From abcbd3d12b0c92aa37384627edb6e1e6fad9b47a Mon Sep 17 00:00:00 2001
From: Greg Hudson <ghudson@mit.edu>
Date: Mon, 30 Mar 2020 15:26:02 -0400
Subject: [PATCH] Correctly import "service@" GSS host-based name

The intended way to specify only a service in a GSS host-based name is
to omit the "@" separator.  Some applications include the separator
but no hostname, and this happened to yield wildcard hostname behavior
prior to commit 996353767fe8afa7f67a3b5b465e4d70e18bad7c when
shortname qualification was added.  To restore this behavior, check in
parse_hostbased() that at least one character is present after the "@"
separator before copying the hostname.  Add a test case to t_gssapi.py.

ticket: 8892
tags: pullup
target_version: 1.18-next

(cherry picked from commit a2f047af0400ba8080dc26033fae2b17534501e2)
(cherry picked from commit dd4364d76925ce1fe21c2ab995554d6af3a2ea12)
---
 src/lib/gssapi/krb5/import_name.c | 4 ++--
 src/tests/gssapi/t_gssapi.py      | 3 +++
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/src/lib/gssapi/krb5/import_name.c b/src/lib/gssapi/krb5/import_name.c
index da2ab1423..21023dd76 100644
--- a/src/lib/gssapi/krb5/import_name.c
+++ b/src/lib/gssapi/krb5/import_name.c
@@ -102,8 +102,8 @@ parse_hostbased(const char *str, size_t len,
     memcpy(service, str, servicelen);
     service[servicelen] = '\0';
 
-    /* If present, copy the hostname. */
-    if (at != NULL) {
+    /* Copy the hostname if present (at least one character after '@'). */
+    if (len - servicelen > 1) {
         hostlen = len - servicelen - 1;
         host = malloc(hostlen + 1);
         if (host == NULL) {
diff --git a/src/tests/gssapi/t_gssapi.py b/src/tests/gssapi/t_gssapi.py
index 54d5cf549..ecf982604 100755
--- a/src/tests/gssapi/t_gssapi.py
+++ b/src/tests/gssapi/t_gssapi.py
@@ -47,6 +47,9 @@ realm.run(['./t_accname', 'p:service2/calvin', 'h:service2'],
           expected_msg='service2/calvin')
 realm.run(['./t_accname', 'p:service2/calvin', 'h:service1'], expected_code=1,
           expected_msg=' found in keytab but does not match server principal')
+# Regression test for #8892 (trailing @ in name).
+realm.run(['./t_accname', 'p:service1/andrew', 'h:service1@'],
+          expected_msg='service1/abraham')
 
 # Test with acceptor name containing service and host.  Use the
 # client's un-canonicalized hostname as acceptor input to mirror what