commit bb1aaab42880489729aeafea27d3569cce60c20b
author Matt Caswell <matt@openssl.org> Thu Nov 05 14:31:11 2015 +0000
committer Matt Caswell <matt@openssl.org> Sun Dec 27 21:59:04 2015 +0000
tree b531ea6f76cc0425be7109a455c2cf5a4918cb8c
parent ef96e4a28fa98cdf44246baab9ec8cdb69914fd9

Fix error when server does not send CertificateStatus message

If a server sends the status_request extension then it may choose
to send the CertificateStatus message. However this is optional.
We were treating it as mandatory and the connection was failing.

Thanks to BoringSSL for reporting this issue.

RT#4120

Reviewed-by: Viktor Dukhovni <viktor@openssl.org>

ssl/statem/statem_clnt.c

diff --git a/ssl/statem/statem_clnt.c b/ssl/statem/statem_clnt.c
index 46cb4b0..d170ad1 100644
--- a/ssl/statem/statem_clnt.c
+++ b/ssl/statem/statem_clnt.c
@@ -303,12 +303,13 @@
         break;
 
     case TLS_ST_CR_CERT:
-        if (s->tlsext_status_expected) {
-            if (mt == SSL3_MT_CERTIFICATE_STATUS) {
-                st->hand_state = TLS_ST_CR_CERT_STATUS;
-                return 1;
-            }
-            return 0;
+        /*
+         * The CertificateStatus message is optional even if
+         * |tlsext_status_expected| is set
+         */
+        if (s->tlsext_status_expected && mt == SSL3_MT_CERTIFICATE_STATUS) {
+            st->hand_state = TLS_ST_CR_CERT_STATUS;
+            return 1;
         }
         /* Fall through */
 
@@ -2155,7 +2156,6 @@
         SSLerr(SSL_F_TLS_PROCESS_CERT_STATUS, SSL_R_LENGTH_MISMATCH);
         goto f_err;
     }
-    OPENSSL_free(s->tlsext_ocsp_resp);
     s->tlsext_ocsp_resp = OPENSSL_malloc(resplen);
     if (s->tlsext_ocsp_resp == NULL) {
         al = SSL_AD_INTERNAL_ERROR;
@@ -2168,20 +2168,6 @@
         goto f_err;
     }
     s->tlsext_ocsp_resplen = resplen;
-    if (s->ctx->tlsext_status_cb) {
-        int ret;
-        ret = s->ctx->tlsext_status_cb(s, s->ctx->tlsext_status_arg);
-        if (ret == 0) {
-            al = SSL_AD_BAD_CERTIFICATE_STATUS_RESPONSE;
-            SSLerr(SSL_F_TLS_PROCESS_CERT_STATUS, SSL_R_INVALID_STATUS_RESPONSE);
-            goto f_err;
-        }
-        if (ret < 0) {
-            al = SSL_AD_INTERNAL_ERROR;
-            SSLerr(SSL_F_TLS_PROCESS_CERT_STATUS, ERR_R_MALLOC_FAILURE);
-            goto f_err;
-        }
-    }
     return MSG_PROCESS_CONTINUE_READING;
  f_err:
     ssl3_send_alert(s, SSL3_AL_FATAL, al);
@@ -2220,6 +2206,28 @@
         return MSG_PROCESS_ERROR;
     }
 
+    /*
+     * Call the ocsp status callback if needed. The |tlsext_ocsp_resp| and
+     * |tlsext_ocsp_resplen| values will be set if we actually received a status
+     * message, or NULL and -1 otherwise
+     */
+    if (s->tlsext_status_expected && s->ctx->tlsext_status_cb != NULL) {
+        int ret;
+        ret = s->ctx->tlsext_status_cb(s, s->ctx->tlsext_status_arg);
+        if (ret == 0) {
+            ssl3_send_alert(s, SSL3_AL_FATAL,
+                            SSL_AD_BAD_CERTIFICATE_STATUS_RESPONSE);
+            SSLerr(SSL_F_TLS_PROCESS_SERVER_DONE,
+                   SSL_R_INVALID_STATUS_RESPONSE);
+            return MSG_PROCESS_ERROR;
+        }
+        if (ret < 0) {
+            ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
+            SSLerr(SSL_F_TLS_PROCESS_SERVER_DONE, ERR_R_MALLOC_FAILURE);
+            return MSG_PROCESS_ERROR;
+        }
+    }
+
 #ifndef OPENSSL_NO_SCTP
     /* Only applies to renegotiation */
     if (SSL_IS_DTLS(s) && BIO_dgram_is_sctp(SSL_get_wbio(s))

ssl/t1_lib.c

diff --git a/ssl/t1_lib.c b/ssl/t1_lib.c
index d9cfe27..e7d9f64 100644
--- a/ssl/t1_lib.c
+++ b/ssl/t1_lib.c
@@ -2847,6 +2847,9 @@
                                                        s->
                                                        initial_ctx->tlsext_servername_arg);
 
+    OPENSSL_free(s->tlsext_ocsp_resp);
+    s->tlsext_ocsp_resp = NULL;
+    s->tlsext_ocsp_resplen = -1;
     /*
      * If we've requested certificate status and we wont get one tell the
      * callback
@@ -2855,12 +2858,9 @@
         && s->ctx && s->ctx->tlsext_status_cb) {
         int r;
         /*
-         * Set resp to NULL, resplen to -1 so callback knows there is no
-         * response.
+         * Call callback with resp == NULL and resplen == -1 so callback
+         * knows there is no response
          */
-        OPENSSL_free(s->tlsext_ocsp_resp);
-        s->tlsext_ocsp_resp = NULL;
-        s->tlsext_ocsp_resplen = -1;
         r = s->ctx->tlsext_status_cb(s, s->ctx->tlsext_status_arg);
         if (r == 0) {
             al = SSL_AD_BAD_CERTIFICATE_STATUS_RESPONSE;