded check in with the end-of-list check; rewrote
    comment and commit message]
    
    ticket: 9219 (new)
    tags: pullup
    target_version: 1.22-next

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

diff --git a/src/lib/krb5/krb/rd_cred.c b/src/lib/krb5/krb/rd_cred.c
index c341eba15..80d49fd8b 100644
--- a/src/lib/krb5/krb/rd_cred.c
+++ b/src/lib/krb5/krb/rd_cred.c
@@ -98,8 +98,9 @@ make_cred_list(krb5_context context, krb5_cred *krbcred,
             goto cleanup;
 
         info = encpart->ticket_info[i];
-        if (info == NULL) {
-            /* We unexpectedly reached the end of the encrypted ticket info. */
+        if (info == NULL || info->client == NULL || info->server == NULL) {
+            /* We unexpectedly reached the end of the encrypted ticket info,
+             * or the ticket info is unexpectedly missing a principal name. */
             ret = KRB5KRB_AP_ERR_MODIFIED;
             goto cleanup;
         }