152 lines
6.2 KiB
Diff
152 lines
6.2 KiB
Diff
From 03265620488b84238c31170356b5f41c80f0e9d9 Mon Sep 17 00:00:00 2001
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From: Matt Rogers <mrogers@redhat.com>
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Date: Mon, 5 Dec 2016 12:17:59 -0500
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Subject: [PATCH] Improve PKINIT UPN SAN matching
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Add the match_client() kdcpreauth callback and use it in
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verify_client_san(). match_client() preserves the direct UPN to
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request principal comparison and adds a direct comparison to the
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client principal, falling back to an alias DB search and comparison
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against the client principal. Change crypto_retreive_X509_sans() to
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parse UPN values as enterprise principals.
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[ghudson@mit.edu: use match_client for both kinds of SANs]
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ticket: 8528 (new)
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(cherry picked from commit 46ff765e1fb8cbec2bb602b43311269e695dbedc)
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---
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src/include/krb5/kdcpreauth_plugin.h | 13 ++++++++++
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src/kdc/kdc_preauth.c | 28 ++++++++++++++++++++--
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src/plugins/preauth/pkinit/pkinit_crypto_openssl.c | 4 +++-
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src/plugins/preauth/pkinit/pkinit_srv.c | 10 ++++----
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4 files changed, 48 insertions(+), 7 deletions(-)
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diff --git a/src/include/krb5/kdcpreauth_plugin.h b/src/include/krb5/kdcpreauth_plugin.h
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index f455effae..92aa5a5a5 100644
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--- a/src/include/krb5/kdcpreauth_plugin.h
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+++ b/src/include/krb5/kdcpreauth_plugin.h
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@@ -221,6 +221,19 @@ typedef struct krb5_kdcpreauth_callbacks_st {
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/* End of version 3 kdcpreauth callbacks. */
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+ /*
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+ * Return true if princ matches the principal named in the request or the
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+ * client principal (possibly canonicalized). If princ does not match,
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+ * attempt a database lookup of princ with aliases allowed and compare the
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+ * result to the client principal, returning true if it matches.
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+ * Otherwise, return false.
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+ */
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+ krb5_boolean (*match_client)(krb5_context context,
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+ krb5_kdcpreauth_rock rock,
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+ krb5_principal princ);
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+
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+ /* End of version 4 kdcpreauth callbacks. */
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+
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} *krb5_kdcpreauth_callbacks;
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/* Optional: preauth plugin initialization function. */
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diff --git a/src/kdc/kdc_preauth.c b/src/kdc/kdc_preauth.c
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index 605fcb7ad..0ce79c667 100644
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--- a/src/kdc/kdc_preauth.c
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+++ b/src/kdc/kdc_preauth.c
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@@ -568,8 +568,31 @@ set_cookie(krb5_context context, krb5_kdcpreauth_rock rock,
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return kdc_fast_set_cookie(rock->rstate, pa_type, data);
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}
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+static krb5_boolean
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+match_client(krb5_context context, krb5_kdcpreauth_rock rock,
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+ krb5_principal princ)
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+{
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+ krb5_db_entry *ent;
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+ krb5_boolean match = FALSE;
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+ krb5_principal req_client = rock->request->client;
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+ krb5_principal client = rock->client->princ;
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+
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+ /* Check for a direct match against the request principal or
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+ * the post-canon client principal. */
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+ if (krb5_principal_compare_flags(context, princ, req_client,
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+ KRB5_PRINCIPAL_COMPARE_ENTERPRISE) ||
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+ krb5_principal_compare(context, princ, client))
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+ return TRUE;
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+
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+ if (krb5_db_get_principal(context, princ, KRB5_KDB_FLAG_ALIAS_OK, &ent))
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+ return FALSE;
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+ match = krb5_principal_compare(context, ent->princ, client);
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+ krb5_db_free_principal(context, ent);
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+ return match;
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+}
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+
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static struct krb5_kdcpreauth_callbacks_st callbacks = {
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- 3,
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+ 4,
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max_time_skew,
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client_keys,
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free_keys,
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@@ -583,7 +606,8 @@ static struct krb5_kdcpreauth_callbacks_st callbacks = {
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client_keyblock,
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add_auth_indicator,
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get_cookie,
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- set_cookie
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+ set_cookie,
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+ match_client
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};
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static krb5_error_code
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diff --git a/src/plugins/preauth/pkinit/pkinit_crypto_openssl.c b/src/plugins/preauth/pkinit/pkinit_crypto_openssl.c
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index 74fffbf32..bc6e7662e 100644
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--- a/src/plugins/preauth/pkinit/pkinit_crypto_openssl.c
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+++ b/src/plugins/preauth/pkinit/pkinit_crypto_openssl.c
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@@ -2190,7 +2190,9 @@ crypto_retrieve_X509_sans(krb5_context context,
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/* Prevent abuse of embedded null characters. */
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if (memchr(name.data, '\0', name.length))
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break;
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- ret = krb5_parse_name(context, name.data, &upns[u]);
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+ ret = krb5_parse_name_flags(context, name.data,
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+ KRB5_PRINCIPAL_PARSE_ENTERPRISE,
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+ &upns[u]);
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if (ret) {
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pkiDebug("%s: failed parsing ms-upn san value\n",
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__FUNCTION__);
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diff --git a/src/plugins/preauth/pkinit/pkinit_srv.c b/src/plugins/preauth/pkinit/pkinit_srv.c
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index 295be25e1..b5638a367 100644
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--- a/src/plugins/preauth/pkinit/pkinit_srv.c
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+++ b/src/plugins/preauth/pkinit/pkinit_srv.c
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@@ -121,6 +121,8 @@ static krb5_error_code
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verify_client_san(krb5_context context,
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pkinit_kdc_context plgctx,
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pkinit_kdc_req_context reqctx,
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+ krb5_kdcpreauth_callbacks cb,
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+ krb5_kdcpreauth_rock rock,
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krb5_principal client,
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int *valid_san)
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{
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@@ -171,7 +173,7 @@ verify_client_san(krb5_context context,
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__FUNCTION__, client_string, san_string);
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krb5_free_unparsed_name(context, san_string);
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#endif
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- if (krb5_principal_compare(context, princs[i], client)) {
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+ if (cb->match_client(context, rock, princs[i])) {
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pkiDebug("%s: pkinit san match found\n", __FUNCTION__);
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*valid_san = 1;
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retval = 0;
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@@ -199,7 +201,7 @@ verify_client_san(krb5_context context,
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__FUNCTION__, client_string, san_string);
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krb5_free_unparsed_name(context, san_string);
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#endif
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- if (krb5_principal_compare(context, upns[i], client)) {
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+ if (cb->match_client(context, rock, upns[i])) {
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pkiDebug("%s: upn san match found\n", __FUNCTION__);
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*valid_san = 1;
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retval = 0;
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@@ -387,8 +389,8 @@ pkinit_server_verify_padata(krb5_context context,
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}
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if (is_signed) {
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- retval = verify_client_san(context, plgctx, reqctx, request->client,
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- &valid_san);
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+ retval = verify_client_san(context, plgctx, reqctx, cb, rock,
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+ request->client, &valid_san);
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if (retval)
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goto cleanup;
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if (!valid_san) {
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