Commit 52200468 authored by Isaac Boukris's avatar Isaac Boukris Committed by Karolin Seeger

CVE-2018-16860 selftest: Add test for S4U2Self with unkeyed checksum

BUG: https://bugzilla.samba.org/show_bug.cgi?id=13685Signed-off-by: 's avatarIsaac Boukris <iboukris@gmail.com>
Signed-off-by: 's avatarAndrew Bartlett <abartlet@samba.org>
parent bc1b0ade
This diff is collapsed.
......@@ -43,7 +43,9 @@
#define TEST_UPN 0x0000040
#define TEST_S4U2SELF 0x0000080
#define TEST_REMOVEDOLLAR 0x0000100
#define TEST_ALL 0x00001FF
#define TEST_AS_REQ_SPN 0x0000200 /* not used */
#define TEST_MITM_S4U2SELF 0x0000400
#define TEST_ALL 0x00007FF
struct test_data {
const char *test_name;
......@@ -61,6 +63,7 @@ struct test_data {
bool upn;
bool other_upn_suffix;
bool s4u2self;
bool mitm_s4u2self;
bool removedollar;
const char *krb5_service;
const char *krb5_hostname;
......@@ -209,6 +212,67 @@ static bool test_accept_ticket(struct torture_context *tctx,
return true;
}
krb5_error_code
_krb5_s4u2self_to_checksumdata(krb5_context context,
const PA_S4U2Self *self,
krb5_data *data);
/* Helper function to modify the principal in PA_FOR_USER padata */
static bool change_for_user_principal(struct torture_krb5_context *test_context,
krb5_data *modified_send_buf)
{
PA_DATA *for_user;
int i = 0;
size_t used;
krb5_error_code ret;
PA_S4U2Self self, mod_self;
krb5_data cksum_data;
krb5_principal admin;
heim_octet_string orig_padata_value;
krb5_context k5_ctx = test_context->smb_krb5_context->krb5_context;
for_user = krb5_find_padata(test_context->tgs_req.padata->val,
test_context->tgs_req.padata->len, KRB5_PADATA_FOR_USER, &i);
torture_assert(test_context->tctx, for_user != NULL, "No PA_FOR_USER in s4u2self request");
orig_padata_value = for_user->padata_value;
torture_assert_int_equal(test_context->tctx,
krb5_make_principal(k5_ctx, &admin, test_context->test_data->realm,
"Administrator", NULL),
0, "krb5_make_principal() failed");
torture_assert_int_equal(test_context->tctx,
decode_PA_S4U2Self(for_user->padata_value.data,
for_user->padata_value.length, &self, NULL),
0, "decode_PA_S4U2Self() failed");
mod_self = self;
mod_self.name = admin->name;
torture_assert_int_equal(test_context->tctx,
_krb5_s4u2self_to_checksumdata(k5_ctx, &mod_self, &cksum_data),
0, "_krb5_s4u2self_to_checksumdata() failed");
torture_assert_int_equal(test_context->tctx,
krb5_create_checksum(k5_ctx, NULL, KRB5_KU_OTHER_CKSUM,
CKSUMTYPE_CRC32, cksum_data.data,
cksum_data.length, &mod_self.cksum),
0, "krb5_create_checksum() failed");
ASN1_MALLOC_ENCODE(PA_S4U2Self, for_user->padata_value.data, for_user->padata_value.length,
&mod_self, &used, ret);
torture_assert(test_context->tctx, ret == 0, "Failed to encode PA_S4U2Self ASN1 struct");
ASN1_MALLOC_ENCODE(TGS_REQ, modified_send_buf->data, modified_send_buf->length,
&test_context->tgs_req, &used, ret);
torture_assert(test_context->tctx, ret == 0, "Failed to encode TGS_REQ ASN1 struct");
free(for_user->padata_value.data);
for_user->padata_value = orig_padata_value;
free_PA_S4U2Self(&self);
krb5_data_free(&cksum_data);
free_Checksum(&mod_self.cksum);
return true;
}
/*
* TEST_AS_REQ and TEST_AS_REQ_SELF - SEND
*
......@@ -598,7 +662,12 @@ static bool torture_krb5_pre_send_tgs_req_canon_test(struct torture_krb5_context
}
*modified_send_buf = *send_buf;
if (test_context->test_data->mitm_s4u2self) {
torture_assert(test_context->tctx, change_for_user_principal(test_context, modified_send_buf),
"Failed to modify PA_FOR_USER principal name");
} else {
*modified_send_buf = *send_buf;
}
return true;
}
......@@ -617,6 +686,7 @@ static bool torture_krb5_post_recv_tgs_req_canon_test(struct torture_krb5_contex
{
KRB_ERROR error;
size_t used;
krb5_error_code expected_error;
/*
* If this account did not have a servicePrincipalName, then
......@@ -627,9 +697,13 @@ static bool torture_krb5_post_recv_tgs_req_canon_test(struct torture_krb5_contex
torture_assert_int_equal(test_context->tctx,
error.pvno, 5,
"Got wrong error.pvno");
expected_error = KRB5KDC_ERR_S_PRINCIPAL_UNKNOWN - KRB5KDC_ERR_NONE;
if (error.error_code != expected_error && test_context->test_data->mitm_s4u2self) {
expected_error = KRB5KRB_AP_ERR_INAPP_CKSUM - KRB5KDC_ERR_NONE;
}
torture_assert_int_equal(test_context->tctx,
error.error_code,
KRB5KDC_ERR_S_PRINCIPAL_UNKNOWN - KRB5KDC_ERR_NONE,
expected_error,
"Got wrong error.error_code");
} else {
torture_assert_int_equal(test_context->tctx,
......@@ -672,6 +746,8 @@ static bool torture_krb5_post_recv_tgs_req_canon_test(struct torture_krb5_contex
torture_assert_int_equal(test_context->tctx,
*test_context->tgs_rep.ticket.enc_part.kvno & 0xFFFF0000,
0, "Unexpecedly got a RODC number in the KVNO, should just be principal KVNO");
torture_assert(test_context->tctx, test_context->test_data->mitm_s4u2self == false,
"KDC accepted PA_S4U2Self with unkeyed checksum!");
free_TGS_REP(&test_context->tgs_rep);
}
torture_assert(test_context->tctx, test_context->packet_count == 0, "too many packets");
......@@ -1845,7 +1921,23 @@ static bool torture_krb5_as_req_canon(struct torture_context *tctx, const void *
*/
if (torture_setting_bool(tctx, "expect_machine_account", false)
&& (test_data->enterprise || test_data->upn == false)) {
if (test_data->mitm_s4u2self) {
torture_assert_int_equal(tctx, k5ret, KRB5KRB_AP_ERR_INAPP_CKSUM,
assertion_message);
/* Done testing mitm-s4u2self */
return true;
}
torture_assert_int_equal(tctx, k5ret, 0, assertion_message);
/* Check that the impersonate principal is not being canonicalized by the KDC. */
if (test_data->s4u2self) {
torture_assert(tctx, krb5_principal_compare(k5_context, server_creds->client,
principal),
"TGS-REP cname does not match requested client principal");
}
torture_assert_int_equal(tctx, krb5_cc_store_cred(k5_context,
ccache, server_creds),
0, "krb5_cc_store_cred failed");
......@@ -2222,11 +2314,25 @@ struct torture_suite *torture_krb5_canon(TALLOC_CTX *mem_ctx)
(i & TEST_NETBIOS_REALM) ? "netbios-realm" : "krb5-realm",
(i & TEST_WIN2K) ? "win2k" : "no-win2k",
(i & TEST_UPN) ? "upn" : "no-upn",
(i & TEST_S4U2SELF) ? "s4u2self" : "normal",
(i & TEST_S4U2SELF) ? (i & TEST_MITM_S4U2SELF) ? "mitm-s4u2self" : "s4u2self" : "normal",
(i & TEST_REMOVEDOLLAR) ? "removedollar" : "keepdollar");
struct test_data *test_data = talloc_zero(suite, struct test_data);
if (i & TEST_MITM_S4U2SELF) {
if (!(i & TEST_S4U2SELF)) {
continue;
}
}
/*
* Due to backport: this flag is not used until Samba
* 4.10
*/
if (i & TEST_AS_REQ_SPN) {
continue;
}
test_data->test_name = name;
test_data->real_realm
= strupper_talloc(test_data,
......@@ -2246,6 +2352,7 @@ struct torture_suite *torture_krb5_canon(TALLOC_CTX *mem_ctx)
test_data->win2k = (i & TEST_WIN2K) != 0;
test_data->upn = (i & TEST_UPN) != 0;
test_data->s4u2self = (i & TEST_S4U2SELF) != 0;
test_data->mitm_s4u2self = (i & TEST_MITM_S4U2SELF) != 0;
test_data->removedollar = (i & TEST_REMOVEDOLLAR) != 0;
torture_suite_add_simple_tcase_const(suite, name, torture_krb5_as_req_canon,
test_data);
......
Markdown is supported
0% or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment