ticket 54

• command:

  docker image build -t nginx .
  docker run -it --add-host website.com.ua:0.0.0.0 nginx
  

• behavior: worker process segmentation fault

• description: Non-default servers may not have ssl context created if there are no certificate defined.

• sketch:

  • ngx_http_ssl_servername at src/http/ngx_http_variables.c:672

    sscf = ngx_http_get_module_srv_conf(r, ngx_http_ssl_module);

    in which #define ngx_http_get_module_srv_conf(r, module) (r)->srv_conf[module.ctx_index]

    sscf is loaded according to the request. Since the requested server has no certificate, the ssl context under sscf is missing. (WATCH OUT: The root cause dates back to how the server config is processed)

  • ngx_http_ssl_servername at src/http/ngx_http_variables.c:681

    SSL_set_verify(ssl_conn, SSL_CTX_get_verify_mode(sscf->ssl.ctx), SSL_CTX_get_verify_callback(sscf->ssl.ctx));

    in which sscf->ssl.ctx = 0x0. And trying to obtain SSL information with a null pointer results in segmentation fault.

• patch: Fixed segfault on ssl servers without cert with SNI