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From 91c608d0eb48435b5b5d2f3631a4bb2a40b8d519 Mon Sep 17 00:00:00 2001
From: Sumit Bose <sbose@redhat.com>
Date: Wed, 10 Oct 2018 15:37:16 +0200
Subject: [PATCH 74/83] p11_child: add OCSP check ot the OpenSSL version
Related to https://pagure.io/SSSD/sssd/issue/3489
Reviewed-by: Jakub Hrozek <jhrozek@redhat.com>
---
src/man/sssd.conf.5.xml | 26 ++-
src/p11_child/p11_child_openssl.c | 346 ++++++++++++++++++++++++++++++++++++++
src/tests/cmocka/test_utils.c | 3 +
src/util/util.c | 2 +
4 files changed, 370 insertions(+), 7 deletions(-)
diff --git a/src/man/sssd.conf.5.xml b/src/man/sssd.conf.5.xml
index c8d53f0..5e3ae48 100644
--- a/src/man/sssd.conf.5.xml
+++ b/src/man/sssd.conf.5.xml
@@ -479,8 +479,8 @@
be replaced with the URL of the OCSP
default responder e.g.
http://example.com:80/ocsp.</para>
- <para>This option must be used together
- with
+ <para>(NSS Version) This option must be
+ used together with
ocsp_default_responder_signing_cert.
</para>
</listitem>
@@ -489,17 +489,29 @@
<term>
ocsp_default_responder_signing_cert=NAME</term>
<listitem>
- <para>The nickname of the cert to trust
- (expected) to sign the OCSP responses.
- The certificate with the given nickname
- must be available in the systems NSS
- database.</para>
+ <para>(NSS Version) The nickname of the
+ cert to trust (expected) to sign the
+ OCSP responses. The certificate with
+ the given nickname must be available in
+ the systems NSS database.</para>
<para>This option must be used together
with ocsp_default_responder.</para>
+ <para>(OpenSSL version) This option is
+ currently ignored. All needed
+ certificates must be available in the
+ PEM file given by
+ pam_cert_db_path.</para>
</listitem>
</varlistentry>
</variablelist>
</para>
+ <para condition="with_nss">
+ This man page was generated for the NSS version.
+ </para>
+ <para condition="with_openssl">
+ This man page was generated for the OpenSSL
+ version.
+ </para>
<para>
Unknown options are reported but ignored.
</para>
diff --git a/src/p11_child/p11_child_openssl.c b/src/p11_child/p11_child_openssl.c
index 000e1c9..d66a2f8 100644
--- a/src/p11_child/p11_child_openssl.c
+++ b/src/p11_child/p11_child_openssl.c
@@ -28,6 +28,7 @@
#include <openssl/x509.h>
#include <openssl/err.h>
#include <openssl/rand.h>
+#include <openssl/ocsp.h>
#include <p11-kit/p11-kit.h>
#include <p11-kit/uri.h>
@@ -42,8 +43,344 @@ struct p11_ctx {
X509_STORE *x509_store;
const char *ca_db;
bool wait_for_card;
+ struct cert_verify_opts *cert_verify_opts;
};
+static OCSP_RESPONSE *query_responder(BIO *cbio, const char *host,
+ const char *path,
+ OCSP_REQUEST *req, int req_timeout)
+{
+ int fd;
+ int rv;
+ OCSP_REQ_CTX *ctx = NULL;
+ OCSP_RESPONSE *rsp = NULL;
+ fd_set confds;
+ struct timeval tv;
+
+ if (req_timeout != -1) {
+ BIO_set_nbio(cbio, 1);
+ }
+
+ rv = BIO_do_connect(cbio);
+
+ if ((rv <= 0) && ((req_timeout == -1) || !BIO_should_retry(cbio))) {
+ DEBUG(SSSDBG_OP_FAILURE, "Error connecting BIO\n");
+ return NULL;
+ }
+
+ if (BIO_get_fd(cbio, &fd) < 0) {
+ DEBUG(SSSDBG_OP_FAILURE, "Can't get connection fd\n");
+ goto err;
+ }
+
+ if (req_timeout != -1 && rv <= 0) {
+ FD_ZERO(&confds);
+ FD_SET(fd, &confds);
+ tv.tv_usec = 0;
+ tv.tv_sec = req_timeout;
+ rv = select(fd + 1, NULL, (void *)&confds, NULL, &tv);
+ if (rv == 0) {
+ DEBUG(SSSDBG_OP_FAILURE, "Timeout on connect\n");
+ return NULL;
+ }
+ }
+
+ ctx = OCSP_sendreq_new(cbio, path, NULL, -1);
+ if (ctx == NULL) {
+ return NULL;
+ }
+
+ if (OCSP_REQ_CTX_add1_header(ctx, "Host", host) == 0) {
+ goto err;
+ }
+
+ if (!OCSP_REQ_CTX_set1_req(ctx, req)) {
+ goto err;
+ }
+
+ for (;;) {
+ rv = OCSP_sendreq_nbio(&rsp, ctx);
+ if (rv != -1)
+ break;
+ if (req_timeout == -1)
+ continue;
+ FD_ZERO(&confds);
+ FD_SET(fd, &confds);
+ tv.tv_usec = 0;
+ tv.tv_sec = req_timeout;
+ if (BIO_should_read(cbio)) {
+ rv = select(fd + 1, (void *)&confds, NULL, NULL, &tv);
+ } else if (BIO_should_write(cbio)) {
+ rv = select(fd + 1, NULL, (void *)&confds, NULL, &tv);
+ } else {
+ DEBUG(SSSDBG_OP_FAILURE, "Unexpected retry condition\n");
+ goto err;
+ }
+ if (rv == 0) {
+ DEBUG(SSSDBG_OP_FAILURE, "Timeout on request\n");
+ break;
+ }
+ if (rv == -1) {
+ DEBUG(SSSDBG_OP_FAILURE, "Select error\n");
+ break;
+ }
+
+ }
+ err:
+ OCSP_REQ_CTX_free(ctx);
+
+ return rsp;
+}
+
+#if OPENSSL_VERSION_NUMBER < 0x10100000L
+#define TLS_client_method SSLv23_client_method
+#define X509_STORE_get0_objects(store) (store->objs)
+#define X509_OBJECT_get_type(object) (object->type)
+#define X509_OBJECT_get0_X509(object) (object->data.x509)
+#endif
+
+OCSP_RESPONSE *process_responder(OCSP_REQUEST *req,
+ const char *host, const char *path,
+ const char *port, int use_ssl,
+ int req_timeout)
+{
+ BIO *cbio = NULL;
+ SSL_CTX *ctx = NULL;
+ OCSP_RESPONSE *resp = NULL;
+
+ cbio = BIO_new_connect(host);
+ if (cbio == NULL) {
+ DEBUG(SSSDBG_OP_FAILURE, "Error creating connect BIO\n");
+ goto end;
+ }
+ if (port != NULL)
+ BIO_set_conn_port(cbio, port);
+ if (use_ssl == 1) {
+ BIO *sbio;
+ ctx = SSL_CTX_new(TLS_client_method());
+ if (ctx == NULL) {
+ DEBUG(SSSDBG_OP_FAILURE, "Error creating SSL context.\n");
+ goto end;
+ }
+ SSL_CTX_set_mode(ctx, SSL_MODE_AUTO_RETRY);
+ sbio = BIO_new_ssl(ctx, 1);
+ cbio = BIO_push(sbio, cbio);
+ }
+
+ resp = query_responder(cbio, host, path, req, req_timeout);
+ if (resp == NULL) {
+ DEBUG(SSSDBG_OP_FAILURE, "Error querying OCSP responder\n");
+ }
+
+ end:
+ BIO_free_all(cbio);
+ SSL_CTX_free(ctx);
+ return resp;
+}
+
+static errno_t do_ocsp(struct p11_ctx *p11_ctx, X509 *cert)
+{
+ OCSP_REQUEST *ocsp_req = NULL;
+ OCSP_RESPONSE *ocsp_resp = NULL;
+ OCSP_BASICRESP *ocsp_basic = NULL;
+ OCSP_CERTID *cid = NULL;
+ STACK_OF(OPENSSL_STRING) *ocsp_urls = NULL;
+ char *url_str;
+ X509 *issuer = NULL;
+ int req_timeout = -1;
+ int status;
+ int ret = EIO;
+ int reason;
+ ASN1_GENERALIZEDTIME *revtime;
+ ASN1_GENERALIZEDTIME *thisupd;
+ ASN1_GENERALIZEDTIME *nextupd;
+ long grace_time = (5 * 60); /* Allow 5 minutes time difference when
+ * checking the validity of the OCSP response */
+ char *host = NULL;
+ char *path = NULL;
+ char *port = NULL;
+ int use_ssl;
+ X509_NAME *issuer_name = NULL;
+ X509_OBJECT *x509_obj;
+ STACK_OF(X509_OBJECT) *store_objects;
+
+ ocsp_urls = X509_get1_ocsp(cert);
+ if (ocsp_urls == NULL
+ && p11_ctx->cert_verify_opts->ocsp_default_responder == NULL) {
+ DEBUG(SSSDBG_CRIT_FAILURE,
+ "No OCSP URL in certificate and no default responder defined, "
+ "skipping OCSP check.\n");
+ return EOK;
+ }
+
+ if (p11_ctx->cert_verify_opts->ocsp_default_responder != NULL) {
+ url_str = p11_ctx->cert_verify_opts->ocsp_default_responder;
+ } else {
+ if (sk_OPENSSL_STRING_num(ocsp_urls) > 1) {
+ DEBUG(SSSDBG_CONF_SETTINGS,
+ "Found more than 1 OCSP URLs, just using the first.\n");
+ }
+
+ url_str = sk_OPENSSL_STRING_value(ocsp_urls, 0);
+ }
+
+ DEBUG(SSSDBG_TRACE_ALL, "Using OCSP URL [%s].\n", url_str);
+
+ ret = OCSP_parse_url(url_str, &host, &port, &path, &use_ssl);
+ if (ret != 1) {
+ DEBUG(SSSDBG_OP_FAILURE, "OCSP_parse_url failed to parse [%s].\n",
+ url_str);
+ ret = EIO;
+ goto done;
+ }
+
+ issuer_name = X509_get_issuer_name(cert);
+ if (issuer_name == NULL) {
+ DEBUG(SSSDBG_CRIT_FAILURE, "Certificate has no issuer, "
+ "cannot run OCSP check.\n");
+ ret = EINVAL;
+ goto done;
+ }
+
+ store_objects = X509_STORE_get0_objects(p11_ctx->x509_store);
+ if (store_objects == NULL) {
+ DEBUG(SSSDBG_CRIT_FAILURE,
+ "No objects found in certificate store, OCSP failed.\n");
+ ret = EINVAL;
+ goto done;
+ }
+
+ x509_obj = X509_OBJECT_retrieve_by_subject(store_objects, X509_LU_X509,
+ issuer_name);
+ if (x509_obj == NULL || X509_OBJECT_get_type(x509_obj) != X509_LU_X509) {
+ DEBUG(SSSDBG_CRIT_FAILURE, "Issuer not found.\n");
+ ret = EIO;
+ goto done;
+ }
+
+ issuer = X509_OBJECT_get0_X509(x509_obj);
+
+ ocsp_req = OCSP_REQUEST_new();
+ if (ocsp_req == NULL) {
+ DEBUG(SSSDBG_OP_FAILURE, "OCSP_REQUEST_new failed.\n");
+ ret = ENOMEM;
+ goto done;
+ }
+
+ cid = OCSP_cert_to_id(EVP_sha1(), cert, issuer);
+ if (cid == NULL) {
+ DEBUG(SSSDBG_OP_FAILURE, "OCSP_cert_to_id failed.\n");
+ ret = EIO;
+ goto done;
+ }
+
+ if (OCSP_request_add0_id(ocsp_req, cid) == NULL) {
+ DEBUG(SSSDBG_OP_FAILURE, "OCSP_request_add0_id failed.\n");
+ ret = EIO;
+ goto done;
+ }
+
+ OCSP_request_add1_nonce(ocsp_req, NULL, -1);
+
+ ocsp_resp = process_responder(ocsp_req, host, path, port, use_ssl,
+ req_timeout);
+ if (ocsp_resp == NULL) {
+ DEBUG(SSSDBG_OP_FAILURE, "process_responder failed.\n");
+ ret = EIO;
+ goto done;
+ }
+
+ status = OCSP_response_status(ocsp_resp);
+ if (status != OCSP_RESPONSE_STATUS_SUCCESSFUL) {
+ DEBUG(SSSDBG_CRIT_FAILURE, "OCSP response error: [%d][%s].\n",
+ status, OCSP_response_status_str(status));
+ ret = EIO;
+ goto done;
+ }
+
+ ocsp_basic = OCSP_response_get1_basic(ocsp_resp);
+ if (ocsp_resp == NULL) {
+ DEBUG(SSSDBG_OP_FAILURE, "OCSP_response_get1_basic failed.\n");
+ ret = EIO;
+ goto done;
+ }
+
+ switch (OCSP_check_nonce(ocsp_req, ocsp_basic)) {
+ case -1:
+ DEBUG(SSSDBG_CRIT_FAILURE, "No nonce in OCSP response. This might "
+ "indicate a replay attack or an OCSP responder which does not "
+ "support nonces. Accepting response.\n");
+ break;
+ case 0:
+ DEBUG(SSSDBG_CRIT_FAILURE, "Nonce in OCSP response does not match the "
+ "one used in the request.\n");
+ ret = EIO;
+ goto done;
+ break;
+ case 1:
+ DEBUG(SSSDBG_TRACE_ALL, "Nonce in OCSP response is the same as the one "
+ "used in the request.\n");
+ break;
+ case 2:
+ case 3:
+ DEBUG(SSSDBG_CRIT_FAILURE, "Missing nonce in OCSP request, this should"
+ "never happen.\n");
+ ret = EIO;
+ goto done;
+ break;
+ default:
+ DEBUG(SSSDBG_CRIT_FAILURE, "Unexpected result of OCSP_check_nonce.\n");
+ }
+
+ status = OCSP_basic_verify(ocsp_basic, NULL, p11_ctx->x509_store, 0);
+ if (status != 1) {
+ DEBUG(SSSDBG_CRIT_FAILURE, "OCSP_base_verify failed to verify OCSP "
+ "response.\n");
+ ret = EIO;
+ goto done;
+ }
+
+ ret = OCSP_resp_find_status(ocsp_basic, cid, &status, &reason,
+ &revtime, &thisupd, &nextupd);
+ if (ret != 1) {
+ DEBUG(SSSDBG_CRIT_FAILURE, "OCSP response does not contain status of "
+ "our certificate.\n");
+ ret = EIO;
+ goto done;
+ }
+
+ if (status != V_OCSP_CERTSTATUS_GOOD) {
+ DEBUG(SSSDBG_CRIT_FAILURE, "OCSP check failed with [%d][%s].\n",
+ status, OCSP_cert_status_str(status));
+ if (status == V_OCSP_CERTSTATUS_REVOKED) {
+ DEBUG(SSSDBG_CRIT_FAILURE, "Certificate is revoked [%d][%s].\n",
+ reason, OCSP_crl_reason_str(reason));
+ }
+ ret = EIO;
+ goto done;
+ }
+
+ if (OCSP_check_validity(thisupd, nextupd, grace_time, -1) != 1) {
+ DEBUG(SSSDBG_CRIT_FAILURE, "OCSP response is not valid anymore.\n");
+ ret = EIO;
+ goto done;
+ }
+
+ DEBUG(SSSDBG_TRACE_ALL, "OCSP check was successful.\n");
+ ret = EOK;
+
+done:
+ OCSP_BASICRESP_free(ocsp_basic);
+ OCSP_RESPONSE_free(ocsp_resp);
+ OCSP_REQUEST_free(ocsp_req);
+
+ OPENSSL_free(host);
+ OPENSSL_free(port);
+ OPENSSL_free(path);
+ X509_email_free(ocsp_urls);
+
+ return ret;
+}
static char *get_pkcs11_uri(TALLOC_CTX *mem_ctx, CK_INFO *module_info,
CK_SLOT_INFO *slot_info, CK_SLOT_ID slot_id,
@@ -191,6 +528,7 @@ errno_t init_verification(struct p11_ctx *p11_ctx,
}
p11_ctx->x509_store = store;
+ p11_ctx->cert_verify_opts = cert_verify_opts;
talloc_set_destructor(p11_ctx, talloc_free_x509_store);
ret = EOK;
@@ -262,6 +600,14 @@ bool do_verification(struct p11_ctx *p11_ctx, X509 *cert)
goto done;
}
+ if (p11_ctx->cert_verify_opts->do_ocsp) {
+ ret = do_ocsp(p11_ctx, cert);
+ if (ret != EOK) {
+ DEBUG(SSSDBG_OP_FAILURE, "do_ocsp failed.\n");
+ goto done;
+ }
+ }
+
res = true;
done:
diff --git a/src/tests/cmocka/test_utils.c b/src/tests/cmocka/test_utils.c
index 1a8699a..c86e526 100644
--- a/src/tests/cmocka/test_utils.c
+++ b/src/tests/cmocka/test_utils.c
@@ -1612,6 +1612,8 @@ static void test_parse_cert_verify_opts(void **state)
&cv_opts);
assert_int_equal(ret, EINVAL);
+/* Only NSS requires that both are set */
+#ifdef HAVE_NSS
ret = parse_cert_verify_opts(global_talloc_context,
"ocsp_default_responder=abc", &cv_opts);
assert_int_equal(ret, EINVAL);
@@ -1620,6 +1622,7 @@ static void test_parse_cert_verify_opts(void **state)
"ocsp_default_responder_signing_cert=def",
&cv_opts);
assert_int_equal(ret, EINVAL);
+#endif
ret = parse_cert_verify_opts(global_talloc_context,
"ocsp_default_responder=abc,"
diff --git a/src/util/util.c b/src/util/util.c
index 53dd9a1..7f475fa 100644
--- a/src/util/util.c
+++ b/src/util/util.c
@@ -1123,6 +1123,7 @@ errno_t parse_cert_verify_opts(TALLOC_CTX *mem_ctx, const char *verify_opts,
}
}
+#ifdef HAVE_NSS
if ((cert_verify_opts->ocsp_default_responder == NULL
&& cert_verify_opts->ocsp_default_responder_signing_cert != NULL)
|| (cert_verify_opts->ocsp_default_responder != NULL
@@ -1135,6 +1136,7 @@ errno_t parse_cert_verify_opts(TALLOC_CTX *mem_ctx, const char *verify_opts,
ret = EINVAL;
goto done;
}
+#endif
ret = EOK;
--
2.9.5
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