From f09eae2a7586c5149fe7eaa497c8ff1be684270f Mon Sep 17 00:00:00 2001 From: Maxim Dounin Date: Mon, 15 Apr 2019 20:14:07 +0300 Subject: [PATCH] Fixed incorrect length handling in ngx_utf8_length(). Previously, ngx_utf8_decode() was called from ngx_utf8_length() with incorrect length, potentially resulting in out-of-bounds read when handling invalid UTF-8 strings. In practice out-of-bounds reads are not possible though, as autoindex, the only user of ngx_utf8_length(), provides null-terminated strings, and ngx_utf8_decode() anyway returns an errors when it sees a null in the middle of an UTF-8 sequence. Reported by Yunbin Liu. --- src/core/ngx_string.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/src/core/ngx_string.c b/src/core/ngx_string.c index 04980f8c3..468e9600c 100644 --- a/src/core/ngx_string.c +++ b/src/core/ngx_string.c @@ -1381,7 +1381,7 @@ ngx_utf8_length(u_char *p, size_t n) continue; } - if (ngx_utf8_decode(&p, n) > 0x10ffff) { + if (ngx_utf8_decode(&p, last - p) > 0x10ffff) { /* invalid UTF-8 */ return n; }