[njs] Fixed potential NULL-pointer dereference (CID 1464584).

[Dmitry Volyntsev]

details:   https://hg.nginx.org/njs/rev/7a8e3f0d52a6
branches:  
changeset: 1453:7a8e3f0d52a6
user:      Dmitry Volyntsev <xeioex at nginx.com>
date:      Tue Jul 07 12:23:42 2020 +0000
description:
Fixed potential NULL-pointer dereference (CID 1464584).

diffstat:

 src/njs_generator.c |  9 +++++++--
 1 files changed, 7 insertions(+), 2 deletions(-)

diffs (19 lines):

diff -r 29ff89055e29 -r 7a8e3f0d52a6 src/njs_generator.c
--- a/src/njs_generator.c	Mon Jul 06 18:37:13 2020 +0000
+++ b/src/njs_generator.c	Tue Jul 07 12:23:42 2020 +0000
@@ -571,8 +571,13 @@ njs_lookup_line(njs_vm_code_t *code, uin
     njs_uint_t         n;
     njs_vm_line_num_t  *map;
 
-    n = (code->lines != NULL) ? code->lines->items : 0;
-    map = (njs_vm_line_num_t *) code->lines->start;
+    n = 0;
+    map = NULL;
+
+    if (code->lines != NULL) {
+        n = code->lines->items;
+        map = (njs_vm_line_num_t *) code->lines->start;
+    }
 
     while (n != 0) {
         if (offset >= map->offset && (n == 1 || offset < map[1].offset)) {