[hackers] [quark] http_send_response: fix undefined behaviour for copying the target string || Hiltjo Posthuma

[git]

commit 444b8f5b32d0263f1a20e18eb3044bfeed334361
Author:     Hiltjo Posthuma <hil...@codemadness.org>
AuthorDate: Mon Mar 5 01:12:09 2018 +0100
Commit:     Laslo Hunhold <d...@frign.de>
CommitDate: Mon Mar 5 01:21:14 2018 +0100

    http_send_response: fix undefined behaviour for copying the target string
    
    ... the format string and buffer were the same (undefined behaviour).

diff --git a/http.c b/http.c
index 98dfb00..118389b 100644
--- a/http.c
+++ b/http.c
@@ -346,10 +346,11 @@ http_send_response(int fd, struct request *r)
 
                /* if we have a vhost prefix, prepend it to the target */
                if (s.vhost[i].prefix) {
-                       if (esnprintf(realtarget, sizeof(realtarget), "%s%s",
+                       if (esnprintf(tmptarget, sizeof(tmptarget), "%s%s",
                                      s.vhost[i].prefix, realtarget)) {
                                return http_send_status(fd, 
S_REQUEST_TOO_LARGE);
                        }
+                       memcpy(realtarget, tmptarget, sizeof(realtarget));
                }
        }