diff --git a/Fix-KDC-null-deref-on-TGS-inner-body-null-server.patch b/Fix-KDC-null-deref-on-TGS-inner-body-null-server.patch new file mode 100644 index 0000000..e756c95 --- /dev/null +++ b/Fix-KDC-null-deref-on-TGS-inner-body-null-server.patch @@ -0,0 +1,47 @@ +From 0a8dfc380fe3b210662ba1b1d452fcec2f84841b Mon Sep 17 00:00:00 2001 +From: Greg Hudson +Date: Tue, 3 Aug 2021 01:15:27 -0400 +Subject: [PATCH] Fix KDC null deref on TGS inner body null server + +After the KDC decodes a FAST inner body, it does not check for a null +server. Prior to commit 39548a5b17bbda9eeb63625a201cfd19b9de1c5b this +would typically result in an error from krb5_unparse_name(), but with +the addition of get_local_tgt() it results in a null dereference. Add +a null check. + +Reported by Joseph Sutton of Catalyst. + +CVE-2021-37750: + +In MIT krb5 releases 1.14 and later, an authenticated attacker can +cause a null dereference in the KDC by sending a FAST TGS request with +no server field. + +ticket: 9008 (new) +tags: pullup +target_version: 1.19-next +target_version: 1.18-next + +(cherry picked from commit d775c95af7606a51bf79547a94fa52ddd1cb7f49) +(cherry picked from commit bb8fa495d00ccd931eec87a01b8920636cf7903e) +(cherry picked from commit dfe383f8251d0edc7e5e08ec5e4fdd9b7f902b2a) +--- + src/kdc/do_tgs_req.c | 5 +++++ + 1 file changed, 5 insertions(+) + +diff --git a/src/kdc/do_tgs_req.c b/src/kdc/do_tgs_req.c +index 463a9c0dd..7c596a111 100644 +--- a/src/kdc/do_tgs_req.c ++++ b/src/kdc/do_tgs_req.c +@@ -208,6 +208,11 @@ process_tgs_req(krb5_kdc_req *request, krb5_data *pkt, + status = "FIND_FAST"; + goto cleanup; + } ++ if (sprinc == NULL) { ++ status = "NULL_SERVER"; ++ errcode = KRB5KDC_ERR_S_PRINCIPAL_UNKNOWN; ++ goto cleanup; ++ } + + errcode = get_local_tgt(kdc_context, &sprinc->realm, header_server, + &local_tgt, &local_tgt_storage, &local_tgt_key); diff --git a/krb5.spec b/krb5.spec index c970b4c..dfe6d1d 100644 --- a/krb5.spec +++ b/krb5.spec @@ -42,7 +42,7 @@ Summary: The Kerberos network authentication system Name: krb5 Version: 1.19.1 -Release: %{?zdpd}11%{?dist}.1 +Release: %{?zdpd}12%{?dist} # rharwood has trust path to signing key and verifies on check-in Source0: https://web.mit.edu/kerberos/dist/krb5/%{version}/krb5-%{version}%{?dashpre}.tar.gz @@ -89,6 +89,7 @@ Patch24: Fix-some-principal-realm-canonicalization-cases.patch Patch25: Allow-kinit-with-keytab-to-defer-canonicalization.patch Patch26: Fix-kadmin-k-with-fallback-or-referral-realm.patch Patch27: Fix-KDC-null-deref-on-bad-encrypted-challenge.patch +Patch28: Fix-KDC-null-deref-on-TGS-inner-body-null-server.patch License: MIT URL: https://web.mit.edu/kerberos/www/ @@ -650,6 +651,10 @@ exit 0 %{_libdir}/libkadm5srv_mit.so.* %changelog +* Wed Oct 20 2021 Antonio Torres - 1.19.1-12 +- Fix KDC null deref on TGS inner body null server (CVE-2021-37750) +- Resolves: #1997602 + * Mon Aug 09 2021 Mohan Boddu - 1.19.1-11.1 - Rebuilt for IMA sigs, glibc 2.34, aarch64 flags Related: rhbz#1991688