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>

diff --git a/ssl/s3_clnt.c b/ssl/s3_clnt.c
index bc5254c81160281257469ab32536f852a1e9f353..8cbf46ad2ffa9f776faee3da687df4a307da63fc 100644 (file)
--- a/ssl/s3_clnt.c
+++ b/ssl/s3_clnt.c
@@ -2350,37 +2350,44 @@ int ssl3_get_cert_status(SSL *s)
     n = s->method->ssl_get_message(s,
                                    SSL3_ST_CR_CERT_STATUS_A,
                                    SSL3_ST_CR_CERT_STATUS_B,
-                                   SSL3_MT_CERTIFICATE_STATUS, 16384, &ok);
+                                   -1, 16384, &ok);
 
     if (!ok)
         return ((int)n);
-    if (n < 4) {
-        /* need at least status type + length */
-        al = SSL_AD_DECODE_ERROR;
-        SSLerr(SSL_F_SSL3_GET_CERT_STATUS, SSL_R_LENGTH_MISMATCH);
-        goto f_err;
-    }
-    p = (unsigned char *)s->init_msg;
-    if (*p++ != TLSEXT_STATUSTYPE_ocsp) {
-        al = SSL_AD_DECODE_ERROR;
-        SSLerr(SSL_F_SSL3_GET_CERT_STATUS, SSL_R_UNSUPPORTED_STATUS_TYPE);
-        goto f_err;
-    }
-    n2l3(p, resplen);
-    if (resplen + 4 != n) {
-        al = SSL_AD_DECODE_ERROR;
-        SSLerr(SSL_F_SSL3_GET_CERT_STATUS, SSL_R_LENGTH_MISMATCH);
-        goto f_err;
-    }
-    if (s->tlsext_ocsp_resp)
-        OPENSSL_free(s->tlsext_ocsp_resp);
-    s->tlsext_ocsp_resp = BUF_memdup(p, resplen);
-    if (!s->tlsext_ocsp_resp) {
-        al = SSL_AD_INTERNAL_ERROR;
-        SSLerr(SSL_F_SSL3_GET_CERT_STATUS, ERR_R_MALLOC_FAILURE);
-        goto f_err;
+
+    if (s->s3->tmp.message_type != SSL3_MT_CERTIFICATE_STATUS) {
+        /*
+         * The CertificateStatus message is optional even if
+         * tlsext_status_expected is set
+         */
+        s->s3->tmp.reuse_message = 1;
+    } else {
+        if (n < 4) {
+            /* need at least status type + length */
+            al = SSL_AD_DECODE_ERROR;
+            SSLerr(SSL_F_SSL3_GET_CERT_STATUS, SSL_R_LENGTH_MISMATCH);
+            goto f_err;
+        }
+        p = (unsigned char *)s->init_msg;
+        if (*p++ != TLSEXT_STATUSTYPE_ocsp) {
+            al = SSL_AD_DECODE_ERROR;
+            SSLerr(SSL_F_SSL3_GET_CERT_STATUS, SSL_R_UNSUPPORTED_STATUS_TYPE);
+            goto f_err;
+        }
+        n2l3(p, resplen);
+        if (resplen + 4 != n) {
+            al = SSL_AD_DECODE_ERROR;
+            SSLerr(SSL_F_SSL3_GET_CERT_STATUS, SSL_R_LENGTH_MISMATCH);
+            goto f_err;
+        }
+        s->tlsext_ocsp_resp = BUF_memdup(p, resplen);
+        if (s->tlsext_ocsp_resp == NULL) {
+            al = SSL_AD_INTERNAL_ERROR;
+            SSLerr(SSL_F_SSL3_GET_CERT_STATUS, ERR_R_MALLOC_FAILURE);
+            goto f_err;
+        }
+        s->tlsext_ocsp_resplen = resplen;
     }
-    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);

diff --git a/ssl/t1_lib.c b/ssl/t1_lib.c
index 37f0ae5be2acbefb412387dc8a609e0fefe215e4..24713194e8b214945e8733cb2e0c2274d3e8f4f4 100644 (file)
--- a/ssl/t1_lib.c
+++ b/ssl/t1_lib.c
@@ -3157,6 +3157,9 @@ int ssl_check_serverhello_tlsext(SSL *s)
     }
 # endif
 
+    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
@@ -3165,14 +3168,9 @@ int ssl_check_serverhello_tlsext(SSL *s)
         && 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
          */
-        if (s->tlsext_ocsp_resp) {
-            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;