Fix CVE-2016-3120

Resolves: #1361051
This commit is contained in:
Robbie Harwood 2016-07-28 21:56:30 +00:00
parent e165eeccda
commit 528404bbf5
2 changed files with 64 additions and 1 deletions

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@ -0,0 +1,57 @@
From 93b4a6306a0026cf1cc31ac4bd8a49ba5d034ba7 Mon Sep 17 00:00:00 2001
From: Greg Hudson <ghudson@mit.edu>
Date: Tue, 19 Jul 2016 11:00:28 -0400
Subject: [PATCH] Fix S4U2Self KDC crash when anon is restricted
In validate_as_request(), when enforcing restrict_anonymous_to_tgt,
use client.princ instead of request->client; the latter is NULL when
validating S4U2Self requests.
CVE-2016-3120:
In MIT krb5 1.9 and later, an authenticated attacker can cause krb5kdc
to dereference a null pointer if the restrict_anonymous_to_tgt option
is set to true, by making an S4U2Self request.
CVSSv2 Vector: AV:N/AC:H/Au:S/C:N/I:N/A:C/E:H/RL:OF/RC:C
ticket: 8458 (new)
target_version: 1.14-next
target_version: 1.13-next
---
src/kdc/kdc_util.c | 2 +-
src/tests/t_pkinit.py | 5 +++++
2 files changed, 6 insertions(+), 1 deletion(-)
diff --git a/src/kdc/kdc_util.c b/src/kdc/kdc_util.c
index 776e130..29f9dbb 100644
--- a/src/kdc/kdc_util.c
+++ b/src/kdc/kdc_util.c
@@ -739,7 +739,7 @@ validate_as_request(kdc_realm_t *kdc_active_realm,
return(KDC_ERR_MUST_USE_USER2USER);
}
- if (check_anon(kdc_active_realm, request->client, request->server) != 0) {
+ if (check_anon(kdc_active_realm, client.princ, request->server) != 0) {
*status = "ANONYMOUS NOT ALLOWED";
return(KDC_ERR_POLICY);
}
diff --git a/src/tests/t_pkinit.py b/src/tests/t_pkinit.py
index b66c458..f0214b6 100755
--- a/src/tests/t_pkinit.py
+++ b/src/tests/t_pkinit.py
@@ -93,6 +93,11 @@ out = realm.run([kvno, realm.host_princ], expected_code=1)
if 'KDC policy rejects request' not in out:
fail('Wrong error for restricted anonymous PKINIT')
+# Regression test for #8458: S4U2Self requests crash the KDC if
+# anonymous is restricted.
+realm.kinit(realm.host_princ, flags=['-k'])
+realm.run([kvno, '-U', 'user', realm.host_princ])
+
# Go back to a normal KDC and disable anonymous PKINIT.
realm.stop_kdc()
realm.start_kdc()
--
2.8.1

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@ -13,7 +13,7 @@
Summary: The Kerberos network authentication system
Name: krb5
Version: 1.14.1
Release: 8%{?dist}
Release: 9%{?dist}
# - Maybe we should explode from the now-available-to-everybody tarball instead?
# http://web.mit.edu/kerberos/dist/krb5/1.13/krb5-1.13.2-signed.tar
# - The sources below are stored in a lookaside cache. Upload with
@ -73,6 +73,7 @@ Patch165: krb5-1.15-kdc_hooks_test.patch
Patch166: krb5-1.14.3-fix_otp_as_key.patch
Patch167: krb5-1.14.3-krad-recv.patch
Patch168: krb5-1.14.4-CVE-2016-3120.patch
License: MIT
URL: http://web.mit.edu/kerberos/www/
@ -273,6 +274,7 @@ ln NOTICE LICENSE
%patch166 -p1 -b .fix_otp_as_key
%patch167 -p1 -b .krad-recv
%patch168 -p1 -b .CVE-2016-3120
# Take the execute bit off of documentation.
chmod -x doc/krb5-protocol/*.txt doc/ccapi/*.html
@ -803,6 +805,10 @@ exit 0
%{_libdir}/libkadm5srv_mit.so.*
%changelog
* Thu Jul 28 2016 Robbie Harwood <rharwood@redhat.com> - 1.14.1-9
- Fix CVE-2016-3120
- Resolves: #1361051
* Wed Jun 22 2016 Robbie Harwood <rharwood@redhat.com> - 1.14.1-8
- Fix incorrect recv() size calculation in libkrad