Add support for providing CRLs to libtls - once a CRL is provided we

enable CRL checking for the full certificate chain.

Based on a diff from Jack Burton <jack at saosce dot com dot au>, thanks!

Discussed with beck@

5 files changed, 67 insertions, 4 deletions

diff --git a/src/lib/libtls/Symbols.list b/src/lib/libtls/Symbols.list
index 3124c64211..6d174bc83a 100644
--- a/src/lib/libtls/Symbols.list
+++ b/src/lib/libtls/Symbols.list
@@ -26,6 +26,8 @@ tls_config_set_ca_path
 tls_config_set_cert_file
 tls_config_set_cert_mem
 tls_config_set_ciphers
+tls_config_set_crl_file
+tls_config_set_crl_mem
 tls_config_set_dheparams
 tls_config_set_ecdhecurve
 tls_config_set_key_file
diff --git a/src/lib/libtls/tls.c b/src/lib/libtls/tls.c
index f64f6d7632..ed857272c4 100644
--- a/src/lib/libtls/tls.c
+++ b/src/lib/libtls/tls.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: tls.c,v 1.67 2017/06/22 18:03:57 jsing Exp $ */
+/* $OpenBSD: tls.c,v 1.68 2017/07/06 17:12:22 jsing Exp $ */
 /*
  * Copyright (c) 2014 Joel Sing <jsing@openbsd.org>
  *
@@ -26,6 +26,8 @@
 #include <openssl/err.h>
 #include <openssl/evp.h>
 #include <openssl/pem.h>
+#include <openssl/safestack.h>
+#include <openssl/ssl.h>
 #include <openssl/x509.h>
 
 #include <tls.h>
@@ -464,8 +466,15 @@ tls_configure_ssl_verify(struct tls *ctx, SSL_CTX *ssl_ctx, int verify)
 {
         size_t ca_len = ctx->config->ca_len;
         char *ca_mem = ctx->config->ca_mem;
+        char *crl_mem = ctx->config->crl_mem;
+        size_t crl_len = ctx->config->crl_len;
         char *ca_free = NULL;
+        STACK_OF(X509_INFO) *xis = NULL;
+        X509_STORE *store;
+        X509_INFO *xi;
+        BIO *bio = NULL;
         int rv = -1;
+        int i;
 
         SSL_CTX_set_verify(ssl_ctx, verify, NULL);
         SSL_CTX_set_cert_verify_callback(ssl_ctx, tls_ssl_cert_verify_cb, ctx);
@@ -499,10 +508,41 @@ tls_configure_ssl_verify(struct tls *ctx, SSL_CTX *ssl_ctx, int verify)
                 goto err;
         }
 
+        if (crl_mem != NULL) {
+                if (crl_len > INT_MAX) {
+                        tls_set_errorx(ctx, "crl too long");
+                        goto err;
+                }
+                if ((bio = BIO_new_mem_buf(crl_mem, crl_len)) == NULL) {
+                        tls_set_errorx(ctx, "failed to create buffer");
+                        goto err;
+                }
+                if ((xis = PEM_X509_INFO_read_bio(bio, NULL, tls_password_cb,
+                    NULL)) == NULL) {
+                        tls_set_errorx(ctx, "failed to parse crl");
+                        goto err;
+                }
+                store = SSL_CTX_get_cert_store(ssl_ctx);
+                for (i = 0; i < sk_X509_INFO_num(xis); i++) {
+                        xi = sk_X509_INFO_value(xis, i);
+                        if (xi->crl == NULL)
+                                continue;
+                        if (!X509_STORE_add_crl(store, xi->crl)) {
+                                tls_set_error(ctx, "failed to add crl");
+                                goto err;
+                        }
+                        xi->crl = NULL;
+                }
+                X509_VERIFY_PARAM_set_flags(store->param,
+                    X509_V_FLAG_CRL_CHECK | X509_V_FLAG_CRL_CHECK_ALL);
+        }
+
  done:
         rv = 0;
 
  err:
+        sk_X509_INFO_pop_free(xis, X509_INFO_free);
+        BIO_free(bio);
         free(ca_free);
 
         return (rv);
diff --git a/src/lib/libtls/tls.h b/src/lib/libtls/tls.h
index 4fad4518f2..1a6701b581 100644
--- a/src/lib/libtls/tls.h
+++ b/src/lib/libtls/tls.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: tls.h,v 1.49 2017/05/06 20:57:45 jsing Exp $ */
+/* $OpenBSD: tls.h,v 1.50 2017/07/06 17:12:22 jsing Exp $ */
 /*
  * Copyright (c) 2014 Joel Sing <jsing@openbsd.org>
  *
@@ -105,6 +105,9 @@ int tls_config_set_cert_file(struct tls_config *_config,
 int tls_config_set_cert_mem(struct tls_config *_config, const uint8_t *_cert,
     size_t _len);
 int tls_config_set_ciphers(struct tls_config *_config, const char *_ciphers);
+int tls_config_set_crl_file(struct tls_config *_config, const char *_crl_file);
+int tls_config_set_crl_mem(struct tls_config *_config, const uint8_t *_crl,
+    size_t _len);
 int tls_config_set_dheparams(struct tls_config *_config, const char *_params);
 int tls_config_set_ecdhecurve(struct tls_config *_config, const char *_name);
 int tls_config_set_key_file(struct tls_config *_config, const char *_key_file);
diff --git a/src/lib/libtls/tls_config.c b/src/lib/libtls/tls_config.c
index 8f0bd70508..fe049d1e4e 100644
--- a/src/lib/libtls/tls_config.c
+++ b/src/lib/libtls/tls_config.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: tls_config.c,v 1.40 2017/05/06 20:59:28 jsing Exp $ */
+/* $OpenBSD: tls_config.c,v 1.41 2017/07/06 17:12:22 jsing Exp $ */
 /*
  * Copyright (c) 2014 Joel Sing <jsing@openbsd.org>
  *
@@ -268,6 +268,7 @@ tls_config_free(struct tls_config *config)
         free((char *)config->ca_mem);
         free((char *)config->ca_path);
         free((char *)config->ciphers);
+        free((char *)config->crl_mem);
 
         free(config);
 }
@@ -299,6 +300,7 @@ tls_config_clear_keys(struct tls_config *config)
                 tls_keypair_clear(kp);
 
         tls_config_set_ca_mem(config, NULL, 0);
+        tls_config_set_crl_mem(config, NULL, 0);
 }
 
 int
@@ -579,6 +581,20 @@ tls_config_set_ciphers(struct tls_config *config, const char *ciphers)
 }
 
 int
+tls_config_set_crl_file(struct tls_config *config, const char *crl_file)
+{
+        return tls_config_load_file(&config->error, "CRL", crl_file,
+            &config->crl_mem, &config->crl_len);
+}
+
+int
+tls_config_set_crl_mem(struct tls_config *config, const uint8_t *crl,
+    size_t len)
+{
+        return set_mem(&config->crl_mem, &config->crl_len, crl, len);
+}
+
+int
 tls_config_set_dheparams(struct tls_config *config, const char *params)
 {
         int keylen;
diff --git a/src/lib/libtls/tls_internal.h b/src/lib/libtls/tls_internal.h
index c0c55216df..bed9d6e7f4 100644
--- a/src/lib/libtls/tls_internal.h
+++ b/src/lib/libtls/tls_internal.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: tls_internal.h,v 1.61 2017/06/22 18:03:57 jsing Exp $ */
+/* $OpenBSD: tls_internal.h,v 1.62 2017/07/06 17:12:22 jsing Exp $ */
 /*
  * Copyright (c) 2014 Jeremie Courreges-Anglas <jca@openbsd.org>
  * Copyright (c) 2014 Joel Sing <jsing@openbsd.org>
@@ -84,6 +84,8 @@ struct tls_config {
         size_t ca_len;
         const char *ciphers;
         int ciphers_server;
+        char *crl_mem;
+        size_t crl_len;
         int dheparams;
         int ecdhecurve;
         struct tls_keypair *keypair;