[njs] Fixed used of uninitialized memory in String.prototype.match().

[Alexander Borisov]

details:   https://hg.nginx.org/njs/rev/b5f72739c00e
branches:  
changeset: 1040:b5f72739c00e
user:      Alexander Borisov <alexander.borisov at nginx.com>
date:      Thu Jul 11 15:42:33 2019 +0300
description:
Fixed used of uninitialized memory in String.prototype.match().

diffstat:

 njs/njs_string.c |  10 ++++++++--
 1 files changed, 8 insertions(+), 2 deletions(-)

diffs (20 lines):

diff -r b4e326104195 -r b5f72739c00e njs/njs_string.c
--- a/njs/njs_string.c	Thu Jul 11 15:33:40 2019 +0300
+++ b/njs/njs_string.c	Thu Jul 11 15:42:33 2019 +0300
@@ -2734,8 +2734,14 @@ njs_string_match_multiple(njs_vm_t *vm, 
             start = p + captures[0];
 
             if (captures[1] == 0) {
-                p = nxt_utf8_next(start, end);
-                string.size = end - p;
+                if (start < end) {
+                    p = nxt_utf8_next(start, end);
+                    string.size = end - p;
+
+                } else {
+                    /* To exit the loop. */
+                    p++;
+                }
 
                 size = 0;
                 length = 0;