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| author | Greg Hudson <ghudson@mit.edu> | 2016-07-19 11:00:28 -0400 |
|---|---|---|
| committer | Tom Yu <tlyu@mit.edu> | 2016-07-19 18:05:20 -0400 |
| commit | 85c3046d42eeb821967ad5625fcb08e8c6177b1a (patch) | |
| tree | 6b40c72ef34f66b57c22f99a654a4ea728c7b871 | |
| parent | 857b82485a67094bbb2d73eb7572366878a4a9a9 (diff) | |
| download | krb5-85c3046d42eeb821967ad5625fcb08e8c6177b1a.zip krb5-85c3046d42eeb821967ad5625fcb08e8c6177b1a.tar.gz krb5-85c3046d42eeb821967ad5625fcb08e8c6177b1a.tar.bz2 | |
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
(cherry picked from commit 93b4a6306a0026cf1cc31ac4bd8a49ba5d034ba7)
ticket: 8458
version_fixed: 1.14.3
| -rw-r--r-- | src/kdc/kdc_util.c | 2 | ||||
| -rwxr-xr-x | src/tests/t_pkinit.py | 5 |
2 files changed, 6 insertions, 1 deletions
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() |