test finalized image filter context before testing image_filter off

this fixes SIGFPE if image filter errors are passed to named location

diff --git a/src/http/modules/ngx_http_image_filter_module.c b/src/http/modules/ngx_http_image_filter_module.c
index 83fc1459ecbac85c422548afa1b48f5693ea360f..fd20550d4d7d41660e42a7ad5fad35e8cf60ab6b 100644 (file)
--- a/src/http/modules/ngx_http_image_filter_module.c
+++ b/src/http/modules/ngx_http_image_filter_module.c
@@ -162,6 +162,13 @@ ngx_http_image_header_filter(ngx_http_request_t *r)
         return ngx_http_next_header_filter(r);
     }
 
+    ctx = ngx_http_get_module_ctx(r, ngx_http_image_filter_module);
+
+    if (ctx) {
+        ngx_http_set_ctx(r, NULL, ngx_http_image_filter_module);
+        return ngx_http_next_header_filter(r);
+    }
+
     conf = ngx_http_get_module_loc_conf(r, ngx_http_image_filter_module);
 
     if (conf->filter == NGX_HTTP_IMAGE_OFF) {
@@ -181,13 +188,6 @@ ngx_http_image_header_filter(ngx_http_request_t *r)
         return NGX_ERROR;
     }
 
-    ctx = ngx_http_get_module_ctx(r, ngx_http_image_filter_module);
-
-    if (ctx) {
-        ngx_http_set_ctx(r, NULL, ngx_http_image_filter_module);
-        return ngx_http_next_header_filter(r);
-    }
-
     ctx = ngx_pcalloc(r->pool, sizeof(ngx_http_image_filter_ctx_t));
     if (ctx == NULL) {
         return NGX_ERROR;