Go into the error state if a fatal alert is sent or received

If an application calls SSL_shutdown after a fatal alert has occured and
then behaves different based on error codes from that function then the
application may be vulnerable to a padding oracle.

CVE-2019-1559

Reviewed-by: Richard Levitte <levitte@openssl.org>

ssl/d1_pkt.c

@@ -1309,6 +1309,7 @@ int dtls1_read_bytes(SSL *s, int type, unsigned char *buf, int len, int peek)
             ERR_add_error_data(2, "SSL alert number ", tmp);
             s->shutdown |= SSL_RECEIVED_SHUTDOWN;
             SSL_CTX_remove_session(s->session_ctx, s->session);
+            s->state = SSL_ST_ERR;
             return (0);
         } else {
             al = SSL_AD_ILLEGAL_PARAMETER;

ssl/s3_pkt.c

@@ -1500,6 +1500,7 @@ int ssl3_read_bytes(SSL *s, int type, unsigned char *buf, int len, int peek)
             ERR_add_error_data(2, "SSL alert number ", tmp);
             s->shutdown |= SSL_RECEIVED_SHUTDOWN;
             SSL_CTX_remove_session(s->session_ctx, s->session);
+            s->state = SSL_ST_ERR;
             return (0);
         } else {
             al = SSL_AD_ILLEGAL_PARAMETER;
@@ -1719,9 +1720,12 @@ int ssl3_send_alert(SSL *s, int level, int desc)
                                           * protocol_version alerts */
     if (desc < 0)
         return -1;
-    /* If a fatal one, remove from cache */
-    if ((level == 2) && (s->session != NULL))
-        SSL_CTX_remove_session(s->session_ctx, s->session);
+    /* If a fatal one, remove from cache and go into the error state */
+    if (level == SSL3_AL_FATAL) {
+        if (s->session != NULL)
+            SSL_CTX_remove_session(s->session_ctx, s->session);
+        s->state = SSL_ST_ERR;
+    }
 
     s->s3->alert_dispatch = 1;
     s->s3->send_alert[0] = level;