Cleaned up r->headers_out.headers allocation error handling. If initialization of a header failed for some reason after ngx_list_push(), leaving the header as is can result in uninitialized memory access by the header filter or the log module. The fix is to clear partially initialized headers in case of errors. For the Cache-Control header, the fix is to postpone pushing r->headers_out.cache_control until its value is completed.

--- a/src/http/modules/perl/nginx.xs
+++ b/src/http/modules/perl/nginx.xs
@@ -510,10 +510,12 @@ header_out(r, key, value)
     header->hash = 1;
 
     if (ngx_http_perl_sv2str(aTHX_ r, &header->key, key) != NGX_OK) {
+        header->hash = 0;
         XSRETURN_EMPTY;
     }
 
     if (ngx_http_perl_sv2str(aTHX_ r, &header->value, value) != NGX_OK) {
+        header->hash = 0;
         XSRETURN_EMPTY;
     }