lwip: tls: enforce checking of server certificates based on CA availability
Instead of relying on some build time configuration to determine if
server certificates need to be checked against CA certificates, do it
based on the availability of such certificates. If no CA is configured
then no check can succeed; on the other hand if we have CA certs then
we should not ignore them. It is always possible to remove the CA certs
(via 'wget cacert 0 0') to force an HTTPS download that would fail
certificate validation.
Signed-off-by: Jerome Forissier <jerome.forissier@linaro.org>
Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
diff --git a/lib/lwip/lwip/src/apps/altcp_tls/altcp_tls_mbedtls.c b/lib/lwip/lwip/src/apps/altcp_tls/altcp_tls_mbedtls.c
index 4642158..fa3d1d7 100644
--- a/lib/lwip/lwip/src/apps/altcp_tls/altcp_tls_mbedtls.c
+++ b/lib/lwip/lwip/src/apps/altcp_tls/altcp_tls_mbedtls.c
@@ -786,6 +786,7 @@
int ret;
struct altcp_tls_config *conf;
mbedtls_x509_crt *mem;
+ int authmode = have_ca ? MBEDTLS_SSL_VERIFY_REQUIRED : MBEDTLS_SSL_VERIFY_NONE;
if (TCP_WND < MBEDTLS_SSL_IN_CONTENT_LEN || TCP_WND < MBEDTLS_SSL_OUT_CONTENT_LEN) {
LWIP_DEBUGF(ALTCP_MBEDTLS_DEBUG|LWIP_DBG_LEVEL_SERIOUS,
@@ -840,7 +841,7 @@
altcp_mbedtls_free_config(conf);
return NULL;
}
- mbedtls_ssl_conf_authmode(&conf->conf, ALTCP_MBEDTLS_AUTHMODE);
+ mbedtls_ssl_conf_authmode(&conf->conf, authmode);
mbedtls_ssl_conf_rng(&conf->conf, mbedtls_ctr_drbg_random, &altcp_tls_entropy_rng->ctr_drbg);
#if ALTCP_MBEDTLS_LIB_DEBUG != LWIP_DBG_OFF
diff --git a/lib/lwip/lwip/src/include/lwip/apps/altcp_tls_mbedtls_opts.h b/lib/lwip/lwip/src/include/lwip/apps/altcp_tls_mbedtls_opts.h
index e41301c..71aa599 100644
--- a/lib/lwip/lwip/src/include/lwip/apps/altcp_tls_mbedtls_opts.h
+++ b/lib/lwip/lwip/src/include/lwip/apps/altcp_tls_mbedtls_opts.h
@@ -100,12 +100,6 @@
#define ALTCP_MBEDTLS_SESSION_TICKET_TIMEOUT_SECONDS (60 * 60 * 24)
#endif
-/** Certificate verification mode: MBEDTLS_SSL_VERIFY_NONE, MBEDTLS_SSL_VERIFY_OPTIONAL (default),
- * MBEDTLS_SSL_VERIFY_REQUIRED (recommended)*/
-#ifndef ALTCP_MBEDTLS_AUTHMODE
-#define ALTCP_MBEDTLS_AUTHMODE MBEDTLS_SSL_VERIFY_OPTIONAL
-#endif
-
#endif /* LWIP_ALTCP */
#endif /* LWIP_HDR_ALTCP_TLS_OPTS_H */