# HG changeset patch
# User Maxim Dounin <mdounin@mdounin.ru>
# Date 1555344789 -10800
# Node ID dbebbb25ae929db535e84a9f8ab8ab24332c9567
# Parent  ce9942d4df5563b8b2a84dbca04f4ce657436d95
OCSP stapling: fixed segfault with dynamic certificate loading.

If OCSP stapling was enabled with dynamic certificate loading, with some
OpenSSL versions (1.0.2o and older, 1.1.0h and older; fixed in 1.0.2p,
1.1.0i, 1.1.1) a segmentation fault might happen.

The reason is that during an abbreviated handshake the certificate
callback is not called, but the certificate status callback was called
(https://github.com/openssl/openssl/issues/1662), leading to NULL being
returned from SSL_get_certificate().

Fix is to explicitly check SSL_get_certificate() result.

diff --git a/src/event/ngx_event_openssl_stapling.c b/src/event/ngx_event_openssl_stapling.c
--- a/src/event/ngx_event_openssl_stapling.c
+++ b/src/event/ngx_event_openssl_stapling.c
@@ -511,6 +511,11 @@ ngx_ssl_certificate_status_callback(ngx_
     rc = SSL_TLSEXT_ERR_NOACK;
 
     cert = SSL_get_certificate(ssl_conn);
+
+    if (cert == NULL) {
+        return rc;
+    }
+
     staple = X509_get_ex_data(cert, ngx_ssl_stapling_index);
 
     if (staple == NULL) {