tls: enforce certificate verification
- add option to use test certificate in the ca chain
- add hostname to extended session endpoint fields and connect api
parameters. If hostname is present, certificate validation is
enforced.
- use /etc/ssl/certs/ca-certificates.crt to bootstrap CA cert. A
different path can be provided via startup config
Change-Id: I046f9c6ff3ae6a9c2d71220cb62eca8f7b10e5fb
Signed-off-by: Florin Coras <fcoras@cisco.com>
diff --git a/src/vnet/session-apps/tls.c b/src/vnet/session-apps/tls.c
index 50c3636..d71dfb4 100644
--- a/src/vnet/session-apps/tls.c
+++ b/src/vnet/session-apps/tls.c
@@ -22,11 +22,13 @@
#include <mbedtls/timing.h>
#include <mbedtls/debug.h>
-#define TLS_DEBUG (0)
-#define TLS_DEBUG_LEVEL_CLIENT (0)
-#define TLS_DEBUG_LEVEL_SERVER (0)
-#define TLS_CHUNK_SIZE (1 << 14)
-#define TLS_USE_OUR_MEM_FUNCS (0)
+#define TLS_DEBUG 0
+#define TLS_DEBUG_LEVEL_CLIENT 0
+#define TLS_DEBUG_LEVEL_SERVER 0
+
+#define TLS_CHUNK_SIZE (1 << 14)
+#define TLS_USE_OUR_MEM_FUNCS 0
+#define TLS_CA_CERT_PATH "/etc/ssl/certs/ca-certificates.crt"
#if TLS_DEBUG
#define TLS_DBG(_lvl, _fmt, _args...) \
@@ -67,6 +69,8 @@
}) tls_ctx_id_t;
/* *INDENT-ON* */
+STATIC_ASSERT (sizeof (tls_ctx_id_t) <= 42, "ctx id must be less than 42");
+
typedef struct tls_ctx_
{
union
@@ -85,6 +89,7 @@
#define parent_app_api_context c_s_index
u8 is_passive_close;
+ u8 *srv_hostname;
mbedtls_ssl_context ssl;
mbedtls_ssl_config conf;
mbedtls_x509_crt srvcert;
@@ -101,6 +106,12 @@
tls_ctx_t *half_open_ctx_pool;
clib_rwlock_t half_open_rwlock;
mbedtls_x509_crt cacert;
+
+ /*
+ * Config
+ */
+ u8 use_test_cert_in_ca;
+ char *ca_cert_path;
} tls_main_t;
static tls_main_t tls_main;
@@ -188,6 +199,7 @@
void
tls_ctx_free (tls_ctx_t * ctx)
{
+ vec_free (ctx->srv_hostname);
pool_put_index (tls_main.ctx_pool[vlib_get_thread_index ()],
ctx->tls_ctx_idx);
}
@@ -416,7 +428,8 @@
return -1;
}
- if ((rv = mbedtls_ssl_set_hostname (&ctx->ssl, "SERVER NAME")) != 0)
+ if ((rv = mbedtls_ssl_set_hostname (&ctx->ssl,
+ (const char *) ctx->srv_hostname)) != 0)
{
TLS_DBG (1, "failed\n ! mbedtls_ssl_set_hostname returned %d\n", rv);
return -1;
@@ -424,14 +437,13 @@
ctx_ptr = uword_to_pointer (ctx->tls_ctx_idx, void *);
mbedtls_ssl_set_bio (&ctx->ssl, ctx_ptr, tls_net_send, tls_net_recv, NULL);
-
mbedtls_debug_set_threshold (TLS_DEBUG_LEVEL_CLIENT);
/*
* 2. Do the first 2 steps in the handshake.
*/
TLS_DBG (1, "Initiating handshake for [%u]%u", ctx->c_thread_index,
- tls_ctx_index (ctx));
+ ctx->tls_ctx_idx);
while (ctx->ssl.state != MBEDTLS_SSL_HANDSHAKE_OVER)
{
rv = mbedtls_ssl_handshake_step (&ctx->ssl);
@@ -439,13 +451,14 @@
break;
}
TLS_DBG (2, "tls state for [%u]%u is %u", ctx->c_thread_index,
- tls_ctx_index (ctx), ctx->ssl.state);
+ ctx->tls_ctx_idx, ctx->ssl.state);
return 0;
}
static int
tls_ctx_init_server (tls_ctx_t * ctx)
{
+ tls_main_t *tm = &tls_main;
application_t *app;
void *ctx_ptr;
int rv;
@@ -468,17 +481,7 @@
rv = mbedtls_x509_crt_parse (&ctx->srvcert,
(const unsigned char *) app->tls_cert,
- mbedtls_test_srv_crt_len);
- if (rv != 0)
- {
- TLS_DBG (1, " failed\n ! mbedtls_x509_crt_parse returned %d", rv);
- goto exit;
- }
-
- /* TODO clone CA */
- rv = mbedtls_x509_crt_parse (&ctx->srvcert,
- (const unsigned char *) mbedtls_test_cas_pem,
- mbedtls_test_cas_pem_len);
+ vec_len (app->tls_cert));
if (rv != 0)
{
TLS_DBG (1, " failed\n ! mbedtls_x509_crt_parse returned %d", rv);
@@ -487,7 +490,7 @@
rv = mbedtls_pk_parse_key (&ctx->pkey,
(const unsigned char *) app->tls_key,
- mbedtls_test_srv_key_len, NULL, 0);
+ vec_len (app->tls_key), NULL, 0);
if (rv != 0)
{
TLS_DBG (1, " failed\n ! mbedtls_pk_parse_key returned %d", rv);
@@ -515,7 +518,7 @@
mbedtls_ssl_cache_set );
*/
- mbedtls_ssl_conf_ca_chain (&ctx->conf, ctx->srvcert.next, NULL);
+ mbedtls_ssl_conf_ca_chain (&ctx->conf, &tm->cacert, NULL);
if ((rv = mbedtls_ssl_conf_own_cert (&ctx->conf, &ctx->srvcert, &ctx->pkey))
!= 0)
{
@@ -539,7 +542,7 @@
* 3. Start handshake state machine
*/
TLS_DBG (1, "Initiating handshake for [%u]%u", ctx->c_thread_index,
- tls_ctx_index (ctx));
+ ctx->tls_ctx_idx);
while (ctx->ssl.state != MBEDTLS_SSL_HANDSHAKE_OVER)
{
rv = mbedtls_ssl_handshake_step (&ctx->ssl);
@@ -548,7 +551,7 @@
}
TLS_DBG (2, "tls state for [%u]%u is %u", ctx->c_thread_index,
- tls_ctx_index (ctx), ctx->ssl.state);
+ ctx->tls_ctx_idx, ctx->ssl.state);
return 0;
exit:
@@ -585,7 +588,7 @@
}
static int
-tls_notify_app_connected (tls_ctx_t * ctx)
+tls_notify_app_connected (tls_ctx_t * ctx, u8 is_failed)
{
int (*cb_fn) (u32, u32, stream_session_t *, u8);
stream_session_t *app_session;
@@ -595,6 +598,9 @@
app = application_get (ctx->parent_app_index);
cb_fn = app->cb_fns.session_connected_callback;
+ if (is_failed)
+ goto failed;
+
sm = application_get_connect_segment_manager (app);
app_session = session_alloc (vlib_get_thread_index ());
app_session->app_index = ctx->parent_app_index;
@@ -632,7 +638,7 @@
if (rv != 0)
break;
}
- TLS_DBG (2, "tls state for %u is %u", tls_ctx_index (ctx), ctx->ssl.state);
+ TLS_DBG (2, "tls state for %u is %u", ctx->tls_ctx_idx, ctx->ssl.state);
if (ctx->ssl.state != MBEDTLS_SSL_HANDSHAKE_OVER)
return 0;
@@ -652,12 +658,17 @@
mbedtls_x509_crt_verify_info (buf, sizeof (buf), " ! ", flags);
TLS_DBG (1, "%s\n", buf);
- /* For testing purposes not enforcing this */
- /* tls_disconnect (tls_ctx_index (ctx), vlib_get_thread_index ());
- return -1;
+ /*
+ * Presence of hostname enforces strict certificate verification
*/
+ if (ctx->srv_hostname)
+ {
+ tls_disconnect (ctx->tls_ctx_idx, vlib_get_thread_index ());
+ tls_notify_app_connected (ctx, /* is failed */ 1);
+ return -1;
+ }
}
- tls_notify_app_connected (ctx);
+ tls_notify_app_connected (ctx, /* is failed */ 0);
}
else
{
@@ -665,7 +676,7 @@
}
TLS_DBG (1, "Handshake for %u complete. TLS cipher is %x",
- tls_ctx_index (ctx), ctx->ssl.session->ciphersuite);
+ ctx->tls_ctx_idx, ctx->ssl.session->ciphersuite);
return 0;
}
@@ -899,6 +910,11 @@
ctx->parent_app_index = sep->app_index;
ctx->parent_app_api_context = sep->opaque;
ctx->tcp_is_ip4 = sep->is_ip4;
+ if (sep->hostname)
+ {
+ ctx->srv_hostname = format (0, "%v", sep->hostname);
+ vec_terminate_c_string (ctx->srv_hostname);
+ }
tls_ctx_half_open_reader_unlock ();
app = application_get (sep->app_index);
@@ -1101,17 +1117,33 @@
tls_main_t *tm = &tls_main;
int rv;
- /* TODO config */
- mbedtls_x509_crt_init (&tm->cacert);
- rv = mbedtls_x509_crt_parse (&tm->cacert,
- (const unsigned char *) mbedtls_test_cas_pem,
- mbedtls_test_cas_pem_len);
- if (rv < 0)
+ if (!tm->ca_cert_path)
+ tm->ca_cert_path = TLS_CA_CERT_PATH;
+
+ if (access (tm->ca_cert_path, F_OK | R_OK) == -1)
{
- clib_warning ("mbedtls_x509_crt_parse returned -0x%x", -rv);
+ clib_warning ("Could not initialize TLS CA certificates");
return -1;
}
- return 0;
+
+ mbedtls_x509_crt_init (&tm->cacert);
+ rv = mbedtls_x509_crt_parse_file (&tm->cacert, tm->ca_cert_path);
+ if (rv < 0)
+ {
+ clib_warning ("Couldn't parse system CA certificates: -0x%x", -rv);
+ }
+ if (tm->use_test_cert_in_ca)
+ {
+ rv = mbedtls_x509_crt_parse (&tm->cacert,
+ (const unsigned char *) test_srv_crt_rsa,
+ test_srv_crt_rsa_len);
+ if (rv < 0)
+ {
+ clib_warning ("Couldn't parse test certificate: -0x%x", -rv);
+ return -1;
+ }
+ }
+ return (rv < 0 ? -1 : 0);
}
clib_error_t *
@@ -1175,6 +1207,24 @@
VLIB_INIT_FUNCTION (tls_init);
+static clib_error_t *
+tls_config_fn (vlib_main_t * vm, unformat_input_t * input)
+{
+ tls_main_t *tm = &tls_main;
+ while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
+ {
+ if (unformat (input, "use-test-cert-in-ca"))
+ tm->use_test_cert_in_ca = 1;
+ else if (unformat (input, "ca-cert-path %s", &tm->ca_cert_path))
+ ;
+ else
+ return clib_error_return (0, "unknown input `%U'",
+ format_unformat_error, input);
+ }
+ return 0;
+}
+
+VLIB_EARLY_CONFIG_FUNCTION (tls_config_fn, "tls");
/*
* fd.io coding-style-patch-verification: ON
*