commit 075141f08b1f7c3a8abbe72d4495f599cfa4879c
author Maxim Dounin <mdounin@mdounin.ru> Mon Jun 28 18:01:24 2021 +0300
committer Maxim Dounin <mdounin@mdounin.ru> Mon Jun 28 18:01:24 2021 +0300
tree cea4cff54ed65fb77fa1bebdc94903100299c26f
parent e361c1dff155a982c2f15e5d0c9fdc81c594269b

Disabled control characters in the Host header.

Control characters (0x00-0x1f, 0x7f) and space are not expected to appear
in the Host header.  Requests with such characters in the Host header are
now unconditionally rejected.

src/http/ngx_http_request.c

diff --git a/src/http/ngx_http_request.c b/src/http/ngx_http_request.c
index 2e7c30f..2d1845d 100644
--- a/src/http/ngx_http_request.c
+++ b/src/http/ngx_http_request.c
@@ -2176,15 +2176,16 @@
             }
             break;
 
-        case '\0':
-            return NGX_DECLINED;
-
         default:
 
             if (ngx_path_separator(ch)) {
                 return NGX_DECLINED;
             }
 
+            if (ch <= 0x20 || ch == 0x7f) {
+                return NGX_DECLINED;
+            }
+
             if (ch >= 'A' && ch <= 'Z') {
                 alloc = 1;
             }